Although no difference in the levels of Pyk2 expression was observed in FAK-deficient tumours (Figure S5a and S5b in Additional file 5), Pyk2 is overexpressed in ErbB2 tumours when compared to adjacent mammary tissue that does not express high levels of activated Erbb2 (Figure S5c in Additional file 5). Here, PTK2 is linked to neoplasm.