Our unbiased genome-wide approach using a CRISPR/Cas9 knockout screen for transformation in KrasG12D immortalized MEFs successfully identified well-known tumor suppressors Trp53 and p19Arf and also candidate genes, such as Fbxw7 and Slc9a3. We tested the potential tumor suppressor function of these genes in vivo using our recently reported CRISPR/Cas9 initiated KrasG12D-driven sarcoma model15. This evidence concerns the gene SLC9A3 and sarcoma.