Chimeric antigen receptor (CAR) T-cell therapy targeting B-cell maturation antigen (BCMA) has provided frequent, deep, and durable responses in relapsed, refractory multiple myeloma (MM), with initial Phase I/II studies reporting 73–100% overall response and 31–69% complete response1–3. The gene discussed is TNFRSF17; the disease is plasma cell myeloma.