In order to strengthen our findings, we analyzed ST6GAL1 promoter methylation and gene expression in a dataset of independent studies (The Cancer Genome Atlas (TCGA) (https://tcga-data.nci.nih.gov)), in total representing 184 different bladder cancer samples (for cohort characteristics see Additional file 1: Table S1). This evidence concerns the gene ST6GAL1 and urinary bladder cancer.