Tumor model generation by somatic Cas9-mediated tumor suppressor gene disruption

Recent cancer genome analyses have provided a wealth of recurrently mutated genes1,2. In vivo functional investigation of putative oncogenes using somatic gene transfer has been successfully exploited as a versatile means for validation of pathogenic relevance. In contrast, for potentially relevant tumor suppressors such functional analyses have been hampered e.g. by insufficient knockdown using RNAi-mediated approaches. In order to provide a flexible method for investigating loss-of-function mutations in tumors, we have established CRISPR/Cas93-6 somatic gene transfer allowing for in vivo gene deletion of candidate tumor suppressors. Here we demonstrate the potential of this approach by somatic knock-out of the Ptch1 gene in the neonatal cerebellum of mice, which leads to formation of medulloblastoma resembling human SHH subgroup tumors7. Such in vivo validation of candidate tumor suppressor genes provides a fast and versatile approach for generation of animal tumor models.