The prognostic significance of p21 and Her-2 gene expression and mutation/polymorphism in patients with gastric adenocarcinoma

Analyses of gene expression status and genetic polymorphisms are methods to identify novel histopathological prognostic factors. In patients with gastric cancer, some cell cycle regulators p53, p21, p27 and Her-2 oncogene have been proposed as prognostic factors. We aimed to investigate the expression and mutation/polymorphism of p21 and Her-2 and also relationship between that genes status and histopathological factors and prognosis in patients with gastric cancer. Forty-four patients with locally advanced gastric cancer were analyzed in this study from January 2000 to December 2008. Clinicopathological parameters, expression and mutation/polymorphism of p21 and Her-2 results were used to predict disease-free survival and overall survival. The positive expression of p21 and Her-2 was observed in 61.4 % (n = 27) and 9.1 % (n = 4) of all 44 tumors, respectively. p21 gene mutation and Her-2 gene polymorphism were detected in 20 % (n = 11) and 2.3 % (n = 1, II phenotype) of cases, respectively. The negative expression of p21 was correlated significantly with diffuse and undifferential type histologies, whole gastric involvement and positive vascular/neural invasion. The median survival rate of patients with negative expression was significantly poorer than that of patients with positive expression of p21 (17 vs. 27 months, p = 0.01, cox regression). p21 mutation was significantly higher in patients with diffuse (p = 0.03) and undifferential (p = 0.02) type histologies. There was no statistically significant association between histopathological parameters and Her-2 gene polymorphism/expression. The negative expression of p21 correlates with disease survival and may be a poor prognostic factor in patients with resected gastric cancer treated with adjuvant chemotherapy.