LAUSR

Extracellular vesicles (EVs), also termed exosomes, mediate communication between cells and organisms through local and distant transport of proteins, nucleic acids and lipids. EVs are reported as biomarkers in cancer. However, transparent reporting is a prerequisite to facilitate interpretation and validation of EV biomarkers in cancer. We convened an international consortium to develop a resource to improve the rigor and interpretation of experiments, record the evolution of EV research and create a dialogue with researchers about relevant experimental parameters. We analyzed 1226 articles with keywords “exosomes” or “extracellular vesicles” published in 2010-2015. Publications that included multiple sample types or isolation methods were separated into multiple entries, resulting in 1742 experiments. Experiments were analyzed using a matrix containing 115 parameters related to sample type, EV isolation and characterization methods. The database is freely accessible and expandable, allowing online deposition of new experiments (http://evtrack.org). To assess current practice in EV experiments, we performed an in-depth analysis of recorded data in the EV-TRACK knowledgebase. This revealed heterogeneity in EV isolation methods and inconsistent reporting of experimental parameters. Differential ultracentrifugation is the most used method (>50%) but with a large heterogeneity in centrifugation steps. In less than 20% of experiments a density gradient was implemented to obtain or at least validate results. Quality controls are often omitted, with more than 2 proteins being checked in 40% and non-EV enriched proteins in less than 15% of experiments (dependent on sample type). From these analyses, 9 relevant experimental parameters were extracted and condensed into a single metric, the EV-METRIC (to MEasure Transparent Reporting of Isolation and Characterization methods). It represents a checklist to assess the completeness of reporting of generic and method-specific information necessary to interpret and validate an experiment. The EV-TRACK platform is a knowledge center for EV biology and methodology that allows data queries, coaches users by providing EV-METRICs and involves them in decision-making on future improvements to the platform. In conclusion, established for and supported by the EV research community, the EV-TRACK platform aims to ensure that experimental guidelines are timely and transparently met, improving the validation of EV biomarkers in cancer. Citation Format: Jan Van Deun, Pieter Mestdagh, Olivier De Wever, Jo Vandesompele, An Hendrix. EV-TRACK: transparent reporting and centralizing knowledge of extracellular vesicles to support the validation of extracellular vesicle biomarkers in cancer research [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr LB-107. doi:10.1158/1538-7445.AM2017-LB-107