In this study, we evaluate the efficacy of EGCG to inhibit the EGFR signaling pathway by studying the phosphorylation status of EGFR, mTOR, STAT3, and p38-MAPK in NSCLC harboring wild-type EGFR (A549 cell line), in-frame deletion of exon 19 mutation (HCC827 cell line), and L858R/T790M double mutation (H1975 cell line). The gene discussed is STAT3; the disease is non-small cell lung carcinoma.