title: PIK3CA mutations in hepatocellular carcinoma in Korea.
abstract: OBJECTIVE
  Phosphatidylinositol 3-kinases/AKT pathway plays a pivotal role in hepatocellular carcinoma (HCC). Mutant PIK3CA, encoding the p110a catalytic subunit, stimulates the AKT pathway and promotes cell growth in various cancers. PIK3CA mutation rate has been usually reported as low frequency (<5%) in HCC except one report from Korea with 35.6%. Therefore, we investigated the frequency of PIK3CA mutations in Korean HCC patients.
  
  
  METHODS
  We sequenced exons1, 3, 4, 6, 7, 8, 9, 19 and 20 of PIK3CA in 268 HCC tumor tissue samples by Sanger method and pyrosequencing assay.
  
  
  RESULTS
  In this study, the mutations were not detected in exons3, 6, 8, and 19, and detected 1 at unknown SNP in exon1 and exon4, 2 at unknown SNP in exon7, 2 at unknown SNP in exon20. However, 1 at unknown SNP, 1 at G1635T and surprisingly all samples at A1634Cin exon9 were detected by Sanger method. Additional experiments with normal tissue, cloning experiments and a pyrosequencing assay revealed that the double peak at A1634C of exon9 is a pseudogene, not true mutation. The mutations found in this study were all different and small numbers, therefore, we cannot conclude specific relationship between clinical characteristics of HCC and mutation of PIK3CA.
  
  
  CONCLUSIONS
  Our study suggests that the rate of PIK3CA mutation in the Korea population is in fact similar to the rates seen elsewhere in the world.
authors.affiliation: Department of Clinical Research, Samsung Biomedical Research Institute, Seoul, Korea.
authors.forename: Heesue
authors.initials: H
authors.lastname: Kim
authors.forename: Cheol-Keun
authors.initials: CK
authors.lastname: Park
authors.forename: Su Jin
authors.initials: SJ
authors.lastname: Lee
authors.forename: Sun Young
authors.initials: SY
authors.lastname: Rha
authors.forename: Kyu Hyun
authors.initials: KH
authors.lastname: Park
authors.forename: Ho Yeong
authors.initials: HY
authors.lastname: Lim
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D044466:Asian People / Q000235:genetics; D006528:Carcinoma, Hepatocellular / Q000235:genetics*; D058534:Class I Phosphatidylinositol 3-Kinases; D005091:Exons; D005260:Female; D006801:Humans; D008113:Liver Neoplasms / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D009154:Mutation; D059645:Mutation Rate; D019869:Phosphatidylinositol 3-Kinases / Q000235:genetics*; D020641:Polymorphism, Single Nucleotide; D056910:Republic of Korea; D055815:Young Adult
chemical_list: D058534:Class I Phosphatidylinositol 3-Kinases; D019869:Phosphatidylinositol 3-Kinases; C484760:PIK3CA protein, human
keywords: PIK3CA; hepatocellular carcinoma; mutation