promoter hypermethylation in primary human bladder cancer is associated with loss of
mRNA expression. (A) Representative MSP results of the ST6GAL1 promoter methylation status in four papillary non-invasive pTa low grade tumors (PAP) as well as four invasive high grade bladder cancer (INV) samples in comparison to four normal tissue specimens (NU). Bands labeled with U and M show unmethylated and methylated DNA, respectively. Percent values reflect methylation frequency (M frequency). Bisulphite-converted unmethylated, genomic (U-co) and polymethylated, genomic (M-co) DNA were used as positive controls. DNA control: genomic, non- bisulphite-converted DNA, NTC: non-template control. (B) Box plot illustrating ST6GAL1 mRNA downregulation according to hypermethylated ST6GAL1 promoter status in bladder cancer (UC). (U): unmethylated tumors. (M): Methylated tumors. Horizontal lines: grouped medians. Boxes: 25–75% quartiles. Vertical lines: range, peak and minimum; *p < 0.05.