Scientists at Tel Aviv University have used CRISPR gene editing in the lab to treat some of the most aggressive of cancers. They improved Glioblastoma (brain cancer) survival rates by 30%, but for metastatic (secondary) ovarian cancer, survival was increased by a huge 80%.

https://www.israel365news.com/161060/gene-editing-technique-successfully-used-for-first-time-by-tel-aviv-university-to-treat-aggressive-metastatic-cancer-in-mice/