[Gastroenteropancreatic neuroendocrine tumor microenvironment and related therapy]

Neuroendocrine tumor(NET) is a kind of highly heterogeneous and ubiquitous tumor, frequently localized in the gastrointestinal tract and pancreas. Surgery combined with regional ablation, endocrine therapy,chemotherapy and targeted therapy presents a favorable prognosis when treated with G1 or G2 gastroenteropancreatic neuroendocrine tumor(GEP-NET). However, there are only limited therapeutic strategies for metastatic unresectable tumors and poorly differentiated NEC,which are closely related to the special tumor microenvironment of neuroendocrine tumors.Targeting tumor microenvironment therapy is an important method in current systematic therapy, but till now the knowledge of neuroendocrine tumor microenvironment and its related treatment are limited. This article will specifically introduce the characteristics of tumor microenvironment in GEP-NET from the following aspects: the formation of enrichment vascular supply in TME,the role of tumor stroma,immune cells and cancer associacted fibroblast, and immune checkpoint and future trend of immunotherapy.