PS-341 does not worsen the myelosuppressive effect of 153-Sm-EDTMP. Blood cell counts in treatment groups bearing 5TGM1-myeloma platelets (A), hemoglobin (B), and white blood cells (C) were monitored on days 12, 21, 25, and 32. Error bars represent the mean ± SD from the counts of 6 mice in each group. (D) Clonogenic assay with enriched hematopoietic progenitor cells from normal mice receiving PS-341 and/or 153-Sm-EDTMP. Data represent relative colony number (CFU-GEMM, CFU-GM, BFU-E, BFU-MK) expressed as a percentage of colony counts in control non–tumor-bearing mice. Bars indicate SD.