A novel route to mouse cancer models

Genome editing tools exploiting the prokaryotic CRISPR/Cas immune system have been successfully applied in many organisms, including mouse and human cells. Here Tyler Jacks and colleagues demonstrate the feasibility of using the CRISPR/Cas system in vivo to induce direct mutation of tumour-suppressor genes and oncogenes in mouse liver. Cancer genes are traditionally studied using genetically engineered mouse models through embryonic stem cell targeting; this work highlights the power of the CRISPR/Cas9 system for rapid genome editing and the development of novel cancer models, as well as for functional genomics studies.