On the other hand, Notch target genes Hes1, Hes5 and Hey2 were expressed with a particular pattern for each gene, with higher Hes1 expression in tumor corticotropes and reduced Hes5 and Hey2 mRNA levels compared with normal pituitary glands, Hey2 being almost undetectable in ATt20 cells. This evidence concerns the gene HES1 and neoplasm.