The role of p130Cas/BCAR1 as a mediator of ErbB2 signalling was initially demonstrated in breast cancer cell lines devoid of ErbB receptors, in which over-expression of ErbB2 was sufficient to induce cell migration by triggering the coupling between p130Cas/BCAR1 and Crk [35]. This evidence concerns the gene BCAR1 and breast carcinoma.