HMGA2 and breast cancer: Knocking down circPOLA2 or HMGA2 or elevating miR-1224-5p reduced the proliferative, migratory, invasive, and anti-apoptotic capacities of BC cells.<h4>Conclusion</h4>Knockdown of circPOLA2 inhibits BC cell proliferation, migration, and invasion and delays BC tumor progression by regulating the miR-1224-5p/HMGA2 axis, providing a new strategy and target for therapeutic intervention in BC.