[Changes in the cell cycle in breast cancer]

Recent advances in the mechanisms of oncogenesis have revealed a close relationship between the cell cycle and apoptosis. The cell cycle goes through a series of kinases and fosfatases activities that enhance the cyclins. In the mammalian cells, the kinases CDK4/6, CDK2, CDK2 and p34 are linked to the cyclins D, E, A, and B When the cell goes from the phase G1 toward mitosis. When the DNA is altered by intrinsic or extrinsic factors, the control checkpoints should stop the cycle in order to repair the damage. If the DNA cannot be repaired, apoptosis is induced. In cancer, the checkpoints do not function and the unstable genome of the cancer cell is repaired. Some of these changes occur in cancer of the breast and are discussed in this review.