Abstract 4814: Inferring liver cancer evolution from spatial and temporal genomic heterogeneity

Nijmegen breakage syndrome (NBS) with NBS1 germ-line mutation is a human autosomal recessive disease characterized by genomic instability and enhanced cancer predisposition. The NBS1 gene codes for a protein, Nbs1(p95/Nibrin), involved in the processing/repair of DNA double-strand breaks. Hepatocellular carcinoma (HCC) is a complex and heterogeneous tumor with several genomic alterations. Recent studies have shown that heterozygous NBS1 mice exhibited a higher incidence of HCC than did wild-type mice. The objective of the present study is to assess whether NBS1 mutations play a role in the pathogenesis of human primary liver cancer, including HBV-associated HCC and intrahepatic cholangiocarcinoma (ICC). Eight missense NBS1 mutations were identified in six of 64 (9.4%) HCCs and two of 18 (11.1%) ICCs, whereas only one synonymous mutation was found in 89 control cases of cirrhosis and chronic hepatitis B. Analysis of the functional consequences of the identified NBS1 mutations in Mre11-binding domain showed loss of nuclear localization of Nbs1 partner Mre11, one of the hallmarks for Nbs1 deficiency, in one HCC and two ICCs with NBS1 mutations. Moreover, seven of the eight tumors with NBS1 mutations had at least one genetic alteration in the TP53 pathway, including TP53 mutation, MDM2 amplification, p14ARF homozygous deletion and promoter methylation, implying a synergistic effect of Nbs1 disruption and p53 inactivation. Our findings provide novel insight on the molecular pathogenesis of primary liver cancer characterized by mutation inactivation of NBS1, a DNA repair associated gene.

The Rho/ROCK (Rho-associated protein kinase) pathway has been found to be frequently upregulated in hepatocellular carcinoma (HCC). Clinico-pathological research has shown that increased RhoA and ROCK2 expression are associated with the presence of tumor microsatellite formation. RhoA is over expressed in 69% of HCC, and high RhoA levels are correlated with poor survival. ROCK2 protein level is upregulated in 54% of HCC, and its expression is associated with intrahepatic metastasis. The ROCK2 knockdown by short hairpin (sh)RNA leads to significant reduction of tumor formation. These observations suggest that Rho/ROCK pathway could be a potential therapeutic target for the treatment of liver cancer. Down-regulation of the Rho/ROCK pathway may inhibit tumor metastasis. However, the role of ROCK1 in HCC metastasis is still not clear. In order to dissect out the roles of ROCK1 and ROCK2 in liver tumor formation and metastasis, we used the shRNAmir- lentiviral system to knockdown ROCK1, ROCK2, and ROCK1/ROCK2 in HCC cell lines. The RNA and protein levels of ROCK1 and ROCK2 were significantly reduced in HCC cell lines that expressed shRNAs targeting ROCK1 and ROCK2. Orthotopically implanted HCC cells carrying shRNA targeted at ROCK1 and ROCK2 either alone or in combination were examined for tumor induction in mice. Our data showed that tumor growth was significantly reduced in those mice inoculated with cells expressing shRNAs. In addition, fewer tumor nodules as compared to the control (Non-target shRNA control) group were seen in those mice. Using qRT-PCR, we confirmed that the decreased ROCK activity was associated with the reduction of ROCK1 and ROCK2 RNA levels in mouse liver samples. Conclusion: our results indicate that both ROCK1 and ROCK2 are important for HCC tumor growth. Moreover, we demonstrated that ROCK1 played a more significant role than ROCK2 in HCC intrahepatic metastasis. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1489. doi:10.1158/1538-7445.AM2011-1489

Hepatocellular carcinoma (HCC) is the fifth most common malignant tumor in men and the seventh in women and understanding the molecular mechanisms of HCC and establishing more effective therapies are critical and urgent issues. Our objective was to study the expression of ferroportin in hepatocellular carcinoma (HCC) tissue samples and the relationship between ferroportin expression and HCC characteristics. Sixty HCC tissues and their corresponding para-cancer liver tissues (PCLT) were obtained from sixty HCC patients who had undergone hepatectomy in the Second Xiangya Hospital of Central South University. Ten normal liver tissue samples were also obtained as a control. Immunohistochemistry (IHC) was performed to analyze the ferroportin expression in HCC, and the relationship between ferroportin expression and HCC clinical pathological characteristics also was analyzed. For the evaluation of IHC results, the comprehensive scoring criteria were met according to the staining intensity and the number of positive staining cells. Western blotting was performed to detect the expression level of ferroportin in HCC cell lines. Ferroportin expression in HCC tissue was significantly lower compared to PCLT and normal liver tissue (P <0.05). Moreover, ferroportin expression was related to liver cancer cell de-differentiation, the severity degree in TNM staging, Edmondson-Steiner grading, intrahepatic metastasis and portal vein invasion. In addition, high expression of ferroportin was observed in normal human liver cell lines L02 and HL7702, whereas weak positive expression and even negative expression of ferroportin were observed in HCC cell lines FOCUS, MHCC-97H, HepG2 and SMMC-7721. Furthermore, among the four kinds of HCC cell lines, the expression level of ferroportin was the lowest in MHCC-97H cells. Ferroportin expression level declines along with the progression of liver cancer, suggesting that the reduction of ferroportin may serve as an important marker for poor HCC prognosis and as a new therapeutic target.

BackgroundHepatocellular carcinoma (HCC) is the fifth most common malignant tumor in men and the seventh in women and understanding the molecular mechanisms of HCC and establishing more effective therapies are critical and urgent issues. Our objective was to study the expression of ferroportin in hepatocellular carcinoma (HCC) tissue samples and the relationship between ferroportin expression and HCC characteristics.MethodsSixty HCC tissues and their corresponding para-cancer liver tissues (PCLT) were obtained from sixty HCC patients who had undergone hepatectomy in the Second Xiangya Hospital of Central South University. Ten normal liver tissue samples were also obtained as a control. Immunohistochemistry (IHC) was performed to analyze the ferroportin expression in HCC, and the relationship between ferroportin expression and HCC clinical pathological characteristics also was analyzed. For the evaluation of IHC results, the comprehensive scoring criteria were met according to the staining intensity and the number of positive staining cells. Western blotting was performed to detect the expression level of ferroportin in HCC cell lines.ResultsFerroportin expression in HCC tissue was significantly lower compared to PCLT and normal liver tissue (P <0.05). Moreover, ferroportin expression was related to liver cancer cell de-differentiation, the severity degree in TNM staging, Edmondson-Steiner grading, intrahepatic metastasis and portal vein invasion. In addition, high expression of ferroportin was observed in normal human liver cell lines L02 and HL7702, whereas weak positive expression and even negative expression of ferroportin were observed in HCC cell lines FOCUS, MHCC-97H, HepG2 and SMMC-7721. Furthermore, among the four kinds of HCC cell lines, the expression level of ferroportin was the lowest in MHCC-97H cells.ConclusionsFerroportin expression level declines along with the progression of liver cancer, suggesting that the reduction of ferroportin may serve as an important marker for poor HCC prognosis and as a new therapeutic target.

Multiple hepatocellular carcinoma (HCC) is categorized into 2 types; multicentric hepatocarcinogenesis (MC) and intrahepatic metastasis (IM). Although discrimination of the types of multiple HCC is of clinical importance, it is quite difficult to determine it correctly even after histological diagnosis. In order to classify multiple HCC into MC and IM, we compared pairs of multiple HCC samples from 12 patients who were clinically diagnosed MC, 6 patients with IM with regard to molecular aberrations, and 2 patients with pairs of primary HCC and extrahepatic metastasis such as adrenal grand and lung metastasis. Exome sequence showed that 125 mutations (90.6%) per patient with IM were common, which were consistent with the result of a pair of primary HCC and extrahepatic metastasis. On the other hand, 138 somatic mutations per tumor, and no common somatic mutations were identified in the 7 patients with MC. Especially only a few passenger mutations were different between IM specimens suggesting that IM pairs developed from the common ancestor. In contrast, 5 patients who clinically diagnosed MC had common mutations (41.7%), which indicates that pairs of HCC of these patients were genetically IM. Notably, mutation signatures obtained from exome sequence data of 2 nodules from the same patients with IM were similar, while those from patients with MC were different by profiling analysis. On the other hand, methylation profile shows that 2 HCC samples from the same patients with MC as well as IM were classified into the same cluster; the methylation status from the different ancestor is similar, and not altered through carcinogenesis. Taken together, comparison of mutations in a pair of HCCs makes it possible to classify multiple HCCs into MC and IM, which is difficult to be correctly determined in clinical practice, and is available to make treatment plans for multiple HCC patients. Furthermore, methylation status of 2 nodules of MC from same patient were similar, while those of mutation signatures were different, which suggests that the epigenomic changes are the earlier event prior to the genomic alterations. Citation Format: Yutaka Midorikawa, Shogo Yamamoto, Kenji Tatsuno, Hiroki Ueda, Shingo Tsuji, Genta Nagae, Tadatoshi Takayama, Hiroyuki Aburatani. Genetic difference between multicentric carcinogenesis and intrahepatic metastasis of hepatocellular carcinoma. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 163.

Introduction: Hepatocellular carcinoma (HCC) is the fifth most common cancer worldwide and the second leading cause of cancer mortality. The transcription factor Late SV40 Factor (LSF) functions as an oncogene in HCC, making it a potential protein target for HCC therapy. LSF overexpression correlates with pathogenesis of liver, colorectal and pancreatic cancers, for which there are limited molecularly targeted therapy options. A library of dihydroquinolinones, termed Factor Quinolinone Inhibitors (FQIs), inhibits LSF-DNA binding and specific LSF-protein interactions in in vitro and in cellular assays. The initial lead compound FQI1 causes dramatic mitotic defects in HCC cell lines but has no toxic consequences on immortalized human hepatocytes or primary mouse hepatocytes. Additionally, FQI1 has proven efficacious in endogenous HCC mouse models, with no evidence of associated toxicity. Methods: A series of dihydroquinolinone compounds were synthesized and tested for potency in two HCC cell lines, Huh7 and SNU423, by a cell proliferation assay. The FQI analogs, FQI34, N-oxide FQI34 and FQI37, were separated by chiral chromatography to the corresponding R and S enantiomers. Direct target engagement of the three lead compounds, FQI1, FQI34 and FQI37, is shown with cellular thermal stability assays on Huh7 cells. Results: More than 20 compounds were synthesized and characterized. Among them, FQI37 showed the most potent activity (GI50 = 70 nM) against Huh7 HCC cells. Structure-activity-relationship studies suggest that the amide portion of quinolinone core is important for optimal activity. Growth inhibition assays revealed enantiomeric specificity; the (S)-enantiomers are more potent than the (R)-compounds and the racemate. The cellular thermal shift assay in Huh7 cells demonstrated the direct target binding of FQIs to LSF in cells at micromolar concentrations. Growth inhibition assays also identified colorectal cancer and pancreatic cancer lines to be sensitive to the dihydroquinolinones treatment. Conclusions: Aryl-dihydroquinolinones are promising small molecule chemotherapies for LSF-driven cancers such as HCC, colorectal cancer, and pancreatic cancer. Citation Format: Niranjana Pokharel, John Kavouris, Jessica Biagi, Ulla Hansen, Scott E. Schaus. Assessing the sensitivity of LSF inhibitors against liver cancer [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 4021.

Radiomics with Machine Learning Improves the Prediction of Microscopic Peritumoral Small Cancer Foci and Early Recurrence in Hepatocellular Carcinoma.

This study was designed to establish risk classifications for early recurrence in hepatocellular carcinoma (HCC) patients with microvascular invasion (MVI) after hepatectomy. The data of 563 HCC patients with MVI after hepatectomy from two hospitals were retrospectively reviewed. Kaplan-Meier curves and Cox proportional hazards regression models were used to analyse early recurrence. The risk classification for early recurrence was established by using classification and regression tree (CART) analysis and validated by using two independent validation cohorts from two hospitals. Multivariate analysis revealed that four indices, namely, infection of chronic viral hepatitis, MVI classification, tumour size, and serum alpha-fetoprotein (AFP), were independent prognostic factors for early recurrence in HCC patients with MVI. By CART analysis, MVI classification and serum AFP became the nodes of a decision tree and 3-stratification classifications that satisfactorily determined the risk of early recurrence were established. The area under the time-dependent receiver operating characteristic curve (AUC) values of the classification for early recurrence at 0.5, 1.0, and 2.0 years were 0.75, 0.73, and 0.71, respectively, which were all significantly higher than three common classic HCC stages (BCLC stage, Chinese stage, and TNM stage). The calibration curves showed good agreement between predictions by classification for early recurrence and actual survival outcomes. These prediction results also were confirmed in the independent internal and external validation cohorts. The 3 stratification classifications enabled satisfactory risk evaluation of early recurrence in HCC patients with MVI after hepatectomy.

Cancer metastasis is a multi-step process that involves a series of tumor-stromal interaction, including extracellular matrix (ECM) remodeling which requires a concerted action of multiple proteolytic enzymes and their endogenous inhibitors. This study investigated the role of tissue inhibitor of metalloproteinases 2 (TIMP2) in the context of hepatocellular carcinoma (HCC) metastasis. We found that TIMP2 was the most significantly downregulated member among the TIMP family in human HCCs. Moreover, TIMP2 underexpression was frequent (41.1%; 23/56) in human HCCs as compared to the corresponding non-tumorous livers and was significantly associated with direct liver invasion into the adjacent liver parenchyma and poorer survival outcomes of the HCC patients. Furthermore, stable silencing of TIMP2 in HCC cell lines enhanced the cell invasive ability and ECM degradation associated with formation of invadopodia-like feature, suggesting that TIMP2 is a negative regulator of HCC metastasis. Furthermore, using orthotopic tumor xenograft model, we demonstrated that ectopic expression of TIMP2 open reading frame in the highly metastatic HCC cell line MHCC-97L not only significantly reduced the incidence of tumor microsatellite formation and venous invasion in the primary hepatic tumor xenografts, but also pulmonary metastasis, suggesting that both extrahepatic and intrahepatic metastasis in HCC was suppressed by TIMP2 expression. Mechanistically, TIMP2 suppression in a hypoxic environment was induced through a regulatory feedback circuit consisting of HIF-1á, miR-210 and HIF-3á. Taken altogether, our findings established that TIMP2 was frequently downregulated in human HCCs and its downregulation was associated with aggressive behavior and poorer patients’ outcome. Its suppression was under the regulation of a novel feedback circuit consisting of HIF-1á/ miR-210/ HIF-3á. Overall, our study has provided solid in vitro and in vivo evidence that TIMP2 is an important regulator of ECM degradation and HCC metastasis. These findings demonstrated that perturbation of the dynamic HIF-1a signaling circuit by miR-210 inhibitor abolished TIMP2 downregulation and suppressed HCC cell invasion. They also support the notion that targeting against HIF-1á signaling is a promising direction to tackle the hypoxic responses in HCC elicited by transarterial chemo-embolization (TACE) treatment to HCC patients. Citation Format: Alan KL Kai, Lo Kong Chan, Regina CL Lo, Joyce Lee, Carmen CL Wong, Jack CM Wong, Irene OL Ng. Downregulation of TIMP2 via HIF-1á/miR-210/HIF-3á regulatory feedback circuit enhances cancer metastasis in hepatocellular carcinoma. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 689.

Liver cancer is an important form of cancer worldwide ranking in the top ten in both incidence and mortality [1]. Over 780,000 new cases of primary hepatocellular carcinoma (HCC) were diagnosed worldwide in 2012, with nearly 750,000 deaths [2]. The American Cancer Society predicts over 35,000 new cases of liver cancer (primary hepatic and hepatic duct) and that nearly 25,000 individuals will die of this disease in the year 2015 [2]. In the US and Europe, primary liver cancer is fairly rare, but in some part of the world, it is the primary type of cancer observed [1, 2]. Universal vaccination for hepatitis B virus (HBV) has led to a decline of the disease in Tawain, while its incidence has been increasing in other regions in part due to hepatitis C virus (HCV) infection spread and the prevalence of non-alcohol liver disease and type 2 diabetes [2]. Environmental influences, including carcinogen exposure, are believed to contribute to its distinct geographical distribution pattern [3]. Although rare genetic disorders can contribute to liver cancer development, ethanol, smoking and dietary factors are known to contribute to its incidence and progression [2, 3]. The prevalence of liver cancer and its high mortality rate indicate the need for appropriate animal models of this disease in order to develop treatment and intervention strategies. In addition, the liver is the primary site for cancer induction in the bioassays used for carcinogen testing indicating the necessity for extrapolation of neoplasms that arise at this site in animals to man. The utility of defining common biomarkers for the conversion of benign to malignant transition will assist in developing appropriate inter-species extrapolation for risk assessment. The inclusion of early lesions from preclinical models will permit assessment of the ability of methods to develop appropriate risk assessment. In addition, analysis of liver cancer development is a useful model for study of the carcinogenic process of solid tumors that arise in both humans and animals. The influence of genetic background and environmental factors on neoplastic development is readily studied in rodent models of this disease. While genetic factors can contribute to primary liver cancer development, environmental factors have an important role in human liver cancer development. The liver is susceptible to liver cancer development by chemicals and rodent liver has been used as a model to understand the role that chemicals play in liver cancer development and progression. The liver is exposed to ingested materials and has a high level of metabolism. In the human, cirrhosis is an important contributor to most primary liver cancer development. Viral hepatitis can lead to cirrhosis and certain chemical exposures to contribute to this baseline liver disease and can exacerbate the potential for liver cancer. These include aflatoxin, ethanol, and potentially other dietary constituents (limited antioxidant intake (selenium, Vitamin E), iron excess, and others). Ethanol and NASH can contribute to the development of cirrhosis and likewise can lead to HCC development. Chemicals that can increase the incidence of neoplasms in animals can be classified into genotoxic and nongenotoxic modes of action. The effects of agents with a carcinogenic potential are dose dependent and exhibit a threshold. Understanding the biological basis of the changes that occur during the cancer induction and progression process, as well as the changes that chemicals induce in the liver will improve our knowledge of the steps and stages in the pathogenesis of primary liver cancer.

Background: Hepatocellular carcinoma (HCC) and intrahepatic cholangiocarcinoma (ICC) are the two most common histologic types of primary liver cancer. Incidence rates of both HCC and ICC are increasing in the United States. Metabolic syndrome, characterized by increased fasting glucose level, central adiposity, dyslipoproteinemia and hypertension, has been linked with HCC and may also modify the risk of ICC. The magnitude of the association, however, has not been investigated at the population level in the US. We therefore examined the association between metabolic syndrome and the development of both primary liver cancers in the general U.S. population. Methods: All persons aged 65 years and older diagnosed with histologically confirmed HCC and ICC between 1993 and 2005 were identified in the SEER-Medicare linked database. The cases were compared to a 5% sample of individuals residing in the same geographic regions of the SEER registries as the cases. The prevalences of metabolic syndrome and other risk factors for HCC (HBV, HCV, unspecified viral hepatitis, alcoholic liver disease, unspecified cirrhosis, biliary cirrhosis, hemochromatosis, Wilson's disease, smoking) and ICC (biliary cirrhosis, cholangitis, cholelithiasis, choledochal cysts, HBV, HCV, unspecified viral hepatitis, alcoholic liver disease, non-specified cirrhosis, inflammatory bowel disease, Crohn's disease, ulcerative colitis, smoking) were compared among the persons who developed cancer and the persons who did not. Adjusted odds ratios and 95% confidence intervals were calculated using logistic regression. Results: A total of 3,649 HCC cases, 743 ICC cases and 195,953 persons without cancer met the study inclusion criteria. Metabolic syndrome was significantly more common among persons who developed HCC (37.1%) and ICC (29.7%) than among persons who did not (17.1%, p&amp;lt;0.0001). In multiple logistic regression analyses that adjusted for demographics features and the other risk factors, metabolic syndrome remained significantly associated with an increased risk for HCC (OR=2.13; 95%CI=1.96-2.31, p&amp;lt;0.0001) and ICC (OR=1.56; 95% CI = 1.32-1.83, p&amp;lt;0.0001). Conclusions: Metabolic syndrome is a risk factor for development of both HCC and ICC in the general U.S. population. Given that approximately one-third of U.S. adults have metabolic syndrome, these findings have implications for the future incidence of both HCC and ICC. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 945. doi:10.1158/1538-7445.AM2011-945

Background: Deregulation of intracellular signaling by various genetic alterations is a hallmark of cancer. Therapeutics targeting such activated signaling pathways have achieved significant progress, but the precise pathway(s) targeted by sorafenib has remained unclear. Methods: Using high-density reverse-phase protein arrays, we profiled the phosphorylation status of 180 signaling molecules in the 120 pathways registered on the NCI-Nature curated database in 23 hepatocellular carcinoma (HCC) cell lines showing different sensitivities to sorafenib. We also sequenced the entire coding regions of 518 protein kinase genes in 20 overlapping HCC cell lines. Results: We identified 25 non-synomymous alterations in the 4 mTOR and MAPK pathway genes (RPS6KA1, RPS6KA6, RPS6KB2, and BRAF) in HCC cell lines 1 to 11. We also found that the levels of phosphorylated S6 ribosomal protein and c-Raf were associated with the sensitivity of the HCC cell lines to sorafenib. A mTOR inhibitor, AZD8055, exerted growth-inhibitory activity against sorafenib-resistant HCC cell lines. Discussion: Although a recent phase III clinical trial has demonstrated the effectiveness of sorafenib in patients with unresectable HCC, only a small proportion of the patients achieved the anticipated therapeutic benefits. The present results indicate cross-talk between the mTOR and MAPK signaling pathways in sorafenib-resistant HCC cell lines. Use of a combination of mTOR and MAPK inhibitors may improve the efficacy of molecular targeting therapy against HCC. Citation Format: Mari Masuda, Kazufumi Honda, Tesshi Yamada. Genomic and proteomic profiling of signaling pathways targeted by a multi-kinase inhibitor, sorafenib. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 4654. doi:10.1158/1538-7445.AM2013-4654

Primary liver cancer, mainly comprising hepatocellular carcinoma (HCC) and intrahepatic cholangiocarcinoma (ICC), remains a major global health problem. Although ICC is clinically different from HCC, their molecular differences are still largely unclear. In this study, precision N‐glycoproteomic analysis was performed on both ICC and HCC tumors as well as paracancer tissues to investigate their aberrant site‐specific N‐glycosylation. By using our newly developed glycoproteomic methods and novel algorithm, termed ‘StrucGP’, a total of 486 N‐glycan structures attached on 1235 glycosites were identified from 894 glycoproteins in ICC and HCC tumors. Notably, glycans with uncommon LacdiNAc (GalNAcβ1‐4GlcNAc) structures were distinguished from their isomeric glycans. In addition to several bi‐antennary and/or bisecting glycans that were commonly elevated in ICC and HCC, a number of LacdiNAc‐containing, tri‐antennary, and core‐fucosylated glycans were uniquely increased in ICC. More interestingly, almost all LacdiNAc‐containing N‐glycopeptides were enhanced in ICC tumor but not in HCC tumor, and this phenomenon was further confirmed by lectin histochemistry and the high expression of β1‐4 GalNAc transferases in ICC at both mRNA and protein expression levels. The novel N‐glycan alterations uniquely detected in ICC provide a valuable resource for future studies regarding to the discovery of ICC diagnostic biomarkers, therapeutic targets, and mechanism investigations.

Predictors of recurrence in early hepatocellular carcinoma patients treated with surgical resection

Mucins are large O-glycoproteins with high carbohydrate content and marked diversity in both the apoprotein and the oligosaccharide moieties. All three mucin types, trans-membrane (e.g., MUC1, MUC4, MUC16), secreted (gel-forming) (e.g., MUC2, MUC5AC, MUC6) and soluble (non-gel-forming) (e.g., MUC7, MUC8, MUC9, MUC20), are critical in maintaining cellular functions, particularly those of epithelial surfaces. Their aberrant expression and/or altered subcellular localization is a factor of tumour growth and apoptosis induced by oxidative stress and several anti-cancer agents. Abnormal expression of mucins was observed in human carcinomas that arise in various gastrointestinal organs. It was widely believed that hepatocellular carcinoma (HCC) does not produce mucins, whereas cholangiocarcinoma (CC) or combined HCC-CC may produce these glycoproteins. However, a growing number of reports shows that mucins can be produced by HCC cells that do not exhibit or are yet to undergo, morphological differentiation to biliary phenotypes. Evaluation of mucin expression levels in precursors and early lesions of CC, as well as other types of primary liver cancer (PLC), conducted in in vitro and in vivo models, allowed to discover the mechanisms of their action, as well as their participation in the most important signalling pathways of liver cystogenesis and carcinogenesis. Analysis of mucin expression in PLC has both basic research and clinical value. Mucins may act as oncogenes and tumour-promoting (e.g., MUC1, MUC13), and/or tumour-suppressing factors (e.g., MUC15). Given their role in promoting PLC progression, both classic (MUC1, MUC2, MUC4, MUC5AC, MUC6) and currently tested mucins (e.g., MUC13, MUC15, MUC16) have been proposed to be important diagnostic and prognostic markers. The purpose of this review was to summarize and update the role of classic and currently tested mucins in pathogenesis of PLC, with explaining the mechanisms of their action in HCC carcinogenesis. It also focuses on determination of the diagnostic and prognostic role of these glycoproteins in PLC, especially focusing on HCC, CC and other hepatic tumours with- and without biliary differentiation.