Tumor weight in mice at day 40 after implantation of MDA231-LM2 breast cancer cells in a control or SPP1 deficient setting undergoing combination treatment with doxorubicin (Adriamycin) and cyclophosphamide (AC regimen). Control, AC and SPP1 def. n = 16 tumors per group, SPP1 def. + AC n = 14 tumors. 