It is found that 3α-Aminocholestane (3AC) results in reduced multiple myeloma (MM) growth in vivo, as determined by quantitation of free human Igλ light chain in the plasma after OPM2 challenge. In addition, reduced numbers of circulating OPM2 cells, as determined by human HLA-ABC staining, is observed in peripheral blood from 3α-Aminocholestane-treated mice compare with vehicle controls. Most importantly, 3α-Aminocholestane treatment results in significantly enhanced survival of mice after tumor challenge. In 3α-Aminocholestane-treated mice that resist treatment, it is found that MM tumors exhibit an upregulation of SHIP2, reminiscent of in vitro treatment of OPM2 cells and suggesting that SHIP1 inhibition may select for tumor cells with increased SHIP2 expression^[2].