This proposition is based in our earlier observations showing that KDM2B, in concert with EZH2, represses a set of microRNAs that regulate several members of the polycomb complexes, including EZH2, SUZ12, BMI1 and RING1B.12 We recognize that these observations were made in studies focusing on breast rather than bladder cancer. This evidence concerns the gene BMI1 and urinary bladder carcinoma.