In the human body, cells are regularly transforming to early stages of a malignancy. These neoplasms are typically recognized and eliminated by immune cells. Only neoplasms that escape from the surveillance of the immune system develop into a clinically relevant cancer. Modern immunotherapies aim at fostering the immune response against cancer cells and provide a powerful alternative to radio- or chemotherapies. By systematic CRISPR/Cas9 screening of more than 1,500 genes, Dr. Theis and his team identified the gene MLLT6 as required for tumor immune resistance. Cell culture experiments demonstrated that the silencing of the gene MLLT6 sensitizes tumor cells for an immune attack providing an alternative route for novel immunotherapies.