This investigation examined the ability of low-metastatic AT-1 and high-metastatic ML and MLL cell lines to adhere to a monolayer of bovine aortic endothelial cells and fibronectin substratum and penetrate a matrigel basement membrane matrix. Cell area, shape factor, and motility as influenced by fibronectin were also examined using these cell lines. The ability of these cells to adhere to fibronectin and traverse matrigel matrix correlated with their metastatic potential. In addition, fibronectin increases cell circularity and reduces cell area as metastatic potential increases within AT-1 to ML or MLL cell lineages.