The sensitivity and PPV of the tumor markers for GI cancers were also very low; those of CEA (cut-off: 5 ng/mL) for upper/lower GI cancers were 7.8% and 3.7%, respectively, and those of CA19-9 (cut-off: 37 U/mL) were 7.4% and 2.7%, respectively. This evidence concerns the gene CEACAM5 and neoplasm.