ERBB2 and breast neoplasm: The absence of a correlation between nuclear Vav1 and the different molecular subtypes was confirmed in breast tumor-derived cells, since Luminal B (BT-474), HER2 (MDA-MB-453) and Claudin-low (MDA-MB-231) cells show similar levels of the protein, indicating that the de-regulation of Vav1 expression and the accumulation of the protein inside the nucleus of breast tumor cells may not be uniquely correlated to any of the known markers of tumorigenic/metastatic properties of breast tumors [16].