SMAD4 and non-small cell lung carcinoma: The serum concentration of Smad4 in poorly differentiated NSCLC (78.65± 15.08 ng/L) was in turn lower than that in moderately differentiated (102.47 ± 19.18 ng/L) and well differentiated NSCLC (155.82 ± 27.63 ng/L) (P < 0.001) (Table 3; Fig. 2d).