CD24 and breast cancer: The Notch intracellular domain is released upon receptor activation and acts as a transcriptional cofactor to promote stemness [10], therefore we examined the levels of Notch1 receptor domains in the CD24+CD29hi stem cell-enriched population [22, 23] from PyMT-Ccr7WT and PyMT-Ccr7−/− murine mammary tumors.