EGFR and breast cancer: For example, compound IV displayed potent cytotoxic activity against breast cancer cell line (MCF-7) with IC50 of 4.33 μM, whereas, the positive control staurosporine showed IC50 of 10.61 μM, also exhibited submicromolar inhibitory activity of EGFR (IC50 = 0.46 μM) comparable to erlotinib (IC50 = 0.23 μM)23.