The detection sensitivity of classical biomarkers and epidemiological factors for gastric cancer was 13% (CEA), 6% (AFP), 6% (CA125), 3% (CA15-3), 14% (CA19-9), 29% (CA72-4), 36% (cytokeratin 19), 13% (NSE), 18% (overweight), 25% (smoking), 10% (alcohol) and 7% (previous history of cancer) (Supplementary information, Table S1). Here, CEACAM5 is linked to cancer.