In preclinical studies, PLX7904 and its optimised analogue PLX8394 had activity in vemurafenib-resistant melanoma lines expressing dimeric V600E-B-Raf splice variants (Zhang et al, 2015) and in paediatric astrocytomas expressing dimeric KIAA1549:B-Raf fusion proteins (Sievert et al, 2013). This evidence concerns the gene BRAF and melanoma.