These include the ECM components fibulin 1 and collagens α1(I) and α1(VIII), the integrin subunits α1, α2, β4 and αV, the proteases cathepsins H and L and matrilysin (MMP7), the protease inhibitor TIMP2, the β-galactoside-binding proteins galectins 2 ,7 and 9 and uPAR, the receptor for urokinase plasminogen activator, a serine protease that has been linked to breast cancer through its association with integrins (van der Pluijm et al, 2001). The gene discussed is PLAU; the disease is breast carcinoma.