STAT3 and head and neck squamous cell carcinoma: After treating Fadu, Cal-27 and Hep-2 cells with different concentrations of DHA, inhibition of STAT3 activation was prominent, but little or no inhibition of Akt and ERK phosphorylation was observed (Fig 3A); the expression of p-Jak2 in three HNSCC cell lines was markedly reduced in a dose-dependent manner; however, neither inhibition of p-SRC nor downregulation of p-EGFR was observed (Fig 3B).