In erlotinib-resistant NSCLC cells (PC-9/ER), miR-223 binds to IGF-1R and affects the IGF-1R/PI3K/Akt/mTOR signaling pathway by reducing the phosphorylation levels of IGF-1R, Akt, S6, and P70S6K (ribosomal protein S6), decreasing cell viability and inducing cell apoptosis after erlotinib treatment. The gene discussed is IGF1R; the disease is non-small cell lung carcinoma.