Mutation and overexpression of the beta-catenin gene may play an important role in primary hepatocellular carcinoma among Chinese people.
OBJECTIVE
To study the role of beta-catenin gene mutation and expression in hepatocellular carcinogenesis.


METHODS
Thirty-four hepatocellular carcinoma (HCC) specimens and adjacent para-cancerous tissues, and four normal liver tissues were analyzed. Subcellular distribution of beta-catenin was examined by immunohistochemistry staining. Mutation and semiquantitative expression of beta-catenin gene exon 3 mRNA were detected by RT-PCR-SSCP and in situ hybridization.


RESULTS
Immunohistochemistry showed that all normal liver tissues and para-cancerous tissues examined showed membranous-type staining for beta-catenin protein, frequently with weak expression in the cytoplasm, but no beta-catenin accumulation in nuclei was found; while in liver cancer, 21 cases (61.8%) of HCC examined showed accumulated type in cytoplasms or nuclei. On SSCP, 15 cases (44.1%) of HCC altogether displayed three kinds of characteristic mutational mobility shifts. No abnormal shifting bands were found in tissues from normal liver or para-cancerous area. The beta-catenin gene exon 3 mRNA expression index of 34 HCCs was higher than that of para-cancerous tissue and normal liver tissue. Using in situ hybridization, the signal corresponding to beta-catenin gene exon 3 mRNA was particularly strong in cytoplasm of HCC when compared with those of paracancerous tissues and normal liver tissues.


CONCLUSIONS
beta-catenin gene mutation and overexpression may have a critical role in malignant progression of hepatic carcinogenesis among Chinese people.
Cui
J
J
Department of Food Science and Human Nutrition, Michigan State University, East Lansing 48824, USA. cuij@msu.edu
Zhou
X
X
Liu
Y
Y
Tang
Z
Z
D006528:Carcinoma, Hepatocellular / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D003598:Cytoskeletal Proteins / Q000096:biosynthesis / Q000235:genetics; D005091:Exons; D015870:Gene Expression; D006801:Humans; D007150:Immunohistochemistry; D008113:Liver Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D009154:Mutation; D018807:Polymorphism, Single-Stranded Conformational; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015534:Trans-Activators; D051176:beta Catenin
C495270:CTNNB1 protein, human; D003598:Cytoskeletal Proteins; D012333:RNA, Messenger; D015534:Trans-Activators; D051176:beta Catenin