Prognostic significance of deletion and over-expression of the p53 gene inepithelial ovarian cancer

Purpose of investigation: To define the deletion or over-expression of p53 genes and their prognostic significance in epithelial ovarian cancers. Methods: A total of 26 patients with epithelial ovarian cancer, who had und ergone second-look laparotomy after primary surgery and six courses of plat inum-based chemotherapy were included in the study. Paraffin-embedded archi val tissue samples of all cases were examined for deletion and over-express ion of p53 gene by FISH and immunohistochemical methods, respectively. The relation between these findings and clinico-pathological prognosticators or survival of the patients were analyzed by the Fisher Exact X-2 test, Cox r egression model and life table analysis. Results: p53 gene deletion, related to single or double allele, was determi ned in all cases with a range of 6% to 75% of the cancer cells. When 40% wa s accepted as the cut-off ratio for the deletion rate, seven (26.9%) of the cases were observed to have p53 deletion. Although p53 over-expression was defined in 12 (46.1%) patients, four of whom were also accompanied by p53 deletion, there was no relation between the p53 deletion and over-expressio n (p>0.05). p53 deletion was also not related to any prognostic factors or survival of the patients (p>0.05). However, cases with p53 over-expression had significantly more advanced stage and higher-grade tumors, and shorter median survival (p>0.05-0.01). Conclusion: p53 gene mutation determined by over-expression of p53 protein has been suggested as an important prognostic factor for epithelial ovarian cancer, however, it has not always been accompanied by p53 deletion.