Elevated expression of human BMI-1 has also been reported in multiple cancer samples by immunohistochemistry or mRNA analysis for oral cancers (Kang et al, 2007), lung cancers (Vonlanthen et al, 2001; Breuer et al, 2004), lymphomas (Dukers et al, 2004; Raaphorst et al, 2004), and breast cancer (Kim et al, 2004; Silva et al, 2006) as well as in cancer cell lines (Satijn et al., 1997; Satijn and Otte, 1999), although the exact function is not known. This evidence concerns the gene BMI1 and breast cancer.