Recently, altered QKI expression was implicated in various human cancers, including colorectal cancer,33 paediatric brain tumours,34 glioma,35 renal clear cell carcinoma,9 lung cancer17 and prostate cancer.18 In this study, we measured QKI‐6 expression and determined its role in regulating bladder cancer in vitro and in vivo, and we also investigated the molecular mechanism underlying QKI‐6’s effect in bladder cancer cells. This evidence concerns the gene QKI and prostate carcinoma.