While, in breast cancer, activated PAR1 is engaged in binding Etk/Bmx via the PH domain, thus occupying this site, it is plausible that the Pro-712/713 proline-rich region of FAK (e.g., Pro-X-X-Pro-X-Arg) associates with the SH3 domain present in Etk/Bmx, connecting PAR1 to integrins via FAK association to Etk/Bmx. This evidence concerns the gene PTK2 and breast cancer.