Our observations appear to corroborate preclinical studies in which EC-FAK regulates blood vessel permeability and metastasis.19,42,55 Given that high EC-pY397-FAK expression levels were associated not only with lymph node stage but also with relapse and that the main cause of relapse is metastatic spread, it is plausible that EC-pY397-FAK also contributes to breast cancer metastasis. Here, PTK2 is linked to breast cancer.