Potential applications of cell cycle manipulation to clinical response

The central organization of cellular life is the highly regulated process of cellular growth and division known as the cell cycle. A normal cell exhibits an exquisitely regulated system of proliferation and differentiation. The cancer cell has escaped these regulatory constraints such that it is able to grow and proliferate without restriction. Understanding the mechanisms controlling the cell cycle in both normal cells and cancer cells may enable researchers to develop more specific anticancer therapies by targeting the abnormalities exhibited by the cancer cell. The cell may be in a state of quiescence or actively cycling. Certain populations of cells are terminally differentiated and no longer have the ability to cycle or proliferate. These various states are becoming more well understood. The cell cycle is composed of four phases: G1, the gap prior to replication; S, the synthetic phase; G2, the gap after replication; M, the mitotic phase leading to cell division. The cell cycle represents a series of discrete phases with a continuum of interdependent activity preparing for each ensuing phase