We examined relative mRNA expression of four Notch receptors (Notch1-4), two Jagged ligands (Jag1 and 2), three Delta-like ligands (Dll1, 3, and 4), and four target genes (Hes1, Hes5, Hey1, and Hey2) in order to determine activation of the Notch signaling pathway in colorectal adenomas (n = 9) and cancers (n = 66). This evidence concerns the gene HES5 and cancer.