CASP9 and head and neck squamous cell carcinoma: C18 CER is mainly synthesized by CERS1.12 Koybasi found in HNSCC cells, overexpression of CERS1 resulted in impaired cell growth, which was related to telomerase activity and mitochondrial dysfunction.12 Similarly, Senkal found that knock-down of CERS1 in HNSCC cells resulted in attenuation of apoptosis due to the repression of casepase-3 and caspase-9 activity.13Moreover, CERS1 is also linked to chemotherapy resistance.