TNFRSF17 and plasma cell myeloma: For example, BCMA on the cell surface can be cleaved by γ-secretase [77], and the resulting reduced cell surface level of BCMA and increased serum level of soluble BCMA could potentially limit the efficacy of BCMA-directed adoptive T-cell therapy by inhibiting CAR T-cell recognition of BCMA on myeloma cells [33,78,79].