SMAD4 and non-small cell lung carcinoma: However, Xie et al evaluated SMAD4 expression by immunohistochemistry in 85 NSCLC patients and analyzed the relationships between SMAD4 expression and the prognosis of NSCLC patients, finding that there was no significant association between SMAD4 and the OS of NSCLC patients.[11] In this study, we found that SMAD4 was correlated with good OS in NSCLC.