Association of PTEN and ARID1A Expression in Patients with Atypical Endometrial Hyperplasia and Concurrent Endometrioid Carcinoma: A Retrospective Cohort Study

Objective: Some endometrial biopsies from patients with atypical hyperplasia/endometrial intraepithelial neoplasia (AH/EIN) show concurrent endometrioid carcinoma (EC). Hysterectomy is the standard treatment for AH/EIN; however, hormonal therapy is also acceptable for women who wish to preserve fertility. Few studies have simultaneously evaluated the expressions of PTEN and ARID1A in endometrial biopsies to predict concurrent EC. This study aim evaluated whether the loss of PTEN and ARID1A expressions in endometrial biopsies indicate the presence of concurrent EC. Material and Methods: Endometrial biopsies from 46 patients with AH/EIN who underwent hysterectomy within 3 months between 2011 and 2021 were reviewed. Loss of or intact PTEN and ARID1A expressions was evaluated using immunohistochemistry. The presence or absence of EC in the hysterectomy specimen indicated the presence or absence of concurrent EC. Logistic regression analysis was used to determine associations. Results: Concurrent EC was found in 32.6% (15/46) of the patients. Loss of PTEN and ARID1A was observed in 54.3% and 8.7% of the endometrial biopsies, respectively. Endometrial biopsies with loss of PTEN expression had an insignificantly higher prevalence of concurrent EC than those with intact PTEN expression (44% versus [vs.] 19%, p-value=0.107). Loss and intact ARID1A expressions showed no difference in the prevalence of concurrent EC (25% vs. 33.3%, p-value=1). Multivariate analysis showed loss of PTEN tended to be associated with concurrent EC (odd ratio [OR]=2.38, 95% CI 0.52–10.96), while loss of ARIDA showed no evidence of association (OR=0.92, 95% CI=0.07–12.97). Conclusion: One-third of the endometrial biopsies with AH/EIN have concurrent EC. The loss of PTEN expression in AH/EIN may indicate the presence of concurrent cancer. However, further studies with larger sample sizes are needed to confirm the results.