title: Clinicopathological Significance of Elevated PIK3CA Expression in Gastric Cancer.
abstract: OBJECTIVE
  PIK3CA is often mutated in a variety of malignancies, including colon, gastric, ovary, breast, and brain tumors. We investigated PIK3CA expression in gastric cancer and explored the relationships between the PIK3CA expression level and clinicopathological features as well as survival of the patients.
  
  
  METHODS
  We examined PIK3CA expression in a tissue microarray of 178 gastric adenocarcinomas by immunohisto-chemistry and reviewed patients' medical records.
  
  
  RESULTS
  In our study, 112 of the 178 gastric cancer patients displayed positive PIK3CA expression. Overexpression of PIK3CA was correlated with low grade differentiation (P=0.001), frequent lymphatic invasion (P=0.032), and high T stage (P=0.040). Patients with positive PIK3CA staining were more likely to display worse overall survival rate than those with negative PIK3CA staining, as determined by Kaplan-Meier survival analysis with log-rank test (P=0.047) and a univariate analysis using the Cox proportional hazard model (hazard ratio=1.832, P=0.051).
  
  
  CONCLUSIONS
  Elevated PIK3CA expression was significantly correlated with tumor invasiveness, tumor phenotypes, and poor patient survival.
authors.affiliation: Department of Pathology, Soonchunhyang University Cheonan Hospital, Soonchunhyang University College of Medicine, Cheonan, Korea.
authors.forename: Si-Hyong
authors.initials: SH
authors.lastname: Jang
authors.affiliation: Department of Pathology, Soonchunhyang University Cheonan Hospital, Soonchunhyang University College of Medicine, Cheonan, Korea.
authors.forename: Kyung-Ju
authors.initials: KJ
authors.lastname: Kim
authors.affiliation: Department of Pathology, Soonchunhyang University Cheonan Hospital, Soonchunhyang University College of Medicine, Cheonan, Korea.
authors.forename: Mee-Hye
authors.initials: MH
authors.lastname: Oh
authors.affiliation: Department of Pathology, Soonchunhyang University Cheonan Hospital, Soonchunhyang University College of Medicine, Cheonan, Korea.
authors.forename: Ji-Hye
authors.initials: JH
authors.lastname: Lee
authors.affiliation: Department of Pathology, Soonchunhyang University Cheonan Hospital, Soonchunhyang University College of Medicine, Cheonan, Korea.
authors.forename: Hyun Ju
authors.initials: HJ
authors.lastname: Lee
authors.affiliation: Department of Pathology, Soonchunhyang University Cheonan Hospital, Soonchunhyang University College of Medicine, Cheonan, Korea.
authors.forename: Hyun Deuk
authors.initials: HD
authors.lastname: Cho
authors.affiliation: Department of General Surgery, Soonchunhyang University Cheonan Hospital, Soonchunhyang University College of Medicine, Cheonan, Korea.
authors.forename: Sun Wook
authors.initials: SW
authors.lastname: Han
authors.affiliation: Department of General Surgery, Soonchunhyang University Cheonan Hospital, Soonchunhyang University College of Medicine, Cheonan, Korea.
authors.forename: Myoung Won
authors.initials: MW
authors.lastname: Son
authors.affiliation: Department of General Surgery, Soonchunhyang University Cheonan Hospital, Soonchunhyang University College of Medicine, Cheonan, Korea.
authors.forename: Moon Soo
authors.initials: MS
authors.lastname: Lee
keywords: Immunohistochemistry; PIK3CA; Stomach neoplasms