Expression and DNA methylation of SLC22A1 and SLC22A3 in hepatocellular carcinoma and adjacent non-tumor tissue. (a,b) Quantitative mRNA expression of SLC22A1 (a) and SLC22A3 (b) in hepatocellular carcinoma (HCC), adjacent non-tumor tissue and histologically normal liver tissue (pooled n = 100, IKP-liverbank). Data represent median and range. (c,d) DNA methylation profiles of SLC22A1 (c) and SLC22A3 (d) in HCC and adjacent non-tumor tissue. DNA methylation (y-axis) at each individual CpG site (x-axis) is given. Methylation profiles show median levels (diamonds) at each CpG position (shaded areas are defined by 25%/75% quantiles). P-values are given for differences in methylation level for CpG sites. *P < 0.05, **P < 0.01 are given on the x-axis. (e) Correlation of SLC22A1 mRNA expression in the 22 HCC samples with DNA methylation of one individual CpG site (SLC22A1_02_CpG_5) in SLC22A1.