At day 30, co-administration of breast cancer cells with CD133+ HPCs (MCF-7 1.43cm3 ± 0.15, MDA-MB-231 1.76 cm3 ± 0.13) significantly increased tumor volumes when compared to that of the mice with breast cancer alone and the cells mixed with CD133- HUCBCs (MCF-7 0.83cm3 ± 0.12, MDA-MB-231 1.03 cm3 ± 0.16; P < 0.05 for all). This evidence concerns the gene PROM1 and neoplasm.