CDK4 and head and neck squamous cell carcinoma: Western blot analysis of MDA-9/Syntenin depleted HNSCC cells demonstrated marked reduction in the expression level of CyclinD1 (CCND1), CDK4, activated STAT3 (Tyr705), PI3K and CTNNB1 and slight decrease in CDK6 expression (Fig. 2B-E).