The role of biomarker in pancreatic neuroendocrine tumor: a narrative review

Pancreatic neuroendocrine tumors (pNET) are heterogenous tumors originated from the diffuse neuroendocrine cells of pancreas, which show the function of synthesis, storage and secretion of peptide hormones and biomimetic amines. Biomarkers play a crucial role in the diagnosing, evaluating prognosis and predicting treatment response for pNET patients. Traditional NET markers such as chromogranin A and Neuron Specific Enolase, as a diagnostic biomarker, have relatively low sensitivity and specificity in pNET patients. The emergence of new types of biomarkers provides more reliable indicators for diagnosis and prognosis evaluation. Among them, NETest score is a promising biomarker with the highest diagnostic sensitivity (80%) and specificity (94%). In addition, this molecule can be also used as a prognostic biomarker, which can predict disease progression and shorter overall survival. Biomarkers related to therapeutic targets, such as vascular endothelial growth factor, vascular endothelial growth factor receptor, and key molecules of mTOR signaling pathway, have capability to predict response of treatment. With the development of next-generation sequencing, chip array, and digital droplet PCR, novel biomarkers such as circulating tumor cells, tumor-derived exosomes, and circulating tumor DNA and mRNA are expected to provide more accurate diagnosis, prognostic information, and prospective therapeutic targets. In this paper, biomarkers of pancreatic neuroendocrine tumor and their role in diagnosis, prognosis, diagnosis, treatment and monitoring are systematically introduced. Our conclusions can provide new basis for clinicians in the diagnosis and treatment process.