PSIP1 and leukemia: Although menin can suppress tumorigenesis in the endocrine lineage, it can also promote oncogenic function in other tissues, such as breast.(42) In the hematopoietic lineage, menin serves as a molecular adaptor that physically links the mixed‐lineage leukemia (MLL) histone methyltransferase with lens epithelium‐derived growth factor (LEDGF), a chromatin‐associated protein implicated in leukemia.(43) Binding of menin to MLL1 leads to upregulation of Hox gene transcription and leukemia in MLL‐rearranged acute myeloid leukemia (AML) and acute lymphocytic leukemia (ALL).(44)