One study regarding the integrative genomic analyses of the HES/HEY family presumed that Notch-independent HES1 and 3 transcription occurred in undifferentiated ES cells, and that Notch-dependent HES1 and 5, HEY1 and 2, and HEYL transcription occurred in fetal, adult or cancer tissue (8). Here, HEY1 is linked to cancer.