Prof Perrotti speaks about the discovery that microRNA can be used to bind to proteins and block their function. Initial results suggest this could be an effective way of treating myeloid leukaemia. The microRNA miR-328 is added to cells in blast crisis where they block the protein C/EBP alpha, causing the blast cells to differentiate and die. Prof Perrotti discusses his hopes for the development of this treatment and explains the difficulties that may be faced translating these results into clinical practice.