Conventional serological tumor markers, such as Cytokeratin-19-fragment CYFRA21-1 (Crfr211), Squamous Cell Carcinoma Antigen (SCC), Carcinoembryonic Antigen (CEA), Carbohydrate Antigen 19-9 (CA 19-9) and Carbohydrate Antigen 15-3 (CA 15-3) have shown suboptimal accuracy in clinical practice. Here, CEACAM5 is linked to neoplasm.