CEACAM5 and neoplasm: Interestingly, serum CEA > 5 μg/ml (P=0.031), serum CA 19-9 > 37 U/ml (P=0.002), tumor sizes > 2.5cm (P=0.002), and positive perineural invasion (P=0.003) were all associated with a poor prognosis in the histopathological subgroup of intestinal- and pancreatobiliary-type (Table 3).