CEACAM6 and gastric cancer: Overexpression of CEACAM6 in SGC-7901 and MKN-45 GC cells and attenuation of CEACAM6 expression in MKN-28 GC cells by pL/shRNA/shR-CEACAM6 lentiviral vectors were confirmed at the protein level by western blot analysis (Fig. 1A).