Neuroendocrine tumors are a heterogeneous group of neoplasms originating from the diffuse endocrine system. Depending on primary location and hormonal status, they range in terms of clinical presentation, prognosis and treatment. Functional tumors often develop symptoms indicating an excess of hormones produced by the neoplasm (exempli gratia insulinoma, glucagonoma and VIPoma) and can be diagnosed using monoanalytes. For non-functional tumors (inactive or producing insignificant amounts of hormones), universal biomarkers have not been established. The matter remains an important unmet need in the field of neuroendocrine tumors. Substances researched over the years, such as chromogranin A and neuron-specific enolase, lack the desired sensitivity and specificity. In recent years, the potential use of Circulating Tumor Cells or multianalytes such as a circulating microRNA and NETest have been widely discussed. They offer superior diagnostic parameters in comparison to traditional biomarkers and depict disease status in a more comprehensive way. Despite a lot of promise, no international standards have yet been developed regarding their routine use and clinical application. In this literature review, we describe the analytes used over the years and cover novel biomarkers that could find a use in the future. We discuss their pros and cons while showcasing recent advances in the field of neuroendocrine tumor biomarkers.

Our study confirms that PCT can be considered as an equivalent alternative for measurement of calcitonin. On the other hand, it is also worth noting that MTC can be a rare cause of very high levels of PTC not resulting from infectious diseases. The diagnostic value of CEA and chromogranin A is much lower and can be within the normal range even in patients with advanced, metastatic MTC. They should be used only as accessory markers.

Background. Vitamin D, known for its role in calcium-phosphorus homeostasis, is also a significant immunomodulatory factor. Vitamin D deficiency has been reported in some autoimmune disorders. Recently, vitamin D level in autoimmune thyroiditis (HT -Hashimoto's thyroiditis) has become the subject of researchers' interest. Objectives. This study aims to assess vitamin 25-OH-D3 levels in HT patients in comparison to a control group in the Polish population. This would be the first attempt conducted in this region with such poor sunlight exposure. Material and Methods. The group we studied consisted of 62 subjects diagnosed with HT (mean age 49.15 ± 15.51) and 32 healthy controls matched with age and sex (mean age 46.09 ± 14.32). All blood samples were collected in the first quarter of the year to minimize the impact of seasonal fluctuations of vitamin D concentrations. Results. In the HT group the mean vitamin D level was 20.09 nmol/L (SD ± 12.66), compared to 30.31 nmol/L (SD ± 19.49) in the controls, p = 0.014. None of the patients and the controls was vitamin D sufficient (75-125 nmol/L). The deficiency (< 50 nmol/L) was significantly more common among HT patients compared to the controls (61-98.4% vs. 27-84.4%, p = 0.029). Conclusions. In conclusion, we found that serum vitamin D concentration is significantly lower in HT patients in comparison to the control group. This suggests vitamin D deficit as one of the risk factors for HT development. Observed vitamin D level was also low in the control group, therefore wider supplementation in general population should be recommended (Adv Clin Exp Med 2015, 24, 5, 801-806).

Purpose. Vitamin D, besides its role in calcium-phosphorus metabolism, turned out to play a significant immunomodulating function. Until now four single nucleotide polymorphisms of vitamin D receptor gene (VDR), rs2228570 (FokI), rs1544410 (BsmI), rs7975232 (ApaI), and rs731236 (TaqI), have been studied in autoimmune thyroid disorders, with conflicting results. Another functional polymorphism of the VDR gene, rs11568820 (Cdx2), has been shown to influence the immune system, although it has not been studied for its association with autoimmune thyroiditis to date. Therefore, the study aimed to evaluate the association of these five VDR gene polymorphisms with susceptibility to autoimmune thyroiditis among Caucasian Polish population. A relationship between the studied polymorphisms and selected clinical features of the disease was additionally assessed. Methods. 223 patients with autoimmune thyroiditis and 130 control subjects were enrolled in the study. VDR polymorphisms were studied by PCR-RFLP or TaqMan real-time PCR. Results. Allele and genotype distributions of any of the studied polymorphisms did not differ significantly between patients and controls. Similarly, frequencies of haplotypes derived from rs1544410-rs7975232-rs731236 (BsmI-ApaI-TaqI) polymorphisms were not significantly different in the two studied groups. However, a weak association between rs1544410 (BsmI) or rs7975232 (ApaI) VDR polymorphisms and thyroid volume was found (p = 0.03 and p = 0.04, resp.). Conclusions. Our results suggest that VDR gene is not a major susceptibility factor for autoimmune thyroiditis development, at least in Caucasian Polish population.

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