Assessment of VEGF and VEGF R1 serum levels in patients with neuroendocrine neoplasms before and after treatment with first-generation somatostatin analogues

Introduction: Vascular endothelial growth factor (VEGF) is a known promoter of angiogenesis that can support neuroendocrine neoplasm (NEN) development. The aim of the study was to evaluate the serum VEGF and vascular endothelial growth factor receptor 1 (VEGF R1) concentration changes in patients with NEN treated with first-generation long-acting somatostatin analogues (SSA). Material and methods: The study comprised 55 controls and 56 NEN patients before and after SSA treatment in various periods of time (months): 1-12 (n = 54), 13-24 (n = 46), 25-36 (n = 35), 37-60 (n = 26), and over 60 months (n = 22). An analysis of medical records and se- rum VEGF and VEGF R1 concentration measurements of NEN patients, by enzyme-linked immunosorbent assay (ELISA) were made. Results: During SSA treatment time, a decrease of the VEGF and an increase of VEGF R1 concentrations was observed. We confirmed significant VEGF differences between 2 pairs of SSA-treated NEN patient subgroups: Group 1-12 vs. Group 37-60 (p = 0.039) and Group 1-12 vs. Group > 60 (p = 0.026). We did not note significant differences of VEGF R1 levels between SSA-treated NEN patient subgroups. Among the studied biomarkers, VEGF R1 exhibited the best performance in distinguishing between NEN patients with controls; area un- der the curve (AUC) = 1 (p < 0.001). Conclusions: The examined angiogenesis factors (VEGF and VEGF R1) seem to have limited usage in the assessment of SSA treatment effectiveness in NEN. However, the assessment of serum levels of these factors may help in the differentiation of NEN patients and healthy controls; in particular, VEGF R1 seems to be a good diagnostic biomarker for NEN patients.