J Gastric Cancer.  2016 Jun;16(2):85-92. 10.5230/jgc.2016.16.2.85.

Clinicopathological Significance of Elevated PIK3CA Expression in Gastric Cancer

• Jang SH
• Kim KJ
• Oh MH
• Lee JH
• Lee HJ
• Cho HD
• Han SW
• Son MW
• Lee MS

• KMID: 2328074
• DOI: http://doi.org/10.5230/jgc.2016.16.2.85

Abstract

PURPOSE
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.
MATERIALS AND 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.

Keyword

PIK3CA; Stomach neoplasms; Immunohistochemistry

MeSH Terms

Adenocarcinoma
Brain Neoplasms
Breast
Colon
Female
Humans
Immunohistochemistry
Medical Records
Ovary
Phenotype
Proportional Hazards Models
Stomach Neoplasms*
Survival Rate

Figure

• 

  Fig. 1 Representative PIK3CA immunohistochemical staining images of gastric cancers (×400) exhibiting intensity score of 0 (A), 1 (B), 2 (C), or 3 (D).

• 

  Fig. 2 (A, B) Normal gastric mucosa, which was used as a negative control, displayed absence of PIK3CA staining (A) or weak PIK3CA staining (B) (×200). (C) Positive PIK3CA staining in tumor glands and negative staining in the adjacent non-tumorous gastric mucosa (×200).

• 

  Fig. 3 Survival curve of the low PIK3CA expression group (n=112) and high PIK3CA group (n=66) as assessed by Kaplan-Meier survival analysis with log-rank test.

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