FN1 and melanoma: Zhou et al. observed that this disintegrin from Agkistrodon contortrix contortrix venom was not able to cause cytotoxicity in MDA-MB-435 cells (human melanoma cells formerly classified as a human breast cancer cell line), and also prevented the binding of these cells to integrins (αvβ3) and extracellular matrix proteins, such as vitronectin and fibronectin, thus inhibiting the adhesion process [22].