To date only three ADCs, gemtuzumab ozogamicin (anti-CD33 antibody conjugated to calicheamicin), brentuximab vedotin (anti-CD30 conjugated to auristatin E), T-DM1 (which consists of the cancer-killing agent emtansine or DM1 linked to the HER2-binding antibody, trastuzumab), have been approved by Food and Drugs Administration [25, 26]. This evidence concerns the gene CD33 and cancer.