Immunohistochemical analysis of alphavbeta5 and alphavbeta6 integrins in the endometrium and endometriosis.

We performed a case-controlled study to study the immunoreactivity patterns and staining intensity of alphavbeta5 and alphavbeta6 integrins in ectopic and eutopic endometrium from women with endometriosis and compared them with those in normal control endometrium. Forty eutopic and ectopic samples from patients with endometriosis were compared with 12 control endometrial samples. Staining was evaluated using a computerized image analysis system by a blinded, independent observer. The immunoreactivity patterns for both alphavbeta5 and alphavbeta6 were very similar. In eutopic endometrium from women with or without endometriosis, the immunostaining intensity score for both integrins was stronger during the secretory than the proliferative phase. Immunoreactivity in endometriosis was greater than in eutopic endometrium. There were no significant menstrual cycle-related staining differences in endometriosis. The percentage of blood vessels immunolabeled was greater in endometriosis than eutopic endometrium from endometriosis patients and greater in eutopic endometrium from these patients compared with control endometrium. Ectopic tissue from patients with stages I and II endometriosis showed significantly higher staining intensity than ectopic tissue from patients with stages III and IV disease. Determination of the specific functional consequences of the differences observed in alphavbeta5 and alphavbeta6 integrin immunostaining may provide an increased understanding regarding the pathogenesis of endometriosis.