title: PIK3CA gene mutations and overexpression: implications for prognostic biomarker and therapeutic target in Chinese esophageal squamous cell carcinoma.
abstract: OBJECTIVE
  To evaluate PIK3CA gene mutations and PIK3CA expression status in Chinese esophageal squamous cell carcinoma (ESCC) patients, and their correlation with clinicopathological characteristics and clinical outcomes.
  
  
  METHODS
  Direct sequencing was applied to investigate mutations in exons 9 and 20 of PIK3CA in 406 Chinese ESCC patients. PIK3CA expression was evaluated using immunohistochemistry analysis. The associations of PIK3CA gene mutations and PIK3CA expression with clinicopathological characteristics and clinical outcome were examined.
  
  
  RESULTS
  Thirty somatic point mutations (30/406, 7.4%) were identified in exon 9 whereas no mutations were detected in exon 20. PIK3CA mutations were not correlated with clinicopathological characteristics or clinical outcomes. However in the ESCC patients with family cancer history, PIK3CA mutations were independently correlated with worse overall survival (multivariate hazard ratio (HR) = 10.493, 95% CI: 2.432-45.267, P = 0.002). Compared to normal esophageal tissue, PIK3CA was significantly overexpressed in cancer tissue (P<0.001). PIK3CA overexpression was independently associated with higher risk of local recurrence (multivariate HR  = 1.435, 95% CI: 1.040-1.979, P = 0.028). In female ESCC patients, PIK3CA overexpression was independently correlated with worse overall survival (multivariate HR  = 2.341, 95% CI: 1.073-5.108, P = 0.033).
  
  
  CONCLUSIONS
  Our results suggest PIK3CA gene mutation and overexpression could act as biomarkers for individualized molecular targeted therapy for Chinese ESCC patients.
authors: Department of Pathology, Cancer Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, P. R. China.
authors: Lin
authors: L
authors: Wang
authors: Department of Pathology, Cancer Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, P. R. China.
authors: Ling
authors: L
authors: Shan
authors: Department of Epidemiology, Cancer Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, P. R. China.
authors: Shaokai
authors: S
authors: Zhang
authors: Department of Pathology, Cancer Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, P. R. China.
authors: Jianming
authors: J
authors: Ying
authors: Department of Pathology, Cancer Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, P. R. China.
authors: Liyan
authors: L
authors: Xue
authors: Department of Pathology, Cancer Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, P. R. China.
authors: Yanling
authors: Y
authors: Yuan
authors: Department of Pathology, Cancer Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, P. R. China.
authors: Yongqiang
authors: Y
authors: Xie
authors: Department of Pathology, Cancer Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, P. R. China.
authors: Ning
authors: N
authors: Lu
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000235:genetics; D002294:Carcinoma, Squamous Cell / Q000175:diagnosis / Q000453:epidemiology / Q000235:genetics* / Q000473:pathology; D002681:China / Q000453:epidemiology; D058534:Class I Phosphatidylinositol 3-Kinases; D004938:Esophageal Neoplasms / Q000175:diagnosis / Q000453:epidemiology / Q000235:genetics* / Q000473:pathology; D000077277:Esophageal Squamous Cell Carcinoma; D004947:Esophagus / Q000378:metabolism / Q000473:pathology*; D005091:Exons; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D008297:Male; D008875:Middle Aged; D019869:Phosphatidylinositol 3-Kinases / Q000235:genetics*; D017354:Point Mutation; D011379:Prognosis; D016019:Survival Analysis
chemical_list: D014408:Biomarkers, Tumor; D019869:Phosphatidylinositol 3-Kinases; D058534:Class I Phosphatidylinositol 3-Kinases; C484760:PIK3CA protein, human