Neuroendocrine Tumors: Genomics and Molecular Biomarkers with a Focus on Metastatic Disease

SIMPLE SUMMARY: Liver metastases secondary to neuroendocrine tumors (NETs) are common at the time of diagnosis and are associated with worse quality of life and overall survival. This review focuses on the biomarkers and genetics associated with NETs, with a particular focus on disease diagnosis, prognosis, and treatment options. Specifically, liver-directed therapies are highlighted as meaningful treatment options for liver-dominant NETs. ABSTRACT: Neuroendocrine tumors (NETs) are considered rare tumors that originate from specialized endocrine cells. Patients often present with metastatic disease at the time of diagnosis, which negatively impacts their quality of life and overall survival. An understanding of the genetic mutations that drive these tumors and the biomarkers used to detect new NET cases is important to identify patients at an earlier disease stage. Elevations in CgA, synaptophysin, and 5-HIAA are most commonly used to identify NETs and assess prognosis; however, new advances in whole genome sequencing and multigenomic blood assays have allowed for a greater understanding of the drivers of NETs and more sensitive and specific tests to diagnose tumors and assess disease response. Treating NET liver metastases is important in managing hormonal or carcinoid symptoms and is imperative to improve patient survival. Treatment for liver-dominant disease is varied; delineating biomarkers that may predict response will allow for better patient stratification.