[Expression of tissue microarray p53, p16 and cyclooxygenase-2 in gastric cancer]

To constructed tissue microarray containing specimens from gastric cancer and adjacent non-cancer tissue to survey the expression of p53, p16 and cyclooxygenase-2 (COX-2), and to obtain a comprehensive survey on the expression of three proteins in gastric cancer progression and their clinical significance.

We constructed a tissue microarray containing 50 specimens from gastric cancer and 78 specimens from adjacent non-cancer tissue, and assayed three different proteins (p53, p16 and COX-2) by immunohistochemistry to consecutive formalin-fixed tissue microarray sections.

In non-cancer tissue, p53, p16 and COX-2 positive staining were 19%, 15% and 74% respectively. In gastric cancer tissue, p53, p16 and COX-2 positive staining were 50%, 54% and 94% respectively. There were a significant difference between two different tissues (P < 0.05). 52% (66/128) cases were COX-2+/p53-, only 1 case were COX-2-/p53+. There was a significant association between COX-2 and p53 (P < 0.05). COX-2 negative expression tissues were found significantly more often in p53-negative than in p53-positive cases. 52% (67/128) cases were COX-2+/p16-, only 1 case were COX-2-/p16+. A significant correlation was recognized between expression of COX-2 and p16 (P < 0.05). Logistic regression analysis revealed that the risk factors of tumorous histotype were p53, p16 and COX-2 positive expression together, determined by Wald chi2 test (P < 0.05; odds ratio, 18.889). There was reciprocal relationship among p53, p16 and COX-2.

Combination analysis of p53, p16 and COX-2 may be useful for the prediction of gastric carcinogenesis.