Further studies found that TGF-β1 secreted by M2-TAMs could increase the stemness characteristics and chemoresistance abilities of ESCC by regulating the TGFβR1-Smad2/3 pathway, revealing a new relationship between tumor-associated macrophages, ESCC NCSCs, and CSCs. This evidence concerns the gene SMAD2 and esophageal squamous cell carcinoma.