Detection of PTEN immunoreactivity in endometrial hyperplasia and adenocarcinoma.

Objective: To investigate PTEN (phosphatase and tensin homolog deleted on chromosome 10) expression in endometrial hyperplasia and adenocarcinoma as analyzed by immunohistochemistry.

Material And Method: PTEN protein expression was evaluated by immunohistrochemical study of 70 paraffin-embedded curettage endometrial tissue samples (10 normal endometrium, 55 endometrial hyperplasia, and 15 endometrial adenocarcinomas) selected from surgical pathology files of the Division of Gynecologic Pathology, Department of Obstetrics and Gynecology, Faculty of Medicine, Chulalongkorn University, from 2001 to 2004. Intensity of epithelial staining of PTEN immunoreactivity in different histologic types was determined.

Results: Absence of PTEN protein expression was detected in 60% of endometrial carcinoma, 60% of atypical endometrial hyperplasia, and 24% of typical endometrial hyperplasia. In endometrial hyperplasia without atypia group, the majority of cases revealed moderate to strong PTEN expression, with 70% in simple hyperplasia and 47% in complex hyperplasia. There is a significant statistical difference of PTEN immunoreactivity among proliferative endometrium, endometrial hyperplasia and endometrial carcinoma group (p = 0.004).

Conclusion: Complete loss of PTEN protein expression was most commonly found in endometrial carcinoma and hyperplasia with cytologic atypia.