FDA-approved MABS are now in clinical use in multiple cancer indications, such asrituximab (anti-CD20) for CLL, cetuximab (anti-EGFR) for EGFR+ colorectal cancer, trastuzumab (anti-HER2) for HER2+ breast cancer, and elotuzumab (anti-SLAMF7) for multiple myeloma. The gene discussed is ERBB2; the disease is B-cell chronic lymphocytic leukemia.