Lin28 promoted cell proliferative signaling like PI3K-AKT-mTOR pathway and its target genes, such as Myc, Hmga2.Lin28 promoted the G0/G1 transition of cell cycle by regulating cell cycle-related factors, such as Cyclin D1 and D2, CDK6.Lin28 inhibited tumor growth by modulating Bcl-2 family members and activating caspases.Lin28 was involved in the anti-angiogenesis effect of the breast cancer. The gene discussed is HMGA2; the disease is breast cancer.