The methylation status of 10 candidate markers (twist1, vav3-as1, fbn1, c9orf50, sfmbt2, kcnq5, fam72c, itga4, kcnj12, znf132) were analyzed in all plasma samples (N = 268) using a qPCR-based assay (Additional file 1: Figure S1 and Additional file 1: Table S1), divided into non-CRC group (Normal, HP, NAA) and AA/CRC group (AA and stage I-IV CRC). This evidence concerns the gene PTGDR and colorectal carcinoma.