Aberrant overexpression of Bmi1 has been reported in multiple tumour types, including breast cancer,14 colon carcinoma,15 melanoma,16 and hepatocellular carcinoma.17 Although upregulation of Bmi1 in human NSCLC has been reported,18 the role of Bmi1 in the pathogenesis of NSCLC and its exact target genes have not been extensively studied. This evidence concerns the gene BMI1 and breast cancer.