Yen TT, et al. - Researchers sought to ascertain the clinical significance of ARID1A loss during tumor progression from complex atypical hyperplasia (CAH) to endometrioid endometrial carcinoma (EEC), as well as to evaluate its role as a prognostic cancer biomarker. The findings from the present study suggested that loss of ARID1A immunoreactivity in endometrial sampling specimens forecasts concurrent carcinoma in subsequent hysterectomy and might play a role in tumor progression and be a prognostic cancer biomarker.