SMAD2 and lung cancer: Inhibition of TGF-β signaling was found to enhance radiosensitivity in glioblastoma, breast cancer and lung cancer.13, 14, 15, 16 Moreover, the involvement of Smad2 in EMT through the increase in Snail expression has also been documented.17 The above findings support the notion that TGF-β/Smad signaling has a pivotal role in tumorigenesis.