Abstract:

Objective To investigate the influence of tamoxifen on the postmenopausal women, and test a hypothesis whether tamoxifen can cause endometrial cancer in the postmenopausal women. Methods Using immunohistochemistry(LSAB) on formalinfixed paraffinembedded endometrium sections to study the phosphatase and tension homology deleted on chromosome ten(PTEN) in endometrium of postmenopausal patients with breast carcinoma who took tamoxifen 40 mg/day for over 2 years and in endometral adenocarcioma, with prolapse uterine endometrium as normal controls. Results There was significant difference among Group tamoxifen, Group carcinoma of endometrium and Group normal endometrium(P<0.05). The differences between the groups of tamoxifen and normal endometrium were significant, the same was seen between carcinoma of endometrium and normal endometrium groups. But no significant difference was found between tamoxifen and carcinoma of endometrium groups. Conclusion The PTEN expression of the breast cancer patients who took tamoxifen 40 mg/day for over 2 years was lower than that in the normal people, and was almost the same as that in the patients of carcinoma of endometrium. Because tamoxifen stimulated postmenopause endometrium in the proliferative phase for a long time, thus made the expression of the PTEN decreased. Loss of PTEN expression is an early event in carcinoma of endometrium. Detection of PTEN protein may be a diagnostic biomarker for the earliest endometrial precancers and carcinoma.

Key words: phosphatase and tension homology deleted on chromosome ten, carcinoma of endometrium, tamoxifen, gene expression