The effect of ErbB2 on BLNK was not unique to MCF10A cells since we found that while treatment of attached human ErbB2-positive breast cancer cells AU565, SKBR3 and BT474 [11] with the therapeutic anti-ErbB2 antibody trastuzumab does not upregulate BLNK protein (Fig. 1C–E, left), trastuzumab noticeably upregulates this protein when these cells are detached from the ECM (Fig. 1C–E, right). This evidence concerns the gene ERBB2 and breast cancer.