USE OF MONOCLONAL-ANTIBODY 1H1, ANTICORTACTIN, TO DISTINGUISH NORMAL AND NEOPLASTIC SMOOTH-MUSCLE CELLS - COMPARISON WITH ANTI-ALPHA-SMOOTHMUSCLE ACTIN AND ANTIMUSCLE-SPECIFIC ACTIN

In preliminary experiments, we found that 1H1, a monoclonal antibody d irected against the v-src substrate cortactin, reacts with smooth musc le, myoepithelium, myofibroblasts, and manophages in fornaldehyde-fixe d human tissues. To evaluate the use of this antibody as a diagnostic reagent, we tested the immunohistochemical distribution of cortactin i n 61 mesenchymal neoplasms, II neuroectodermal neoplasms, and eight em bryonal epithelial neoplasms. The results were compared with those obt ained using antibodies against cu-smooth muscle actin and muscle-speci fic actin on a similar set of tissues. With the exception of positive staining in rhabdomyosarcoma, in this series only tumors with smooth m uscle differentiation appeared to contain cortactin (16 of 19 leiomyos arcomas, one infantile fibrosarcoma, one malignant fibrous histiocytom a). Immunoelectron mircoscopy localized cortactin to the actin-associa ted dense bodies of the microfilament network. We conclude that cortac tin may be a useful adjunct to alpha-smooth muscle actin and muscle-sp ecific actin as a marker for the study and diagnosis of smooth muscle neoplasms and related lesions. Copyright (C) 1995 by W.B. Saunders Com pany