Immunohistochemical evaluation of PTEN protein in patients with endometrial intraepithelial neoplasia compared to endometrial adenocarcinoma and proliferative phase endometrium

Abstract

Objective: The aim of this study was to reclassify endometrial hyperplasia cases and examine PTEN protein immunoreactivity compared to cases with endometrial adenocarcinoma and proliferative endometrium.

Design: Endometrial samples from 37 women with endometrial hyperplasia with atypia were reclassified as endometrial intraepithelial neoplasia (EIN). Eighteen were complex and 19 were simple endometrial hyperplasia. Twenty-our cases of EIN, ten endometrial adenocarcinoma cases and ten proliferative phase endometrium sections were immunostained for PTEN expression. PTEN expression was documented according to the degree of immunoreactivity as complete loss, partial loss and present.

Results: Twenty-four of 37 (64%) women with endometrial hyperplasia were reclassified as EIN. Complete loss of PTEN immunoreactivity was found in only one of the 24 EIN patients (4.2%), partial loss in eight of 24 (33.3%) and present in 15 of 24 (62.5%). There were no difference in PTEN immunoreactivity between EIN, endometrial adenocarcinoma and endometrial proliferation (p = 0.342). PTEN immunoreactivity was partially lost in seven and present in three of the patients with endometrial adenocarcinoma. None of the patients expressed complete loss of PTEN immunoreactivity in this group.

Conclusion: EIN classification may provide a better and more objective assessment of endometrial hyperplasia cases. PTEN expression showed no differences among the cases of EIN, endometrial carcinoma and proliferative phase endometrium.