BCMA CAR mRNA can express the CAR protein targeting human BCMA. BCMA CAR mRNA can trigger the transient expression of CAR, enabling T cells to be targeted without the need for permanent genetic modification. BCMA is a member of the tumor necrosis factor receptor superfamily 17 (TNFRSF17), also known as B-cell maturation antigen (CD269), which promotes B-cell survival and plays a role in regulating humoral immunity. BCMA is highly expressed in multiple myeloma and is a biomarker for the diagnosis of multiple myeloma.