TNFRSF17 copy number and BCMA protein expression correlate with PFS. (A) Tumor cell TNFRSF17 mRNA expression, gene activity score (normalized counts within chromatin accessible gene promoters), copy number, BCMA MFI, and sBCMA in relation to PFS in patients receiving anti-BCMA CAR T-cell therapy (n = 15). (B) Kaplan-Meier survival curve by TNFRSF17 copy number status detected in plasma cells before GSI exposure. (C) Percent change in sBMCA levels measured in the serum after GSI treatment compared with pretreatment baseline levels. All comparisons to baseline except the 1-hour measurement were statistically significant (Wilcoxon rank-sum test, P < .05).