Elevated CEA and CA19-9 serum levels independently predict advanced pancreatic cancer at diagnosis. - van Manen, Labrinus; Groen, Jesse V.; Putter, Hein; Vahrmeijer, Alexander L.; Swijnenburg, Rutger-Jan; Bonsing, Bert A.; Mieog, J. Sven D. (Biomarkers, 2020)