Cell adhesion molecules (CAMs) such as intercellular adhesion molecule (ICAM-1), vascular adhesion molecule (VCAM-1), and lymphocyte function-associated antigen (LFA-1) facilitate interaction among cells of various lineages and are therefore crucial in the complex processes of inflammation and tumor growth (1 ,2) . This chapter discusses the mechanisms of action of CAMs and offers methodologic information for their detection and identification in fresh-frozen lung tissue. In particular, this chapter describes our experience with these CAM ’s in pulmonary non-small cell carcinoma and also in non-neoplastic tissue compartments of the lung such as endothelial cells, lymphocytes, fibroblasts, alveolar epithelial cells, and bronchial epithelial cells.