In this retrospective study on banked tissue, we found that alpha-actinin and talin were completely de-expressed in both endometriosis and endometrioid carcinoma tissue. Some patchy, depolarized labeling for ezrin was noted in the endometrioid carcinoma but not in endometriosis. The loss of these proteins in both endometriosis and endometrioid carcinoma tissue indicates a significant change in the integrity of these tissues compared with normal and the possibility that individual cells may break away from the parent histology due to loss of cell adhesion. It also indicates a similarity between endometrioid cancer and endometriosis with respect to epithelial cell function and adhesion.