Search

Cancer develops through the accumulation of genetic and epigenetic aberrations. To identify sequential molecular alterations that occur during the development of hepatocellular carcinoma (HCC), we compared 52 early and 108 overt HCC samples by genome sequencing. Gene mutations in the p53/RB1 pathway, WNT pathway, MLL protein family, SWI/SNF complexes, and AKT/PI3K pathway were common in HCC. In the early phase of all entities, TERT was the most frequently upregulated gene owing to diverse mechanisms. Despite frequent somatic mutations in driver genes, including CTNNB1 and TP53 , early HCC was a separate molecular entity from overt HCC, as each had a distinct expression profile. Notably, WNT target genes were not activated in early HCC regardless of CTNNB1 mutation status because β-catenin did not translocate into the nucleus due to the E-cadherin/β-catenin complex at the membrane. Conversely, WNT targets were definitively upregulated in overt HCC, with CTNNB1 mutation associated with downregulation of CDH1 and hypomethylation of CpG islands in target genes. Similarly, cell-cycle genes downstream of the p53/RB pathway were upregulated only in overt HCC, with TP53 or RB1 gene mutations associated with chromosomal deletion of 4q or 16q. HCC was epigenetically distinguished into four subclasses: normal-like methylation, global-hypomethylation (favorable prognosis), stem-like methylation (poor prognosis), and CpG island methylation. These methylation statuses were globally maintained through HCC progression. Collectively, these data show that as HCC progresses, additional molecular events exclusive of driver gene mutations cooperatively contribute to transcriptional activation of downstream targets according to methylation status. SIGNIFICANCE: In addition to driver gene mutations in the WNT and p53 pathways, further molecular events are required for aberrant transcriptional activation of these pathways as HCC progresses., (©2020 American Association for Cancer Research.)

Multiple hepatocellular carcinoma (HCC) is divided into two categories: intrahepatic metastasis (IM), which is a true relapse of HCC, and multicentric origin (MO), which is a second primary tumor. Clinical diagnosis of multiple HCC is usually made based on tumor location and/or time to recurrence; however, it is often difficult to distinguish the two types of multiple HCC. Using 41 matched pairs of multiple HCC specimens, we confirmed the accuracy of clinical diagnoses using exome sequence data and investigated the importance of discriminating the type of multiple HCC. Genomic analysis revealed that 18 (43.9%) patients diagnosed as having genomic IM had common mutations in a pair of HCC tumors with the main tumor of these patients being more progressive compared to those with genomic MO. The accuracy of clinical diagnosis based on lobe (Definition 1) and segment (Definition 2) were 68.3% and 78.0%, respectively. Intriguingly, recurrence ≥2 years after initial surgery for 3 patients was IM. The survival of patients with clinical IM was significantly shorter than for those with clinical MO based on both Definition 1 (P = 0.045) and Definition 2 (P = 0.043). However, mean survival was not different between the patients with genomic IM and those with MO (P = 0.364). Taken together, genomic analysis elucidated that liver cancer may spread more extensively and more slowly than previously thought. In addition, distinguishing multiple HCC as IM or MC may have provided biological information but was not of clinical importance with respect to patient prognosis., (© 2019 The Authors. Cancer Science published by John Wiley & Sons Australia, Ltd on behalf of Japanese Cancer Association.)

Purpose: Hepatitis B viral (HBV) DNA is frequently integrated into the genomes of hepatocellular carcinoma (HCC) in patients with chronic HBV infection (chronic HBV, hereafter), whereas the frequency of HBV integration in patients after the disappearance of HBV (prior HBV, hereafter) has yet to be determined. This study aimed to detect integration of HBV and adeno-associated virus type 2 (AAV2) into the human genome as a possible oncogenic event., Experimental Design: Virome capture sequencing was performed, using HCC and liver samples obtained from 243 patients, including 73 with prior HBV without hepatitis C viral (HCV) infection and 81 with chronic HBV., Results: Clonal HBV integration events were identified in 11 (15.0%) cases of prior HBV without HCV and 61 (75.3%) cases of chronic HBV ( P < 0.001). Several driver genes were commonly targeted by HBV, leading to transcriptional activation of these genes; TERT [four (5.4%) vs. 15 (18.5%)], KMT2B [two (2.7%) vs. five (6.1%)], CCNE1 [zero vs. one (1.2%)], CCNA2 [zero vs. one (1.2%)]. Conversely, CCNE1 and CCNA2 were, respectively, targeted by AAV2 only in prior HBV. In liver samples, HBV genome recurrently integrated into fibrosis-related genes FN1, HS6ST3, KNG1 , and ROCK1 in chronic HBV. There was not history of alcohol abuse and 3 patients with a history of nucleoside analogue treatment for HBV in 8 prior HBV with driver gene integration., Conclusions: Despite the seroclearance of hepatitis B surface antigen, HBV or AAV2 integration in prior HBV was not rare; therefore, such patients are at risk of developing HCC., (©2019 American Association for Cancer Research.)

Diverse epidemiological factors are associated with hepatocellular carcinoma (HCC) prevalence in different populations. However, the global landscape of the genetic changes in HCC genomes underpinning different epidemiological and ancestral backgrounds still remains uncharted. Here a collection of data from 503 liver cancer genomes from different populations uncovered 30 candidate driver genes and 11 core pathway modules. Furthermore, a collaboration of two large-scale cancer genome projects comparatively analyzed the trans-ancestry substitution signatures in 608 liver cancer cases and identified unique mutational signatures that predominantly contribute to Asian cases. This work elucidates previously unexplored ancestry-associated mutational processes in HCC development. A combination of hotspot TERT promoter mutation, TERT focal amplification and viral genome integration occurs in more than 68% of cases, implicating TERT as a central and ancestry-independent node of hepatocarcinogenesis. Newly identified alterations in genes encoding metabolic enzymes, chromatin remodelers and a high proportion of mTOR pathway activations offer potential therapeutic and diagnostic opportunities.

Analysis of acetylation and tri-methylation of the same residue of histone molecules might identify a subset of hepatocellular carcinoma (HCC) with aggressive behavior. In the present study, we examined acetylation and tri-methylation of lysine 27 on histone H3 (H3K27ac and H3K27me3, respectively) because these two modifications are known to exhibit opposite effects (enhancing and silencing) on gene expression. Neoplastic and non-neoplastic tissues from 198 HCC cases were immunostained with specific monoclonal antibodies against H3K27ac and H3K27me3. The stained tissues were evaluated by an image analyzing program to generate histological scores (H-scores, range 0-300), which were determined by multiplying the percentage of positive-stained cells with the classified immunohistochemical marker intensity (0-3). HCC tissues showed significantly higher H3K27ac (156.7±86.8) and H3K27me3 H-scores (151.8±78.1) compared with the background liver (40.3±33.0 and 64.7±45.6, respectively) (both P<0.001). The cases with H-scores of high-H3K27ac/high-H3K27me3 (n = 54) showed significant correlation with poor differentiation of morphology (P<0.01) and p53-positive staining (P<0.05), and poor prognosis (P<0.01). Confocal microscopy revealed segregated intranuclear localization of both modifications in the individual cancer cells: H3K27ac localization in central euchromatin regions and H3K27me3 in peripheral heterochromatin regions. Concurrent acetylation and methylation at H3K27 occurs in HCC cells in association with p53 abnormalities. These findings demonstrate that image analyzer-assisted H-scores of H3K27ac and H3K27me3 identified an aggressive subgroup of HCC, and could serve as a prognostic marker for HCC.

Chronic infections by hepatitis B virus (HBV) and hepatitis C virus (HCV) appear to be the most significant causes of hepatocellular carcinoma (HCC). Aberrant promoter methylation is known to be deeply involved in cancer, including in HCC. In this study, we analyzed aberrant promoter methylation by methylated DNA immunoprecipitation-on-chip analysis on a genome-wide scale in six HCCs including three HBV-related and three HCV-related HCCs, six matched noncancerous liver tissues, and three normal liver tissues. Candidate genes with promoter methylation were detected more frequently in HCV-related HCC. Candidate genes methylated preferentially to HBV-related or HCV-related HCCs were detected and selected, and methylation levels of the selected genes were validated by quantitative methylation analysis using MALDI-TOF mass spectrometry using 125 liver tissue samples, including 61 HCCs (28 HBV-related HCCs and 33 HCV-related HCCs) and 59 matched noncancerous livers, and five normal livers. Among analyzed genes, preferential methylation in HBV-related HCC was validated in one gene only. However, 15 genes were found to be methylated preferentially in HCV-related HCC, which was independent from age. Hierarchical clustering of HCC using these genes stratified HCV-related HCC as a cluster of frequently methylated samples. The 15 genes included genes inhibitory to cancer-related signaling such as RAS/RAF/ERK and Wnt/beta-catenin pathways. Methylation of dual specificity phosphatase 4 (DUSP4), cytochrome P450, family 24, subfamily A, polypeptide 1 (CYP24A1), and natriuretic peptide receptor A (NPR1) significantly correlated with recurrence-free survival. It was indicated that genes methylated preferentially in HCV-related HCC exist, and that DNA methylation might play an important role in HCV-related HCC by silencing cancer-related pathway inhibitors, and might perhaps be useful as a prognostic marker.

Background: Although many reports on the treatment of hepatocellular carcinoma (HCC) by microwave coagulation have been published recently, none have incorporated data for the long-term therapeutic efficacy of laparoscopic microwave coagulation (LMC). In the current study, the efficacy of LMC was assessed., Methods: The authors performed LMC under local anesthesia in 69 previously untreated patients with solitary HCCs < or = 4.0 cm in greatest dimension. The maximum diameter for the tumors averaged 22.6 +/- 7.4 mm. Long-time survival rate was evaluated according to the size and histologic grade of the tumor., Results: The 5-year overall cumulative survival rate for the 69 patients was 63.9%. The 5-year overall survival rate for patients with well differentiated HCC was 78.9%, whereas patients with moderately or poorly differentiated HCC had a 5-year overall survival rate of 38.9%. The 5-year cumulative survival rate for patients with HCCs < or = 2.0 cm in diameter was 76.0%, and 56.3% for patients with HCCs >2.0 cm. Twelve patients (17.4%) showed local tumor recurrence during the follow-up period. Local tumor recurrence was observed in 6 of 21 patients with moderately or poorly differentiated HCCs (28.6%) and in 6 of 40 patients with well differentiated HCCs (15.0%). The 3-year cancer-free survival rate for patients with well differentiated HCC was 44.4%, whereas it was 12.2% for patients with moderately or poorly differentiated HCC., Conclusions: A major factor that influenced outcome in LMC was tumor cell differentiation. LMC procedures were best suited for treatment of well differentiated HCC., (2005 American Cancer Society.)

Background: The use of a new end-fire type laparoscopic US probe with a forward-viewing convex-array transducer allows the caudate lobe of the liver to be accessed. This study evaluated the preliminary results of treatment of hepatocellular carcinoma in the caudate lobe by using this new instrument., Methods: Three patients with hepatocellular carcinoma in the caudate lobe were selected. A laparoscopic US probe, with a forward-viewing convex-array transducer at the tip and a guide groove for puncture on the back, was used to monitor the position of the radiofrequency ablation needle during the treatment., Results: Ablation was performed without complication in all cases. Complete necrosis of the tumor was confirmed by postoperative CT. At a mean follow-up of 30.3 months, no local recurrence was observed in any patient., Conclusions: Radiofrequency ablation of hepatocellular carcinoma in the caudate lobe of the liver by using a new laparoscopic US probe with a forward-viewing convex-array transducer at the tip was safe and effective.