CREBBP and cancer: Anti-tumor effects have previously been demonstrated for GSK-J4, a selective H3K27 histone demethylase inhibitor, in several animal models of cancers.<h4>Methods</h4>To characterize the effect of GSK-J4, drug response profiling, CRISPR-Dropout Screening, BH3 profiling and immunoblotting were carried out in ALL cell lines or patient derived samples.<h4>Results</h4>Here we provide evidence that GSK-J4 downregulates cyclic AMP-responsive element-binding protein (CREB) and CREBBP in B-cell precursor-ALL cell lines and patient samples.