BACKGROUND: Exosomes are extracellular vesicles released by almost all cell types, including cancer cells, into bodily fluids such as saliva, plasma, breast milk, semen, urine, cerebrospinal fluid, amniotic fluid, synovial fluid and sputum. Their key function being intercellular communication with both neighbouring as well as distant cells. Cancer exosomes have been shown to regulate organ-specific metastasis. However, little is known about the functional differences and molecular consequences of normal cells responding to exosomes derived from normal cells compared to those derived from cancer cells.
METHODS: Here, we characterised and compared the transcriptome profiles of primary human normal oral keratinocytes (HNOK) in response to exosomes isolated from either primary HNOK or head and neck squamous cell carcinoma (HNSCC) cell lines.
RESULTS: In recipient HNOK cells, we found that regardless of normal or cancer derived, exosomes altered molecular programmes involved in matrix modulation (MMP9), cytoskeletal remodelling (TUBB6, FEZ1, CCT6A), viral/dsRNA-induced interferon (OAS1, IFI6), anti-inflammatory (TSC22D3), deubiquitin (OTUD1), lipid metabolism and membrane trafficking (BBOX1, LRP11, RAB6A). Interestingly, cancer exosomes, but not normal exosomes, modulated expression of matrix remodelling (EFEMP1, DDK3, SPARC), cell cycle (EEF2K), membrane remodelling (LAMP2, SRPX), differentiation (SPRR2E), apoptosis (CTSC), transcription/translation (KLF6, PUS7). We have also identified CEP55 as a potential cancer exosomal marker.
CONCLUSIONS: In conclusion, both normal and cancer exosomes modulated unique gene expression pathways in normal recipient cells. Cancer cells may exploit exosomes to confer transcriptome reprogramming that leads to cancer-associated pathologies such as angiogenesis, immune evasion/modulation, cell fate alteration and metastasis. Molecular pathways and biomarkers identified in this study may be clinically exploitable for developing novel liquid-biopsy based diagnostics and immunotherapies.

Star-PAP, a nuclear phosphatidylinositol (PI) signal-regulated poly(A) polymerase (PAP), couples with type I PI phosphate kinase α (PIPKIα) and controls gene expression. We show that Star-PAP and PIPKIα together regulate 3'-end processing and expression of pre-mRNAs encoding key anti-invasive factors (

The Leucine zipper tumor suppressor gene 1 (LZTS1/FEZ1) gene was originally identified as a potential tumor suppressor. However, the expression pattern and the role of LZTS1 in the progression of colorectal cancer (CRC) have not been well characterized. Herein, we reported that LZTS1 was markedly reduced in CRC tissues compared with matched adjacent normal intestine epithelial tissues. In analysis of 160 CRC specimens, we revealed that decreased expression of LZTS1 was correlated to aggressive characteristics and poor survival of patients with CRC. Moreover, we found that expression of LZTS1 in CRC cells significantly inhibited cell proliferation in vitro and prohibited tumor growth in vitro. On the contrary, silence of LZTS1 promoted cell proliferation and tumor growth in CRC cells. Furthermore, we demonstrated that LZTS1 inhibited cell proliferation and tumor growth in CRC in part via suppression of AMT-mTOR, subsequently down-regulating p27Kip and up-regulating cyclin D1. These findings suggest that LZTS1 plays a potential tumor suppressor role in CRC progression and represents a valuable clinical prognostic marker of this disease.

The present study aimed to investigate the possible molecular mechanisms underlying the pathogenesis of metastatic osteosarcoma (OS), by examining the microarray expression profiles of normal samples, and metastatic and non‑metastatic OS samples. The GSE9508 gene expression profile was downloaded from the Gene Expression Omnibus database, which included 11 human metastatic OS samples, seven non‑metastatic OS samples and five normal samples. Pretreatment of the data was performed using the BioConductor package in R language, and the differentially expressed genes (DEGs) were identified by a t‑test. Furthermore, function and pathway enrichment analyses of the DEGs were conducted using a molecule annotation system. A differential co‑expression network was also constructed, and the submodules were screened using MCODE in Cytoscape. A total of 965 genes were identified as DEGs in metastatic OS. The DEGs were shown to participate in the regulation of DNA‑dependent transcription, the composition of the nucleus, cytoplasm and membrane, and protein and nucleotide binding. Furthermore, the screened DEGs were significantly associated with the ribosome, axon guidance and the cytokine‑cytokine receptor interaction pathway. Certain hub genes were identified in the constructed differential co‑expression network, including matrix metalloproteinase 1 (MMP1), smoothened (SMO), ewing sarcoma breakpoint region 1 (EWSR1) and fasciculation and elongation protein ζ‑1 (FEZ1). Brain selective kinase 2 (BRSK2) and aldo‑keto reductase family 1 member B10 (AKRIB10) were present in the screened submodules. The results of the present study suggest that genes, including MMP1, SMO, EWSR1, FEZ1, BRSK2 and AKRIB10, may be potential targets for the diagnosis and treatment of metastatic OS.

The FEZ1/LZTS1 (FEZ1) gene maps to chromosome 8p22 and is frequently altered in human cancer. FEZ1 has been proposed as a candidate tumour suppressor gene and its loss may contribute to tumour progression. We have analysed the expression of FEZ1 protein in tissues from ovarian carcinomas in relation to clinico-pathological variables, response to chemotherapy and disease-free and overall survival. FEZ1 status was assessed by immunohistochemistry. Cytoplasmic staining for FEZ1 protein was absent or drastically reduced in 38% of tumours. FEZ1 protein expression was not related to tumour grade, histotype, disease-free survival, or overall survival. On the contrary, it was significantly correlated with age and with FIGO stage of disease. This finding indicates that FEZ1 is involved in ovarian carcinogenesis. Moreover, loss of FEZ1 protein significantly predicted a complete treatment response in patients who received taxane-based chemotherapy. In conclusion, the reduction or loss of FEZ1 protein could be an aid to the clinical management of patients affected by ovarian carcinoma.

FEZ1/LZTS1 is a tumor suppressor gene located in chromosomal band 8p22, and methylation has been identified as a mechanism for its loss of function in tumors. Chromosomal deletion at 8p22 is also frequent in breast cancer. We therefore examined whether LZTS1 plays a role in breast cancer. We analyzed expression of LZTS1 at both the RNA and protein levels, and promoter methylation in a number of primary tumors and cell lines from breast cancer. We also examined the association between LZTS1 expression and different clinicopathological parameters of breast cancer. We found that the expression of LZTS1 mRNA was reduced in 25 of 50 (50%) primary tumors and 29 of 30 (97%) breast cancer cell lines. Immunohistochemical staining showed that LZTS1 protein was absent or down-regulated in 72 (72%) of 100 primary breast carcinomas. Reduced expression of LZTS1 at either the RNA or protein level was significantly correlated with lymph node metastases (P < 0.05). DNA methylation analysis revealed that the LZTS1 gene was frequently methylated in both cell lines and primary tumors from breast cancer, and the extent of DNA methylation was correlated with reduced expression of the gene. These findings suggest that LZTS1 plays a role in the development and progression of breast cancer at least through promoter methylation-mediated transcriptional downregulation.

Both entry and exit from mitosis are driven through the fine modulation of Cdk1 activity by several proteins or protein complexes. It is well established that to entry into the M-phase a cell requires Cdk1 to be fully activated in the nucleus by the Cdc25A, B and C phosphatases. Then, at the onset of anaphase Cdk1 activity suddenly drops mainly due to Cyclin B1 degradation, thus allowing exit from M-phase. Recent data demonstrate that high Cdk1 activity is necessary also for proper chromosome segregation, since its premature drop determines acceleration of the progression from prophase to metaphase eventually with incorrect division of the DNA content. A primary role in maintaining high Cdk1 activity during prophase and metaphase is played by Cdc25C phosphatase. During the M-phase, the activity of Cdc25C is regulated by the FEZ1/LZTS1 (LZTS1) tumor suppressor gene, which is able to prevent Cdc25C degradation in mitotic cells. As a consequence, Lzts1 absence in mice results in accelerated mitotic progression, improper chromosome segregation and, eventually, in increased incidence of both spontaneous and carcinogen-induced cancer formation.

AIM: To study the loss of heterozygosity (LOH) at 8p21-23 locus in diffuse gastric cancer.
METHODS: To evaluate the involvement of this region in gastric cancer, we used eight microsatellite markers covering two Mb of mentioned region, to perform a high-resolution analysis of allele loss in 42 cases of late diffuse gastric adenocarcinoma.
RESULTS: Six of these STS makers: D8S1149, D8S1645, D8S1643, D8S1508, D8S1591, and D8S1145 showed 36%, 28%, 37%, 41%, 44% and 53% LOH, respectively.
CONCLUSION: A critical region of loss, close to the NAT2 locus and relatively far from FEZ1 gene currently postulated as tumor suppressor gene in this region.

Transitional cell carcinoma of the bladder is a common tumor. While most patients presenting superficial disease can be expected to do well following treatment, still many patients will return to our office with muscle invasive and metastatic disease. Survival in advanced bladder cancer is less than 50%. Tumors of similar histologic grade and stage have variable behavior, suggesting that genetic alterations must be present to explain the diverse behavior of bladder cancer. It is hoped that through the study of the subtle genetic alterations in bladder cancer, important prognostic and therapeutic targets can be exploited. Many new diagnostic tests and gene therapy approaches rely on the identification and targeting of these unique genetic alterations. A review of literature published on the molecular genetics of bladder cancer from 1970 to the present was conducted. A variety of molecular genetic alterations have been identified in bladder cancer. Oncogenes (H-ras, erbB-2, EGFR, MDM2, C-MYC, CCND1), tumor suppressor genes (p53, Rb, p21, p27/KIP1, p16, PTEN, STK15, FHIT, FEZ1/LZTS1, bc10), telomerase, and methylation have all been studied in bladder cancer. Several have proven to be potentially useful clinical targets in the prognosis and therapy of bladder cancer such as staining for p53 and gene therapy strategies such as p53 and fez1. Clinical trials targeting HER2/neu and the EGFR pathways are underway. The UroVysion bladder cancer assay relies on FISH to detect genetic alterations in this disease. Continuing identification of the molecular genetic alterations in bladder cancer will enhance future diagnostic and therapeutic approaches to bladder cancer. Capitalizing on these alterations will allow early detection, providing important prognostic information and unique targets for gene therapy and other therapeutic approaches.

Members of the leucine zipper tumor suppressor (LZTS) protein family are thought to play roles in cell growth modulation. The two currently known members were identified by analyzing genomic and chromosomal alterations reported to be either involved or deleted in various types of cancer, suggesting a causative relationship. By means of computational biology, we have now identified a novel member of the LZTS protein family named LZTS3. The corresponding gene was localized to chromosome 20p13 and consisted of three exons. The novel LZTS3 protein demonstrated a high similarity to LAPSER1/LZTS2 and FEZ1/LZTS1, two members of the LZTS family. The conserved FEZ1 domain contains a leucine zipper motif similar to the cAMP-responsive activating transcription factor 5. As FEZ1 inhibits cancer cell growth through the regulation of mitosis and its alteration resulted in abnormal cell growth, the LZTS3 protein was expected to have similar functions during cancer differentiation. Furthermore, the protein was conserved in vertebrates, as orthologs could be identified in mouse, rat, and zebrafish. The intracellular localization of the LZTS3 protein was predicted to be nuclear by means of Reinhardt's neural network and the k-nearest neighbor algorithm. An RT-PCR-based expression profile available from the human unidentified gene-encoded (HUGE) database demonstrated the highest expression in the brain and kidney, accompanied by lower expression in multiple other tissues.

Genomic deletions of the short arm of chromosome 8 are common in many human cancers and are frequently associated with a more aggressive tumour phenotype. One of the regions of loss of heterozygosity (LOH) on 8p22 identified in bladder cancer contains two genes, LZTS1 (FEZ1) and DBC2 (RHOBTB2) that have been shown to be mutated at low frequency in other cancers. We screened a panel of bladder tumours and bladder tumour-derived cell lines for mutations in these genes. Forty two percent of the tumours were found to have LOH in the 8p22 region and many of the cell lines have known loss of 8p. Several known polymorphisms and novel polymorphisms were detected. One possible mutation of LZTS1 (G374S) was found in a cell line. The functional significance of this is unknown but the novel serine residue created may represent a novel phosphorylation site. In DBC2, we found a single somatic mutation in a tumour (E349D) that lies in a highly conserved region of the protein. mRNA levels for both genes were reduced in the majority of bladder cancer cell lines. We conclude that neither LZTS1 nor DBC2 is commonly mutated in bladder cancer. However, neither can yet be excluded as the target of 8p22 LOH. The finding of a somatic mutation of DBC2 in a tumour sample and the down-regulation of both gene transcripts in bladder tumour cell lines may indicate that an alternative mechanism of inactivation of the second allele, for example promoter hypermethylation, is more common than mutation and this must now be examined.

Chromosomal deletions are often observed in lung cancers suggesting that inactivation of tumor suppressor genes plays an important role in the development of this neoplasm. The region around chromosome 8p22 is a frequent and early target of these deletions and has therefore been investigated for the presence of candidate genes. The FEZ1/LZTS1 gene, located at 8p22, is inactivated in many cancers with 8p deletions, including prostate, esophageal, gastric, bladder, and breast cancer and the Fez1 protein has been shown to suppress growth of cancer cells and to regulate mitosis. To elucidate the role of FEZ1 in lung cancer, we have analyzed its expression by immunohistochemistry in 103 primary lung cancer specimens including 98 non-small cell lung cancers (57 adenocarcinomas, 32 squamous cell carcinomas, 7 large cell carcinomas, and 2 others) and five small cell carcinomas. Absence of Fez1 protein expression was observed in 27 cases (26%) and additional 43 cases (42%) showed strong reduction in immunoreactivity. There was a positive association between loss of FEZ1 expression and tumor grading (P = 0.0345) and a tendency toward a reduction in the mortality rate in subjects with strong FEZ1 expression. Overall, these data indicate an important role for FEZ1 in lung cancer and suggest the possibility that it may serve as a novel prognostic indicator.

BACKGROUND: Collecting duct carcinoma (CDC) is a rare but very aggressive variant of kidney carcinoma that arises from the epithelium of Bellini's ducts, in the distal portion of the nephron. In order to gain an insight into the biology of this tumor we evaluated the expression of five genes involved in the development of renal cancer (FEZ1/LZTS1, FHIT, TP53, P27kip1, and BCL2).
METHODS: We studied eleven patients who underwent radical nephrectomy for primary CDC. All patients had an adequate clinical follow-up and none of them received any systemic therapy before surgery. The expression of the five markers for tumor initiation and/or progression were assessed by immunohistochemistry and correlated to the clinicopathological parameters, and survival by univariate analysis.
RESULTS: Results showed that Fez1 protein expression was undetectable or substantially reduced in 7 of the 11 (64%) cases. Fhit protein was absent in three cases (27%). The overexpression of p53 protein was predominantly nuclear and detected in 4 of 11 cases (36%). Immunostaining for p27 was absent in 5 of 11 cases (45.5%). Five of the six remaining cases (90%) showed exclusively cytoplasmic protein expression, where, in the last case, p27 protein was detected in both nucleus and cytoplasm. Bcl2 expression with 100% of the tumor cells positive was observed in 4 of 11 (36%) cases. Statistical analysis showed a statistical trend (P = 0.06) between loss and reduction of Fez1 and presence of lymph node metastases.
CONCLUSIONS: These findings suggest that Fez1 may represent not only a molecular diagnostic marker but also a prognostic marker in CDC.

Allelic deletions on the short arm of chromosome 8 (8p) are frequent events in several human malignancies, including oral cancer. We have examined and found two common regions of deletion on 8p (8p12, 8p22) in oral squamous cell carcinomas (SCC)s. The possible involvement of FEZ1/LZTS1 (FEZ1) gene, a candidate tumor suppressor gene, mapped at 8p22, was also evaluated. Here we analyzed whether FEZ1 alterations play a role in the development and progression of oral SCCs. In the present study, we examined FEZ1 expression in 31 primary oral SCCs and 8 SCC-derived cell lines by reverse transcription-PCR (RT-PCR). Thirty-five percent of tumors (11 of 31) and 100% of cell lines (8 of 8) showed absent or reduced mRNA gene expression. To investigate the mechanism for silencing, cells were cultured with 5-aza-2'-deoxycytidine and all the cell lines showed restoration by the demethylating agent. These findings suggest that inactivation of the FEZ1 gene may contribute to the development of oral SCCs.

PURPOSE: The FEZ1/LZTS1 (FEZ1) gene, located on chromosome 8p22 (8p22), was identified recently as a candidate tumor suppressor gene. Because loss of heterozygosity at 8p21-22 is a frequent event in lung cancers, we studied FEZ1 alteration in short-term cultures of resected lung cancer tumors and cell lines.
EXPERIMENTAL DESIGN: We examined FEZ1 expression in 17 non-small cell lung cancer (NSCLC), 19 small cell lung cancer (SCLC) cell lines, and 6 pairs of short-term cultures of resected NSCLCs and accompanying nonmalignant bronchial cells (NBECs) by reverse transcription-PCR and Western blotting. To investigate the mechanism for silencing, cells were cultured with 5-aza-2'-deoxycytidine or trichostatin A. We screened for genomic mutations by PCR-single-strand conformational polymorphism.
RESULTS: Thirteen of 17 NSCLC (76%) and 3 of 19 SCLC (16%) of cell lines showed absent expression (P = 0.001). Of the paired NSCLC-NBEC cultures, 3 of 6 showed loss of expression in tumor cell cultures. In the cell lines retaining expression, the amplicon products in SCLCs were more intense than those of NSCLCs and NBECs. Expression of FEZ1 was not restored by 5-aza-2'-deoxycytidine and trichostatin A. Although FEZ1 expression was moderately correlated with loss of heterozygosity of specific microsatellite makers at 8p21-22 in NSCLC cell lines, it was strongly correlated to D8S261 and LPL loci in SCLC cell lines. No mutation was found within cording region of FEZ1 by PCR-single-strand conformational polymorphism.
CONCLUSIONS: We found differential FEZ1 expression in NSCLC and SCLC cell lines, and the absent expression in 3 of 6 short-term cultures of NSCLC tumors. FEZ1 may be related to tumorigenesis of lung cancer.

FEZ1/LZTS1 is a tumor suppressor gene that maps to chromosome 8p22, a chromosomal region frequently deleted in many human malignancies, including transitional cell carcinoma (TCC) of the urinary bladder. FEZ1/LZTS1 alterations have been reported in esophageal, breast, prostate, and gastric carcinomas. Fez1 expression was studied in five TCC-derived cancer cell lines by Western blot analysis and in 60 primary TCCs of the urinary bladder by immunohistochemistry. Fez1 protein was absent or reduced in four of five cell lines and in 37 of 60 primary TCC examined. We also restored Fez1 protein expression in human SW780 TCC-derived cells lacking endogenous Fez1 protein to study the effects of Fez1 expression on cell proliferation, cell kinetics, and tumorigenicity in BALB/c nude mice. In vitro transduction of SW780 Fez1-negative cell, with Ad-FEZ1, inhibited cell growth, altered cell cycle progression, and suppressed subcutaneous tumor growth in nude mice. These results suggest that FEZ1/LZTS1 gene plays a role in the development of TCC of the urinary bladder by acting as a bona fide tumor suppressor gene both in vitro and in vivo.

Numerous LOH and mutation analysis studies in different tumor tissues, including prostate, indicate that there are multiple tumor suppressor genes (TSGs) present within the human chromosome 8p21-22 and 10q23-24 regions. Recently, we showed that LZTS1 (or FEZ1), a putative TSG located on 8p22, has the potential to function as a cell growth modulator. We report here the cloning, gene organization, cDNA sequence characterization and expression analysis of LAPSER1, an LZTS1-related gene. This gene maps within a subregion of human chromosome 10q24.3 that has been reported to be deleted in various cancers, including prostate tumors, as frequently as the neighboring PTEN locus. The complete LAPSER1 cDNA sequence encodes a predicted protein containing various domains resembling those typically found in transcription factors (P-Box, Q-rich and multiple leucine zippers). LAPSER1 is expressed at the highest levels in normal prostate and testis, where multiple isoforms are seen, some of which are either undetectable or differentially expressed in some prostate tumor tissues and cell lines. Over-expression of LAPSER1 cDNA strongly inhibited cell growth and colony-forming efficiencies of most cancer cells assessed. Together these data suggest that LAPSER1 is another gene involved in the regulation of cell growth whose loss of function may contribute to the development of cancer.

The FEZ1/LZTS1 gene maps to chromosome 8p22, a region that is frequently deleted in human tumors. Alterations in FEZ1/LZTS1 expression have been observed in esophageal, breast, and prostate cancers. Here, we show that introduction of FEZ1/LZTS1 into Fez1/Lzts1-negative cancer cells results in suppression of tumorigenicity and reduced cell growth with accumulation of cells at late S-G(2)/M stage of the cell cycle. Fez1/Lzts1 protein is hyperphosphorylated by cAMP-dependent kinase during cell-cycle progression. We found that Fez1/Lzts1 is associated with microtubule components and interacts with p34(cdc2) at late S-G(2)/M stage in vivo. Present data show that FEZ1/LZTS1 inhibits cancer cell growth through regulation of mitosis, and that its alterations result in abnormal cell growth.

Deletions in the 8p21-22 region of the human genome are among the most common genetic alterations in prostate carcinomas. Several studies in different tumor tissues, including prostate, indicate that there are probably multiple tumor suppressor genes (TSGs) present in this region. To identify candidate TSGs on 8p22 a YAC contig spanning this region was assembled and YAC clones retrofitted with a selectable marker (neo) were transferred into rat prostate AT6.2 cells. Two overlapping YAC clones showed greatly reduced colony-forming efficiency, indicating they may carry a TSG. Two BAC clones encompassing the overlapping region also appeared to exert suppressive effects on the growth of AT6.2 cells. Database searches for genes mapped to the critical region identified a gene known as FEZ1 (LZTS1) as a potential candidate suppressor gene. Subsequent experiments showed that over-expression of LZTS1 cDNA inhibited stable colony-forming efficiencies of AT6.2, HEK-293 and LNCaP cells. In contrast, LZTS1-transfected Rat-1 and RM1 cells were growth-stimulated. Database searches also identified additional isoforms of the LZTS1 mRNA, as well as LZTS1 protein domains reminiscent of those found in transcription factors. Together these data suggest that the LZTS1 gene is involved in the regulation of cell growth and its loss of function may contribute to the development of prostatic carcinomas, as well as other cancers.

PURPOSE: Loss of heterozygosity (LOH) involving the short arm of chromosome 8 (8p) is a common feature of the malignant progression of human tumors, including gastric cancer. We have cloned and mapped a candidate tumor suppressor gene, FEZ1/LZTS1, to 8p22. Here we have analyzed whether FEZ1/LZTS1 alterations play a role in the development and progression of gastric carcinoma.
EXPERIMENTAL DESIGN: We examined Fez1/Lzts1 expression in 8 gastric carcinoma cell lines by Western blot, and in 88 primary gastric carcinomas by immunohistochemistry. Twenty-six of these 88 primary gastric carcinomas were also microdissected and tested for LOH at the FEZ1/LZTS1 locus and for mutation of the FEZ1/LZTS1 gene. Furthermore, we studied the FEZ1/LZTS1 gene regulation and transcriptional control and the methylation status of the 5' region of the gene in all 8 gastric carcinoma cell lines.
RESULTS: Fez1/Lzts1 protein was barely detectable in all of the gastric cancer cell lines tested and was absent or significantly reduced in 39 of the 88 (44.3%) gastric carcinomas analyzed by immunohistochemistry, with a significant correlation (P < 0.001) to diffuse histotype. DNA allelotyping analysis showed allelic loss in 3 of 17 (18%) and microsatellite instability in 4 of 17 (23.5%) cases informative for D8S261 at the FEZ1/LZTS1 locus. When we compared the presence of LOH with Fez1/Lzts1 expression, we found loss of protein expression in all three of the tumors with allelic imbalance at D8S261. A missense mutation was detected in one case that did not express Fez1/Lzts1. Hypermethylation of the CpG island flanking the Fez1/Lzts1 promoter was evident in six of the eight cell lines examined as well as in the normal control.
CONCLUSIONS: Our findings support FEZ1/LZTS1 as a candidate tumor suppressor gene at 8p in a subtype of gastric cancer and suggest that its inactivation is attributable to several factors including genomic deletion and methylation.

The worldwide incidence of hepatocellular carcinoma (HCC) is approximately one million cases a year. This makes HCC one of the most frequent human malignancies, especially in Asia and Africa, although the incidence is increasing also in the western world. HCC is a complication of chronic liver disease, with cirrhosis as the most important risk factor. Viral co-pathogenesis makes cirrhosis due to hepatitis B (HBV) and hepatitis C virus (HCV) infection a very important factor in the development of HCC. As curative therapy is often ruled out due to the late detection of HCC, it would be attractive to find parameters which predict malignant transformation in HBV- and HCV-infected livers. This study has used comparative genomic hybridization (CGH) to analyse 26 HCCs (11 non-viral, nine HBV, six HCV) and 12 concurrent dysplasias (five non-viral, five HBV, two HCV). Frequent gain (> or =25% of all tumours) was detected, in decreasing order of frequency, on 8q (69%), 1q (46%), 17q (46%), 12q (42%), 20q (31%), 5p (27%), 6q (27%), and Xq (27%). Frequent loss (> or =25% of all tumours) was found, in decreasing order of frequency, on 8p (58%), 16q (54%), 4q (42%), 13q (39%), 1p (35%), 4p (35%), 16p (35%), 18q (35%), 14q (31%), 17p (31%), 9p (27%), and 9q (27%). Minimal overlapping regions could be determined at multiple locations (candidate genes in parentheses). Minimal regions of overlap for deletions were assigned to 4p14-15 (PCDH7), 8p21-22 (FEZ1), 9p12-13, 13q14-31 (RB1), 14q31 (TSHR), 16p12-13.1 (GSPT1), 16q21-23 (CDH1), 17p12-13 (TP53), and 18q21-22 (DPC4, DCC). Minimal overlapping amplified sites could be seen at 8q24 (MYC), 12q15-21 (MDM2), 17q22-25 (SSTR2, GH1), and 20q12-13.2 (MYBL2, PTPN1). A single high level amplification was seen on 5q21 in an HBV-related tumour. Aberrations appeared more frequent in HBV-related HCCs than in HCV-associated tumours (p=0.008). This was most prominent with respect to losses (p=0.004), specifically loss on 4p (p=0.007), 16q (p=0.04), 17p (p=0.04), and 18q (p=0.03). In addition, loss on 17p was significantly lower in non-viral cancers than in HBV-related HCC (p<0.001). Furthermore, loss on 13q was more prevalent in HCCs in non-cirrhotic livers (p=0.02), thus suggesting a different, potentially more aggressive, pathway in neoplastic progression. A tendency (p=0.07) was observed for loss on 9q in high-stage tumours; no specific changes were found in relation to tumour grade. A subset of the HCC-associated genetic changes was disclosed in the preneoplastic stage, i.e. liver cell dysplasia. This group of dysplasias showed frequent gain on 17q (25%) and frequent loss on 16q (33%), 4q (25%), and 17p (25%). The majority of the dysplasias with alterations revealed genetic changes that were also present in the primary tumour. In conclusion, firstly, this study has provided a detailed map of genomic changes occurring in HCC of viral and non-viral origin, and has suggested candidate genes. Loss on 17p, including the TP53 region, appeared significantly more prevalent in HBV-associated liver cancers, whereas loss on 13q, with possible involvement of RB1, was distinguished as a possible genetic biomarker. Secondly, CGH analysis of liver cell dysplasia, both viral and non-viral, has revealed HCC-specific early genetic changes, thereby confirming its preneoplastic nature. Finally, genes residing in these early altered regions, such as CDH1 or TP53, might be associated with hepatocellular carcinogenesis.

Intrahepatic cholangiocarcinoma (ICC) is the second most common malignant primary tumor of the liver in Japan. Despite progress in operative techniques and adjuvant therapy, the prognosis of ICC remains very poor. Therefore, it is important to investigate the mechanism of carcinogenesis and progression of ICC. We screened allelic losses at 6 loci, including that of novel tumor-suppressor gene FEZ1 on chromosome 8p, and at 5 microsatellite loci to define the association with tumor-suppressor genes (HNPCC, APC, RB1, p53, DCC) in tumors from 18 unrelated ICC patients by PCR-loss of heterozygosity (LOH) assay and correlated the alterations with clinicopathological parameters. As a result, 61.1% (11 of 18) of patients showed LOH at 1 of the loci at least, and microsatellite instability was observed in 16.7% (3 of 18). At locus D8S258, relatively frequent LOH was detected (17.6%) compared with other loci on chromosome 8p. Among the other 5 chromosomal arms tested, the highest frequency of LOH (23.5%) was observed at D17S153. Fifty percent of cases with the mass-forming + periductal infiltrating type were frequently detected by LOH at D8S258 compared to cases of the mass-forming or intraductal growth type. In conclusion, we show that 1 putative tumor-suppressor gene on 8p22 may relate to progression of ICC and suggest that the p53 tumor-suppressor gene may be associated with carcinogenesis of ICC.

Alterations of human chromosome 8p occur frequently in many tumors. We identified a 1.5-Mb common region of allelic loss on 8p22 by allelotype analysis. cDNA selection allowed isolation of several genes, including FEZ1. The predicted Fez1 protein contained a leucine-zipper region with similarity to the DNA-binding domain of the cAMP-responsive activating-transcription factor 5. RNA blot analysis revealed that FEZ1 gene expression was undetectable in more than 60% of epithelial tumors. Mutations were found in primary esophageal cancers and in a prostate cancer cell line. Transcript analysis from several FEZ1-expressing tumors revealed truncated mRNAs, including a frameshift. Alteration and inactivation of the FEZ1 gene may play a role in various human tumors.