Using immunohistochemical methods, we analyzed the association between nuclear p53 overexpression and various clinicopathological parameters in patients with endometrial cancers. Formalin-fixed and paraffin-embedded tissue sections from 139 cases of endometrial cancer (endometrioid type, 126; serous papillary type, 12; and clear-cell type, 1) were stained with anti-p53 monoclonal antibody (MAb) DO7. Overexpression of p53 was associated with high malignant potential, including extensive muscular invasion, advanced surgical stage, high histological grade, serous papillary type and a personal history of cancer. Lymph-node metastasis was also related to p53 overexpression with marginal significance. Survival curves determined by the Kaplan-Meier method and univariate analysis showed p53 overexpression to be associated with a poor outcome in endometrial cancer patients. However, multivariate analysis using the stepwise Cox proportional-hazard model showed that whereas lymph-node metastasis, a personal history of cancer and muscular invasion were related to poor survival rates, p53 overexpression was not. Consequently, p53 overexpression itself does not appear to be an independent prognostic factor in endometrial cancer, although a still larger sample of patient material would be required to assess this issue definitively.