JAG1 and head and neck squamous cell carcinoma: However, in a study of the association between NOTCH1 and HEY1 in HNSCC, it was shown that HEY1 expression was independent of the activation of NOTCH1, was not associated with either JAG1 or NICD1 expression, and the high expression of HEY1 was associated with a poor prognosis in patients with HNSCC 32.