Studies On Treatment Strategies And Molecular Pathological Features For Infiltrative Hepatocellular Carcinoma

Hepatocellular carcinoma(HCC)is the fifth most common malignant tumor in the world,with high worldwide morbidity and mortality.For a long time,scholars are focusing on the different morphologies in HCC which are closely related to their biological behavior and prognosis.It is believed that the gross morphology of HCC is closely associated with its molecular pathological features.In 2011,one research team from medical school of Johns Hopkins University first proposed a HCC subtype with infiltrative growth(named as infiltrative hepatocellular carcinoma,iHCC).Its main clinical features include:?It is commonly associated with hepatitis B virus infection.?Compared to the common HCC,it has different imaging characteristics with minimal and inconsistent arterial enhancement.The lesions have blurred boundary and are likely to have vascular invasion.?Most patients with iHCC have markedly elevated alpha-fetoprotein(AFP)values.As soon as the concept of iHCC was put forward,it immediately attracted the attention of the scholars worldwide.It is generally believed that iHCC has infiltrative growth pattern and is easily to have vascular invasion,intrahepatic spread and distant metastasis,which is the most malignant subtype of HCC.However,due to the high invasion and metastasis in iHCC,the majority of cases were diagnosed at the late stage and lost the chance to receive radical treatments.Therefore,it is very difficult to collect the clinical,imaging and pathological data to deeply make studies on iHCC.From 2013,our research team started to pay close attention to the clinical and basic research on iHCC.Our relative research results on iHCC are listed as follows:?The incidence of iHCC in our country is higher than that in other Asian and European countries because of HBV-infection.It accounted for 30%of HCC,which was significantly higher than that in Europe and Japan from 5 to 10%.?iHCC has the worst prognosis among the different HCC subtypes.?Based on the observation of a large number of clinical cases,we first reported that iHCC also existed in HCC cases at early and intermediate stages.Therefore,this study focuses on the clinical and basic research on iHCC.It mainly includes the following three parts:?Select the appropriate staging system for treatment strategies and prognosis analysis on iHCC.?Explore the appropriate treatment strategy by analyzing clinical and prognosis information on iHCC patients receiving hepatic resection.? Explore the molecular pathological features and specific genes on iHCC by whole-exome sequencing.Part 1 Select the appropriate staging system for treatment strategies and prognosis analysis on infiltrative hepatocellular carcinomaAim:This study aims to investigate the prognostic performance of Hong Kong Liver Cancer(HKLC)classification in a Chinese cohort of HBV-related HCC patients.Methods:A total of 668 HCC patients between 2003 and 2012 were included.Performances of HKLC and Barcelona Clinic Liver Cancer(BCLC)system were compared using Akaike information criterion(AIC),concordance-index(c-index)and area under the receiver operating characteristic curve(AUC).Independent prognostic factors of survival were identified using univariate and multivariate analyses.Results:Independent predictors of survival were Child-Pugh grade(P=0.009),LDH(P<0.001)and ALB(P=0.001)levels,tumor location(p=0.032).tumor number(P<0.001).tumor size(P<0.001)and vascular invasion(P<0.001).Discriminatory ability was shown better for HKLC(AUC at 1-,3-,5-year were 0.740,0.695 and 0.615,respectively)than BCLC(AUC at 1-,3-,5-year were 0.622,0.569 and 0.548,respectively).Based on AIC and c-index,HKLC had a higher predictive power for survival(AIC=4709.480,c-index=0.805)than BCLC(AIC=4852.708,c-index=0.717).Conclusions:In our selected patient population whose main etiology is hepatitis B,HKLC system was more suitable for predicting prognosis in a Chinese cohort of HBV-related HCC patients than BCLC classification.Part 2 Analysis of clinical characteristics of infiltrative hepatocellular carcinoma receiving hepatic resectionAim:This study aims to assess the outcomes,effects of anatomical resection,and prognostic factors in a cohort of Chinese patients with infiltrative hepatocellular carcinoma(iHCC)undergoing hepatectomy.Methods:Data from 47 patients with iHCC undergoing hepatectomy were analyzed in a retrospective study.Independent prognostic factors of overall survival(OS)and recurrence-free survival(RFS)were identified using univariate and multivariate analyses.Correlations between microvascular invasion(MVI)and clinicopathological features were assessed using the ?2 test,Student t test or the Mann-Whitney U test.Survival outcomes were estimated using the Kaplan-Meier method.Results:The median OS was 27.37 months and the 1-year RFS rate were 61.7%.Alpha-fetoprotein(AFP)level was not a specific parameter in iHCC patients undergoing hepatectomy.Anatomic resection was significantly associated with increased RFS(P=0.007).Patients showing MVI were observed with decreased RFS(P<0.001).A high LDH level was significantly associated with decreased OS and RFS(P=0.003 and,P=0.020,respectively).MVI was shown correlated with the levels of aspartate aminotransferase(AST),gamma glutamyl transpeptidase(GGT)and lactate dehydrogenase(LDH).Subgroup analysis indicated that in mild MVI group,survival outcome was significantly more favorable in patients with high LDH level(P=0.019).Conclusions:iHCC patients are related with higher MVI rate and patients may still derive survival benefit from anatomic resection at early and intermediate stages.MVI classification could be used to identify iHCC patients with a poorer survival,especially those with high preoperative LDH level.Part 3 Study on the molecular pathological characteristics of infiltrative hepatocellular carcinomaAim:This study aims to identify the gene expression signature of infiltrative hepatocellular carcinoma(iHCC)compared with single nodular(SN)-type HCC according to the gross classification.Methods:The whole exome sequencing was performed in 6 matched HCC tumor/normal pairs(3 infiltrative type and 3 single nodular type)from 6 patients who received curative hepatectomy.Subsequent validation using Sanger sequencing and real-time PCR was performed in 30 HCC tumor samples(15 infiltrative type and 15 single nodular type).Results:Following whole exome sequencing,Sanger sequencing and bioinformatics analysis,it revealed significant difference of iHCC from SN-type HCC in gene patterns.Particularly,a typical growth factor receptor tyrosine kinase FGFR3 was predominantly mutated in iHCC.One nonsynonymous variant c.G285T(p.Q95H)and five additional mutations(c.G938A:p.G313D,c.G1291A:p.A431T,c.C1355G:p.T452R,c.C1377T:p.L459L and c.A1445T:p.E482V)were investigated by whole exome and Sanger sequencing,respectively.Immunohistochemical studies confirmed the specific expression of FGFR3 in iHCC samples.Conclusions:Our studies indicated that FGFR3 may be a candidate oncogene in tumor progression and a promising therapeutic target in iHCC patients who had early recurrence.