In a case, the phase III PHENIX study considerably observed that, in women with HER2+ metastatic BC, the combination of capecitabine and pyrotinib increased the median progression-free survival (PFS; 11.1 months vs. 4.1 months) by 7.0 months, improving the objective response rate (ORR; 68.6% vs. 16.0%) compared to capecitabine alone. The gene discussed is ERBB2; the disease is breast cancer.