Aberrations In Hepatocellular Carcinoma Research Articles

The Role of Chronic Liver Diseases in the Emergence and Recurrence of Hepatocellular Carcinoma: An Omics Perspective.

Hepatocellular carcinoma (HCC) typically develops from a background of cirrhosis resulting from chronic inflammation. This inflammation is frequently associated with chronic liver diseases (CLD). The advent of next generation sequencing has enabled extensive analyses of molecular aberrations in HCC. However, less attention has been directed to the chronically inflamed background of the liver, prior to HCC emergence and during recurrence following surgery. Hepatocytes within chronically inflamed liver tissues present highly activated inflammatory signaling pathways and accumulation of a complex mutational landscape. In this altered environment, cells may transform in a stepwise manner toward tumorigenesis. Similarly, the chronically inflamed environment which persists after resection may impact the timing of HCC recurrence. Advances in research are allowing an extensive epigenomic, transcriptomic and proteomic characterization of CLD which define the emergence of HCC or its recurrence. The amount of data generated will enable the understanding of oncogenic mechanisms in HCC from the CLD perspective and provide the possibility to identify robust biomarkers or novel therapeutic targets for the treatment of primary and recurrent HCC. Importantly, biomarkers defined by the analysis of CLD tissue may permit the early detection or prevention of HCC emergence and recurrence. In this review, we compile the current omics based evidence of the contribution of CLD tissues to the emergence and recurrence of HCC.

Multi-omics data integration reveals novel drug targets in hepatocellular carcinoma

BackgroundGenetic aberrations in hepatocellular carcinoma (HCC) are well known, but the functional consequences of such aberrations remain poorly understood.ResultsHere, we explored the effect of defined genetic changes on the transcriptome, proteome and phosphoproteome in twelve tumors from an mTOR-driven hepatocellular carcinoma mouse model. Using Network-based Integration of multi-omiCS data (NetICS), we detected 74 ‘mediators’ that relay via molecular interactions the effects of genetic and miRNA expression changes. The detected mediators account for the effects of oncogenic mTOR signaling on the transcriptome, proteome and phosphoproteome. We confirmed the dysregulation of the mediators YAP1, GRB2, SIRT1, HDAC4 and LIS1 in human HCC.ConclusionsThis study suggests that targeting pathways such as YAP1 or GRB2 signaling and pathways regulating global histone acetylation could be beneficial in treating HCC with hyperactive mTOR signaling.

Cancer-related genetic changes in multistep hepatocarcinogenesis and their correlation with imaging and histological findings.

The landscape of cancer-related genetic aberrations in hepatocellular carcinoma (HCC) has gradually become clear through recent next-generation sequencing studies. However, it remains unclear how genetic aberrations correlate with imaging and histological findings. Using 117 formalin-fixed paraffin-embedded specimens of primary liver tumors, we undertook targeted next-generation sequencing of 50 cancer-related genes and digital polymerase chain reaction of hTERT. After classifying tumors into several imaging groups by hierarchal clustering with the information from gadoxetic acid enhanced magnetic resonance imaging, contrast-enhanced computed tomography, contrast-enhanced ultrasound, and diffusion-weighted imaging magnetic resonance imaging, the correlation between genetic aberrations and imaging and histology were investigated. Most frequent mutations were hTERT (61.5%), followed by TP53 (42.7%), RB1 (24.8%), and CTNNB1 (18.8%). Liver tumors were classified into six imaging groups/grades, and the prevalence of hTERT mutations tended to increase with the advancement of imaging/histological grades (P = 0.026 and 0.13, respectively), whereas no such tendency was evident for TP53 mutation (P = 0.78 and 1.00, respectively). Focusing on the mutations in each tumor, although the variant frequency (VF) of hTERT did not change (P = 0.36 and 0.14, respectively) in association with imaging/histological grades, TP53 VF increased significantly (P = 0.004 and <0.001, respectively). In multivariate analysis, stage III or IV (hazard ratio, 3.64; P = 0.003), TP53 VF ≥ 50% (hazard ratio, 3.79; P = 0.020) was extracted as an independent risk for recurrence in primary HCC patients. Increased prevalence of hTERT mutation and increased TP53 mutation VF are characteristic features of HCC progression, diagnosed with imaging/histological studies.

PTTG1 is involved in TNF-α-related hepatocellular carcinoma via the induction of c-myc.

Hepatocellular carcinoma (HCC) is a malignant disease caused by a variety of factors. However, the genomic and molecular aberrations in HCC are largely unknown. Herein, pituitary tumor transforming gene 1 (PTTG1) was discovered as a potential inflammation‐related oncogene in HCC, and its functions and molecular mechanisms were investigated. mRNA expression microarray, real‐time polymerase chain reaction (PCR), immunohistochemistry, and western blotting analyses revealed that PTTG1 is upregulated in HCC. Further in vitro and in vivo studies indicated that the proinflammatory cytokine tumor necrosis factor‐α (TNF‐α) induces PTTG1 expression, and PTTG1 was found to upregulate c‐myc, a well‐known oncogene. Downregulation of PTTG1 reduced c‐myc and proliferating cell nuclear antigen (PCNA) expression and inhibited cell proliferation. Interestingly, inhibition of c‐myc by 10058‐F4 did not affect PTTG1, which suggests that PTTG1 regulates c‐myc expression. Furthermore, PTTG1 expression levels are inversely correlated with HCC patient survival, indicating an independent prognostic biomarker for patients with HCC. Our data demonstrate that PTTG1 is involved in TNF‐α‐related HCC via c‐myc induction and that PTTG1 may be a potential therapeutic target for HCC.

Management of hepatocellular in the United States.

Hepatocellular carcinoma (HCC) is a major cause of cancer burden globally. In the United States, the incidence of HCC is forecast to continue to rise for the next 15 years. Patients with HCC vary markedly owing to heterogeneous tumor characteristics and concomitant liver dysfunction. In the United States and Europe, HCC is staged and managed according to the Barcelona Clinic Liver Cancer (BCLC) system. For very early and early stage HCC, or BCLC 0/A, liver transplant is the optimal treatment option. Liver resection and radiofrequency or microwave ablation are alternative treatment options. For intermediate stage HCC, or BCLC B, transarterial chemoembolization (TACE) is the standard of care. An alternative locoregional therapy, transarterial radioembolization using yttrium-90, has shown comparable outcomes with TACE and may be used in patients for whom TACE is contraindicated. For advanced stage HCC, or BCLC C, systemic chemotherapy with sorafenib, a multikinase inhibitor, is the only evidence-based treatment option available. Another multikinase inhibitor, regorafenib, was recently approved as a second-line therapy for this patient group. Randomized clinical trials investigating other agents in enriched patient groups and novel therapeutics including checkpoint inhibitors are underway. Patient with prohibitive performance status and/or end stage liver dysfunction are classified terminal stage HCC, or BCLC D, and are managed with best supportive care. The future direction for the management of HCC will rely on continuing efforts to uncover molecular pathways and actionable genetic aberrations in HCC.

Focal Adhesion Kinase: Insight into Molecular Roles and Functions in Hepatocellular Carcinoma.

Hepatocellular carcinoma (HCC) is the third leading cause of cancer-related death worldwide. Due to the high incidence of post-operative recurrence after current treatments, the identification of new and more effective drugs is required. In previous years, new targetable genes/pathways involved in HCC pathogenesis have been discovered through the help of high-throughput sequencing technologies. Mutations in TP53 and β-catenin genes are the most frequent aberrations in HCC. However, approaches able to reverse the effect of these mutations might be unpredictable. In fact, if the reactivation of proteins, such as p53 in tumours, holds great promise as anticancer therapy, there are studies arguing that chronic activation of these types of molecules may be deleterious. Thus, recently the efforts on potential targets have focused on actionable mutations, such as those occurring in the gene encoding for focal adhesion kinase (FAK). This tyrosine kinase, localized to cellular focal contacts, is over-expressed in a variety of human tumours, including HCC. Moreover, several lines of evidence demonstrated that FAK depletion or inhibition impair in vitro and in vivo HCC growth and metastasis. Here, we provide an overview of FAK expression and activity in the context of tumour biology, discussing the current evidence of its connection with HCC development and progression.

Diverse Signaling Pathways and Current Status of Molecular Targeted Treatments for Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is one of the leading causes of death associated with cancer. Various molecular mechanisms are involved in HCC development. Alterations in these molecular mechanisms include chromosomal instability, gene mutations, and variations in protein expressions. A number of cell signaling pathways that are associated with the occurrence of apoptosis, cell proliferation, and angiogenesis provide new prospects for the development of HCC treatments. Newly designed, potential therapeutic regimens target specific receptors, kinases, and vital proteins. Sorafenib is the only FDA-approved drug for HCC treatment, and it has been found that the complex genomic aberrations in HCC can be overcome using combination therapy. For example, therapeutic benefits have been gained using sorafenib with doxorubicin, oxaliplatin, cisplatin, and monoclonal antibodies. In addition, elumetinib, carbozantinib, and refametinib may be effective when used in combination with sorafenib. Drugs that target several signaling pathways have shown promising results in phase 3 clinical trials, and clinical studies using these drugs have changed the management strategy for HCC, particularly with the use of combination therapeutic regimens. Such research has improved the current standards of care and influenced clinical decision making.

Epigenetic signatures of alcohol abuse and hepatitis infection during human hepatocarcinogenesis.

Hepatocellular carcinoma (HCC) is the second most common cause of cancer deaths worldwide. Deregulated DNA methylation landscapes are ubiquitous in human cancers. Interpretation of epigenetic aberrations in HCC is confounded by multiple etiologic drivers and underlying cirrhosis. We globally profiled the DNA methylome of 34 normal and 122 liver disease tissues arising in settings of hepatitis B (HBV) or C (HCV) viral infection, alcoholism (EtOH), and other causes to examine how these environmental agents impact DNA methylation in a manner that contributes to liver disease. Our results demonstrate that each 'exposure' leaves unique and overlapping signatures on the methylome. CpGs aberrantly methylated in cirrhosis-HCV and conserved in HCC were enriched for cancer driver genes, suggesting a pathogenic role for HCV-induced methylation changes. Additionally, large genomic regions displaying stepwise hypermethylation or hypomethylation during disease progression were identified. HCC-HCV/EtOH methylomes overlap highly with cryptogenic HCC, suggesting shared epigenetically deregulated pathways for hepatocarcinogenesis. Finally, overlapping methylation abnormalities between primary and cultured tumors unveil conserved epigenetic signatures in HCC. Taken together, this study reveals profound epigenome deregulation in HCC beginning during cirrhosis and influenced by common environmental agents. These results lay the foundation for defining epigenetic drivers and clinically useful methylation markers for HCC.

Aberrant gene expression profiles in hepatocellular carcinoma detected by microdissection

The aim of this study was to identify genomic aberrations in hepatocellular carcinoma (HCC) by using laser capture microdissection (LCM) combined with microarray analysis. Samples were procured by LCM from HCC and patient-matched normal liver tissue surgically resected from 4 patients. RNA was isolated from the samples and reverse transcribed into cDNA. After 2-cycle linear amplification and 2-color fluorescent labeling, the cRNA was hybridized onto a whole genome microarray. All genes expressed in the normal and HCC samples were counted and analyzed. Differentially expressed genes were identified and the top 10 up and downregulated genes (totally 20 genes) were further evaluated. LCM was able to accurately capture 50-200 cells from HCC and control tissues. The microarray spectrum showed satisfactory detection of HCC-enriched genes. A total of 1361 differentially expressed genes were identified, among which, 607 were upregulated and 754 were downregulated. Among the top 20 up and downregulated genes, 4 genes had not been documented in the literature as being differentially expressed in any tumors. Thus, LCM is an effective approach for identifying aberrantly expressed genes in HCC, and may lead to the discovery of biomarkers for diagnostic and therapeutic applications.

PTEN Enhances the Sensitivity of Human Hepatocellular Carcinoma Cells to Sorafenib

Hepatocellular carcinoma (HCC) is a complex and heterogeneous tumor with several genomic alterations and ranks as the third highest cause of cancer-related death globally. The unresectable or metastatic HCC has very poor prognosis. Although multikinase inhibitor sorafenib can increase the survival of patients with advanced HCC, it is becoming apparent that combination therapies are critical to overcome the complex genomic aberrations in HCC. PTEN, as one of the most commonly inactivated genes in HCC, exerts a wide range of antitumor effects. In this study, we found that PTEN was downregulated in HCC tissues, especially in those tissues with extrahepatic metastasis. And negative PTEN expression cases showed increased proliferation activity. Overexpression of PTEN significantly reduced the proliferation of tumor cells HepG2. In addition, HepG2 cells transfected with PTEN were more sensitive to sorafenib in terms of its ability to inhibit proliferation and to induce apoptosis. Moreover, overexpression of PTEN decreased phosphorylation of MEK, a key downstream effector of RAF/MEK/ERK cascade, and levels of cyclin D1, antiapoptotic Bcl-2, and VEGF. These observations indicated that combination therapies with sorafenib and PTEN overexpression have potential to further improve therapeutic options for HCC.

Molecular targeted therapies in hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) is a complex and heterogeneous tumor with several genomic alterations. There is evidence of aberrant activation of several signaling cascades such as epidermal growth factor receptor (EGFR), Ras/extracellular signal-regulated kinase, phosphoinositol 3-kinase/mammalian target of rapamycin (mTOR), hepatocyte growth factor/mesenchymal-epithelial transition factor, Wnt, Hedgehog, and apoptotic signaling. Recently a multikinase inhibitor, sorafenib, has shown survival benefits in patients with advanced HCC. This advancement represents a breakthrough in the treatment of this complex disease and proves that molecular therapies can be effective in HCC. It is becoming apparent, however, that to overcome the complexity of genomic aberrations in HCC, combination therapies will be critical. Phase II studies have tested drugs blocking EGFR, vascular endothelial growth factor/platelet-derived growth factor receptor, and mTOR signaling. No relevant data has been produced so far in combination therapies. Future research is expected to identify new compounds to block important undruggable pathways, such as Wnt signaling, and to identify new oncogenes as targets for therapies through novel high-throughput technologies. Recent guidelines have established a new frame for the design of clinical trials in HCC. Randomized phase II trials with a time-to-progression endpoint are proposed as pivotal for capturing benefits from novel drugs. Survival remains the main endpoint to measure effectiveness in phase III studies. Patients assigned to the control arm should receive standard-of-care therapy, that is, chemoembolization for patients with intermediate-stage disease and sorafenib for patients with advanced-stage disease. Biomarkers and molecular imaging should be part of the trials, in order to optimize the enrichment of study populations and identify drug responders. Ultimately, a molecular classification of HCC based on genome-wide investigations and identification of patient subclasses according to drug responsiveness will lead to a more personalized medicine.

Array-based comparative genomic hybridization reveals recurrent chromosomal aberrations and Jab1 as a potential target for 8q gain in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the major malignancies worldwide. We have previously characterized global gene expression patterns in HCC using microarrays. Here, we report the analysis of genomic DNA copy number among 49 HCC samples using BAC array-based comparative genomic hybridization (CGH). We observed recurrent and characteristic chromosomal aberrations, including frequent DNA copy number gains of 1q, 6p, 8q and 20q, and losses of 4q, 8p, 13q, 16q and 17p. We correlated gene expression with array CGH data, and identified a set of genes whose expression levels correlated with common chromosomal aberrations in HCC. Especially, we noticed that high expression of Jab1 in HCC significantly correlated with DNA copy number gain at 8q. Quantitative microsatellite analysis further confirmed DNA copy number gain at the Jab1 locus. Overexpression of Jab1 in HCC was also validated using real-time RT-PCR, and Jab1 protein levels were studied by immunohistochemistry on tissue microarrays. Functional analysis in HCC cell lines demonstrated that Jab1 may regulate HCC cell proliferation, thereby having a potential role in HCC development. In conclusion, this study shows that array-based CGH provides high resolution mapping of chromosomal aberrations in HCC, and demonstrates the feasibility of correlating array CGH data with gene expression data to identify novel oncogenes and tumor suppressor genes.

Poly(ADP-Ribose) Polymerase-1 Is a Component of the Oncogenic T-Cell Factor-4/β-Catenin Complex

T-cell factor (TCF)-4 regulates a certain set of genes related to growth and differentiation of intestinal epithelial cells. Aberrant transactivation of these TCF-4-regulated genes by beta-catenin protein plays a crucial role in early intestinal carcinogenesis, and the transcriptional machinery of the TCF-4/beta-catenin complex is likely to contain targets for molecular therapy. We explored the molecular composition of the TCF-4/beta-catenin transcriptional complex by means of proteomics. A protein of approximately 112 kilodaltons was consistently coimmunoprecipitated with FLAG-tagged TCF-4 transiently expressed in HEK293 cells, and the protein was identified by mass spectrometry as poly(ADP-ribose) polymerase-1 (PARP-1). PARP-1 physically interacted with TCF-4 and augmented the transcriptional activity of the beta-catenin/TCF-4 complex. Knockdown of PARP-1 by RNA interference significantly suppressed both transcriptional activity and proliferation by colorectal cancer cells. Auto-polyADP-ribosylation of the PARP-1 protein induced by DNA damage inhibited the functional interaction of PARP-1 with TCF-4. PARP-1 was overexpressed in the intestinal adenomas of patients with familial adenomatous polyposis and multiple intestinal polyposis mice. The expression of PARP-1 was closely associated with the accumulation of beta-catenin and with the undifferentiated status of intestinal epithelial cells. In this study, we identified PARP-1 as a novel coactivator of the beta-catenin/TCF-4 complex. Although PARP-1 has been believed to play a protective role against carcinogenesis, these expression patterns and functional properties of PARP-1 were highly suggestive of its participation in early colorectal carcinogenesis.

Identification of Four Distinct Regions of Allelic Imbalances on Chromosome 1 by the Combined Comparative Genomic Hybridization and Microsatellite Analysis on Hepatocellular Carcinoma

Frequent chromosome 1 abnormalities detected in human hepatocellular carcinoma have been implicated in early genetic events of liver carcinogenesis. Recurrent loss of 1p with a common deleted region 1p36–p34 has been reported from microsatellite analysis, whereas common gain of the whole chromosome q-arm was described from several comparative genomic hybridization studies. The relationships between copy number changes and allelic status however remains unclear. In this study, we have conducted a simultaneous comparative genomic hybridization and microsatellite analysis study on chromosome 1 in 31 hepatocellular carcinoma cases. Microsatellite analysis revealed frequent loss of heterozygosity on 1p at loci D1S468 (74%), D1S450 (67%), D1S2667 (65%), D1S2697 (75%), D1S199 (52%), and D1S234 (67%) corresponded to the distal 1p36 region and coincided with 12 cases (86%) that presented losses on 1p by comparative genomic hybridization analysis. Although comparative genomic hybridization indicated a common deleted region of 1p36–p35 in the current series, microsatellite analysis has refined the smallest overlapping region (SOR) to 1p36.13–p36.22. Gain of 1q as revealed by comparative genomic hybridization suggested low and high-level gains, and cases that displayed an amplicon below the heterochromatic region 1q21–q25. Common allelic imbalances of polymorphic markers D1S2635 (64%), D1S484 (67%), D1S2878 (65%), D1S196 (70%), D1S249 (64%) D1S2785 (75%), D1S2842 (73%) and D1S2836 (74%) that corresponded to the regions 1q23.1–q24.2, 1q32.1 and 1q43–q44 were detected. Three distinct regions of allelic imbalances were thus suggested on recurring 1q gain found in hepatocellular carcinoma. Furthermore, microsatellite analysis has enabled a mapping of common overrepresented regions and suggested SOR on 1q23.1–q23.3 (D1S2635-D1S2878), 1q25.1–q31.1 (D1S452-D1S238), and 1q43 (D1S2785-D1S2842). Our current study has refined chromosome 1 aberrations in hepatocellular carcinoma to four regions of allelic imbalances. The SORs delineated should provide basis for further molecular investigation in hepatocarcinogenesis on genes residing on these chromosomal regions.

Assessment of chromosomal losses and gains in hepatocellular carcinoma

We examined the chromosomal changes of 22 hepatocellular carcinomas (HCCs) by comparative genomic hybridization (CGH) analysis and compared the results with that of allelotype by polymerase chain reaction based loss of heterozygosity (PCR-LOH) analysis. By CGH analysis, frequent chromosomal losses were noted in the chromosomal region of 4q (59%), 8p (77%), and 16q (50%), whereas gains were noted in 1q (86%) and 8q (77%). All of these chromosomal arms were revealed to have frequent allelic imbalances by PCR-LOH analysis, however, 9% of chromosomal aberrations were detected only by CGH analysis and 2% were detected only by PCR-LOH analysis. Our results suggest that CGH analysis gives more precise results for the screening of chromosomal aberrations in HCCs than that of PCR-LOH analysis with randomly selected microsatellite markers.

Analysis of chromosomal aberrations in large hepatocellular carcinomas by comparative genomic hybridization

Hepatocellular carcinoma (HCC) is a very common and highly malignant tumor, associated mainly with chronic viral hepatitis, cirrhosis of any cause, aflatoxin exposure and ethanol consumption. The aim of this study was to map genomic aberrations in HCC by a recently developed technique: comparative genomic hybridization (CGH). We applied CGH on 17 liver specimens, of which seven were HCCs. The rest were benign liver tumors, cirrhotic and normal livers, and other liver malignancies. Our study included mainly large tumors (mean size 10.5 cm) unrelated to viral hepatitis or cirrhosis. Our CGH analysis detected genomic imbalances in 42% of HCCs. The common aberrations included DNA gains of 1q, 9p, and 8q and DNA losses of 17p, 13q, 9q, 4q, and 11q. Also, we detected trisomies 8, 9, 18 and 21, which have not been reported previously. Gains and losses of DNA found in this study probably involve oncogenes and tumor suppressor genes that play a role in the puzzle of hepatocarcinogenesis. This study also suggests a possible link between the size of the tumor and the burden of genetic changes.

Differentiation of liver cell adenomas from well-differentiated hepatocellular carcinomas by comparative genomic hybridization.

Liver cell adenomas (LCAs) are rare tumours which may be difficult to differentiate from low-grade hepatocellular carcinomas (HCCs). This study used comparative genomic hybridization (CGH) to look for cytogenetic aberrations which would serve to distinguish between these tumours. For this purpose, ten LCAs and six well-differentiated HCCs were analysed and the results were compared with those reported previously for 15 well-differentiated HCCs. Aberrations were seen in 2/10 LCAs: a gain of chromosome 7p was observed in one and gains of 17q and 20 in a second case. In 6/6 well-differentiated HCCs, up to 13 aberrations were detectable, with a mean of 7.2 aberrations per case in chromosome sites 1q, 4p, 4q, 5p, 5q, 6p, 6q, 7p, 7q, 8p, 8q, 10q, 11p, 13q, 14q, 16p, 16q, 17p, 17q, 20p, 20q, and 21q. Aberrations focused on gains or losses of six chromosome sites, 1q, 4q, 8p, 8q, 16p, and 17p; in all HCC samples, at least two of these sites were affected. None of these aberrations occurred in any of the LCAs analysed. CGH is therefore helpful in distinguishing between LCA and well-differentiated HCC. Detection of one or more of the six most frequent aberrations in HCC supports the diagnosis of carcinoma and makes LCA unlikely.

Investigation of Chromosomal Aberrations in Hepatocellular Carcinoma by Fluorescence In Situ Hybridization

Molecular cytogenetic approaches have been applied only rarely in the characterization of hepatocellular carcinoma (HCC). The aim in this study was to evaluate aberrations, particularly deletions, of specific chromosomal regions in HCC. Dual-color fluorescence in situ hybridization (FISH) was performed on intact nuclei from touch preparations of 17 HCCs and 1 hepatic adenoma. Each touch preparation was hybridized with a digoxigenin-labeled centromere probe and a biotin-labeled unique sequence probe from the same chromosome. This approach permitted the simultaneous evaluation of ploidy changes and chromosome arm deletions. Eight noncentromeric chromosome regions, 3p14, 4q21, 6q14, 6q21, 8p12, 8p22, 9p21, and 9p24 were selected for study on the basis of their having been implicated as tumor suppressor regions in HCC or other common types of carcinoma. Together with the 5 corresponding centromeric probes on chromosomes 3, 4, 6, 8, and 9, a total of 13 chromosome loci were evaluated. All cases of hepatocellular carcinoma showed at least one deletion or aneuploidy. The hepatic adenoma was all diploid. Chromosome 4q21 showed the highest rate of deletion (76.5%) and aneusomy (88%). The second and the third were chromosome 8p22 and 6q14, which showed 59% and 47% of deletion, respectively. A 4q21 deletion is also the most frequent single chromosome aberration. Prominent tumor heterogeneity and variable deletion patterns were noted. Interphase FISH was an efficient means for evaluating numerical and structural chromosome aberrations in HCCs. Most HCCs contained deletions of known tumor suppressor regions (4q and 8p), and a novel deletion hotspot was demonstrated on chromosome band 6q14.

Chromosomal abnormality in hepatocellular carcinoma by comparative genomic hybridisation in Taiwan

The elucidation of the genetic changes of hepatocellular carcinoma (HCC) is very important for understanding the molecular mechanism of liver carcinogenesis. In order to identify the gains or losses in DNA sequence copy number in HCC, we used comparative genomic hybridisation to study 40 cases (44 tumours) of HCC. Tumour DNA and DNA from non-neoplastic liver tissue were labelled with different fluorochromes and then simultaneously hybridised to normal metaphase spread chromosomes. An image acquisition system was used to quantitate signal intensities contributed by tumour and reference DNA along the entire length of each chromosome. Regions of amplification and deletion were demonstrated as quantitative alterations. Losses were prevalent on chromosome regions 16q (43%), 17p (20%), 13q (20%), 4q (15%) and 8p (15%). Gains frequently occurred on 8q (30%), 1q (20%), 6p (20%) and 17q (18%). Hepatitis B virus carriers had a significantly higher frequency of losses on chromosome 16q. Furthermore, the minimal region of losses was narrowed down to 16q11-q22. This study confirms the presence of previously known chromosomal aberrations in HCC and highlights a new significant correlation between losses on chromosome 16q and hepatitis B virus carriers.

Chromosomal aberrations in hepatocellular carcinomas: Relationship with pathological features

Fluorescence in situ hybridization performed on tissue sections can reveal chromosomal abnormalities related to histopathological features. This technique was performed on serial frozen sections from seven normal livers and 29 hepatocellular carcinomas (HCCs) using pericentromeric repeat-specific probes for chromosomes 1, 4, 6, 7, 8, 16, and 17. For each HCC and each probe, the percentage of cells showing one, two, or more than two signals was counted and compared with the distribution in the normal liver. According to these results, HCCs were categorized as monosomic, disomic, or polysomic (more than two signals) for the chromosome tested. These data were compared with the main histopathological characteristics of HCC. Chromosome gains were very common, preferentially affecting chromosome 1 (23 of 27 cases, 85%), chromosome 16 (16 of 27 cases, 59%), chromosome 7 (16 of 29 cases, 55%), chromosome 6 (15 of 29 cases, 52%) and chromosome 8 (14 of 29 cases, 48%). Monosomy was seen more rarely, affecting preferentially chromosome 16 (19%), chromosome 17 (14%), and chromosome 4 (10%). A significant correlation was observed between aneusomy of chromosome 4 and tumor size (P < .05) or the presence of vascular embolism (P < .05). In conclusion, chromosomal gains are frequent genetic events in human HCC. A significant association between a gain in chromosome 4 and large tumor size or vascular embolism suggests that this genetic abnormality is a late event in liver carcinogenesis.