NANOG and breast cancer: Exposure of HCC1954 and SUM159 cells to hypoxia induced: increased migration and invasion; increased ALDH1 and NANOG expression; and enrichment of CD24−CD44+ and mammosphere-forming cells, all of which were lost in subclones expressing shRNA targeting PLXNB3.54 Since migration, invasion, and CSC properties are all fundamental to metastatic breast cancer cells, we injected MDA-MB-231 subclones with altered PLXNB3 expression into the mammary fat pad of immunodeficient female mice.