Takafumi Nishimura

Aberrant Methylation of Multiple Tumor Suppressor Genes in Aging Liver, Chronic Hepatitis, and Hepatocellular Carcinoma

Aberrant DNA methylation is an important epigenetic alteration in hepatocellular carcinoma (HCC). However, the molecular processes underlying the methylator phenotype and the contribution of hepatitis viruses are poorly understood. The current study is a comprehensive methylation analysis of human liver tissue specimens. A total of 176 liver tissues, including 77 pairs of HCCs and matching noncancerous liver and 22 normal livers, were analyzed for methylation. Methylation of 19 epigenetic markers was quantified, and the results were correlated with different disease states and the presence or absence of hepatitis B virus (HBV) and hepatitis C virus (HCV) infections. Based on methylation profiles, the 19 loci were categorized into 3 groups. Normal liver tissues showed methylation primarily in group 1 loci (HIC‐1, CASP8, GSTP1, SOCS1, RASSF1A, p16, APC), which was significantly higher than group 2 (CDH1, RUNX3, RIZ1, SFRP2, MINT31) and group 3 markers (COX2, MINT1, CACNA1G, RASSF2, MINT2, Reprimo, DCC) (P < 0.0001). Noncancerous livers demonstrated increased methylation in both group 1 and group 2 loci. Methylation was significantly more abundant in HCV‐positive livers compared with normal liver tissues. Conversely, HCC showed frequent methylation at each locus investigated in all 3 groups. However, the group 3 loci showed more dense and frequent methylation in HCV‐positive cancers compared with both HBV‐positive cancers and virus‐negative cancers (P < 0.0001). Conclusion: Methylation in HCC is frequent but occurs in a gene‐specific and disease‐specific manner. Methylation profiling allowed us to determine that aberrant methylation is commonly present in normal aging livers, and sequentially progresses with advancing stages of chronic viral infection. Finally, our data provide evidence that HCV infection may accelerate the methylation process and suggests a continuum of increasing methylation with persistent viral infection and carcinogenesis in the liver. (HEPATOLOGY 2008.)

Disruption of the p16/Cyclin D1/Retinoblastoma Protein Pathway in the Majority of Human Hepatocellular Carcinomas

p16, cyclin D1 and retinoblastoma protein (pRB) regulate G1 to S transition and are commonly targeted in various cancers. However, few studies have simultaneously examined all components of the p16/cyclin D1/pRB pathway (RB pathway) in hepatocellular carcinoma (HCC). To clarify the role of the disruption of the RB pathway in HCC, we analyzed p16, pRB and cyclin D1 in 47 HCCs. Inactivation of p16 was detected in 30 of 47 HCCs (64%) by Western blot analysis and significantly correlated with hypermethylation of the promoter of this gene. pRB expression was found to be absent in 13 of 47 HCCs (28%) by immunohistochemistry. We found that 38 of 47 HCCs (81%) contained at least one inactivation in either pRB or p16. Furthermore, there was a significant inverse correlation between p16 and pRB inactivation (p = 0.041). Overexpression of cyclin D1 was detected in 5 of 47 HCCs (11%) by immunohistochemistry. The cases with cyclin D1 overexpression exhibited an advanced clinicopathological appearance and also contained inactivation of pRB and/or p16. These findings suggest that inactivation of pRB and/or p16 is a major event in human hepatocarcinogenesis, while cyclin D1 overexpression may confer additional growth advantages to the tumor in addition to pRB and/or p16 inactivation in HCC.

UGT1A1*6 polymorphism is most predictive of severe neutropenia induced by irinotecan in Japanese cancer patients

BackgroundGene polymorphisms of the UDP-glucuronosyltransferase 1 family, polypeptide A1 (UGT1A1) contribute to individual variations in adverse events among patients administered irinotecan, and the distribution of the polymorphisms shows large interethnic differences. Variation in the solute carrier organic anion-transporter family, member 1B1 (SLCO1B1) gene also has a significant effect on the disposition of irinotecan in Asian cancer patients. In the present study, we evaluated the association of genetic polymorphisms of UGT1A1 and SLCO1B1 with irinotecanrelated neutropenia in Japanese cancer patients.MethodsOne hundred and thirty-five consecutive patients treated with irinotecan were enrolled. Genotypes of UGT1A1 (*60, *28, *6, and *27) and SLCO1B1 (*1b, *5, and haplotype *15) were determined by direct sequencing. Severe neutropenia refers to events observed during the first cycle of irinotecan treatment.ResultsSevere neutropenia was observed in 29 patients (22%). Six patients were homozygous and 48 heterozygous for UGT1A1*6. Only 1 patient was homozygous for UGT1A1*28. Homozygosity for UGT1A1*6 was associated with a high risk of severe neutropenia (odds ratio [OR], 7.78; 95% confidence interval [CI], 1.36 to 44.51). No significant association was found between severe neutropenia and other UGT1A1 polymorphisms or SLCO1B1 polymorphisms.ConclusionThese findings suggest that the UGT1A1*6 polymorphism is a potential predictor of severe neutropenia caused by irinotecan in Japanese cancer patients.

Neutrophil-to-lymphocyte ratio for predicting palliative chemotherapy outcomes in advanced pancreatic cancer patients

Several previous studies reported that the neutrophil‐to‐lymphocyte ratio (NLR) could be a promising prognostic factor for patients with cancer. We aimed to determine the prognostic value of NLR in patients with advanced pancreatic cancer (APC) following palliative chemotherapy. We retrospectively reviewed 252 consecutive APC patients receiving palliative chemotherapy between January 2006 and December 2012. We classified the patients according to the pretreatment NLR values (≤5 or >5) into two groups and investigated the difference in treatment outcomes, including time to treatment failure (TTF) and overall survival (OS). A total of 212 patients had pretreatment NLR values of ≤5 (group A), while 40 patients had an NLR of >5 (group B). TTF and OS were significantly shorter in group B than in group A (3.1 vs. 8.7 months and 6.0 vs. 12.8 months, respectively; both P < 0.01). After adjustment for putative prognostic factors, including distant metastasis, status of recurrent/unresectable disease, pretreatment carbohydrate antigen 19‐9 levels, and carcinoembryonic antigen levels using the Cox regression model, elevated pretreatment NLR remained an independent poor prognostic factor for OS (hazard ratio, 1.92; 95% confidence interval, 1.27–2.90; P < 0.01). In addition, patients in group B whose NLR dropped to ≤5 before the second cycle of chemotherapy showed longer TTF and OS compared with those whose NLR remained at >5. Our results support the idea that NLR can be a promising prognostic and predictive marker for APC patients receiving palliative chemotherapy.

Comprehensive allelotyping of well-differentiated human hepatocellular carcinoma with semiquantitative determination of chromosomal gain or loss.

Allelic imbalance (AI), which represents certain chromosomal gains or losses, has been described in human hepatocellular carcinoma (HCC), but the impact of AI on the early stage of hepatocarcinogenesis has not been fully clarified. Moreover, no previous allelotype studies have identified the difference in chromosomal gain and loss that results in AI. To resolve these problems, we examined 18 well‐differentiated HCCs with comprehensive allelotyping by using 400 microsatellite markers with semiquantitative assessment of chromosomal gain or loss. To detect allelic gain effectively, the cutoff value of the allelic imbalance index was set at 0.70. Each allele showing imbalance was subjected to multiplex PCR with use of a retained allele as an internal control to determine whether the imbalance was the result of chromosomal gain or loss. High frequencies of chromosomal gains were detected at 1q (D1S196‐D1S2785, 56%), 5q (D5S647‐D5S2027, 44%), 6p (6pter‐D6S309, 33%), 7 (7pter‐D7S657, 22%), and 8q (D8S514‐qter, 44%), whereas chromosomal losses were frequently observed at 1p (1pter‐D1S234, 22%), 8p (8pter‐D8S549, 44%), and 17p (17pter‐D17S921, 28%). The extent of overall chromosomal aberration was closely related to the maximum tumor diameter (P = 0.002) and the presence of hepatitis B surface antigen (P = 0.03). Recurrent chromosomal losses at 1p and 8p and gains at 1q and 8q, even in HCCs with a minimal extent of aberrant chromosomes, indicate that these alterations were critical in the early stage of hepatocarcinogenesis. On the other hand, deletions of 13q and 16q were infrequent and were seen only in the most aberrant cases, which suggested that these were late events.

Prognostic Impact of Multiple Allelic Losses on Metastatic Recurrence in Hepatocellular Carcinoma after Curative Resection

Loss of heterozygosity (LOH) on chromosomes 13q, 16q and 17p has been associated with the progression of hepatocellular carcinoma (HCC). To investigate the prognostic impact of such LOH, we examined the metastasis-free survival of curatively resected HCC cases, in whom these LOHs were analyzed. Among the 49 HCC patients examined, the frequency of LOHs was 28% on 13q, 33% on 16q and 40% on 17p. The patients were followed up for metastatic recurrence after surgery and for analysis of the relationship between chromosomal changes and patients’ metastasis-free survival. Univariate survival analysis showed the presence of LOH on 16q, 17p and the number of chromosomes with LOH were significantly and negatively associated with metastasis-free survival, indicating that patients with LOH on multiple chromosomes had a poorer prognosis after surgery than those with LOH on a single chromosome or no LOH. Multivariate Cox survival analysis identified the presence of LOH on 16q and the number of chromosomes with LOH as the most significant independent negatively predictive factors for metastasis-free survival. These findings indicate that accumulation of chromosomal changes is associated with metastatic behavior, and that LOH on 16q was the most useful prognostic indicator for metastasis after curative resection of HCC.

Postoperative detection of α-fetoprotein mRNA in blood as a predictor for metastatic recurrence of hepatocellular carcinoma

Background: We tested for the presence of α‐fetoprotein (AFP) mRNA by using nested RT‐PCR in the peripheral blood of hepatocellular carcinoma (HCC) patients who had undergone curative surgery, and investigated the occurrence of intrahepatic and/or extrahepatic metastasis thereafter, to reveal the optimal timing of blood sampling for the prediction of metastatic recurrence.

Associations between glutathione S-transferase π Ile105Val and glyoxylate aminotransferase Pro11Leu and Ile340Met polymorphisms and early-onset oxaliplatin-induced neuropathy

PURPOSE Although the risk of oxaliplatin-induced neuropathy depends on cumulative oxaliplatin dose, susceptibility to this adverse event differs greatly among patients. In this study, we investigated the associations between oxaliplatin-induced neuropathy and the following polymorphisms: glutathione S-transferase pi (GSTP1) Ile(105)Val, and glyoxylate aminotransferase (AGXT) Pro(11)Leu and AGXT Ile(340)Met. EXPERIMENTAL DESIGN Eighty-two Japanese patients with histologically confirmed colorectal cancer who received at least six cycles of the modified FOLFOX6 (m-FOLFOX6) regimen were enrolled. To minimize differences in cumulative oxaliplatin dose between patients, oxaliplatin-induced neuropathy was evaluated using an oxaliplatin-specific scale during the 2-week period after completion of the sixth cycle of treatment. RESULTS Forty-four patients developed grade 2/3 oxaliplatin-induced neuropathy. There were more patients carrying at least one GSTP1(105)Val allele among the group with grade 2/3 neuropathy (18/44, 41%) than among the group with grade 1 neuropathy (9/38, 24%), although the difference was not statistically significant (P=0.098). There were similar numbers of patients carrying at least one AGXT(105)Met allele in the grade 2/3 neuropathy (7/44, 16%) and grade 1 neuropathy groups (5/38, 13%; P=0.725). The AGXT(11)Leu allele was not found in any of our patients or controls. CONCLUSIONS We found no significant association between oxaliplatin-induced neuropathy and the GSTP1 Ile(105)Val and AGXT Ile(340)Met polymorphisms. Given that no AGXT(11)Leu allele was found among our study population (n=177), evaluating this polymorphism in Japanese patients in future studies is likely to be uninformative.

Discrete breakpoint mapping and shortest region of overlap of chromosome arm 1q gain and 1p loss in human hepatocellular carcinoma detected by semiquantitative microsatellite analysis.

Recurrent chromosomal gain at 1q is one of the most common features of human hepatocellular carcinoma (HCC), but how the gain at 1q contributes to hepatocarcinogenesis is still unclear. To identify the target genes, precise determination of the shortest region of overlap (SRO) and of breakpoints is necessary. Similarly, the role of loss at 1p, which is also a major cytogenetic aberration in HCC, needs to be determined. Fifty HCCs were examined with the aid of 59 microsatellite markers distributed throughout both arms of chromosome 1. To detect allelic gain effectively, the cutoff value of the allelic imbalance index was set at 0.70. Alleles showing imbalance were subjected to multiplex PCR, using a retained allele as an internal control, to determine whether the imbalance was the result of chromosomal gain or loss. The SRO of the gains was defined as D1S2878–D1S2619 (1q23.–q25.3, 16.9 Mb), which involved 36 cases (72%). Gains in the number of copies of certain oncogenes within this region seemed to be critical for the pathogenesis of HCC. In contrast, the centromeric breakpoints of these gains varied, but they tended to occur mainly in the pericentromeric region (26 of 50 cases, 52%). Rearrangement of specific genes associated with the gains is unlikely. On the other hand, the SRO of deletion was defined as D1S2893–D1S450 (1p36.32–p36.22, 5.1 Mb). Four known putative tumor‐suppressor genes (TP73, RIZ1, NBL1/DAN, and CDKN2C) were outside the SRO, suggesting the presence of other candidate genes with critical roles in hepatocarcinogenesis.

Unique Association between Global DNA Hypomethylation and Chromosomal Alterations in Human Hepatocellular Carcinoma

Global DNA hypomethylation is a characteristic feature of cancer cells that closely associates with chromosomal instability (CIN). However, the association between these characteristics during hepatocarcinogenesis remains unclear. Herein, we determined the relationship between hypomethylation and CIN in human hepatocellular carcinoma (HCC) by analyzing 179 HCCs, 178 matched non-tumor livers and 23 normal liver tissues. Hypomethylation at three different repetitive DNA (rDNA) sequences and hypermethylation of 12 CpG loci, including 11 tumor suppressor gene (TSG) promoters, were quantified using MethyLight or combined bisulfite restriction analysis. Fractional allelic loss (FAL) was used as a marker for CIN, calculated by analyzing 400 microsatellite markers. Gains and losses at each chromosome were also determined using semi-quantitative microsatellite analysis. The associations between rDNA hypomethylation and FAL, as well as between TSG hypermethylation and FAL were investigated. Significantly more hypomethylation was observed in HCC tissues than in normal liver samples. Progression of hypomethylation during carcinogenesis was more prominent in hepatitis C virus (HCV)-negative cases, which was in contrast to our previous reports of significantly increased TSG methylation levels in HCV-positive tumors. Absence of liver cirrhosis and higher FAL scores were identified as independent contributors to significant hypomethylation of rDNA in HCC. Among the chromosomal alterations frequently observed in HCC, loss of 8p, which was unique in the earliest stages of hepatocarcinogenesis, was significantly associated with hypomethylation of rDNA by multivariable analysis (p = 0.0153). rDNA hypomethylation was also associated with a high FAL score regardless of tumor differentiation (p = 0.0011, well-differentiated; p = 0.0089, moderately/poorly-differentiated HCCs). We conclude that DNA hypomethylation is an important cause of CIN in the earliest step of HCC, especially in a background of non-cirrhotic liver.