P53 PROTEIN OVEREXPRESSION AS A PREDICTOR OF THE RESPONSE TO CHEMOTHERAPY IN GASTRIC-CANCER

This study was performed to evaluate p53 overexpression as a predictor of the response to chemotherapy of patients with gastric cancer. The subjects comprised 20 patients with Stage IV gastric cancer and three, vith locally recurrent lesions, all of whom were treated with 5-fluoro uracil (5-FU) plus cisplatin (CDDP) for 4 weeks, Of the total 23 patie nts there were 10 responders; 2 showing complete response (CR) and 8, partial response (PR). Specimens obtained by endoscopic biopsy were im munohistochemically stained using anti-p53 protein and bcl-2 protein a ntibody. Of the 10 responders, 7 demonstrated negative p53 staining, a nd of the 13 nonresponders, 11 demonstrated positive p53 staining (P = 0.013). Tissue from 3 of the responders and 7 of the nonresponders th at stained for bcl-2 were positive prior to chemotherapy; however, the re was no association between bcl-2 staining and chemotherapeutic effe ct. In conclusion, immunohistochemical identification of p53 in pretre atment tissue may represent a useful predictor for chemotherapeutic ou tcome in patients with gastric cancer.