In addition to the immunological functions (Li et al., 2004, 2006; Liu and Zheng, 2007), recent studies have implicated CD24 function in tumorigenesis and progression of multiple cancer types, including carcinomas in lung, prostate, ovarian, breast, and brain (Kristiansen et al., 2002, 2003; Fillmore and Kuperwasser, 2007; Sagiv et al., 2008). The gene discussed is CD24; the disease is carcinoma.