Comparative analysis of Ki-67, p53, and p21(WAF1CIP1) expression in tamoxifen associated endometrial carcinomas

Objective: To determine clinicopathologic parameters, expression of proliferation markers, and immunohistochemical oncogene expression in endometrial cancers in patients with a history of breast cancer with and without tamoxifen use. Methods: Thirty endometrial carcinoma specimens were examined from patients with a previous history of breast cancer. Patients who had taken tamoxifen (15) were compared to non-users (15). Immunohistochemical staining was performed for p53, Ki-76, and p21(WAF1/CIP1), overexpression was defined as greater than 10% positivity. Results: Patient populations were statistically similar. P53 was overexpressed in 73% of tamoxifen users compared to 53% of non-user specimens. p21(WAF1/CIP1) was overexpressed in 33% of users and 47% of non-users. Tamoxifen users had shorter time to diagnosis of endometrial cancer that non-users. Conclusions: In this small study, tamoxifen associated tumors expressed p53 more frequently than non-users, while the opposite was observed with p21(WAF1/CIP1). This suggests that p53 mutations might play a role in development of tamoxifen associated tumors.