Role of tumor suppressor gene PTEN in pathogenesis of endometriosis

AIM: To investigate the expression of phosphatase and tension homologue deleted on chromosome 10, the tumor suppressor gene PTEN, in ectopic endometrium in patients with endometriosis and to study the role of PTEN in the pathogenesis of the disease. METHODS: The expression of PTEN in ectopic endometrium in 37 patients with endometriosis, including 20 ovarian endometriosis and 17 adenomyosis patients, was analyzed by using in situ hybridization method. Thirty-threc patients with uterine myoma were taken as controls. RESULTS: The PTEN expression level in the ectopic endometrium decreased significantly as compared with that in the controls (48.6% vs 93.9%, P=0.0002), and all the positive signals were mainly seen in the cytoplasm. The gene expression showed a cyclic change both in patients with endometriosis and in controls. The PTEN staining was found to be more frequent in secretory phase than in proliferative phase. But the difference was statistically significant only in the control group (P= 0.0102). The PTEN positivity rate in the patients with adenomyosis was 55.0% and in those with ovarian endometriosis was 52.9%. No significant difference was found between the two groups (P=0.4018). The expression of PTEN mRNA was significantly correlated with the stage of the endometriosis (P= 0.0026). CONCLUSION: The change of the PTEN expression may be involved in the pathophysiology of endometriosis.