Evaluation of Loss of Paired Box 2 Gene Expression in Endometrial Hyperplasia for Detecting Endometrial Intraepithelial Neoplasia

Abstract

Introduction: Endometrial Hyperplasia (EH) is a nonneoplastic proliferation of endometrial glands, resulting from the action of unopposed estrogen, which if unchecked for long, can cause certain genetic alterations that eventually lead to the development of endometrial adenocarcinoma. Paired Box 2 (PAX2) is a gene coding for a transcription factor required during embryonic development, which has been found to mutate early during endometrial carcinogenesis. Aim: Our study aimed at evaluating loss of PAX2 gene expression in different types of EHs and analyzing its utility in detecting Endometrial Intra-epithelial Neoplasia (EIN). Materials and Methods: It was a cross-sectional study conducted in the duration of 1.5 years, from January 2014 to June 2015. Total 50 cases diagnosed as EH were categorised as one of the four WHO sub-types. Further, these were catergorised as per EIN classification. Thereafter, PAX2 immunohistochemical staining was applied and percentage loss of PAX2 staining was evaluated and the results obtained were analysed statistically. Mainly Chi-square test and ANOVA test were applied. Results: Simple hyperplasia without atypia was found to be the most common sub type where as simple hyperplasia with atypia the least common. 29/33 (87.89%) cases of simple hyperplasia without atypia showed 50%. 13/14 (92.86%) of the EIN cases showed PAX2 loss >50%, thus showing a more consistent loss of PAX2. Conclusion: Hence, it is concluded that >50% loss of PAX2 staining indicates early endometrial carcinogenesis, and is suggested as an aid in the diagnosis of EIN.

Keywords

• biomarker
• endometrial carcinogenesis
• endometrial pre-cancer lesion