CDKN1A and head and neck squamous cell carcinoma: Another study has also showed that simultaneous treatment with EGCG and erlotinib, an inhibitor of EGFR-tyrosine kinase, strongly induced cell cycle arrest and apoptosis via p53-dependent induction of p21, p27, and Bim, and p53-dependent inhibition of NF-κB and its antiapoptotic target, Bcl-2 in squamous cell carcinoma of the head and neck cells (SCCHN) [36].