FOLR1 and neoplasm: Twelve of 26 considered genes did not show statistically significant differential methylation in any of the sample groups compared to healthy urothelium, despite a trend towards hypermethylation in ARG1, BHMT, BHMT2, CBS, DNMT3A, DNMT3B, FOLR3, SHMT1 and SMOX, and a trend towards hypomethylation in FOLR1/2 and MAT2B and in the corresponding tumor-adjacent, histologically benign urothelium.