HEY1 and esophageal squamous cell carcinoma: Notch signaling pathway components (including Notch receptors, ligands, or targets genes such as HES1, HEY1, or HEY2) were found to be amplified or overexpressed in a subset of tongue tumor samples 80, in HNSCC tumors over normal mucosa 81, in OSCC 82, 83, 84, and frequently in ESCC samples 85.