[Immunocytochemical study of the myoepithelial cells in fibrocystic disease and ductal carcinoma of the breast].

Myoepithelial cells (MC) were identified and the pattern of their distribution in dysplasia and duct carcinoma of the mammary gland was studied using a monospecific antiserum to smooth-muscle myosin of the human uterus, by the indirect Coons' method under luminescent microscope. Samples of the operation material from 10 patients with fibrous-cystic mastopathy and 26 patients with duct carcinoma were examined. In solid (7 observations) and comedo (4 observations) carcinomas with the structure of cancer in situ, MC were found intact in the periphery. In invasive growth of these tumors as well as in scirrhus (5 observations) and adenocarcinoma (10 observations) MC disappeared from the duct structures and were absent in carcinoma proliferates. Positive immunofluorescence in the conventional location of MC in the alveolar duct system of the mammary gland allows sufficiently valid identification and study of the distribution and changes in these cells. The immunocytochemical verification of MC in dysplasia and duct carcinoma indicates the possibility of using MC as markers of duct carcinoma in situ; MC disappearance from the duct structures characterizes the beginning of the infiltrative tumor growth.