Immunoblot detection of CEA in pancreatic, gastric, and colorectal cancer cells. Cell lysate samples of each cell line (10 μg protein/lane) were analyzed by immunoblotting with the anti-CEA mouse monoclonal antibody (1:3,000 dilution), either directly (A) or after PNGase F treatment (B). PNGase F treatment was undergone to cleave N-glycan chain from proteins. ACTB (actin-ß) was also detected as an internal loading control. The detected bands were separated into three regions, indicated as Regions 1, 2, and 3.