A chemical combinatorial screening of JQ1 with around 1900 compounds aimed at finding effective small molecule combination therapies with BETi revealed PI3K inhibitors to be the most potent partners against neuroblastoma both in vitro and in animal models.96 The combination of PI3K inhibitors and BETi also proved to repress the proliferation of ovarian cancer cells with acquired resistance to BETi.98 It remains unclear precisely how BETi enhance the effects of PI3K inhibitors—perhaps it stems from transcriptional repression of RTKs themselves, or their downstream effectors. This evidence concerns the gene PIK3CA and neuroblastoma.