 The development of mesenchymal stem cells, MSCs, as cell-based drug delivery vectors for cancer has significant promise, but their limited tumor tropism and broad biodistribution raise concerns for toxicity to non-target peripheral tissues. Synthetic engineering platforms are being developed to improve tumor-selective targeting via increased homing efficiency and or specificity of drug activation, which are already being evaluated clinically. However, the lack of robust quantification and widespread adoption of standardized methodologies with high sensitivity and resolution has impeded progress in accurately comparing studies and enhancing MSC-based drug delivery strategies for cancer therapy. This article was authored by Timothy E. G Kruger, Daniel L. J. Thorik, Samuel Adenmead and others.