Liquid Biopsies for Neuroendocrine Tumors: Circulating Tumor Cells, DNA, and MicroRNAs

Effective management of neuroendocrine tumors depends on early diagnosis, personalized risk stratification, and monitoring response to therapy. During cancer progression, tumors shed circulating tumor cells, circulating tumor DNA, and microRNAs into the bloodstream. Analysis of these biomarkers offers the prospect of a liquid biopsy to predict/monitor therapeutic responses, assess drug resistance, and quantify residual disease. Compared with single-site biopsies, these entities have the potential to inform intratumor heterogeneity and tumor evolution in a reproducible and less invasive way. This article summarizes the state of the art on the potential role of these markers as prognostic and predictive factors in neuroendocrine tumors.