IRF4 and colorectal carcinoma: For instance, if a high specificity is required but a 50% sensitivity for CRC is acceptable, as is already the case in some screening programs around the world that use a conservative fecal haemoglobin concentration cut-off for FIT [26], this is achievable by detection of just methylated IRF4 DNA in blood alone, although this approach would require further validation in a true screening context.