One of these methods is using serum tumor markers, although it is not too much specific at early stages of tumors, it is a reliable method in the end stages of cancers and can be helpful diagnosing benign cases from malignancies.(5) These tumor markers include Neurocarcinoma specific enolase (NSE), Carcinoembryonic antigen (CEA), Cyfra21 (fragmented cytokeratin19), Cancer Antigen 19-9 (CA19-9), Cancer Antigen 15-3 (CA15-3), granulocyte colony stimulating factors (G-CSF).(2) Cyfra21 is a chopped cytokeratin19, which is soluted in serum and it is a useful tumor marker in blood circulation. Here, CEACAM5 is linked to cancer.