Non-invasive screening for neuroendocrine tumors-Biogenic amines as neoplasm biomarkers and the potential improvement of “gold standards”

Early, noninvasive diagnosis of tumors is relevant, especially for rare, often asymptomatic, thus − hard to detect in curable stages of the disease - tumors, as neuroendocrine tumors (NET). To avoid or supplement the NET management via application of invasive biopsy or expensive imagining techniques, the biochemical evaluation of biomarkers from easy accessible body fluids could be the great, potential diagnostic or prognostic tool. Nevertheless, already existed biochemical diagnostic tools for NET must be improved. Biogenic amines' (BA) determination in biological samples is significant for the description of the most NET, such as pheochromocytoma, neuroblastoma or carcinoid tumor. The bioanalytical approaches applied for the analysis of BA concentration in patient's body fluids still are required to be improved. It is caused by the low BA levels in real samples, their distinct physiochemical properties, light sensitiveness and easy degradation in the presence of oxygen, among others. Moreover, the interpretation of single analyte result is not clinically sufficient recently and more precise biomarkers or - more ideally - panels of several biomarkers are considered to be simultaneously measured and analyzed. Therefore, the NET-management “gold standards” can be routinely modified. Accordingly, presented review will focus on the recent status of BA analysis treated as the potential biomarker in terms of analytical method development applied for the real patients' samples analysis. Furthermore, the main advantages of current dominance of panel of biomarkers analysis for the NET patients diagnosis, follow up and monitoring of the therapy, will be underlined.