SMAD2 and lung cancer: For example, in lung cancer, curcumin inhibits EMT through the PI3K/Akt/mTOR signaling pathways [6], in renal tubular epithelial cells, it inhibits EMT through the PPARγ pathway [40], in triple-negative breast cancer cells, it inhibits EMT through the TGF-β and PI3K/Akt signaling pathways [41], in human colorectal cancer, it inhibits EMT through the TGF-β/Smad2/3 signaling pathway [42], while in pancreatic cancer, it inhibits EMT through the PI3K/Akt/NF-κB signaling pathway [43].