Objective: The p53 signature, which (although morphologically unremarkable) displays diffuse and strong p53 nuclear staining, has been proposed to be a precursor of serous endometrial intraepithelial carcinoma. We examined the overexpression of p53 in postmenopausal endometrial glands.
Methods: Postmenopausal endometrial tissues of 82 women with benign disease, including 10 hormone users, were evaluated in this study. Tissues with endometrial hyperplasia and/or polyps were excluded based on a histopathologic review. Expressions of estrogen receptor-α, Ki-67, and p53 were immunohistochemically examined. Apoptotic cells were identified using a terminal deoxynucleotidyl transferase dUTP nick end labeling assay. Overexpression of p53 was categorized as moderate to strong in more than 50% of glandular cell nuclei.
Results: Focal glandular overexpression of p53 was observed in 1 (9%) of 10 and in 8 (11%) of 72 postmenopausal endometrial tissue specimens in women with and women without a history of hormone use, respectively. Among nonhormone users, the median Ki-67 and apoptotic indices in the postmenopausal endometrial glands of women with and women without overexpression of p53 were 16% and 6% (P = 0.007) and 1% and 1% (P = 0.345), respectively. All postmenopausal endometrial glands were positive for estrogen receptor-α, regardless of the overexpression of p53. The postmenopausal endometrial glands of estrogen users exhibited significantly higher Ki-67 and apoptotic indices than those of nonestrogen users (P = 0.001 and P < 0.001, respectively).
Conclusions: Overexpression of p53 may be responsible for the high proliferative activity of postmenopausal endometrial glandular cells associated with conditions of low apoptotic cell death.