European Hepatocellular Carcinoma Research Articles

Chemerin and Chemokine-like Receptor 1 Expression Are Associated with Hepatocellular Carcinoma Progression in European Patients.

The chemoattractant protein chemerin is protective in experimental hepatocellular carcinoma (HCC), and high expression in HCC tissues of Asian patients was related to a favorable prognosis. Studies from Asia found reduced expression of chemerin in HCC compared to para-tumor tissues while our previous analysis observed the opposite. Aim of this study was to correlate chemerin expression in HCC tissues with disease severity of European patients Hepatocyte chemerin protein expression was assessed by immunohistochemistry in HCC tissue of 383 patients, and was low in 24%, moderate in 49% and high in 27%. High chemerin protein in the HCC tissues was related to the T stage, vessel invasion, histologic grade, Union for International Cancer Control (UICC) stage and tumor size. Chemokine-like receptor 1 (CMKLR1) is a functional chemerin receptor. CMKLR1 protein in hepatocytes was low expressed in HCC tissues of 36%, moderate in tissues of 32% and high in 32% of the HCCs. Tumor CMKLR1 was associated with the T stage, vessel invasion, histologic grade and UICC stage. Notably, sex-specific analysis revealed that associations of chemerin and CMKLR1 expression with HCC progression were significant in males but not in females. The tumor chemerin and CMKLR1 protein expression were not related to steatosis, inflammation and fibrosis grades. In summary, chemerin as well as CMKLR1 protein were related to disease severity of European HCC patients, and this was significant in males. This observation is in contrast to Asian patients where higher chemerin in the tumors was protective. Current analysis provides evidence for ethnicity and sex-related differences of tumor expressed chemerin and HCC severity.

Dickkopf-Related Protein 1 as Response Marker for Transarterial Chemoembolization of Hepatocellular Carcinomas.

Simple SummaryThe response of hepatocellular carcinomas (HCC) to transarterial chemoembolization (TACE) is variable. In view of the dynamic development of treatment options for HCCs, an early selection of the most effective therapy for maximizing individual treatment success has a high medical need. We show that serum levels of circulating Dickkopf-related protein 1 (DKK-1) are associated with a 12-week response to subsequent TACE in European patients. DKK-1 levels also allowed for identification of responders in patients with normal levels of alpha fetoprotein. Our findings are a step toward developing DKK-1 as a novel HCC response marker and an impulse to investigate the mechanisms underlying the treatment response of HCCs.Background and Aims: In the treatment of hepatocellular carcinoma (HCC), response prediction to transarterial chemoembolization (TACE) based on serum biomarkers is not established. We have studied the association of circulating Dickkopf-related protein 1 (DKK-1) with baseline characteristics and response to TACE in European HCC patients. Methods: Patients with HCC treated with TACE from 2010 to 2018 at a tertiary referral hospital were retrospectively enrolled. Levels of DKK-1 were measured in serum samples collected before TACE. Response was assessed according to mRECIST criteria at week 12 after TACE. Results: Ninety-seven patients were enrolled, including seventy-nine responders and eighteen refractory. Before TACE, median DKK-1 serum levels were 922 [range, 199–4514] pg/mL. DKK-1 levels were lower in patients with liver cirrhosis (p = 0.002) and showed a strong correlation with total radiologic tumor size (r = 0.593; p < 0.001) and with Barcelona Clinic Liver Cancer stages (p = 0.032). Median DKK-1 levels were significantly higher in refractory patients as compared to responders (1471 pg/mL [range, 546–2492 pg/mL] versus 837 pg/mL [range, 199–4515 pg/mL]; p < 0.001), and DKK-1 could better identify responders than AFP (AUC = 0.798 vs. AUC = 0.679; p < 0.001). A DKK-1 cutoff of ≤1150 pg/mL was defined to identify responders to TACE with a sensitivity of 78% and specificity of 77%. DKK-1 levels were suitable to determine response to TACE in patients with low AFP serum levels (AFP levels < 20 ng/mL; AUC = 0.843; 95% CI [0.721–0.965]; p = 0.003). Conclusion: DKK-1 levels in serum are strongly associated tumor size and with response to TACE in European HCC patients, including those patients with low AFP levels.

Genome instability is associated with ethnic differences between Asians and Europeans in hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) is one of the deadliest cancer types with diverse etiological factors across the world. Although large scale genomic studies have been conducted in different countries, integrative analysis of HCC genomes and ethnic comparison across cohorts are lacking.Methods: We first integrated genomes of 1,349 HCC patients from five large cohorts across the world and applied multiple statistical methods in identifying driver genes. Subsequently, we systematically compared HCC genomes and transcriptomes between Asians and Europeans using the TCGA cohort.Results: We identified 29 novel candidate driver genes, many of which are infrequent tumor suppressors driving late-stage tumor progression. When we systematically compared ethnic differences in the genomic landscape between Asian and European HCCs using the TCGA cohort (n = 348), we found little differences in driver frequencies. Through multi-modal integrative analysis, we found higher genomic instability in Asians together with a collection of molecular events ranging from tumor mutation burden (TMB), copy number alterations as well as transcriptomic subtypes segregating distinctively between two ethnic backgrounds. Strikingly, we identified an Asian specific transcriptomic subtype with multiple ethnically enriched genomic alterations, in particular chromosome 16 deletion, leading to a clinically aggressive RNA subgroup unique to Asians. Integrating multi-modal information, we found that survival models predict patient prognosis much better in Asians than in Europeans, demonstrating a higher potential for precision medicine applications in Asia.Conclusion: For the first time, we have uncovered an unprecedented amount of genomic differences segregating distinctively across ethnicities in HCC and highlighted the importance of differential disease biology and management in HCC across ethnic backgrounds.

Prognostic evaluation of HCC patients undergoing surgical resection: an analysis of 8 different staging systems

PurposeNo consensus exists regarding the most appropriate staging system to predict overall survival (OS) for hepatocellular carcinoma (HCC) in surgical candidates. Thus, we aimed to determine the prognostic ability of eight different staging systems in a European cohort of patients undergoing liver resection for HCC.MethodsPatients resected for HCC between 2010 and 2019 at our institution were analyzed with Kaplan-Meier and Cox regression analyses. Likelihood ratio (LR) χ2 (homogeneity), linear trend (LT) χ2 (discriminatory ability), and Akaike Information Criterion (AIC, explanatory ability) were used to determine the staging system with the best overall prognostic performance.ResultsLiver resection for HCC was performed in 160 patients. Median OS was 39 months (95% confidence interval (CI): 32–46 months) and median RFS was 26 months (95% CI: 16–34 months). All staging systems (BCLC, HKLC, Okuda, CLIP, ITA.LI.CA staging and score, MESH, and GRETCH) showed significant discriminatory ability regarding OS, with ITA.LI.CA score (LR χ2 30.08, LT χ2 13.90, AIC 455.27) and CLIP (LR χ2 28.65, LT χ2 18.95, AIC 460.07) being the best performing staging systems.ConclusionsITA.LI.CA and CLIP are the most suitable staging system to predict OS in European HCC patients scheduled for curative-intent surgery.

Chemerin Is Induced in Non-Alcoholic Fatty Liver Disease and Hepatitis B-Related Hepatocellular Carcinoma.

Simple SummaryHepatocellular carcinoma (HCC) is a frequent liver cancer and high expression of bioactive chemerin in hepatocytes was protective in experimental HCC models. The main risk factors for HCC are non-alcoholic fatty liver disease (NAFLD), hepatitis B and C infections. The current analysis showed that chemerin protein was induced in HCC tissues of NAFLD and hepatitis B infected patients. This upregulation was modest in patients with unknown disease etiology and not detected in hepatitis C infected patients. Protein levels of the chemerin receptor CMKLR1 strongly declined in the tumors of NAFLD patients and patients with unclear disease etiology but not in patients with viral infections. Our results demonstrate that the expression of chemerin in HCC is related to disease etiology and this could also apply to the role of chemerin in human HCC. In contrast to the present findings, chemerin was shown to be low in the HCC tissues of Asian patients with mostly viral disease etiology and this indicates ancestry-specific regulation of chemerin in HCC.Chemerin is protective in experimental models of hepatocellular carcinoma (HCC). Noteworthy, chemerin mRNA and protein were reduced in HCC tissues of Asian patients with mostly hepatitis B disease etiology. The current study nevertheless showed that chemerin protein was induced in tumor tissues of European HCC patients with non-alcoholic fatty liver disease (NAFLD) and patients with unclear disease etiology. A similar regulation was observed in hepatitis B virus (HBV), but not in hepatitis C virus (HCV), related HCC. The apparent discrepancy between the regulation of chemerin in HBV-HCC obtained from our study and recent reports led us to use the chemerin antibodies applied in the previous assays. These antibodies could not equally detect different chemerin isoforms, which were overexpressed in HepG2 cells. Higher chemerin protein in HCC was nevertheless confirmed by the use of all antibodies. Chemerin protein was low in Huh7 and PLC/PRF/5 cells whereas HepG2 and Hep3B cells had chemerin protein similar as primary human hepatocytes. Besides, the anti-tumor effects of retinoids in hepatocyte cell lines did not enclose upregulation of chemerin, which was initially discovered as a tazarotene induced protein in the skin. Finally, protein levels of the chemerin receptor, chemokine-like receptor 1 (CMKLR1), declined in non-viral, and tended to be lower in HBV-HCC tissues suggesting reduced chemerin activity in the tumors. To sum up, our work showed an opposite regulation of chemerin and CMKLR1 in NAFLD and HBV associated HCC. In HCV-HCC neither chemerin nor its receptor were changed in the tumor tissues. Current findings do not support a critical role of total chemerin protein levels in HCC of non-viral and viral etiology. Accordingly, tumor-localized chemerin protein was not associated with tumor-node-metastasis classification.

Body Composition Is an Independent Predictor of Outcome in Patients with Hepatocellular Carcinoma Treated with Sorafenib

Background: Previous studies have suggested body composition as a predictor of sorafenib toxicity and outcome in patients with advanced hepatocellular carcinoma (HCC). Large studies on the impact of body composition parameters in European HCC patients are lacking. Our aim was to validate the prognostic value of body composition parameters in Dutch patients with HCC treated with sorafenib. Patients and Methods: A retrospective analysis was performed in a cohort of HCC patients treated with sorafenib at two Dutch tertiary referral centers between 2007 and 2016. Body composition (adipose and skeletal muscle tissue) was measured at baseline by computed tomography (CT). Low skeletal muscle mass (SMM) and density were defined using published cut-offs. Body composition parameters were correlated with overall survival (OS), time to progression, response rate, and toxicity. Results: A total of 278 patients were included, mostly Child-Pugh class A (85%) and Barcelona Clinic Liver Cancer (BCLC) stage C (73%), with a median OS of 9.5 months (95% CI 8.1–11.0). Patients with combined low SMM and low total adipose tissue index (TATI) (n = 68, 25%) had a poor median OS (5.8, 95% CI 4.8–6.8) compared with other patients (11.7, 95% CI 9.4–14.0). Combined low SMM and low TATI remained an independent predictor of OS (HR 1.56, 95% CI 1.15–2.11, p = 0.004) after adjusting for known prognostic factors. There was no association between body composition and sorafenib toxicity. Conclusions: In Dutch HCC patients treated with sorafenib, the combined presence of low SMM and low TATI was associated with impaired survival, independent of known prognostic factors. CT assessment of body composition may provide additional prognostic information prior to sorafenib treatment.

Usefulness of the MESH score in a European hepatocellular carcinoma cohort.

The Barcelona Clinic Liver Cancer classification is the most widely - used hepatocellular carcinoma (HCC) staging system because it is simple, precise and linked to a treatment algorithm based on randomized studies. But each group includes a broad spectrum of tumors, with limited therapeutic options, particularly for intermediate and advanced stages. Consequently, different additional scoring systems have been proposed to refine the prognosis and/or to improve the management. But until now, there is no consensus. Liu et al proposes a new scoring system, based on a large HCC cohort, with patients at different stages, treated using diverse modalities. This score includes six parameters used in current practice. It is simple to calculate, reliable, with an ability to predict survival superior to other systems, which also works with our European HCC cohort. The MESH score may be especially useful to differentiate subgroups with different prognosis for each treatment modality.

Etiologic influence on chromosomal aberrations in European hepatocellular carcinoma identified by CGH

Previous studies suggest different pathways in the molecular development of hepatocellular carcinoma (HCC). We investigated the pattern of chromosomal imbalances in HCC depending on the type of underlying liver disease as detected by comparative genomic hybridization in 67 cases of primary HCC occurring in non-cirrhotic livers (n=30), in liver cirrhosis (LC) related to alcohol intake (n=9), cryptogenic or metabolic changes (n=11), and chronic viral hepatitis B or C (n=17). HCC were treated by liver resection in 48 patients and transplantation in 19 patients. The 10-year disease-free and overall survival rates were 51% and 68%, respectively. The copy number changes occurring in more than 10% of cases were gains at 8q (55%), 1q (49%), 7q (15%), 7p (13%), 6p (12%), and 20q (12%), as well as losses at 8p (55%), 4q (33%), 6q (33%), 13q (25%), 14q (24%), 17p (22%), 16q (19%), 1p (18%), 18q (16%), 9p (13%), 10q (13%), 4p (12%), and 9q (12%). HCC arising in alcoholic LC showed a different pattern with significantly fewer net changes (p=0.008), particularly fewer chromosomal gains (p=0.008) and fewer breakpoints (p=0.003) compared to the other investigated HCC subgroups. Future clinical studies should evaluate the prognostic relevance of these findings.

744P - Early Data from a Phase I Study of Nintedanib (BIBF 1120) in Asian Patients with advanced Hepatocellular Carcinoma

ABSTRACT Background Nintedanib is an oral, triple angiokinase inhibitor targeting VEGFRs, PDGFRs and FGFRs. This multicentre, open-label, phase I/randomised phase II study (NCT00987935; phase II ongoing) evaluated the efficacy, safety and pharmacokinetics of nintedanib versus sorafenib in patients (pts) with advanced hepatocellular carcinoma (HCC) from Asia, where HCC is endemic and has unique clinical features. Phase I data are presented. Methods Phase I pts had histologically, cytologically or clinically confirmed HCC, ECOG performance status ≤2, Child-Pugh (CP) score ≤7, and ≤1 line of prior systemic therapy. Using a 3 + 3 design, pts were stratified into two groups by liver function and CP score: (I) AST and ALT ≤2 x upper limit of normal (ULN), and CP 5–6; (II) AST or ALT >2 x to ≤5 x ULN, or CP 7. Nintedanib (given continuously in 28-day courses) was started at 50mg bid (group II) or 100mg bid (group I) and increased in 50mg bid increments up to 200mg bid. Therapy was continued until no clinical benefit or undue toxicity. The phase I primary endpoint was the maximum-tolerated dose (MTD) of nintedanib. Results Overall, 35 pts have received nintedanib: 11 in group I(100/150/200 mg bid, n = 4/3/4; median [range] duration: 140 [10–337] days) and 24 in group II (50/100/150/200 mg bid, n = 3/7/3/11; median [range] duration: 81 [2–587] days). In group I, no dose-limiting toxicities (DLTs) were seen at any dose during the first course. In group II, one pt experienced a DLT (CTCAE Grade [G] 3 AST increase) at 100 mg bid in Course 1 (dose-escalation phase). The MTD of nintedanib was thus 200 mg bid in both groups. DLTs seen after MTD assessment were G4 gastrointestinal (GI) haemorrhage/anaemia (50 mg bid), G3 ALT increase (150 mg bid), G3 GI haemorrhage (150 mg bid), G3 hypertension (200 mg bid; n = 2) and G4 gastric ulcer (200 mg bid). The most common adverse events, by system organ class, were GI (83%) and general/administration site disorders (51%), and investigations (51%). Hypertension and rash (any grade) occurred in 6 and 8 pts, respectively. Conclusions Nintedanib has an acceptable safety profile in this Asian HCC population. As in other cancer types and European HCC pts, the MTD of nintedanib was 200 mg bid. Disclosure C. Yen: Chia-Jui Yen: research funding from Boehringer Ingelheim. Y. Shen: Ying-Chun Shen: research funding from Boehringer Ingelheim. H. Shiah: Her-Shyong Shiah: research funding from Boehringer Ingelheim. J. Chen: Jo-Pai Chen: research funding from Boehringer Ingelheim. C. Hsu: Chiun Hsu: research funding from Boehringer Ingelheim. C. Hsu: Chih-Hung Hsu: research funding from Boehringer Ingelheim. D.C. Huang: Dennis Chin-Lun Huang: employee of Boehringer Ingelheim. J. Hocke: Julia Hocke: employee of Boehringer Ingelheim. W. Su: Wu-Chou Su: research funding from Boehringer Ingelheim. A. Cheng: Ann-Lii Cheng: research funding from Boehringer Ingelheim.

Absence of epstein–barr virus DNA in the tumor cells of european hepatocellular carcinoma

The Epstein–Barr virus (EBV) has recently been associated with hepatocellular carcinoma (HCC) arising in Japanese patients. We analyzed 82 cases of HCC from Germany and the U.K. for the presence of EBV DNA and viral gene products within tumor cells. Initial screening of whole sections using quantitative (Q)-PCR detected EBV DNA in 9/58 U.K. cases and in 9/24 German cases; in positive cases viral load was very low, ranging between 1.4 and 49.1 copies of the EBV genome/1000 cell equivalents, compared to much higher values for EBV-positive Hodgkin’s disease and nasopharyngeal carcinoma controls (range, 714–3259/1000 cells). EBV DNA was not detected in the tumor cells of any of the Q-PCR-positive cases either by Q-PCR of pure tumor cell populations isolated by laser capture microdissection or by isotopic in situ hybridization. Furthermore, none of the German or U.K. HCC tumors tested positive for EBER or EBNAI expression in tumor cells. Our results provide strong evidence that HCCs from the U.K. or Germany are not associated with EBV.

Loss of CD95 expression is linked to most but not all p53 mutants in European hepatocellular carcinoma.

Experimental data have shown p53-dependent CD95 induction to be associated with increased levels of apoptosis after cytostatic treatment in hepatoma cells. A study of Japanese hepatocellular carcinoma (HCC) has reported an inverse correlation between CD95 and p53 expression. To examine the interaction of p53 and CD95 in tumors we investigated which alterations in p53 can be linked to loss of CD95 expression in European HCC. In 39 tumors we analyzed CD95 by immunohistochemistry and assessed the correlation between the findings of the p53 status as determined by immunohistochemistry and single-strand conformation polymorphism with polymerase chain reaction sequencing. In 10 of 14 tumors with evidence of p53 aberration there was also loss of CD95 expression, compared to 6 of 25 samples with apparent wild-type p53 (P<0.01). Three tumors with p53 mutations but sustained CD95 expression showed single base substitutions mapping to a narrow region of 20 codons in p53. A significant correlation with differentiation status of the tumor was found for the p53 aberration but not for CD95 expression. This is the first study to link loss of CD95 expression to specific p53 alterations in HCC. Functional p53 appears to be a major factor for CD95 expression in hepatocytes, the loss of which could contribute to chemoresistance and possibly immune evasion in hepatocellular carcinoma. Sustained CD95 expression in tumors with certain p53 aberrations may indicate functional heterogeneity of p53 mutants.

P53 mutations in British patients with hepatocellular carcinoma: Clustering in genetic hemochromatosis

Background & Aims: Environmental factors are important in the etiology of hepatocellular carcinoma (HCC). Aflatoxin B1 causes a specific point mutation in the p53 tumor-suppressor gene in exposed individuals. In Western populations, mutations of this gene seem to be less frequent. We have investigated the role of p53 mutations in tumorigenesis in British patients with HCC. The aim of this study was to determine the frequency and mutational spectrum of the p53 gene in HCCs from British patients. Methods: DNA from 170 HCCs, of well-defined etiology, in British patients was analyzed by single-stranded conformational polymorphism using the polymerase chain reaction technique. Mutations were then characterized by direct sequencing. Results: Twenty-nine percent of tumors had p53 mutations. Ten of 14 (71%) hemochromatotic cancers had mutations within the p53 gene, and clustering of these mutations at codon 220 (A-G) was found in 5 cases; 3 others had T-A mutations. No clustering was found in HCCs with other etiologies. Conclusions: p53 mutations are more common than was thought in Northern European HCCs. This is the first demonstration of p53 mutational clustering in HCCs from hemochromatotic subjects. GASTROENTEROLOGY 1999;117:154-160

Clinical significance of circulating anti-p53 antibodies in European patients with hepatocellular carcinoma.

p53 alterations are considered to be predictive of poor prognosis in hepatocellular carcinoma (HCC) and may induce a humoral response. Anti-p53 serum antibodies were assessed by enzyme-linked immunosorbent assay (ELISA) using purified recombinant human p53 on 130 European HCC patients before treatment and during the clinical course of the disease. p53 immunohistochemistry was performed on tumours from the 52 patients who underwent surgery, and DNA sequencing analysis was initiated when circulating anti-p53 antibodies were detected. Nine (7%) HCC patients had anti-p53 serum antibodies before treatment. During a mean period of 30 months of follow-up, all the negative patients remained negative, even when recurrence was observed. Of the nine positive patients, eight were still positive 12–30 months after surgery. The presence of anti-p53 serum antibodies was correlated neither with mutation of the p53 gene nor the serum alpha-fetoprotein levels and clinicopathological characterics of the tumours. However, a greater incidence of vascular invasion and accumulation of p53 protein were observed in the tumours of these patients (P < 0.03 and P < 0.01 respectively) as well as a better survival rate without recurrence (P = 0.05). In conclusion, as was recently shown in pancreatic cancer, anti-p53 serum antibodies may constitute a marker of relative ‘good prognosis’ in a subgroup of patients exhibiting one or several markers traditionally thought to be of bad prognosis. © 1999 Cancer Research Campaign

Microsatellite instability in European hepatocellular carcinoma.

Genetic instability has been detected in many types of cancers but poorly investigated in hepatocellular carcinoma (HCC). We have studied the incidence of microsatellite instability (MI) at eight highly polymorphic microsatellite markers and the poly A tract BAT26 and tested for mutations at two sites of repetitive sequence (poly-A nucleotides 709-718 and GT repeat-nucleotides 1931-1936) in the Transforming Growth Factor beta (TGFbeta) type II receptor (RII) gene, in a group of 46 European HCCs and the surrounding nontumour tissue. This analysis showed that 63% of HCCs exhibit MI in at least one chromosome locus and 41% in two or more loci. No mutations of the TGFbetaRII gene were found in the MI positive tumours. No correlation was found with clinicopathological characteristics of the tumours such as cirrhosis, etiology, number of nodules, Edmondson's grade and vascular invasion. However, in patients who had a rearranged D16S402 microsatellite in their tumour, the recurrent disease and the number of nodules were significantly higher than in the others (P<0.005 and P<0.02, respectively). We propose to consider D16S402 rearrangement in HCC as a prognostic factor to identify patients presenting a higher risk of recurrence.

P53 protein accumulation in European hepatocellular carcinoma is not always dependent on p53 gene mutation

Background/Aims : Immunohistochemical reactivity for p53 protein is common in various human malignancies and often related to p53 gene mutation. However, in some tumor types, accumulation of wild-type p53 has been shown. Previously, we analyzed 96 European hepatocellular carcinomas using immunohistochemistry and found that 31% of these tumors overexpressed p53 in the cell nucleus. The aim of the present study was to establish whether p53 positivity correlates with the presence of structural p53 gene abnormalities in European hepatocellular carcinoma. Methods : DNA from 20 tumors, 10 with strong immunostaining and 10 with undetectable staining for p53, was extracted from frozen sections, and the entire coding portion of the p53 gene was sequenced. Results : Five of the 10 tumors containing high levels of p53 protein showed missense point mutations. The remaining 5 tumors with high p53 levels showed the wild-type coding sequence. One of the 10 tumors containing undetectable levels of p53 protein had a 1-base pair deletion in the splice acceptor site of intron 4. Conclusions : The results strongly suggest that, in European hepatocellular carcinomas, stabilization of the p53 protein depends on factors other than p53 gene mutation, such as binding to other molecules of cellular or viral origin.

Differences in the hepatitis C virus genotypes in different countries

We recently classified the hepatitis C virus (HCV) into 4 types (HCV-PT, -K1, -K2a and -K2b) according to differences in nucleotide sequences. It was found that HCV-PT, the prototype reported from the U.S.A., was rare in Japan, suggesting that distribution of HCV genotypes may be different in various countries. The prevalence of HCV genotypes was therefore compared in different countries. Genotyping of HCV was performed by slot-blot hybridization analysis using cDNA probes specific to each type of HCV or by restriction fragment length polymorphism analysis. In 121 Japanese non-cancer patients, the prevalence of HCV genotypes was 77.7% for HCV-K1, 16.5% for HCV-K2a and 5.0% for HCV-K2b. HCV-PT was detected in only 1 patient (0.8%). The prevalence in 43 Japanese hepatocellular carcinoma (HCC) patients was 74.4% for HCV-K1, 18.6% for HCV-K2a and 4.7% for HCV-K2b. HCV-PT was found in only 1 sample. In 19 European non-cancer patients, HCV-PT was found in 42.1% and HCV-K1 was found in 52.6%. HCV-K2 was not found. All 7 samples from European HCC patients were HCV-K1, indicating a significantly higher prevalence than in non-cancer patients. In 13 Brazilian non-cancer patients, the distribution pattern was similar to that of the Europeans. In 10 samples from the U.S.A., HCV-PT was found in 70% and HCV-K2 was found in 1 sample. In 18 Chinese non-cancer patients, HCV-K1 was found in 44.4%, HCV-K2a in 50.0% and HCV-K2b in 5.6% HCV-PT was not found. Two samples from Chinese HCC patients were HCV-K1.(ABSTRACT TRUNCATED AT 250 WORDS)