The tumour suppressor gene MEN1 is mutated in patients with a dominantly inherited tumour syndrome, multiple endocrine neoplasia type 1 (MEN1) []. The MEN1 gene encodes a protein known as Menin, which is located predominantly in the nucleus. Menin has been shown to interact with the mixed lineage leukemia (MLL) protein, a histone H3 lysine 4 methyltransferase, and plays a critical role in hematopoiesis and leukemogenesis [].