Along these lines, the results reported here also indicate that the kinase activity of FAK is required for 4T1 murine breast cancer cell pulmonary metastasis: the pharmacological inhibition of FAK kinase activity by BI 853520 is consistent with the previously reported findings that the kinase domain of FAK is required for metastatic outgrowth of 4T1 cells42. Here, PTK2 is linked to breast carcinoma.