In addition, CerS6 downregulation was observed in ER stress induced by tunicamycin or suberoylanilide hydroxamic acid, and the knockdown of CerS6 was involved in ATF-6 activation and ER stress-mediated apoptosis in head and neck squamous cell carcinoma (HNSCC) cell lines42. This evidence concerns the gene ATF6 and head and neck squamous cell carcinoma.