Neuroendocrine Tumour Markers

Neuroendocrine cells occur throughout the body, they are particularly prominent in the gastrointestinal tract, pancreas, C cells of the thyroid, adrenal medulla, parathyroid tissue, respiratory tract, skin, and genitourinary system. Neuroendocrine cells are characterized by the presence of dense core secretory vesicles in the cytoplasm which are used to store, process, and secrete hormones. Neuroendocrine tumours (NETs) occur in all these tissues. Due to thseir rarity, heterogeneity, varied and vague symptoms, and often slow-growing tumours, NETs can be a diagnostic challenge. Tumour biomarkers are required for diagnosis and follow-up. An ideal NET biomarker would be one that is secreted exclusively by the tumour cells and can be used for screening, prognostic indication, estimation of tumour burden, and surveillance. Although none of the currently available biomarkers completely fits this ideal, when measured in combination, they are useful for diagnosis, monitoring response to therapy and surveillance. Due to NET defective processing of pro-hormones, any new biomarker should also be able to detect these aberrant forms to increase the sensitivity of the test.