Expression And Mutations Of PIK3CA Gene In Hepatocellular Carcinomas

BACKGROUND&OBJECTIVE Phosphatidylinositol 3-kinase catalytic alpha polypeptide gene(PIK3CA),has been reported with high frequency somatic mutation in human carcinoma,most of the mutation was occurred in the hotspot region,the exon 9 and exon 20 of PIK3CA,the present study aimed to test the expression and mutation of PIK3CA gene in hepatocellular carcinomas.METHODS Hepatocellular carcinoma(HCC)samples of carcinomas tissue and corresponding beside tissue were collected from Jan.2007 to Oct. 2007 in the Department of Hepatobiliary & Vascular Surgery of the 1st Affiliated Hospital in Guangxi Medical University,and the diagnosis were verified by pathology.The exonl,9 and 20 of PIK3CA gene were detected by PCR-SSCP and the product of PCR was sequenced.In addition,immnohis -tochemistry SP method was employed to test the expression of PIK3CA gene in carcinomas tissue and corresponding beside tissue.RESULTS No mutation in carcinomas tissue and corresponding beside tissue was found in exon 1,9 and 20 of PIK3CA gene by PCR-SSCP and DNA sequencing,while abnormal superimposed peaks was presented on the sequenced graph of exon 9 in the 25 case of carcinomas tissue.The immnohistochemistry results showed that:(1)expression of PIK3CA in carcinomas(50.81%)was higher than in the corresponding beside tissue (14.75%).(2)The expression of PIK3CA gene was relationship withthe size of tumor and the integrity of capsule(p＜0.05).CONCLUSION(1)Mutations maybe occur in PIK3CA gene among Guangxi patients with HCC,but the ratio of hotspot mutations in the PIK3CA gene is low.(2)There exists amplification of PIK3CA gene in the HCC in Guangxi,the expression of PIK3CA gene was remarkable higher than in the corresponding side tissue,but its relation to the prognosis need to be further studied.