Notably, this increase not only included common MTC-related biomarkers carcinoembryonic antigen (CEA, also called CEACAM5), calcitonin-related polypeptide beta (CALCB) and CEA cell adhesion molecule 6 (CEACAM6), but was also seen in other broad-spectrum neuroendocrine markers such as chromogranin A/B (CHGA/CHGB), synaptophysin (SYP), secretogranin II/III (SCG2/3) and neural cell adhesion molecule 1 (NCAM1, also called CD56) (Fig. 5f). Here, SYP is linked to medullary thyroid gland carcinoma.