Previous studies of oncogenes, tumor suppressor genes, and proliferation markers in endometrial adenocarcinoma have obtained conflicting results regarding the usefulness of these markers in predicting prognosis. This study examined p53, PCNA, and c-erbB-2 immunohistochemically to clarify the relationship of these markers to each other and to FIGO stage, myometrial invasion, and survival. We studied 64 cases of endometrial carcinoma, treated between 1988 and 1995, for overexpression of p53, percentage of PCNA expression (PCNA index), and c-erbB-2 cytoplasmic membrane staining. Thirty-two percent of tumors expressed p53, 39% displayed a PCNA index of > = 25%, and 69% expressed c-erbB-2. p53 overexpression was significantly associated with stage (p=0.027), PCNA index > = 25% (p=0.005), c-erbB-2 expression (p=0.018), and vital status (p=0.04). PCNA index > = 25% was associated with stage (p=0.008), myometrial invasion (p=0.008), and c-erbB-2 expression (p=0.05), and weakly associated with vital status (p=0.07). No associations were observed for c-erbB-2 with stage, invasion, or vital status. There was some suggestion of a decreased survival in patients whose tumors overexpressed p53 (Log Rank; p=0.09) or had a PCNA index > = 25% (Log Rank; p=0.13). Additional, larger studies are needed to evaluate the prognostic value of PCNA and p53 expression in endometrial adenocarcinoma.