VLA-3 DISTRIBUTION IN NORMAL AND NEOPLASTIC NONLYMPHOID HUMAN TISSUES

Using monoclonal antibody (mAb) M-Kid 2 to the alpha3beta1 heterodimer , we have evaluated immunohistochemically the in vivo expression of th e Vla-3 integrin in normal and transformed non-lymphoid human tissues. In normal tissues the alpha3beta1 complex displays a polarized distri bution at the baso-lateral aspect of most keratinizing and glandular e pithelia. In addition the integrin is detected in perineurium, basal l amina of smooth muscular fibers, vascular media, podocytes and Bowman' s capsule, myoepithelial cells of the parotid and breast, and in pulmo nary alveoli. Neoplastic transformation is associated with qualitative and quantitative changes in expression of this integrin. The loss of polarized distribution often occurs in various malignancies. Furthermo re, a significant decrease in expression occurs in 13% of the colon-re ctum carcinomas, 75% of the ductal invasive, and 40% of the lobular in vasive breast carcinomas. Among the lung malignancies tested, the smal l cell lung carcinomas (SCLC) were found to be consistently unreactive with mAb M-Kid 2. Analysis of Vla-3 expression in established tumor c ell lines demonstrated that the integrin is almost invariably expresse d by the plastic adherent cell subpopulations.