GREM1 and neoplasm: As shown in Figure 5B, anti-Grem1 therapy significantly reduced MM tumor burden in vivo at the experimental endpoint by 54.5% (p = 0.0012; median BLI; IgG control antibody, 1.56 × 107 photons/sec (interquartile range: 1.12 × 106–1.02 × 108)) vs. anti-Grem1 antibody, 6.46 × 106 photons/sec (interquartile range: 5.10 × 105–4.65 × 107, Figure 5B).