In summary, DNA collected from blood and stool samples of CRC patients has been analysed with the purpose of discovering hypermethylated genes that are CRC specific. Hypermethylation of these specific genes in blood samples have been associated with poor prognosis (p16, HLTF, TMEFF1, ALX4, VIM, and FBN2), early diagnosis (APC, TAC1, SEPT9, NEUROG1, RASSF1A, SDC2, and THBD) and potential recurrence markers for CRC patients (p16 and TFPI2). Especially THBD and SDC2 show great promise as markers of early stage CRC, and the fact that it seems possible to use DNA methylation in blood as a marker of disease recurrence warrants further research, using these genes individually or in concert with others. Hypermethylation of DNA in stool samples of CRC patients have not been analysed as thoroughly as in blood samples, though detection of hypermethylated DNA fragments in stool samples could be used when screening for CRC. SFRP2, TMEFF2, SPG20, TFPI2, and PHACTR3 have shown promise in the detection of CRC at early stages or in premalignant lesions. The fact that PHACTR3 could be detected in iFOBT-fluid (reaching increased sensitivity and specificity) indicates a possible new screening method, where DNA hypermethylation is analysed in one stool sample. There are however issues regarding the analytical sensitivity of hypermethylated DNA in stool-samples from CRC patients. The diagnostic sensitivity for right-sided tumours is lower than for left-sided tumours suggesting DNA degradation in the colonic lumen before stool excretion. This promotes blood as the media of choice for detection of hypermethylated genes as biomarkers in the diagnosis, prognosis and recurrence detection of CRC.