STAT3 and head and neck squamous cell carcinoma: Molecular effects of EGCG on human HNSCC cell lines such as YCU-N861 and YCU-H891 were examined and results of this study showed that treatment with EGCG inhibited phosphorylation of the EGFR, signal transducer, activator of transcription3 (Stat3), and extracellular regulated kinase (ERK) proteins [71].