p53 immunoreactivity in endometrial metaplasia with dysfunctional uterine bleeding

Overexpression of p53 has been reported in endometrial carcinomas, especially in uterine papillary serous carcinoma (UPSC), to correlate with worse prognosis. Endometrial metaplasia is commonly encountered in patients with 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 might not show overexpression of p53 and would thus help to distinguish it from carcinomas of non-endometrioid histology.

Paraffin-embedded tissue of endometrial biopsies with papillary metaplasia (22 cases), tubal metaplasia (five cases) and eosinophilic meta-plasia (seven cases) from patients with DUB were immunostained for p53 immunoreactivity. No evidence of hyperplasia was noted in any of the cases selected for the study. Twenty-eight cases of UPSC were included for comparison. Our study showed p53 overexpression in 25 of 28 (89%) UPSC. Weak and heterogeneous p53 immunoreactivity was present in 10 of 22 (45%) papillary metaplasias, four of five (80%) tubal metaplasias and four of seven (57%) eosinophilic metaplasias. Follow-up of 16-45 (median 32) months was unremarkable except for one patient with eosinophilic metaplasia who had simple endometrial hyperplasia in subsequent biopsy.

The presence of weak and heterogeneous p53 immunoreactivity in metaplastic endometrium is unexpected and might be a consequence of DNA damage. Intense, diffuse and homogeneous p53 staining favours carcinoma.