156). We have shown that GATA4promoter methylation is highly prevalent in CRC, suggesting that methylation is an earlyevent in colorectal carcinogenesis. GATA4 methylation, detected infaecal DNA has potential to be used as a biomarker for improving pre-selection tests forcolonoscopy (Ref. 80), especially if theclinical and analytical sensitivity and specificity can be improved by adding additionalbiomarkers and by introducing sensitive analysis techniques such as for examplemethylation on beads technology (Ref. 157). This evidence concerns the gene GATA4 and colorectal carcinoma.