Distribution of integrin cell adhesion receptors in normal and malignant lung tissue

The integrins are a family of transmembrane glycoproteins that serve as cell-cell and cell-substratum adhesion molecules and help regulate cellular morphology, differentiation, and proliferation. The integrin repertoire of a cell may therefore influence its behavior under resting conditions or following malignant transformation. For this reason, the distribution of integrins in normal lung tissues was determined using monoclonal antibodies against integrins of the β1 (VLA) and β3 (cytoadhesin) subfamilies and compared with the distribution in a limited number of lung carcinomas. The integrin subunits that bind to collagen and laminin (α1, α2, α3, and α6) and the αv subunit, which can pair with β1, β3, or β5 and promote fibronectin, fibrinogen, or vitronectin binding, were the predominant integrins expressed on the major cell types of the lung, i.e., bronchial epithelium, vascular endothelium, and smooth muscle. Strong expression of the α5β1 fibronectin receptor and the β3 subunit was restricted to the end...