In our case, the use of CRISPR/Cas9 results in complete deletion of Tfap4, evident by loss of TFAP4 protein (Fig. 2A), whereas the pre-leukaemic cells Tonc et al. examined retained one allele of Tfap4, albeit some of these cells selected for loss of the second allele, highlighting that there is potent selection for loss of Tfap4 in c-MYC-driven lymphoma development. This evidence concerns the gene MYC and lymphoma.