It also plays an important role in the development of various human cancers, including erbB2-overexpressing (erbB2+) breast cancer [15,16], castration-resistant prostate cancer (CRPC) [17], platinum-resistant/refractory ovarian cancer [18,19], and EGFR tyrosine kinase inhibitor (TKI)-resistant non-small cell lung cancer (NSCLC) [20,21]. The gene discussed is ERBB2; the disease is breast cancer.