The overexpression of miR-224 promotes cell proliferation, anti-apoptosis, migration, and invasion via directly targeting the TNFα-induced protein 1 (TNFAIP1), SMAD4, caspase 3, and p21 in non-small cell lung cancer (NSCLC), colorectal cancer (CRC), and hepatocellular and prostate cancers [14–19]. The gene discussed is SMAD4; the disease is non-small cell lung carcinoma.