TNFRSF17 and plasma cell myeloma: Treatment of multiple myeloma primary samples with the GSI PF-03084014 at concentrations of 1 to 1,000 nmol/L significantly increased BCMA expression at the multiple myeloma cell surface in 3 of 4 samples with a median rise in MFI from 601 to 1,381 after treatment with GSI at 100 nmol/L (Fig. 5C).