T-DM1, an antibody drug conjugate (ADC), was approved in 2013 after demonstrating improved median PFS and OS over lapatinib plus capecitabine in EMILIA, a Phase III randomized controlled trial of patients with HER2 + advanced breast cancer previously treated with trastuzumab and a taxane (PFS: 9.6 vs. 6.4 months; OS: 30.9 vs. 25.1 months) [15]. Here, ERBB2 is linked to breast cancer.