PROM1 and breast cancer: Following culture of each type of breast cancer cells alone, with CD133+ HPCs or CD133- HUCBCs separately in Transwell chambers for 24 h, we found that the numbers of invaded cells that had been cultured with CD133+ HPCs (MCF-7160 cells±15, MDA-MB-231222 cells±5) were significantly greater than that of the cells cultured alone or with CD133- HUCBCs (MCF-7 26 cells±11, MDA-MB-231 72 cells±9; P < 0.05 for all, Fig. 4a and b) in two different lines.