We have investigated the role of integrins in the epithelial to mesenchymal transition (EMT) induced by either collagen or fibroblast growth factor-1 (FGF-1) in the rat bladder carcinoma cell line NBT-II. The major collagen-binding receptor is the α2β1 integrin. An increase in expression of α2β1 integrin coincided with EMT induced by either collagen or FGF-1. When both inducers were present, a further increase in α2 expression was observed which correlated with an enhancement in the speed of locomotion. Overexpression of human α2 in NBT-II cells did not trigger EMT but rendered cells more sensitive to the dispersing effect of collagen and FGF-1. Anti-human α2 blocking antibodies affected cell scattering and motility induced by either collagen or FGF-1. These data demonstrate that α2β1 integrin is the mediator of the cell scattering effect induced by collagen. They also indicate that a functional α2 integrin is essential for the motile behavior of NBT-II cells during the FGF-1 induced EMT.