Exploration of neuroblastoma xenograft models for the analysis of tumoral cell-free RNA in murine blood plasma

While xenografts are well suited to discern tumoral (human) from host (murine) RNA, it remains unclear which factors influence release of tumor RNA. In this project the authors studied the effect of cell line, tumor size, injection site, and vascularization on exRNA shedding of tumor into blood plasma. It was found that xenografts derived from IMR-32 cell line have a significantly higher proportion of tumoral exRNA in the plasma. Additionally, a tumor size of minimal 1000 mm3 is required to detect sufficient tumoral exRNA. Finally, orthotopic implantation of IMR-32 cells increases the amount of tumoral exRNA in plasma, while no difference was found for SK-N-BE(2C) cells.