On the other hand, GSK-J4, which is highly specific for H3K27 demethylation, appears to have impact in diffuse intrinsic pontine glioma (DIPG) radiosensitivity, reducing the expression of IR-induced HR DNA DSB repair-related genes, such as PCNA, XRCC1, FANCA, and POLD1. 35 In addition, apoptotic triggering was performed using simultaneous GSK-J4 and APR-246 (apoptosis inducer), targeting mutant p53 in the same tumor model.36 Remarkably, we found that treatment of 22Rv1-RR cells with GSK-J4 restored low p53 levels, consequently leading to significant sensitization to IR exposure. This evidence concerns the gene XRCC1 and diffuse intrinsic pontine glioma.