Smad7 expression in patients with diabetes. Serum Smad7 expression levels were determined by RT-qPCR in patients with diabetes. *P<0.05. Smad7, SMAD family member 7; RT-qPCR, reverse transcription-quantitative polymerase chain reaction; DN, patients with diabetic nephropathy; C, healthy controls; D, patients with diabetes without complications; DR, patients with diabetic retinopathy; DC, patients with diabetic cardiomyopathy; DL, patients with diabetic lung diseases.