Research IndicatorsGraph generated 02 September 2019 using data from PubMed using criteria.
Mouse over the terms for more detail; many indicate links which you can click for dedicated pages about the topic. Tag cloud generated 01 September, 2019 using data from PubMed, MeSH and CancerIndex
Specific Cancers (4)
Data table showing topics related to specific cancers and associated disorders. Scope includes mutations and abnormal protein expression.
Note: list is not exhaustive. Number of papers are based on searches of PubMed (click on topic title for arbitrary criteria used).
OMIM, Johns Hopkin University
Referenced article focusing on the relationship between phenotype and genotype.
International Cancer Genome Consortium.
Summary of gene and mutations by cancer type from ICGC
Cancer Genome Anatomy Project, NCI
COSMIC, Sanger Institute
Somatic mutation information and related details
GEO Profiles, NCBI
Search the gene expression profiles from curated DataSets in the Gene Expression Omnibus (GEO) repository.
Latest Publications: HLTF (cancer-related)
Liu L, Liu H, Zhou Y, et al.HLTF suppresses the migration and invasion of colorectal cancer cells via TGF‑β/SMAD signaling in vitro.
Int J Oncol. 2018; 53(6):2780-2788 [PubMed
] Related Publications
Helicase‑like transcription factor (HLTF) has been identified as a tumor suppressor gene. The hypermethylation of HTLF is frequently observed in various types of cancer, including colorectal cancer (CRC). However, the mechanisms through which HLTF suppresses CRC progression remain unclear. Thus, the aim of the present study was to explore the biological function of HLTF in CRC cells and the underlying mechanisms. CRC tissues and cells were used to detect the expression of HLTF. Wound‑healing and Transwell assays were performed to assess the motility of CRC cells. The results revealed that HLTF expression was significantly associated with the differentiation status, invasion depth, lymph node metastasis and distant metastasis. A low HLTF expression was significantly associated with a poor survival. Furthermore, HTLF knockdown or ectopic overexpression significantly promoted or suppressed the motility of CRC cells, respectively. With regard to the underlying molecular mechanisms, the protein expression of HTLF was upregulated when the CRC cells were stimulated with transforming growth factor (TGF)‑β, and HLTF upregulation induced an increase in SMAD4 and p‑SMAD2/3 expression and a decrease in levels of the TGF‑β/SMAD pathway downstream genes, Vimentin and zinc finger e‑box binding homeobox 1 (ZEB1). On the whole, the findings of this study suggest that HLTF is negatively associated with the progression of CRC, and its overexpression suppresses the migration and invasion of CRC cells by targeting the TGF‑β/SMAD pathway.
Das R, Kundu S, Laskar S, et al.Assessment of DNA repair susceptibility genes identified by whole exome sequencing in head and neck cancer.
DNA Repair (Amst). 2018 Jun - Jul; 66-67:50-63 [PubMed
] Related Publications
Head and neck cancer (HNC), the sixth most common cancer globally, stands second in India. In Northeast (NE) India, it is the sixth most common cause of death in males and seventh in females. Prolonged tobacco and alcohol consumption constitute the major etiological factors for HNC development, which induce DNA damage. Therefore, DNA repair pathway is a crucial system in maintaining genomic integrity and preventing carcinogenesis. The present work was aimed to predict the consequence of significant germline variants of the DNA repair genes in disease predisposition. Whole exome sequencing was performed in Ion Proton™ platform on 15 case-control samples from the HNC-prevalent states of Manipur, Mizoram, and Nagaland. Variant annotation was done in Ion Reporter™ as well as wANNOVAR. Subsequent statistical and bioinformatics analysis identified significant exonic and intronic variants associated with HNC. Amongst our observed variants, 78.6% occurred in ExAC, 94% reported in dbSNP and 5.8% & 9.3% variants were present in ClinVar and HGMD, respectively. The total variants were dispersed among 199 genes with DSBR and FA pathway being the most mutated pathways. The allelic association test suggested that the intronic variants in HLTF and RAD52 gene significantly associated (P < 0.05) with the risk (OR > 5), while intronic variants in PARP4, RECQL5, EXO1 and PER1 genes and exonic variant in TDP2 gene showed protection (OR < 1) for HNC. MDR analysis proposed the exonic variants in MSH6, BRCA2, PALB2 and TP53 genes and intronic variant in RECQL5 genetic region working together during certain phase of DNA repair mechanism for HNC causation. In addition, other intronic and 3'UTR variations caused modifications in the transcription factor binding sites and miRNA target sites associated with HNC. Large-scale validation in NE Indian population, in-depth structure prediction and subsequent simulation of our recognized polymorphisms is necessary to identify true causal variants related to HNC.
BACKGROUND: The relapse rate in early stage non-small cell lung cancer (NSCLC) after surgical resection is high. Prognostic biomarkers may help identify patients who may benefit from additional therapy. The Helicase-like Transcription Factor (HLTF) is a tumor suppressor, altered in cancer either by gene hypermethylation or mRNA alternative splicing. This study assessed the expression and the clinical relevance of wild-type (WT) and variant forms of HLTF RNAs in NSCLC.
METHODS: We analyzed online databases (TCGA, COSMIC) for HLTF alterations in NSCLC and assessed WT and spliced HLTF mRNAs expression by RT-ddPCR in 39 lung cancer cell lines and 171 patients with resected stage I-II NSCLC.
RESULTS: In silico analyses identified HLTF gene alterations more frequently in lung squamous cell carcinoma than in adenocarcinoma. In cell lines and in patients, WT and I21R HLTF mRNAs were detected, but the latter at lower level. The subgroup of 25 patients presenting a combined low WT HLTF expression and a high I21R HLTF expression had a significantly worse disease-free survival than the other 146 patients in univariate (HR 1.96, CI 1.17-3.30; p = 0.011) and multivariate analyses (HR 1.98, CI 1.15-3.40; p = 0.014).
CONCLUSION: A low WT HLTF expression with a high I21R HLTF expression is associated with a poor DFS.
Lam K, Pan K, Linnekamp JF, et al.DNA methylation based biomarkers in colorectal cancer: A systematic review.
Biochim Biophys Acta. 2016; 1866(1):106-20 [PubMed
] Related Publications
Since genetic and epigenetic alterations influence the development of colorectal cancer (CRC), huge potential lies in the use of DNA methylation as biomarkers to improve the current diagnosis, screening, prognosis and treatment prediction. Here we performed a systematic review on DNA methylation-based biomarkers published in CRC, and discussed the current state of findings and future challenges. Based on the findings, we then provide a perspective on future studies. Genome-wide studies on DNA methylation revealed novel biomarkers as well as distinct subgroups that exist in CRC. For diagnostic purposes, the most independently validated genes to study further are VIM, SEPT9, ITGA4, OSM4, GATA4 and NDRG4. These hypermethylated biomarkers can even be combined with LINE1 hypomethylation and the performance of markers should be examined in comparison to FIT further to find sensitive combinations. In terms of prognostic markers, myopodin, KISS1, TMEFF2, HLTF, hMLH1, APAF1, BCL2 and p53 are independently validated. Most prognostic markers published lack both a multivariate analysis in comparison to clinical risk factors and the appropriate patient group who will benefit by adjuvant chemotherapy. Methylation of IGFBP3, mir148a and PTEN are found to be predictive markers for 5-FU and EGFR therapy respectively. For therapy prediction, more studies should focus on finding markers for chemotherapeutic drugs as majority of the patients would benefit. Translation of these biomarkers into clinical utility would require large-scale prospective cohorts and randomized clinical trials in future. Based on these findings and consideration we propose an avenue to introduce methylation markers into clinical practice in near future. For future studies, multi-omics profiling on matched tissue and non-invasive cohorts along with matched cohorts of adenoma to carcinoma is indispensable to concurrently stratify CRC and find novel, robust biomarkers. Moreover, future studies should examine the timing and heterogeneity of methylation as well as the difference in methylation levels between epithelial and stromal tissues.
Rasmussen SL, Krarup HB, Sunesen KG, et al.Hypermethylated DNA as a biomarker for colorectal cancer: a systematic review.
Colorectal Dis. 2016; 18(6):549-61 [PubMed
] Related Publications
AIM: Improved methods for early detection of colorectal cancer (CRC) are essential for increasing survival. Hypermethylated DNA in blood or stool has been proposed as a biomarker for CRC. Biochemical methods have improved in recent years, and several hypermethylated genes that are sensitive and specific for CRC have been proposed. Articles describing the use of hypermethylated promoter regions in blood or stool as biomarkers for CRC were systematically reviewed.
METHOD: A systematic literature search was performed using the Medline, Web of Science and Embase databases. Studies were included if they analysed hypermethylated genes from stool or blood samples in correlation with CRC. Studies in languages other than English and those based on animal models or cell lines were excluded.
RESULTS: The literature search yielded 74 articles, including 43 addressing blood samples and 31 addressing stool samples. In blood samples, hypermethylated ALX4, FBN2, HLTF, P16, TMEFF1 and VIM were associated with poor prognosis, hypermethylated APC, NEUROG1, RASSF1A, RASSF2A, SDC2, SEPT9, TAC1 and THBD were detected in early stage CRC and hypermethylated P16 and TFPI2 were associated with CRC recurrence. In stool samples, hypermethylated BMP3, PHACTR3, SFRP2, SPG20, TFPI2 and TMEFF2 were associated with early stage CRC.
CONCLUSION: Hypermethylation of the promoters of specific genes measured in blood or stool samples could be used as a CRC biomarker and provide prognostic information. The majority of studies, however, include only a few patients with poorly defined control groups. Further studies are therefore needed before hypermethylated DNA can be widely applied as a clinical biomarker for CRC detection and prognosis.
Cheng CK, Chan NP, Wan TS, et al.Helicase-like transcription factor is a RUNX1 target whose downregulation promotes genomic instability and correlates with complex cytogenetic features in acute myeloid leukemia.
Haematologica. 2016; 101(4):448-57 [PubMed
] Free Access to Full Article Related Publications
Helicase-like transcription factor is a SWI/SNF chromatin remodeling factor involved in various biological processes. However, little is known about its role in hematopoiesis. In this study, we measured helicase-like transcription factor mRNA expression in the bone marrow of 204 adult patients with de novo acute myeloid leukemia. Patients were dichotomized into low and high expression groups at the median level for clinicopathological correlations. Helicase-like transcription factor levels were dramatically reduced in the low expression patient group compared to those in the normal controls (n=40) (P<0.0001). Low helicase-like transcription factor expression correlated positively with French-American-British M4/M5 subtypes (P<0.0001) and complex cytogenetic abnormalities (P=0.02 for ≥3 abnormalities;P=0.004 for ≥5 abnormalities) but negatively with CEBPA double mutations (P=0.012). Also, low expression correlated with poorer overall (P=0.005) and event-free (P=0.006) survival in the intermediate-risk cytogenetic subgroup. Consistent with the more aggressive disease associated with low expression, helicase-like transcription factor knockdown in leukemic cells promoted proliferation and chromosomal instability that was accompanied by downregulation of mitotic regulators and impaired DNA damage response. The significance of helicase-like transcription factor in genome maintenance was further indicated by its markedly elevated expression in normal human CD34(+)hematopoietic stem cells. We further demonstrated that helicase-like transcription factor was a RUNX1 target and transcriptionally repressed by RUNX1-ETO and site-specific DNA methylation through a duplicated RUNX1 binding site in its promoter. Taken together, our findings provide new mechanistic insights on genomic instability linked to helicase-like transcription factor deregulation, and strongly suggest a tumor suppressor function of the SWI/SNF protein in acute myeloid leukemia.
Dhont L, Mascaux C, Belayew AThe helicase-like transcription factor (HLTF) in cancer: loss of function or oncomorphic conversion of a tumor suppressor?
Cell Mol Life Sci. 2016; 73(1):129-47 [PubMed
] Related Publications
The Helicase-like Transcription Factor (HLTF) belongs to the SWI/SNF family of proteins involved in chromatin remodeling. In addition to its role in gene transcription, HLTF has been implicated in DNA repair, which suggests that this protein acts as a tumor suppressor. Accumulating evidence indicates that HLTF expression is altered in various cancers via two mechanisms: gene silencing through promoter hypermethylation or alternative mRNA splicing, which leads to the expression of truncated proteins that lack DNA repair domains. In either case, the alteration of HLTF expression in cancer has a poor prognosis. In this review, we gathered published clinical and molecular data on HLTF. Our purposes are (a) to address whether HLTF alterations could be considered as cancer drivers or passengers and (b) to determine whether its different functions (transcription or DNA repair) could be diverted in clonal selection during cancer progression.
Singh TD, Gupta S, Shrivastav BR, Tiwari PKEpigenetic profiling of gallbladder cancer and gall stone diseases: Evaluation of role of tumour associated genes.
Gene. 2016; 576(2 Pt 2):743-52 [PubMed
] Related Publications
BACKGROUND: As on today, the global mortality rate of gallbladder cancer is still very high. Both genetic and epigenetic alterations play pivotal roles in the development of cancer. We selected seven tumour associated genes, implicated in other cancers, to assess their methylation status in gallbladder cancer and gallstone diseases.
AIM OF STUDY: To study the promoter methylation of certain tumour associated genes in the molecular pathogenesis of gallbladder cancer and gall stone diseases.
MATERIALS AND METHODS: Methylation specific PCR for seven tumour associated genes, viz., MASPIN, 14-3-3 sigma gene, THBS1, FLNC, HLTF, COX-2 and SOCS1, was performed in 50 gallbladder cancer (GBC), 30 gall stone diseases (GSD) and their respective adjacent control tissues. Semi-quantitative PCR and immunohistochemistry was carried out to check the expression level. Student's t-test was carried out to compare the differences in the methylation and expression patterns between cases and control tissues.
RESULTS: We observed methylation of CpG islands in seven of the studied markers, but, the frequency of methylation was found varying among different samples. Of them, 14-33 sigma showed methylation in 45 GBC (90%; p=0.0001) and 25 GSD (86.66%; p=0.001), MASPIN in 35 GBC (70%; p=0.0008) and 18 GSD (51.43%; p=0.040), FLNC in 16 GBC (32%; p=0.0044) and 9 GSD (25.71%; p=ns), THBS1 in 26 GBC (52%; p=0.0009) and 10 GSD (28.57%; p=0.0505), HLTF in 8 GBC (16%; p=ns) and 2 GSD (5.71%; p=ns), COX2 in 10 GBC (20%; p=ns) and 6 GSD (17.14%; p=ns) and SOCS-1 in 3 GBC samples only (6%; p=ns), but not in GSD. Semi-quantitative PCR revealed down regulation in MASPIN, 14-3-3 sigma, THBS1, HLTF, COX2 and SOCS1 in advanced gallbladder cases. Immunohistochemistry further confirmed the down-regulation of SOCS1 in GBC.
CONCLUSION: The present study infers that accumulation of epigenetic alterations increases poor prognosis of GBC patients. Out of seven genes, MASPIN and THBS1 play key epigenetic role in GBC, but not in GSD. The reason for downregulation of SOCS1 only in GBC, and unaltered expression of 14-3-3 sigma protein in all the GBC and GSD tissue samples is not clear. Further investigation on the expression pattern of these genes in GBC cell lines may elucidate their likely functional role in in association with gallbladder cancer.
Ye C, Sun NX, Ma Y, et al.MicroRNA-145 contributes to enhancing radiosensitivity of cervical cancer cells.
FEBS Lett. 2015; 589(6):702-9 [PubMed
] Related Publications
In our study, transcriptome microarrays are used to identify differentially expressed miRNAs and mRNAs in cervical cancer specimens. We find that microRNA-145 (miR-145) expression is significantly decreased in cervical cancer tissues and cell lines, and is associated with advanced cancer stages, large tumor size and moderate/poor differentiation. We show that miR-145 targets the DNA damage repair-associated gene Helicase-like transcription factor (HLTF), which is involved in radio-resistance. Moreover, miR-145 over-expression in cervical cancer cells enhances radiosensitivity in vitro and in vivo. These results indicate that targeting miR-145 may be a novel radiosensitizing strategy for cervical cancer.
BACKGROUND: Hypermethylation of DNA is an epigenetic alteration commonly found in colorectal cancer (CRC) and can also be detected in blood samples of cancer patients. Methylation of the genes helicase-like transcription factor (HLTF) and hyperplastic polyposis 1 (HPP1) have been proposed as prognostic, and neurogenin 1 (NEUROG1) as diagnostic biomarker. However the underlying mechanisms leading to the release of these genes are unclear. This study aimed at examining the possible correlation of the presence of methylated genes NEUROG1, HLTF and HPP1 in serum with tissue breakdown as a possible mechanism using serum lactate dehydrogenase (LDH) as a surrogate marker. Additionally the prognostic impact of these markers was examined.
METHODS: Pretherapeutic serum samples from 259 patients from all cancer stages were analyzed. Presence of hypermethylation of the genes HLTF, HPP1, and NEUROG1 was examined using methylation-specific quantitative PCR (MethyLight). LDH was determined using an UV kinetic test.
RESULTS: Hypermethylation of HLTF and HPP1 was detected significantly more often in patients with elevated LDH levels (32% vs. 12% [p = 0.0005], and 68% vs. 11% [p < 0.0001], respectively). Also, higher LDH values correlated with a higher percentage of a fully methylated reference in a linear fashion (Spearman correlation coefficient 0.18 for HLTF [p = 0.004]; 0.49 [p < .0001] for HPP1). No correlation between methylation of NEUROG1 and LDH was found in this study. Concerning the clinical characteristics, high levels of LDH as well as methylation of HLTF and HPP1 were significantly associated with larger and more advanced stages of CRC. Accordingly, these three markers were correlated with significantly shorter survival in the overall population. Moreover, all three identified patients with a worse prognosis in the subgroup of stage IV patients.
CONCLUSIONS: We were able to provide evidence that methylation of HLTF and especially HPP1 detected in serum is strongly correlated with cell death in CRC using LDH as surrogate marker. Additionally, we found that prognostic information is given by both HLTF and HPP1 as well as LDH. In sum, determining the methylation of HLTF and HPP1 in serum might be useful in order to identify patients with more aggressive tumors.
García-Baquero R, Puerta P, Beltran M, et al.Methylation of tumor suppressor genes in a novel panel predicts clinical outcome in paraffin-embedded bladder tumors.
Tumour Biol. 2014; 35(6):5777-86 [PubMed
] Related Publications
DNA methylation of tumor suppressor genes (TSGs) represents a frequent and early epigenetic event with potential applications for cancer detection and disease evolution. Our aim was to examine the stratification and prognostic biomarker role of the methylation of a novel panel of TSGs in bladder cancer. The methylation status of 18 TSGs was evaluated in bladder cancer cells (n=14) and paraffin-embedded primary bladder tumors (n=61), using a methylation-specific multiplex ligation-dependent probe amplification assay (MS-MLPA). Recurrence, progression, and disease-specific survival were analyzed using univariate and multivariate Cox models. PRDM2, HLTF, ID4, DLC1, BNIP3, H2AFX, CACNA1G, TGIF, and CACNA1A were discovered methylated in bladder cancer. The methylation of RUNX3 (p=0.026), TWIST1 (p=0.009), SFRP4 (p=0.002), and CCND2 (p=0.027) correlated to tumor stage. Univariate analyses indicated prognostic associations for recurrence (DLC1, SFRP5, H2AFX, CACNA1G), progression (DLC1, SFRP5, CACNA1G), disease-specific (PRDM2, DLC1, SFRP5, CACNA1G, and TIMP3), and overall survival (SFRP5 and TIMP3). In multivariate analyses, several TSGs remained as independent prognosticators for recurrence (SFRP5, H2AFX), progression (CACNA1G), and disease-specific survival (SFRP5). Thus, a novel set of TSGs was identified, frequently methylated in bladder cancer cells and tumors. TSG methylation allowed histopathologic and outcome stratification using paraffin-embedded tumors. This is clinically relevant by offering a strategy for the management of patients affected with uroepithelial neoplasias in pathology routine laboratories.
Gastric cancer is one of the most common malignancies and remains the second leading cause of cancer-related death worldwide. Over 70% of new cases and deaths occur in developing countries. In the early years of the molecular biology revolution, cancer research mainly focuses on genetic alterations, including gastric cancer. Epigenetic mechanisms are essential for normal development and maintenance of tissue-specific gene expression patterns in mammals. Disruption of epigenetic processes can lead to altered gene function and malignant cellular transformation. Recent advancements in the rapidly evolving field of cancer epigenetics have shown extensive reprogramming of every component of the epigenetic machinery in cancer, including DNA methylation, histone modifications, nucleosome positioning, noncoding RNAs, and microRNAs. Aberrant DNA methylation in the promoter regions of gene, which leads to inactivation of tumor suppressor and other cancer-related genes in cancer cells, is the most well-defined epigenetic hallmark in gastric cancer. The advantages of gene methylation as a target for detection and diagnosis of cancer in biopsy specimens and non-invasive body fluids such as serum and gastric washes have led to many studies of application in gastric cancer. This review focuses on the most common and important phenomenon of epigenetics, DNA methylation, in gastric cancer and illustrates the impact epigenetics has had on this field.
García-Baquero R, Puerta P, Beltran M, et al.Methylation of a novel panel of tumor suppressor genes in urine moves forward noninvasive diagnosis and prognosis of bladder cancer: a 2-center prospective study.
J Urol. 2013; 190(2):723-30 [PubMed
] Related Publications
PURPOSE: Changes in DNA methylation of tumor suppressor genes early in carcinogenesis represent potential indicators of cancer detection and disease evolution. We examined the diagnostic, stratification and prognostic biomarker roles in urine of the methylation of a novel panel of tumor suppressor genes in bladder cancer.
MATERIAL AND METHODS: We evaluated the methylation of 18 tumor suppressor genes in 2 prospective, independent sets of urine samples (training set of 120 preparations and validation set of 128) from patients with bladder cancer (170) and controls (78) using methylation specific multiplex ligation-dependent probe amplification. Diagnostic performance was evaluated with ROC curves. Recurrence, progression and disease specific survival were analyzed using univariate and multivariate Cox models.
RESULTS: PRDM2, HLTF, ID4, DLC1, BNIP3, H2AFX, CACNA1G, TGIF and CACNA1A were methylated in bladder cancer. CCND2, SCGB3A1, BNIP3, ID4 and RUNX3 were the most frequently methylated tumor suppressor genes in each urine set. Methylation of several tumor suppressor genes correlated with clinicopathological variables, such as stage, tumor grade, focality or age. ROC analysis revealed significant diagnostic accuracy for RUNX3 and CACNA1A in the training set, and for RUNX3 and ID4 in the validation set. On univariate and multivariate analysis CACNA1A methylation correlated with recurrence in the training set, while in the validation set PRDM2 and BNIP3 were significantly associated with recurrence and disease specific survival, respectively.
CONCLUSIONS: Tumor suppressor gene methylation allowed for histopathological and clinical stratification. Urine methylation has noninvasive usefulness not only for diagnostic assessment but also as independent bladder cancer prognosticators.
Zhang X, Li HM, Liu Z, et al.Loss of heterozygosity and methylation of multiple tumor suppressor genes on chromosome 3 in hepatocellular carcinoma.
J Gastroenterol. 2013; 48(1):132-43 [PubMed
] Related Publications
BACKGROUND: Genetic and epigenetic alterations are the two key mechanisms in the development of hepatocellular carcinoma (HCC). However, how they contribute to hepatocarcinogenesis and the correlation between them has not been fully elucidated.
METHODS: A total of 48 paired HCCs and noncancerous tissues were used to detect loss of heterozygosity (LOH) and the methylation profiles of five tumor suppressor genes (RASSF1A, BLU, FHIT, CRBP1, and HLTF) on chromosome 3 by using polymerase chain reaction (PCR) and methylation-specific PCR. Gene expression was analyzed by immunohistochemistry and reverse transcription (RT)-PCR.
RESULTS: Sixteen of 48 (33.3 %) HCCs had LOH on at least one locus on chromosome 3, and two smallest common deleted regions (3p22.3-24.3 and 3p12.3-14.2) were identified. RASSF1A, BLU, and FHIT showed very high frequencies of methylation in HCCs (100, 81.3, and 64.6 %, respectively) and noncancerous tissues, but not in liver tissues from control patients. Well-differentiated HCCs showed high methylation frequencies of these genes but very low frequencies of LOH. Furthermore, BLU methylation was associated with an increased level of alpha-fetoprotein, and FHIT methylation was inversely correlated with HCC recurrence. In comparison, CRBP1 showed moderate frequencies of methylation, while HLTF showed low frequencies of methylation, and CRBP1 methylation occurred mainly in elderly patients. Treatment with 5-aza-2'-deoxycytidine demethylated at least one of these genes and restored their expression in a DNA methylation-dependent or -independent manner.
CONCLUSIONS: Hypermethylation of RASSF1A, BLU, and FHIT is a common and very early event in hepatocarcinogenesis; CRBP1 methylation may also be involved in the later stage. Although LOH was not too frequent on chromosome 3, it may play a role as another mechanism in hepatocarcinogenesis.
BACKGROUND: HLTF (Helicase-like Transcription Factor) is a DNA helicase protein homologous to the SWI/SNF family involved in the maintenance of genomic stability and the regulation of gene expression. HLTF has also been found to be frequently inactivated by promoter hypermethylation in human colon cancers. Whether this epigenetic event is required for intestinal carcinogenesis is unknown.
RESULTS: To address the role of loss of HLTF function in the development of intestinal cancer, we generated Hltf deficient mice. These mutant mice showed normal development, and did not develop intestinal tumors, indicating that loss of Hltf function by itself is insufficient to induce the formation of intestinal cancer. On the Apcmin/+ mutant background, Hltf- deficiency was found to significantly increase the formation of intestinal adenocarcinoma and colon cancers. Cytogenetic analysis of colon tumor cells from Hltf-/-/Apcmin/+ mice revealed a high incidence of gross chromosomal instabilities, including Robertsonian fusions, chromosomal fragments and aneuploidy. None of these genetic alterations were observed in the colon tumor cells derived from Apcmin/+ mice. Increased tumor growth and genomic instability was also demonstrated in HCT116 human colon cancer cells in which HLTF expression was significantly decreased.
CONCLUSION: Taken together, our results demonstrate that loss of HLTF function promotes the malignant transformation of intestinal or colonic adenomas to carcinomas by inducing genomic instability. Our findings highly suggest that epigenetic inactivation of HLTF, as found in most human colon cancers, could play an important role in the progression of colon tumors to malignant cancer.
Philipp AB, Stieber P, Nagel D, et al.Prognostic role of methylated free circulating DNA in colorectal cancer.
Int J Cancer. 2012; 131(10):2308-19 [PubMed
] Related Publications
DNA hypermethylation is frequently found in colorectal cancer (CRC). Methylation of helicase-like transcription factor (HLTF) and hyperplastic polyposis 1 (HPP1) are potential and carcinoembryonic antigen (CEA) is an established prognostic factor in serum of patients with CRC. The aim of this study was to perform a direct comparison of the prognostic roles of these markers. Methylation status of HLTF and HPP1 was examined in pretherapeutic sera of 311 patients with CRC and matched primary tissues of 54 stage IV patients using methylation-specific quantitative PCR. CEA was determined using an immunoenzymometric assay. Methylation of HLTF and HPP1 DNA in serum significantly correlated with tumor size, stage, grade and metastatic disease. HPP1 methylation correlated with nodal status. Overall survival was shortened in case of methylation of HLTF or HPP1 or elevated levels of CEA (p < 0.0001 for all). In stage IV, patients survival was impaired if HLTF (p = 0.0005) or HPP1 (p = 0.0003) were methylated or CEA was above the median of 27 ng/ml (p = 0.002). Multivariate analysis revealed that methylation of HLTF [hazard ratio (HR) 1.8, p = 0.0438], HPP1 (HR 1.6, p = 0.0495) and CEA >27 ng/ml (HR 1.7, p = 0.0317) were independent prognostic factors in stage IV. The combination of any two or all three of these factors outperformed each marker on its own. In conclusion, the presence of methylated DNA of the genes HLTF or HPP1 in serum are independent prognostic factors in metastasized CRC. Prospective validation is required to determine their usefulness in clinical routine along with the established marker CEA.
Wang J, Li Q, Ou Y, et al.Recombination adenovirus-mediated human lactoferrin cDNA inhibits the growth of human MCF-7 breast cancer cells.
J Pharm Pharmacol. 2012; 64(3):457-63 [PubMed
] Related Publications
OBJECTIVES: Human lactoferrin, an 80 kDa iron-binding glycoprotein, has antitumour effects. We have explored the potential therapeutic role of re-expressing human lactoferrin gene product in human breast cancer.
METHODS: A recombinant adenovirus expressing the human lactoferrin cDNA (ad-hLTF) was constructed and used to infect breast cancer cells.
KEY FINDINGS: Seventy-two hours after infection, ad-hLTF had considerable cytotoxicity on MCF-7 cells. A time-course study showed that ad-hLTF infection of MCF-7 cells at 100 plaque-forming units per cell increased the number of cells in G(0) /G(1) phase and appeared markedly at Sub-G(1) apoptotic peak. The presence of apoptotic cells was confirmed using Annexin V-fluoresecein isothiocyanate apoptosis detection by flow cytometry. Ad-hLTF also resulted in a decrease of Bcl-2 protein and an increase in Bax protein.
CONCLUSIONS: Ad-hLTF plays an important role in the induction of cell cycle arrest and apoptosis in MCF-7 cells. The results demonstrated that ad-hLTF could have potential benefits in the treatment of breast cancer.
Wang J, Li Q, Ou Y, et al.Inhibition of tumor growth by recombinant adenovirus containing human lactoferrin through inducing tumor cell apoptosis in mice bearing EMT6 breast cancer.
Arch Pharm Res. 2011; 34(6):987-95 [PubMed
] Related Publications
Human lactoferrin (hLTF), an 80-kDa iron-binding glycoprotein, has antitumor activity. In this study, a recombinant adenovirus containing the human lactoferrin cDNA (ad-rhLTF) was constructed and its effect on tumor growth was investigated in mice bearing EMT6 breast cancer. Ad-rhLTF was injected seven times within 14 days into the tumor site at two concentrations (10(8) and 5 × 10(8) pfu/mL) in mice bearing EMT6 breast cancer. Injected ad-rhLTF had considerable cytotoxicity on mice breast cancer, and significantly reducing the weight of tumor produced and increasing the tumor inhibition rate up to 52.64%. The presence of apoptotic cells was confirmed using TUNEL staining and flow cytometry assays. At the same time, RTPCR and Western blot analyses demonstrated that ad-rhLTF also decreased expression of Bcl-2 and increased Bax and caspase 3 expressions. Therefore, we conclude that ad-rhLTF inhibits tumor growth by inducing tumor cell apoptosis in mice with breast cancer by triggering the mitochondrial-dependent pathway and activation of caspase 3. The results indicate that ad-rhLTF might be a promising drug for breast cancer gene therapy.
Guo W, Dong Z, Guo Y, et al.Aberrant methylation of the CpG island of HLTF gene in gastric cardia adenocarcinoma and dysplasia.
Clin Biochem. 2011; 44(10-11):784-8 [PubMed
] Related Publications
OBJECTIVES: To investigate the promoter methylation of HLTF in the tissues and plasma of patients with gastric cardia adenocarcinoma (GCA) and dysplasia.
DESIGN AND METHODS: Nested MSP approach was used to detect HLTF methylation status.
RESULTS: The frequency of HLTF methylation in high grade dysplasia and GCA tumor tissues was significantly higher than that in chronic inflammation tissues and was significantly associated with upper gastrointestinal cancers (UGIC) family history and protein and mRNA expression of the gene. HLTF methylation was not found in the plasma of patients with chronic inflammation and low grade dysplasia, while 4.0% (1/25) of patients with high grade dysplasia and 20.8% of (20/96) GCA patients were detected with hypermethylation of HLTF in the plasma.
CONCLUSIONS: In all, HLTF methylation may exist in gastric cardia dysplasia stages and may play important role in the development of GCA especially in individuals with UGIC family history.
Herbst A, Rahmig K, Stieber P, et al.Methylation of NEUROG1 in serum is a sensitive marker for the detection of early colorectal cancer.
Am J Gastroenterol. 2011; 106(6):1110-8 [PubMed
] Related Publications
OBJECTIVES: Colorectal cancer is the third most common cancer and a major cause of cancer-related deaths. Early detection of colonic lesions can reduce the incidence and mortality of colorectal cancer. Colonoscopy is the screening test for colorectal cancer with the highest efficacy, but its acceptance in the general public is rather low. To identify suitable tumor-derived markers that could detect colorectal cancer in blood samples, we analyzed the methylation status of a panel of genes in sera of affected patients.
METHODS: Using methylation-specific quantitative PCR, we analyzed the methylation of ten marker genes in sera of healthy individuals and patients with colorectal cancer.
RESULTS: Only HLTF, HPP1/TPEF, and NEUROG1 DNA methylation was detectable in at least 50% of patients with colorectal cancers. Whereas HLTF and HPP1/TPEF preferentially detected advanced and metastasized colorectal cancers, NEUROG1 methylation was detectable in UICC stages I-IV at a similar rate. Compared with other methylation markers, such as ALX4, SEPT9, and vimentin, NEUROG1 shows a higher sensitivity for colorectal cancer at UICC stages I and II. At a specificity of 91%, NEUROG1 reached a sensitivity of 61% (confidence interval, 50.4-70.6%) for the detection of colorectal cancers. Furthermore, detection of NEUROG1 methylation was independent of age and gender.
CONCLUSIONS: Methylation of the NEUROG1 gene is frequently found in sera of patients with colorectal cancers independent of tumor stage. The quantitative detection of NEUROG1 DNA methylation in serum is a suitable approach for the non-invasive screening for asymptomatic colorectal cancer.
BACKGROUND: Changes in DNA methylation of crucial cancer genes including tumor suppressors can occur early in carcinogenesis, being potentially important early indicators of cancer. The objective of this study was to examine a multiplexed approach to assess the methylation of tumor suppressor genes as tumor stratification and clinical outcome prognostic biomarkers for lung cancer.
METHODS: A multicandidate probe panel interrogated DNA for aberrant methylation status in 18 tumor suppressor genes in lung cancer using a methylation-specific multiplex ligation-dependent probe amplification assay (MS-MLPA). Lung cancer cell lines (n = 7), and primary lung tumors (n = 54) were examined using MS-MLPA.
RESULTS: Genes frequently methylated in lung cancer cell lines including SCGB3A1, ID4, CCND2 were found among the most commonly methylated in the lung tumors analyzed. HLTF, BNIP3, H2AFX, CACNA1G, TGIF, ID4 and CACNA1A were identified as novel tumor suppressor candidates methylated in lung tumors. The most frequently methylated genes in lung tumors were SCGB3A1 and DLC1 (both 50.0%). Methylation rates for ID4, DCL1, BNIP3, H2AFX, CACNA1G and TIMP3 were significantly different between squamous and adenocarcinomas. Methylation of RUNX3, SCGB3A1, SFRP4, and DLC1 was significantly associated with the extent of the disease when comparing localized versus metastatic tumors. Moreover, methylation of HTLF, SFRP5 and TIMP3 were significantly associated with overall survival.
CONCLUSIONS: MS-MLPA can be used for classification of certain types of lung tumors and clinical outcome prediction. This latter is clinically relevant by offering an adjunct strategy for the clinical management of lung cancer patients.
Cho S, Cinghu S, Yu JR, Park WYHelicase-like transcription factor confers radiation resistance in cervical cancer through enhancing the DNA damage repair capacity.
J Cancer Res Clin Oncol. 2011; 137(4):629-37 [PubMed
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Helicase-like transcription factor (HLTF) is a member of the SWI/SNF (mating type switching/sucrose non-fermenting) family of ATPases/helicases and also has a RING-finger motif characteristic of ubiquitin ligase proteins. These features have led to suggestions that HLTF functions like yeast Rad5, which promotes replication through DNA lesions via a post-replication repair pathway. However, the function of HLTF in higher eukaryotes is still unknown. Herein, we found the overexpression of HLTF in radiation recurrent human uterine cervical carcinoma tissues when compared to disease free survived patients tissues. In this study, we used RNA interference techniques to investigate the potential function of HLTF in cervical cancer cell line HeLa and found that the cell proliferation was reduced by knockdown (KD) of HLTF. A host-cell reactivation assay showed that the capacity for repair to DNA damage induced by X-ray irradiation was reduced in HLTF KD cells. X-rays also increased apoptosis in HLTF KD cells. These results suggest that HLTF is involved in DNA repair and apoptosis in cancer cells, which might represent a target for gene therapies of human cancer.
Mouse models of intestinal tumors have advanced our understanding of the role of gene mutations in colorectal malignancy. However, the utility of these systems for studying the role of epigenetic alterations in intestinal neoplasms remains to be defined. Consequently, we assessed the role of aberrant DNA methylation in the azoxymethane (AOM) rodent model of colon cancer. AOM induced tumors display global DNA hypomethylation, which is similar to human colorectal cancer. We next assessed the methylation status of a panel of candidate genes previously shown to be aberrantly methylated in human cancer or in mouse models of malignant neoplasms. This analysis revealed different patterns of DNA methylation that were gene specific. Zik1 and Gja9 demonstrated cancer-specific aberrant DNA methylation, whereas, Cdkn2a/p16, Igfbp3, Mgmt, Id4, and Cxcr4 were methylated in both the AOM tumors and normal colon mucosa. No aberrant methylation of Dapk1 or Mlt1 was detected in the neoplasms, but normal colon mucosa samples displayed methylation of these genes. Finally, p19(Arf), Tslc1, Hltf, and Mlh1 were unmethylated in both the AOM tumors and normal colon mucosa. Thus, aberrant DNA methylation does occur in AOM tumors, although the frequency of aberrantly methylated genes appears to be less common than in human colorectal cancer. Additional studies are necessary to further characterize the patterns of aberrantly methylated genes in AOM tumors.
Lee BB, Lee EJ, Jung EH, et al.Aberrant methylation of APC, MGMT, RASSF2A, and Wif-1 genes in plasma as a biomarker for early detection of colorectal cancer.
Clin Cancer Res. 2009; 15(19):6185-91 [PubMed
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PURPOSE: To identify epigenetic molecular makers in plasma for the early detection of colorectal cancer.
EXPERIMENTAL DESIGN: We retrospectively analyzed the methylation status of 10 genes in fresh-frozen tissues and corresponding plasma samples from 243 patients with stage I and II sporadic colorectal cancer, 276 healthy individuals, and plasma from 64 colorectal adenoma patients using methylation-specific PCR. The methylation score (Mscore) was used to find molecular markers with high sensitivity and specificity.
RESULTS: Of the 243 colorectal cancer tissues, methylation was detected in 18% for p14, 34% for p16, 27% for APC, 34% for DAPK, 32% for HLTF, 21% for hMLH1, 39% for MGMT, 24% for RARbeta2, 58% for RASSF2A, and 74% for Wif-1. Receiver operator characteristic curve analysis in plasma from 243 patients with cancer and 276 healthy individuals showed that the M score of any single gene had a sensitivity of <40% after controlling for age, sex, and tumor location. The specificity of the M score was not different between multigene and single gene analyses, but the sensitivity of the M score was significantly increased by multigene analysis. For all patients, the M score in a model including APC, MGMT, RASSF2A, and Wif-1 genes had a sensitivity of 86.5% and a specificity of 92.1% when 1.6 was used as a cutoff. In this model, the M score had a positive predictive value of 90.6% and a negative predictive value of 88.8%.
CONCLUSION: The present study suggests that tumor-specific methylation of APC, MGMT, RASSF2A, and Wif-1 genes might be a valuable biomarker in plasma for the early detection of colorectal cancer.
Sturm RA, Larsson MGenetics of human iris colour and patterns.
Pigment Cell Melanoma Res. 2009; 22(5):544-62 [PubMed
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The presence of melanin pigment within the iris is responsible for the visual impression of human eye colouration with complex patterns also evident in this tissue, including Fuchs' crypts, nevi, Wolfflin nodules and contraction furrows. The genetic basis underlying the determination and inheritance of these traits has been the subject of debate and research from the very beginning of quantitative trait studies in humans. Although segregation of blue-brown eye colour has been described using a simple Mendelian dominant-recessive gene model this is too simplistic, and a new molecular genetic perspective is needed to fully understand the biological complexities of this process as a polygenic trait. Nevertheless, it has been estimated that 74% of the variance in human eye colour can be explained by one interval on chromosome 15 that contains the OCA2 gene. Fine mapping of this region has identified a single base change rs12913832 T/C within intron 86 of the upstream HERC2 locus that explains almost all of this association with blue-brown eye colour. A model is presented whereby this SNP, serving as a target site for the SWI/SNF family member HLTF, acts as part of a highly evolutionary conserved regulatory element required for OCA2 gene activation through chromatin remodelling. Major candidate genes possibly effecting iris patterns are also discussed, including MITF and PAX6.
Herbst A, Wallner M, Rahmig K, et al.Methylation of helicase-like transcription factor in serum of patients with colorectal cancer is an independent predictor of disease recurrence.
Eur J Gastroenterol Hepatol. 2009; 21(5):565-9 [PubMed
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BACKGROUND: CpG island hypermethylation is a common epigenetic event in colorectal cancer. The presence of simultaneous methylation of multiple genes is associated with poor prognosis in many types of tumours including colorectal cancer. We have shown earlier that the hypermethylation of the genes HLTF and HPP1/TPEF are independent prognostic serum markers in colorectal cancer identifying patients with increased risk of death. The purpose of this study was to analyse whether these factors also identify patients at risk of disease recurrence after curative surgery.
METHODS: Pretherapeutic sera of 106 patients curatively resected for colorectal cancer with known 5-year follow-ups were analysed for the presence of methylation of the genes HLTF and HPP1/TPEF.
RESULTS: HLTF serum methylation was associated with an increased risk of disease recurrence by a factor of 2.7 (95% confidence interval: 1.2-6.0; P=0.014). Multivariate analysis showed methylated HLTF serum DNA to be independently associated with poor outcome and a relative risk of disease recurrence of 2.5 (95% confidence interval: 1.1-5.6; P=0.023).
CONCLUSION: Here, we show for the first time that a DNA methylation-based surrogate marker can serve as a predictor of disease recurrence in colorectal cancer.
Capouillez A, Decaestecker C, Filleul O, et al.Helicase-like transcription factor exhibits increased expression and altered intracellular distribution during tumor progression in hypopharyngeal and laryngeal squamous cell carcinomas.
Virchows Arch. 2008; 453(5):491-9 [PubMed
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The helicase-like transcription factor (HLTF) belongs to the SWI/SNF family of proteins that use the energy from adenosine triphosphate hydrolysis to remodel chromatin during a variety of cellular processes. HLTF is also involved in DNA repair. Using computer-assisted microscopy, the immunohistochemical expression of HLTF was determined using a series of 100 hypopharyngeal and 56 laryngeal squamous cell carcinomas (SCCs) compared to tumor-free epithelia (60 cases) and dysplasias (92 cases). In hypopharyngeal SCC tumor progression, increased HLTF expression was associated with the percentage of immunopositive epithelial tissue areas (p = 0.02) and the staining intensity of the positive area (p = 0.0005). In the cases of laryngeal lesions, the immunolabeling intensity of HLTF significantly decreased with malignancy (p = 0.01). We also observed a significant shift of HLTF expression from the cytoplasm toward the nuclear compartment (p = 0.0007). Our data reveal an association between the presence of HLTF and neoplastic progression of hypopharyngeal and laryngeal SCCs.
Debauve G, Capouillez A, Belayew A, Saussez SThe helicase-like transcription factor and its implication in cancer progression.
Cell Mol Life Sci. 2008; 65(4):591-604 [PubMed
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The helicase-like transcription factor (HLTF) belongs to the SWI/SNF family of chromatin-remodeling factors. Several SWI/SNF genes are disrupted in cancer, suggesting their possible role as tumor suppressors. Similarly, the HLTF gene was found to be inactivated by hypermethylation in a significant number of colon, gastric and uterine tumors, indicating that HLTF silencing may confer a growth advantage and that HLTF could be considered as a tumor suppressor gene. However, 20-fold HLTF overexpression was detected in various transformed cell lines, suggesting that HLTF could be associated with neoplastic transformation and act more like an oncogene. Moreover, HLTF activation was recently linked to the initial steps of carcinogenesis in an experimental model of estrogen-induced kidney tumors. Those apparently contradictory observations suggest that HLTF might play various roles in cancer. In this review, we will try to reconcile all these data in order to specify the role of HLTF in cancer progression.
Kang MY, Lee BB, Kim YH, et al.Association of the SUV39H1 histone methyltransferase with the DNA methyltransferase 1 at mRNA expression level in primary colorectal cancer.
Int J Cancer. 2007; 121(10):2192-7 [PubMed
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This study was aimed at investigating the involvement of the SUV39H1 histone methyltransferase on the epigenetic change of euchromatic promoter in colorectal cancer. We retrospectively analyzed the mRNA levels of SUV39H1 and the promoter methylation of the p14(ARF), p16(INK4a) and HLTF genes as well as the mRNA levels of DNA methyltransferase 1 (DNMT1) in fresh frozen tissues from 219 colorectal cancer patients. The mRNA levels of the SUV39H1 and DNMT1 were assessed via quantitative real-time PCR and the methylation profiles of the CpG islands were determined using methylation-specific PCR. The mRNA levels of SUV39H1 and DNMT1 were elevated in 25% and 42% of 219 colorectal cancers, respectively. The hypermethylation of the p14(ARF), p16(INK4a) and HLTF genes occurred in 36%, 51% and 34% of the patients. The elevated mRNA levels of SUV39H1 were not associated with the hypermethylation of the 3 genes. However, the mRNA levels of DNMT1 were significantly different between patients with elevated mRNA levels of SUV39H1 and those without (1.62 +/- 0.84, 0.91 +/- 0.81, respectively; p = 0.007). Patients with elevated mRNA levels of SUV39H1 showed a higher prevalence of DNMT1 elevation than those without (61 vs. 35%, p = 0.0008). Patients with an elevated mRNA level of SUV39H1 had a 2.71 (95% CI = 1.09-4.48, p = 0.002) times greater risk of an elevated mRNA level of DNMT1, after controlling for age and gender. In conclusion, the present study suggests that SUV39H1 is significantly associated with DNMT1, but not with euchromatic promoter methylation in colorectal cancer.
Jo H, Kang S, Kim JW, et al.Hypermethylation of the COX-2 gene is a potential prognostic marker for cervical cancer.
J Obstet Gynaecol Res. 2007; 33(3):236-41 [PubMed
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AIM: The aim of the present study was to evaluate the DNA hypermethylation profiles of 14 genes known to be associated with tumor behavior and their clinical significance in cervical cancer.
METHOD: The clinical features of 82 patients with stage IB cervical cancer were analyzed in terms of DNA hypermethylation of 14 genes (hMLH1, p16, COX-2, CDH1, APC, DAPK, MGMT, p14, RASSF1A, RUNX3, TIMP3, FHIT, THBS1, and HLTF).
RESULTS: Of 14 genes investigated, only hypermethylation of COX-2 showed significant association with poor disease-free survival (P = 0.001). To further investigate an alteration in COX-2 expression by DNA hypermethylation, immunohistochemistry for COX-2 protein was performed in the cervical cancer tissues. We found no significant association between hypermethylation and expression patterns of the COX-2 gene.
CONCLUSIONS: The present results suggest that DNA hypermethylation of the COX-2 gene may be a potential prognostic marker in early stage cervical cancer, the underlying mechanism of which is independent of gene silencing.