Indeed, our previous study showed that TGFβ/Smad signaling is constitutively active in K19+ HCC‐CSCs, that siRNA‐based K19 knockdown suppresses pSmad2 expression in K19+ cells, that K19 overexpression rescues pSmad2 expression in K19− cells, and that K19 is functionally associated with cell proliferation and EMT through TGFβ/Smad signaling 14, 22. This evidence concerns the gene TGFB1 and hepatocellular carcinoma.