Toshimasa Okada

Analysis of DNA copy number aberrations in hepatitis C virus-associated hepatocellular carcinomas by conventional CGH and array CGH

To clarify the genetic aberrations involved in the development and progression of hepatitis C virus-associated hepatocellular carcinoma (HCV-HCC), we investigated DNA copy number aberrations (DCNAs) in 19 surgically resected HCCs by conventional CGH and array CGH. Conventional CGH revealed that increases of DNA copy number were frequent at 1q (79% of the cases), 8q (37%), 6p (32%), and 10p (32%) and that decreases were frequent at 17p (79%), 16q (58%), 4q (53%), 13q (42%), 10q (37%), 1p (32%), and 8p (32%). In general, genes that showed DCNAs by array CGH were usually located in chromosomal regions with DCNAs detected by conventional CGH analysis. Increases in copy numbers of the LAMC2, TGFB2, and AKT3 genes (located on 1q) and decreases in copy numbers of FGR/SRC2 and CYLD (located on 1p and 16q, respectively) were observed in more than 30% of tumors, including small, well-differentiated carcinomas. These findings suggest that these genes are associated with the development of HCV-HCC. Increases of MOS, MYC, EXT1, and PTK2 (located on 8q) were detected exclusively in moderately and poorly differentiated tumors, suggesting that these alterations contribute to tumor progression. In conclusion, chromosomal and array CGH technologies allow identification of genes involved in the development and progression of HCV-HCC.

Differential gene expression in distinct virologic types of hepatocellular carcinoma: association with liver cirrhosis

Using oligonucleotide microarray data of 45 hepatocellular carcinoma (HCC) samples, we evaluated gene expression in hepatitis B virus-positive and hepatitis C virus-positive HCCs (HBV- and HCV-HCCs) for an association with liver cirrhosis (LC). In all, 89 genes were expressed differentially between HBV-HCCs associated with LC and those not associated with LC. Among them, tumors from LC patients showed significantly lower expression levels of 72 genes and significantly higher levels of 17 genes than the levels found in tumors from non-LC patients. The former included genes responsible for signal transduction, transcription, metabolism, and cell growth. The latter included a tumor suppressor gene and a cell-growth-related gene. Only eight genes were expressed differentially between HCV-HCCs associated with and without LC. Our findings provide as a framework for clarifying the role of LC in HBV- and HCV-related hepatocarcinogenesis.

Gene expression profile linked to p53 status in hepatitis C virus‐related hepatocellular carcinoma

To clarify the role of p53 in 22 hepatitis C virus (HCV)‐infected hepatocellular carcinomas (HCCs), we compared the gene expression profiles of HCCs with wild‐type p53 (wt‐p53) (n=17) and those with mutant‐type p53 (mt‐p53) (n=5) by oligonucleotide microarray analysis. Among 83 p53‐related genes identified by a supervised learning method, 25 were underexpressed, and 58 were overexpressed in mt‐p53 HCCs compared with wt‐p53 HCCs. With a computer search, we identified consensus p53‐binding sequences in the 3‐kb region upstream of the translation initiation site in 59 of the 83 genes, suggesting that the in vivo p53‐associated transcription system is very complicated. These data will provide additional insights into p53‐related pathogenesis in HCV‐infected HCC.

Self-organizing-map-based molecular signature representing the development of hepatocellular carcinoma

Using high‐density oligonucleotide array, we comprehensively analyzed expression levels of 12 600 genes in 50 hepatocellular carcinoma (HCC) samples with positive hepatitis C virus (HCV) serology (well (G1), moderately (G2), and poorly (G3) differentiated tumors) and 11 non‐tumorous livers (L1 and L0) with and without HCV infection. We searched for discriminatory genes of transition (L0 vs. L1, L1 vs. G1, G1 vs. G2, G2 vs. G3) with a supervised learning method, and then arranged the samples by self‐organizing map (SOM) with the discriminatory gene sets. The SOM arranged the five clusters on a unique sigmoidal curve in the order L0, L1, G1, G2, and G3. The sample arrangement reproduced development‐related features of HCC such as p53 abnormality. Strikingly, G2 tumors without venous invasion were located closer to the G1 cluster, and most G2 tumors with venous invasion were located closer to the G3 cluster (P = 0.001 by Fishers exact test). Our present profiling data will serve as a framework to understand the relation between the development and dedifferentiation of HCC.

Involvement of c-myc-regulated genes in hepatocellular carcinoma related to genotype-C hepatitis B virus

Purpose: The purpose of this study was to elucidate the molecular basis of hepatocellular carcinoma (HCC) caused by genotype-C hepatitis B virus (HBV). Methods: We compared molecular profiles of 15 HCCs and five non-tumorous livers, all of which were associated with genotype-C HBV infection, using DNA microarray technology. Results: Our supervised learning identified 237 genes whose expression differed between HCCs and non-tumorous livers. This result was validated by a false discovery rate of 0%. Levels of expression of 35 and 202 genes were higher and lower, respectively, in HCCs than in non-tumorous livers. Among the 237 genes, we highlighted the top 35 upregulated and top 35 downregulated genes in tumor. Interestingly, when overlapping genes were excluded, 12 (e.g., NM23-H2, MCM7, PARP1, YWHAH, HSPB1, and MSH2) of the top 34 upregulated genes and five (e.g., MT1A and MT3) of the top 33 downregulated genes were c-myc-regulated genes. The microarray data for five randomly selected genes (MCM7, UBE2L3, PPIA, CXCL12, and ASS) were confirmed by quantitative real-time reverse transcription-polymerase chain reaction. Conclusions: Our results indicate that many c-myc-regulated genes are involved in genotype-C-HBV-related HCC, suggesting that c-myc is related to the hepatocarcinogenic activity of genotype-C HBV.

The Risk Factors and Measures of Postoperative Infection in Liver Surgery

はじめに: CDCガイドラインで示された危険因子と周術期培養の結果より肝切除時の術後感染症を検討した. 対象と方法: 2003年1月から2005年6月までの間の肝切除症例80例を対象とした. 術前の鼻汁, 胃液培養, 術後第1 病日の喀痰, 胆汁, 腹水培養を施行した. 術後感染症の発症の有無とその危険因子について検討した. 結果: 鼻汁, 胃液, 喀痰, 胆汁, 腹水培養から, それぞれ感染性細菌が27%, 59%, 52%, 19%, 5% 検出された. 術後感染症は19%(15/80例) に発症した. 術後感染症起因菌の73%(11/15例) は周術期培養検出菌と同一であった. 鼻汁, 胃液, 喀痰, 胆汁もしくは腹水の保菌と術後感染症との関係を単変量解析したところ喀痰, 胆汁, 腹水の保菌が有意な危険因子であった (p<0.05). 年齢, 性別, 耐糖能異常, 肥満, 肝機能, 肝線維化, 術中出血量, 手術時間, 術式, 保菌 (喀痰, 胆汁, もしくは腹水) を用い術後感染症の危険因子を多変量解析したところ性別, 耐糖能異常, 肝線維化, 手術時間, 保菌が有意な危険因子であった (p<0.05). 考察: 肝硬変を有する肝切除症例は感染性細菌を高率に保菌し, 術後感染症のハイリスクグループである. また, 周術期の喀痰, 胆汁, 腹水の保菌は術後感染症の危険因子であり, その情報は適切な術後感染治療薬の選択に有用である.