Background: Mutations of the p53 gene belong to the most common genetic alterations in human cancer that have been implicated in tumorigenesis and tumor progression. Although p53 expression appears to be correlated with prognosis in patients with breast cancer and some other types of cancer, its prognostic role in gastric cancer is still uncertain. In the present study, therefore, the prognostic impact of p53 expression was evaluated in 418 patients with curatively resected gastric carcinomas without residual tumor (RO-resection).
Methods: Tumor sections of 418 RO-resected gastric carcinomas were stained with the monoclonal antibody DO-1 after microwave processing. p53 expression was statistically compared with clinico-pathologic features and postoperative survival.
Results: p53 expression was detected in 57.5% of all tumors, with strong inter- and intratumor heterogeneity. No immunoreactivity was observed in the normal mucosa adjacent to the tumor. Statistically, no significant correlation between p53 overexpression and depth of invasion, lymph node involvement, or grade of tumor differentiation was detected. The correlations with blood vessel invasion (P = 0.049) and lymphatic vessel invasion (P = 0.047) were of marginal significance. Survival analysis revealed no significant impact of p53 expression on survival, the 5-year survival rates were 40.6% +/- 7.8% for patients with p53 positive tumors and 49.2% +/- 8.9% for patients with p53 negative tumors (P = 0.43). Furthermore, no correlation with survival was found when four different levels of p53 expression were analyzed (P = 0.51). p53 expression had no influence on survival, in either the lymph node positive or negative groups.
Conclusions: The data suggest that the immunohistochemical detection of p53 expression is at present not a predictor of outcome of patients with gastric cancer or to identify subgroups of patients who may be at higher risk.