Haploinsufficiency of 53BP1 accelerated tumorigenesis in a mouse model of glioma that was similarly affected by the loss of ATM or CHK2, also implicating the DDR-dependent functions of 53BP1 in tumor suppression (Squatrito et al., 2012; Squatrito et al., 2010). The gene discussed is TP53BP1; the disease is neoplasm.