Relation between p53 Protein Overexpression and Survival of Gastric Cancer Patients Who Underwent Surgery and Early Postoperative Intraperitoneal Chemotherapy

PURPOSE: In spite of curative surgery and early postoperative intraperitoneal chemotherapy, the prognosis of patients with gastric cancer involving the serosal surface is poor. The aim of this study was to analyze p53 protein overexpression in these patients and to clarify the usefulness of p53 mutation as a prognostic indicator. METHODS: p53 protein overexpression was assessed by immunohistochemistry in 123 gastric cancer specimens. The correlation between p53 protein overexpression and clinicopathologic parameters and prognosis of the patients were analyzed. RESULTS: Overexpression of p53 protein was identified in 67 (54.5%) tumors and was more frequent in differentiated tumors than in undifferentiated tumors (67.4% vs. 46.8%; P=0.026). However, there were no statistically significant differences in the frequency of p53 protein overexpression according to age, sex, depth of invasion, lymph node metastasis, distant metastasis, pathologic stage, and Lauren classification. There was no statistically significant difference in 5-year survival rate according to the p53 protein overexpression (P=0.565). CONCLUSION: Overexpression of p53 protein could not predict the effectiveness of early postoperative intraperitoneal chemotherapy. Therefore, it could not be used as a prognostic indicator in patients with advanced gastric cancer who underwent gastrectomy and early postoperative intraperitoneal chemotherapy.

p53 Gene Mutation in Gastric Cancer Tissue

PURPOSE: p53 is one of the most commonly mutated genes in human tumors. The aim of this study was to analyze p53 mutation in gastric cancer and its correlations with the clinicopathologic variables to clarify the usefulness of p53 mutation as a prognostic factor. MATERIALS AND METHODS: Specimens from 331 patients with gastric cancer who underwent a gastrectomy between March 1999 and April 2001 at the Kyungpook National University Hospital were used. p53 gene mutations were assessed by using a polymerase chain-reaction single-strand conformation polymorphism (PCR-SSCP) analysis. The correlations between p53 gene mutation and clinocopathologic parameters were analyzed. RESULTS: p53 mutations were found in 66 (19.9%) tumors. Among those 66 cases, mutations were seen in 23 tumors at exon 5, in 8 at exon 6, in 21 at exon 7, and in 17 at exon 8. Two mutations were shown in 3 tumors. Thirty-six (23.1%) of 156 intestinal-type tumors and 19 (13.1%) of 145 diffuse-type tumors showed p53 gene mutation (P=0.007). The frequency of p53 gene mutation didn't show any significant differences according to age, sex, stage, location, or gross type. Exon 5 mutations showed more frequently in intestinal-type tumors than in diffuse-type tumors (9.7% vs. 2.8%, P=0.024), and p53 mutation were more frequent in lymph nodes metastasis group than lymph nodes non-metastasis group with statistical significance (25.0% vs 15.6%, P=0.034). The five-year survival rate showed no statistically significant difference with p53 mutation (P=0.704). CONCLUSION: p53 mutations assessed by PCR-SSCP had little value as a prognostic factor after gastrectomy in patients with gastric cancer.