Cell-cycle dysregulation in breast cancer: Breast cancer therapies targeting the cell cycle

Breast cancer is the most commonly diagnosed cancer in American women. The underlying mechanisms that cause aberrant cell proliferation and tumor grow th involve conserved pathways, which include components of the cell cycle m achinery. Proto-oncogenes, growth factors, and steroids have been implicate d in the pathogenesis of breast cancer. Surgery, local irradiation, and che motherapy have been the mainstay of treatment for early and advanced stage disease. Potential targets for selective breast cancer therapy are herein r eviewed. Improved understanding of the biology of breast cancer has led to more specific "targeted therapies" directed at biological processes that ar e selectively deregulated in the cancerous cells. Examples include tamoxife n for estrogen receptor positive tumors and imunoneutralizing antibodies su ch as trastuzumab for Her2/neu overexpressing tumors. Other novel anticance r agents such as paclitaxel, a microtubule binding molecule, and flavopirid ol, a cyclin dependent kinase inhibitor, exert their anticancer effects by inhibiting cell cycle progression.