MEN1 and early-onset autosomal dominant Alzheimer disease: Unraveling the distinct molecular functions of the menin proteolytic fragments and whether these are tissue specific or context dependent may ultimately provide new insights into menin’s actions as a tumor suppressor, and further fundamental knowledge regarding the development of cholinergic synapses in the CNS, as well as neurodegenerative conditions such as Alzheimer’s disease in which NTF50, nAChR51, and tumor suppressor function52, 53 are compromised.