NPDC1 (neural proliferation, differentiation and control 1) is a membrane-associated protein that functions as a tumor suppressor and regulator of neural development. The protein contains a signal peptide, transmembrane segment, and nuclear localization signal, with strong expression in adult brain regions including hippocampus, frontal lobe, and temporal lobe 1. NPDC1 suppresses oncogenic transformation and down-regulates neural cell proliferation 1. Mechanistically, NPDC1 forms a functional complex with mGluR4 at the cell surface that mediates α-synuclein fibril binding and internalization, contributing to neurodegeneration in Parkinson's disease models 2. In cancer contexts, NPDC1 exhibits dual roles: it serves as a potential biomarker for monitoring mesenchymal stem cell therapy response in Alzheimer's disease 3 and shows increased activity in relapsed B-cell acute lymphoblastic leukemia 4. Paradoxically, NPDC1 is upregulated in KRAS-mutant colorectal cancer where it promotes tumor proliferation through PI3K/AKT signaling activation 5. NPDC1 is also subject to epigenetic regulation, being a target of miR-505 in Parkinson's disease models 6 and showing differential methylation patterns in marsupial genomic imprinting 7. These findings indicate NPDC1's complex roles in neural development, neurodegeneration, and cancer progression.