SMAD complexes regulate the expression of target genes and are involved in many processes, such as inflammation and apoptosis.[6,7] Accumulative studies have shown that SMAD4 is involved in tumor invasion, metastasis and prognosis various tumors, such as cholangiocarcinoma and pancreatic cancer.[8,9] Moreover, many studies have detected the clinicopathological and prognostic significance of SMAD4 expression in NSCLC patients, but the potential clinicopathological value of Smad4 in NSCLC is inconsistent. The gene discussed is SMAD4; the disease is cholangiocarcinoma.