The results showed that in 881 CRC patients, the mutations of SMAD1 and SMAD6 were 1.9%, SMAD2 was 7%, SMAD3 and SMAD5 were 5%, SMAD4 was 18%, and the mutation rate was 4% for SMAD7 and 2.8% for SMAD9. The gene discussed is SMAD4; the disease is colorectal carcinoma.