VAV1 and breast cancer: The subcellular localization of Vav1 was also investigated in 5 human breast tumor-derived cell lines (BT-474, MCF7, MDA-MB-453, MDA-MB-468 and MDA-MB-231) representing the most frequent subtypes of breast cancer in terms of immunoprofile, molecular phenotype and in vivo tumorigenicity [18, 19].