PTEN expression in tamoxifen-associated endometrial cancers

Tamoxifen is associated with increased rates of endometrial hyperplasia and adenocarcinoma. Our previous work suggested tamoxifen-associated endometrial cancers might be associated with p53 mutations. PTEN, a tumor suppressor gene, is altered in low-grade endometrial carcinoma. This study evaluates PTEN immunohistochemical (IHC) expression in tamoxifen-associated endometrial cancers. Materials and Methods: Twenty-eight endometrial carcinoma specimens were examined from patients with a history of breast cancer. Patients who had taken Tamoxifen (15) were compared to non-users (13). IHC staining was performed for PTEN; over-expression was defined as greater than 70% positivity. Results: The mean duration of tamoxifen use was 3.3 years (3 - 171 months). Four out of 15 (27%) tamoxifen users expressed PTEN compared with 2 out of 13 (15%) of non-users. Conclusion: In this study, it appears that tamoxifen-associated endometrial cancers are not significantly different from sporadic endometrial cancer with regards to PTEN IHC expression, although there is a trend towards retained PTEN expression.