ADAM9 (A disintegrin and metallopeptidase domain 9, MDC9, meltrin gamma), is a type 1 transmembrane protein that has been associated with cancer development and metastases. ADAM9 is consistently overexpressed in various human cancers, and plays a role in tumorigenesis in mouse models. ADAM9 cleaves and releases a number of molecules with important roles in tumorigenesis and angiogenesis, such as EGF, FGFR2iiib, Tie-2, Flk-1, EphB4, CD4, VCAM-1, and VE-cadherin, and could represent a potential therapeutic target in tumors where it is highly expressed. ADAM9 belongs to a family of transmembrane, disintegrin-containing metalloproteinases involved in protein ectodomain shedding and cell-cell and cell-matrix interactions. ADAM-9 adhesive domain plays a role in regulating the motility of cells by interaction with beta1 integrins and modulates MMP synthesis.