MAPK3 and non-small cell lung carcinoma: To determine whether EGFR down‐regulation by miR‐134 can result in weakened EGFR signaling, we examined the activation of p‐EGFR, p‐ERK1/2, p‐AKT and p‐STAT3 in four NSCLC cell lines (A549, H1299, H520 and H1975) after miR‐134 overexpression.