The neuropeptide-related genes, including PPY and members of the NPY family (e.g., NPY, NPY1R, NPY2R, NPY4R, NPY5R, PYY), form a distinct cluster characterized by strong co-expression and shared pathway interactions, indicating a potential role in neuroendocrine signaling relevant to glioblastoma. The gene discussed is NPY2R; the disease is glioblastoma.