It has been reported that dacomitinib has effective anticancer activity in various cancers, including EGFR-mutation-positive NSCLC, HER2-positive gastric cancer, HER2-amplified breast cancer, human bladder cancer, and cetuximab-resistant head and neck cancer cell lines [51,54,57,94,95]. The gene discussed is ERBB2; the disease is urinary bladder cancer.