We next investigated if the ability of the dI (F4) or dIII (A5) specific IgGs to block signaling correlated with the ability to inhibit growth of a panel of ERBB2-positive breast (BT-474 & SK-BR-3) and gastric (NCI-N87) cells as well as the EGFR-positive renal cancer cell line (ACHN). Here, EGFR is linked to renal carcinoma.