This is preclinical work but fascinating new approach. CRISPR is a gene editing tool which can be programmed to cut out any gene. This first attempt is proof of the principle that it can be directed to tumors inside a live animal. The possibilities are endless, perhaps starting with other genes in the tumor like the MGMT gene which creates a repair enzyme which offers resistance to Temodar, or to genes in the entire body such as any of the oncogenes like the BRCA genes which increase chances of many types of cancer.