Evaluation of LRP6, SFRP3, and DVL1 Protein Concentrations in Serum of Patients with Gastroenteropancreatic or Bronchopulmonary Neuroendocrine Tumors

<b>Introduction:</b> Neuroendocrine tumors are a diverse group of tumors predominantly found in the gastrointestinal tract or respiratory system. <b>Methods</b>: This retrospective study aimed to measure the serum concentrations of LRP6 (low-density lipoprotein receptor-related protein 6), SFRP3 (secreted frizzled-related protein 3), and DVL1 (segment polarity protein dishevelled homolog) using the ELISA method in patients with NETs (N = 80) and a control group (N = 62). We evaluated the results against various demographic, clinicopathological, and biochemical characteristics. <b>Results</b>: Our analyses revealed that the concentration of SFRP3 in patients with neuroendocrine tumors was significantly elevated (<i>p</i> < 0.001) compared to the control group. Additionally, DVL1 concentrations were significantly higher (<i>p</i> < 0.01) in patients with BP-NETs compared to GEP-NETs. Furthermore, DVL1 analysis showed a moderate negative correlation with chromogranin A (<i>p</i> < 0.001) and weak negative correlations with serotonin (<i>p</i> < 0.05) and 5-HIAA (<i>p</i> < 0.05). Significant negative correlations were also observed between DVL1 and age in the control group (<i>p</i> < 0.01), and between LRP6 and Ki-67 in the study group. <b>Conclusions:</b> These results suggest that changes in the SFRP3 and DVL1 pathways play a key role in NET development. Elevated levels of these proteins highlight their importance in tumor biology, with SFRP3 and DVL1 potentially being crucial in NET molecular mechanisms. Further research is needed to explore their roles and potential in diagnosis and treatment.