The activation of the TGF-β/smad signaling pathway mediates apoptosis, contributing to its anti-oncogenic effect in lung cancer, which is supported by studies showing that TGF-β1 plays an important role in mediating apoptosis of small cell lung cancer cells [15] and that the TGF-β1/smad2 signaling pathway is responsible for dexamethasone-induced apoptosis of human lung A549 adenocarcinoma cells [16]. Here, TGFB1 is linked to small cell lung carcinoma.