P53 immunoreactivity in endometrial metaplasia with dysfunctional uterine bleeding

Aim: Overexpression of p53 has been reported in endometrial carcinomas, esp ecially in uterine papillary serous carcinoma (UPSC), to correlate with wor se prognosis. Endometrial metaplasia is commonly encountered in patients wi th dysfunctional uterine bleeding (DUB) and may on occasion be difficult to distinguish from atypical endometrial hyperplasia or carcinoma on biopsies . The present study was initiated in the belief that metaplastic tissue mig ht not show overexpression of p53 and would thus help to distinguish it fro m carcinomas of non-endometrioid histology. Methods and results: Paraffin-embedded tissue of endometrial biopsies with papillary metaplasia (22 cases), tubal metaplasia (five cases) and eosinoph ilic metaplasia (seven cases) from patients with DUE were immunostained for p53 immunoreactivity. No evidence of hyperplasia was noted in any of the c ases selected for the study. Twenty-eight cases of UPSC were included for c omparison. Our study showed p53 overexpression in 25 of 28 (89%) UPSC. Weak and heterogeneous p53 immunoreactivity was present in 10 of 22 (45%) papil lary metaplasias, four of live (80%) tubal metaplasias and four of seven (5 7%) eosinophilic metaplasias. Follow-up of 16-45 (median 32) months was unr emarkable except for one patient with eosinophilic metaplasia who had simpl e endometrial hyperplasia in subsequent biopsy. Conclusions: The presence of weak and heterogeneous p53 immunoreactivity in metaplastic endometrium is unexpected and might be a consequence of DNA da mage. Intense, diffuse and homogeneous p53 staining favours carcinoma.