p53 nuclear accumulation in preneoplastic lesions and stage I uterine endometrioid adenocarcinoma.

A total of 118 endometrial neoplastic and preneoplastic lesions comprising 43 uterine endometrioid adenocarcinoma at stage I, 40 complex (adenomatous) hyperplasias and 35 atypical hyperplasias were examined for p53 nuclear accumulation to assess the incidence of p53 alterations in infiltrating carcinomas and to verify if p53 aberrations may allow the identification of a subset of premalignant cases with high risk of progression. No specific immunostaining was observed in the cases of complex hyperplasia without atypias. One (3%) of 35 atypical hyperplasias showed focal areas of p53 immuno-reactivity. The overall frequency of p53 overexpression in endometrial carcinomas was 54%. The distribution of cases with nuclear accumulation of p53 was significantly different (p=0.01) in tumours with different degree of invasiveness. In addition, p53 nuclear accumulation was observed more often in tumours with moderate (G2) or poor differentiation (G3) (p=0.03). Our data indicate that p53 aberrations are not early events in endometrial carcinogenesis and may be related with tumour progression and aggressiveness.