NT-proBNP as a neuroendocrine tumor biomarker: beyond heart failure.

Introduction: Neuroendocrine tumors (NETs) are rare neoplasms that occur in various locations throughout the body. Despite their usually benign character, they might manifest with distant metastases. N-terminal prohormone of brain natriuretic peptide (NT-proBNP) has previously been described as a useful biomarker in diagnosing carcinoid heart disease (CHD), a common advanced NETs manifestation. We observed plasma concentrations of NT-proBNP in metastatic midgut NETs over a 4-year period. Objectives: We aimed to explore NT-proBNP concentrations in states of varying levels of cell proliferation and disease status. Our goal was to investigate NT-proBNP's role in predicting disease progression in relation to previous research and up-to-date scientific guidelines. Patients and methods: We performed a retrospective multivariate analysis of NT-proBNP concentrations in 41 midgut NETs patients treated with somatostatin analogs, all with liver metastases. NT-proBNP concentrations were measured in every patient across 16 evenly distanced time points over a 48-month period and were compared to variables such as sex, age, grading, Ki-67, primary tumor location, and CT findings. Results: NT-proBNP concentrations correlated positively with higher liver tumor burden, higher grading, high Ki-67 levels, and with progressive disease in CT. There were no differences in NT-proBNP levels with regard to primary location (ileum vs jejunum), sex, and age. Conclusion: We conclude that NT-proBNP is a useful analyte for monitoring NETs progression, due to its increased concentration in scenarios implying increased cellular proliferation. These long-term follow-up results align with previous findings and suggest an additional role for NT-proBNP in diagnostic algorithms, beyond a CHD biomarker.

Association of COVID-19 mortality with serum selenium, zinc and copper: Six observational studies across Europe.

Introduction: Certain trace elements are essential for life and affect immune system function, and their intake varies by region and population. Alterations in serum Se, Zn and Cu have been associated with COVID-19 mortality risk. We tested the hypothesis that a disease-specific decline occurs and correlates with mortality risk in different countries in Europe. Methods: Serum samples from 551 COVID-19 patients (including 87 non-survivors) who had participated in observational studies in Europe (Belgium, France, Germany, Ireland, Italy, and Poland) were analyzed for trace elements by total reflection X-ray fluorescence. A subset (n=2069) of the European EPIC study served as reference. Analyses were performed blinded to clinical data in one analytical laboratory. Results: Median levels of Se and Zn were lower than in EPIC, except for Zn in Italy. Non-survivors consistently had lower Se and Zn concentrations than survivors and displayed an elevated Cu/Zn ratio. Restricted cubic spline regression models revealed an inverse nonlinear association between Se or Zn and death, and a positive association between Cu/Zn ratio and death. With respect to patient age and sex, Se showed the highest predictive value for death (AUC=0.816), compared with Zn (0.782) or Cu (0.769). Discussion: The data support the potential relevance of a decrease in serum Se and Zn for survival in COVID-19 across Europe. The observational study design cannot account for residual confounding and reverse causation, but supports the need for intervention trials in COVID-19 patients with severe Se and Zn deficiency to test the potential benefit of correcting their deficits for survival and convalescence.

Circulating Neuroendocrine Tumor Biomarkers: Past, Present and Future.

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.

Determination of neuron-specific enolase in patients with midgut-type tumour treated with somatostatin analogues.

INTRODUCTION: The biochemical diagnosis of neuroendocrine tumours (NETs) uses assays of specific and nonspecific markers. Nonspecific markers include, among others, neuron-specific enolase (NSE). The aim of this study was to evaluate NSE in patients with midgut type tumours treated with somatostatin analogues. MATERIAL AND METHODS: The study group of patients with NETs of the small intestine included 41 patients. Grade G1 was found in 19 cases, while G2 was seen in the remaining 22 cases. Liver metastases were found in all patients studied. The examined group of patients was treated with somatostatin analogues receiving octreotide LAR at a dose of 30 mg. The control of biochemical parameters was performed every 3 months and imaging examinations every 6 months. The Immuno-Biological Laboratories kit was used for determination of NSE concentration, where reference values were 12.5-25 ng/mL. RESULTS: In the G1 group of patients, the median value of NSE concentration was 134.67 ng/mL, while in the G2 group, the value was 234.55 ng/mL and was significantly higher than in the G1 group (p = 0.003). In the determination of NSE concentration values according to the degree of liver involvement, in the group of patients with 10% liver involvement, the median value of NSE concentration was 143.21 ng/mL, while in the group with 25% liver involvement, the value was 251.82 ng/mL (p < 0.001). In the analysis of NSE concentration assessment in patients with disease progression, the median value was 234.65 ng/mL compared to the group with disease stabilization, where the median NSE value was significantly lower and amounted to 136.27 ng/mL (p < 0.001). CONCLUSIONS: In our study, we observed that NSE concentration values were significantly higher among patients with NET midgut type tumour with histological grade G2 and in patients with 25% liver involvement and progression of the disease process.