P53 protein expression in gastric adenocarcinoma. Negative predictor of survival after postoperative adjuvant chemotherapy

Background. The aim of the present study was to evaluate the influence of p 53 protein on the survival of patients undergoing radical gastrectomy and p ostoperative adjuvant chemotherapy for gastric cancer. Patients and Methods . It was a retrospective study of 46 patients with gastric adenocarcinoma ( Stage II and III of the Japanese staging system). Alypatients were treated by curative radical gastrectomy with regional lymphadenectomy plus adjuvant chemotherapy. This regime included Mitomycin (20 mg one hour before surger y, followed by 10mg the day after) and Fluorinated Pyrimidine (UFT) (400 mg /m2/day orally) (started four weeks after operation, and continued for one year). Immunohistochemical expression of p53 protein was determined on tumo r samples from the removed specimens. The influence of p53 on survival was assessed in a Cox's proportional hazard regression analysis. Results. Sixte en tumors (34.7%) manifested nuclear overexpression of p53 protein. Patient s with p53-negative tumors showed higher cumulative survival at 4 years fol low-up than patients with p53-positive tumors (82% versus 45%) (p<0.01). Mu ltivariate analysis identified p53 overexpression as a negative independent predictive factor (hazard ratio: 11.15) (95% CI: 1.93-64.42). Multivariate analysis performed on patients with Stage III tumors, separately, confirme d the predictive effect of p53 overexpression. Conclusion. The results sugg est that postoperative adjuvant chemotherapy acted differently in p53-posit ive than in p53-negative gastric tumors. Absence of p53 overexpression is a ssociated to longer survival when adjuvant therapy is administered.