Our findings to date suggest that regulation of CD24 expression in tumor cells is due in part to the balance of Bcl-2 and TGF-βR1 signaling via downstream activities of ATM and NDRG2, a notable tumor suppressor gene product that regulates CD24 expression to decrease the metastatic potential of breast cancer cells. The gene discussed is TGFBR1; the disease is breast carcinoma.