Malignant PCs in MM and AL amyloidosis share several key features which are of relevance to immunotherapeutic approaches, including the surface expression of CD38 [22], B-cell maturation antigen (BCMA) [23], and G-protein-coupled receptor, class C group 5 member D (GPRC5D) [24]. The gene discussed is GPRC5D; the disease is AL amyloidosis.