Integrins are heterodimeric cell surface receptors composed of alpha and beta subunits which mediate cell-cell and cell-extracellular matrix attachments. Integrin beta2 (CD18) associates with integrin alpha L (CD11a) to form the leukocyte function-associated antigen-1 (LFA-1) with integrin alpha M (CD11b) to form Complement Receptor 3 (CR3) and with integrin alpha X (CD11c) to form Complement Receptor 4 (CR4). Each integrin receptor can bind various Intercellular adhesion molecules (ICAMs). Aberrant integrin expression has been found in many epithelial tumors. Changes in integrin expression have been shown to be important for the growth and early metastatic capacity of melanoma cells.