Oncotest GmbH 1 article published in JoVE Medicine Depletion of Mouse Cells from Human Tumor Xenografts Significantly Improves Downstream Analysis of Target Cells David J. Agorku1, Stefan Tomiuk1, Kerstin Klingner2, Stefan Wild1, Silvia Rüberg1, Lisa Zatrieb1, Andreas Bosio1, Julia Schueler2, Olaf Hardt1 1R&D Reagents, Miltenyi Biotec GmbH, 2In vivo Tumorbiology, Oncotest GmbH Human tumor xenografts are vascularized and infiltrated by cells of mouse origin during the growth phase in vivo. To circumvent the bias caused by these contaminating cells during downstream analysis, we developed a method allowing for comprehensive depletion of all mouse cells by magnetic cell sorting.