Plasma was collected from patients with atherosclerosis and healthy individuals to determine the expression of miR-503-5p, smad/TGF-β signaling pathway molecules (smad7, smurf1, smurf2, and TGF-β1) using reverse transcription-quantitative polymerase chain reaction (RT-qPCR). The gene discussed is TGFB1; the disease is atherosclerosis.