For example, the trastuzumab of T-DM1 can bind to the HER2 receptor of cancer cells and block the formation of heterodimer between HER2 and HER1, HER3 or HER4, which inhibits the signal transduction pathways (like PI3K or MAPK) of cell survival and proliferation to induce the cell apoptosis.121. The gene discussed is ERBB2; the disease is cancer.