CEACAM5 and neoplasm: Serum concentrations of the tumor markers alpha fetoprotein (AFP), carcinoembryonic antigen (CEA), and carbohydrate antigen 19.9 (CA19.9) were also significantly elevated in DEN/2AAF-treated rats compared to untreated normal rats, and these responses were also significantly reversed by naringin or NDNP (Figure 1).