The invention is directed to composition and methods for the diagnosis, treatment and prevention of various disorders including but not limited to cancer and neurological disorders. In particular, the invention is directed to compositions and methods for the inhibition of PC4.L'invention concerne une composition et des procédés pour le diagnostic, le traitement et la prévention de divers troubles comprenant, entre autres, le cancer et des troubles neurologiques. En particulier, l'invention concerne des compositions et des procédés pour l'inhibition de PC4.