The integrin family of cell adhesion proteins promotes the attachment and migration of cells on the surrounding extracellular matrix (ECM). Through signals transduced upon integrin ligation by ECM proteins or immunoglobulin superfamily molecules, this family of proteins plays key roles in regulating tumour growth and metastasis as well as tumour angiogenesis. Several integrins play key roles in promoting tumour angiogenesis and tumour metastasis. Antagonists of several integrins (alpha5beta1, alphavbeta3 and alphavbeta5) are now under evaluation in clinical trials to determine their potential as therapeutics for cancer and other diseases.