Furthermore, recent studies with methylated WIF1 (Wnt inhibitory factor 1) and NPY (neuropeptide Y) showed that hypermethylation of their gene promoters is detectable in both CRC tissue and corresponding ctDNA [121], while post-surgery detection of methylated BCAT1 (branched-chain amino acid transaminase 1) and IKZF1 (IKAROS family zinc finger 1) in ctDNA in CRC patients was associated with increased risk of residual disease and its subsequent recurrence [122]. The gene discussed is IKZF1; the disease is colorectal carcinoma.