Compared with the BMI1 copy number variation (CNV) in bladder cancer patients sensitive to chemotherapy in TCGA data sets, BMI1 locus was highly amplified in bladder cancer patients resistant to chemotherapy (P = 0.0254, Figure 7A–7D), suggesting that ectopic BMI1 amplification involved in the chemoresistance of bladder cancer. Here, BMI1 is linked to urinary bladder cancer.