title: Potential role of Helicobacter pylori in hepatocarcinogenesis.
abstract: Helicobacter species can induce carcinoma in the liver of certain mice. Furthermore, Helicobacter pylori (H. pylori) exhibits hepatotoxicity in vitro. These reports indicate that H. pylori may play a role in hepatocarcinogenesis. The aim of this study was to assess the presence of H. pylori in human hepatocellular carcinoma (HCC) to determine if H. pylori may affect the development of this disease. Liver specimens from 15 HCC patients dissected into tumor and non-tumor tissues were examined for H. pylori by PCR using two sets of primers for 16S rRNA and urease B. DNA sequencing analysis was performed to confirm that PCR products with 16S rRNA primers were derived from H. pylori DNA. The specimens were also examined for H. pylori by immunohistochemistry using anti-H. pylori antibody. H. pylori was found in 13 of 15 tumor tissues, not in the non-tumor tissues. By contrast, Escherichia coli and Bacteroides fragilis, frequent colonizers of gut, were not detected by PCR in the HCC tumors. Ten cirrhotic liver tissue specimens and seven normal liver tissue specimens were also negative for H. pylori DNA by PCR. The nucleotide sequence of the amplified fragment shared 100% identity with the 16S rRNA gene of H. pylori. H. pylori was also detected in HCC tissue by immunohistochemical analysis. The presence of H. pylori in human HCC tissue was demonstrated by PCR and immunohistochemical analysis. These findings suggest that H. pylori might contribute to the development of HCC. Further study is needed to prove the pathogenetic role of H. pylori in the development of human HCC.
authors.affiliation: Division of Gastroenterology and Hepatology, Department of Internal Medicine, The Jikei University School of Medicine, Minato-ku, Tokyo 105-8461, Japan.
authors.forename: Kyoko
authors.initials: K
authors.lastname: Ito
authors.forename: Mariko
authors.initials: M
authors.lastname: Nakamura
authors.forename: Gotaro
authors.initials: G
authors.lastname: Toda
authors.forename: Michiko
authors.initials: M
authors.lastname: Negishi
authors.forename: Akira
authors.initials: A
authors.lastname: Torii
authors.forename: Tsuneya
authors.initials: T
authors.lastname: Ohno
mesh_terms: D004587:Electrophoresis, Agar Gel; D016481:Helicobacter Infections / Q000378:metabolism*; D016480:Helicobacter pylori / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D007150:Immunohistochemistry; D008113:Liver Neoplasms / Q000209:etiology* / Q000378:metabolism; D016133:Polymerase Chain Reaction; D012336:RNA, Ribosomal, 16S
chemical_list: D012336:RNA, Ribosomal, 16S