SMAD2 and esophageal squamous cell carcinoma: In esophageal squamous cell carcinoma (ESCC), neuronal vesicle trafficking-associated protein 1 (NSG1) amplifies glycolysis and lactate production through activation of the TGF-β/p-SMAD2 axis, which drives epithelial–mesenchymal transition (EMT) and accelerates tumor progression [54].