Although the T-DM1 group had a higher incidence of thrombocytopenia and elevated serum transaminase levels, the lapatinib combined with capecitabine group had a more pronounced incidence of diarrhea, nausea, vomiting, and hand-foot syndrome (Diéras et al., 2017).Another clinical trial named TH3RESA (NCT01419197) aimed to evaluate the efficacy and safety of T-DM1 compared to physician’s choice of treatment in HER2-positive metastatic breast cancer patients who had previously received trastuzumab, lapatinib, and taxanes. The gene discussed is ERBB2; the disease is Thrombocytopenia.