As models of EGFR+/PDGFRβ− cell lines, we used breast cancer BT-474 and epidermoid carcinoma A431 cell lines, which express moderate and high levels of EGFR, respectively, without expressing PDGFRβ ([23, 44] and Supplementary Fig. 6), and are thus recognized by CL4 [19] but not Gint4.T [35, 39]. Here, EGFR is linked to squamous cell carcinoma.