Serum Visfatin/eNAMPT as a Biomarker in Pancreatic and Small Intestine Neuroendocrine Tumors: A Cross-Sectional Study and Future Perspectives.

Background: Neuroendocrine tumors (NETs) remain a problematic area in endocrine oncology due to their non-specific symptoms and lack of reliable biomarkers. Visfatin/eNAMPT's involvement in tumorigenesis has been described in several malignancies. In NETs, NAMPT inhibition was explored as a potential therapeutic option; however, serum visfatin and its role as a biomarker have not been studied. Objectives: We aimed to measure serum visfatin concentrations in NETs and evaluate visfatin's potential as a diagnostic biomarker. Methods: We conducted a single-center, cross-sectional study of 77 patients with NETs (33 pancreatic and 44 small intestinal) and 29 controls. Patient demographics, tumor characteristics, and clinical data were analyzed, and serum visfatin levels were measured using ELISA. Statistical analyses were performed in Python, including Mann-Whitney U and Kruskal-Wallis tests, Spearman's correlation, multiple linear regression, and ROC curve analysis. Results: Serum visfatin was higher in NETs compared to controls (median [IQR]: 6.94 [2.11-236.17] vs. 1.59 [1.1-9.24] ng/mL, p = 0.004). ROC curves showed moderate diagnostic performance (AUC = 0.68), with concentrations above 2.11 ng/mL achieving 75.3% sensitivity and 58.6% specificity. In NETs, visfatin did not differ based on WHO grade (G1/G2, p = 0.31), primary site (pancreas/small intestine, p = 0.95), sex (p = 0.89), age (p = 0.13), and when stratified by primary site and grade (p = 0.18). Multiple linear regression confirmed no association between visfatin and the study variables (R-squared = 0.036, all p > 0.2). Conclusions: This is the first study examining serum visfatin as a diagnostic biomarker in NETs. Visfatin concentrations show moderate discriminatory ability between NETs and controls, independent of tumor and clinical characteristics. Further research should involve larger cohorts and comparisons to established biomarkers.