Expression of miR-224 in non-small cell lung cancer (NSCLC) tissues and cell lines. The expression levels were measured by qRT-PCR. A MiR-224 expression was significantly lower in NSCLC tissues than in the corresponding non-cancerous tissues. MiR-224 expression levels were calculated by the 2−ΔCt method and normalized to U6 small nuclear RNA. B miR-224 expression was down-regulated in NSCLC cell lines A549, H460, 95D, and H358, compared to normal human bronchial epithelial cell line 16HBE.