Several recently developed techniques have been applied to the study of endometrial lesions. These include the evaluation of K-ras abnormalities in patients with endometrial hyperplasia to identify those at high risk to develop carcinoma, the analysis of p53 abnormalities to distinguish between endometrial hyperplasia and carcinoma, the use of p53 for predicting clinical outcome in patients with endometrial carcinoma, and PCNA immunostaining of endometrial lesions with secretory activity. However, these studies should be regarded at this juncture as auxiliary, at best, to the cytological and histopathologic examination of human endometrial disorders.