The potency of quercetin-3-methyl ether was exploited to induce cell cycle arrest in the G2/M phase, and up-regulation of the phosphorylation level of cyclin B1 (Ser 147) to potently block the growth of breast cancer cells that are resistant or sensitive to lapatinib, a reversible inhibitor of EGFR and HER2 [271]. Here, ERBB2 is linked to breast cancer.