TGFB1 and gastric cancer: In this study, to determine whether GRP78 regulates the expression of the TGF-β1-mediated stemness marker OCT4 in human gastric cancer, we evaluated the expression of TGF-β1 and OCT4 in AGS cells with GRP78 overexpression and knockdown by using Western blotting and enzyme-linked immunosorbent assay (ELISA).