Objective: Since several investigations did not demonstrate the presence of altered p53 in endometrial hyperplasias, it has been concluded that these alterations constitute a relatively late event in endometrial carcinoma. The aim of the present study was to assess the presence of p53 in the tissue adjacent to endometrial carcinoma in attempt to elu­cidate the relationship between these tissues. Methods: New slides were prepared from paraffin-embeded tissue blocks of 49 endometrial endometrioid carcinoma hysterec­tomy specimens so that in each case tumor tissue and adjacent uninvolved endometrium were represented. Immunohistochemical staining for p53 detection was then performed. Results: In 43 of the 49 hysterectomy specimens evaluated, the tissue adjacent to the endometrial carcinoma was non hyperpla­stic and in six it was hyperplastic. Positive immunohistochemical staining was found in 22 (44.9%) of endometrial carcinomas and in eight (16.3%) of the adjacent tissues. A statistically significant higher percentage of hyperplastic adjacent tissues than non-hyper­plastic adjacent tissues were immunohistochemically p53 positive (50.0% vs 11.3%; p = 0.047). Conclusions: Our findings may indicate that p53 alterations are not necessarily a late event in endometrial endometrioid carcino­genesis. Since a large proportion of tissues adjacent to endometrial carcinoma do not show p53 alterations, other early cellular events may also play a role.