Ex vivo drug screening: an emerging paradigm in the treatment of childhood cancer

Developing and providing the right therapy for the right patient (or personalized targeted treatments) is key to reducing side-effects and improving survival in childhood cancers. Most efforts aiming to personalize childhood cancer treatment use genomic analysis of malignancies to identify potentially targetable genetic events. But it is becoming clear that not all patients will have an actionable change, and in those that do there is no additional way to determine if treatments will be effective. Ex vivo drug screening is a laboratory technique used to test the effects of various drugs or compounds, on biological tissues or cells that have been removed from an organism. This information is then used to predict which cancer treatments will be most effective based on the therapeutic response in the tissue or cells removed from that individual. Its utility in personalizing treatments in childhood cancer is increasingly recognized. In this review we describe the different methods for ex vivo drug screening and the advantages and disadvantages of each technique. We also present recent evidence that ex vivo screening may have utility in a variety of childhood malignancies including an overview of current clinical trials appraising its use. Finally, we discuss the research questions and hurdles that must be overcome before ex vivo screening can be widely used in pediatric oncology.