The link between proteasome inhibitors and PRES is unknown, although inhibition of the proteasome reduces activation of transcription factor nuclear factor-kappa B and therefore several growth factors, including VEGF—which could feasibly be the responsible mechanism by which PRES is caused, as described in the section “VEGF inhibitors” [61]. This evidence concerns the gene VEGFA and Posterior Leukoencephalopathy Syndrome.