Prinses Maxima Center for Pediatric Oncology 1 article published in JoVE Cancer Research Longitudinal Intravital Imaging of Brain Tumor Cell Behavior in Response to an Invasive Surgical Biopsy Maria Alieva1, Anne C. Rios1 1Cancer Genomics Netherlands, Prinses Máxima Center for Pediatric Oncology Here we describe a method for high-resolution time-lapse multiphoton imaging of brain tumor cells before and after invasive surgical intervention (e.g., biopsy) within the same living animal. This method allows studying the impact of these invasive surgical procedures on tumor cells' migratory, invasive, and proliferative behavior at a single cell level.