Fluorescence in situ Hybridization and Immunohistochemical Analysis of p53 Expression in Endometrial Cancer: Prognostic Value and Relation to Ploidy

Background Endometrial carcinoma is the most common gynecological malignancy. Several molecular biological characteristics have been studied for their potential value in patient management. Objectives Our objectives were to compare p53 immunohistochemical expression with P53 gene status determined by fluorescence in situ hybridization (FISH) and to compare these characteristics with ploidy and with classical clinical and histological prognostic factors. Materials and Methods We reviewed stored specimens from 43 patients with endometrial cancer diagnosed in 1999–2004. P53 FISH and immunohistochemistry were performed, together with imaging cytometry to calculate DNA ploidy. Results Thirteen of the 43 endometrial carcinomas (30.2%) showed P53 loss of heterozygosity (LOH). P53 LOH correlated with the histological type ( P = .03) and the histological grade ( P = .004). Quantitative immunohistochemical expression of p53 protein correlated with the histological type ( P = .0001). With a cutoff of 10% of p53-positive cells, p53 overexpression correlated with the histological type ( P = .003) and grade ( P = .0008). No relation was found between P53 LOH or immunohistochemical expression and the disease stage, the depth of myometrial invasion, lymph node status, lymphovascular space involvement, recurrence, or death from cancer. Nondiploid carcinomas showed deeper myometrial invasion than diploid carcinomas ( P = .01). No relation was observed between ploidy and qualitative or semiquantitative p53 expression or P53 LOH. Conclusion In endometrial cancer, FISH analysis of P53 status adds no significant prognostic information compared with immunohistochemical p53 analysis.