REN and polycystic ovary syndrome: The hub genes identified in this review indicate that exercise therapy in PCOS may affect the protease system, renin–angiotensin system, inflammatory signal transduction, neuroactive ligand–receptor interaction, and other pathways through the G protein-coupled receptor signaling pathway, neuropeptide signaling pathway, endocrine process, and other biological processes and regulate apoptosis, cell cycle, and intercellular communication.