LAMP5 (lysosomal-associated membrane protein 5) is a lysosomal membrane protein with emerging roles in neuronal function and cancer biology. In the nervous system, LAMP5 marks a population of GABAergic inhibitory interneurons 1 that are critical for regulating neuronal network excitability. Loss of LAMP5+ interneurons drives hyperexcitation and network dysfunction in Alzheimer's disease, with LAMP5 interneuron degeneration observed in multiple AD mouse models 2. During early childhood development, LAMP5+RELN+ interneurons undergo protracted tangential migration into the entorhinal cortex until age 2-3 years, potentially shaping sensory and spatial information processing 1. In cancer, LAMP5 acts as a multifunctional oncoprotein. In multiple myeloma, LAMP5 stabilizes the transcription factor IRF4 and promotes its nuclear transport, activating c-MYC transcription in a feedback loop that drives disease progression 3. LAMP5 is uniquely overexpressed in neoplastic plasma cells and correlates with worse prognosis 45. In gastric cancer, LAMP5 promotes metastasis through EMT and autophagy pathways 6. In bladder cancer, LAMP5 facilitates proliferation via the FBXW11/p27 axis and is associated with reduced immunotherapy efficacy 7. These findings establish LAMP5 as both a neuroprotective factor and oncogenic driver with significant therapeutic implications.