We observed that lapatinib, a small-molecule ErbB2/EGFR inhibitor used for treatment of ErbB2-positive breast cancer, strongly upregulates Irf6 in detached ErbB2-positive human breast cancer cells BT-474, AU-565, and HCC-1419 (Fig. 1d, e) [4]. This evidence concerns the gene ERBB2 and breast cancer.