CEACAM5 and cancer: Additional laboratory tests reported an alpha fetoprotein (AFP) concentration of 2.8 ng/mL (< 7.0), a remarkably high cancer antigen concentration: CA 19–9: 1000 U/mL (< 27), CA 12–5: 1679 U/mL (< 35), and a carcinoembryonic antigen (CEA) concentration of 1000.0 ng/mL (< 4.3).