Previous studies indicated several miRNAs were downregulated in tumours due to the hypermethylated status of CpG islands in the promoter region.13, 14 To evaluate the methylation status of CLCN5 and the regulatory impact on miR‐502‐5p in BCa, RT‐qPCR was performed to demonstrate the expression changes of miR‐502‐5p in T24 and UM‐UC3 cell lines after 5‐aza‐CdR treatment. Here, CLCN5 is linked to neoplasm.