SMAD2 and cancer: Nevertheless, unlike in other cancer types such as colon cancer, mutations in TGFBR2 and SMAD2/4 genes appear to be uncommon in NSCLC, according to previously reported studies [11, 12] and analysis of the catalog of somatic mutations in cancer (COSMIC), suggesting that additional mechanisms involved in maintaining constitutive activation of TGF-β signaling cascades are to be revealed in NSCLC.