The Cell Cycle, Cellular Growth, and Cancer
Research and The Cell Cycle, Cellular Growth, and Cancer
Lee Hartwell, who won the Nobel prize for his work on the cell cycle, also leads the Fred Hutchinson Cancer Center. He recently described what he felt are the most promising directions for cancer research: prevention, early detection and the exploitation of the immune system to fight cancer (Hartwell, 2008).
Prevention means gaining an understanding of what causes cancer so we can avoid it. The first thing that may come to your mind is cigarettes. The link between cigarette smoke and lung cancer is well established and it is thought to cause mutations in a cell's DNA. Cancer can also be caused by viruses, as is the case with hepatitis B and human papillomavirus. Viruses can alter a cell's DNA or they can alter the cell cycle of the host cell directly, resulting in uncontrolled growth. Currently researchers are trying to gain an understanding of the heritable changes that contribute to a cell's ability to grow uncontrollably and invade other tissues. Cancer progresses from contained growth of the cancer clone to expansion into other tissues. It is the expansion of the cancer into other tissues that becomes the most difficult to treat. This is why early detection is critical for a cancer patient's survival and therefore a hot area for cancer research.
It has become apparent recently that there is a link between inflammation and cancer, even in cancers that are thought to be caused by environmental factors such as smoking or asbestos. For example, tobacco smoke isn't a mutagen of a cell's DNA, it also triggers chronic inflammation. Some chronic inflammatory disorders, such as irritable bowel syndrome, increase an individual's risk of cancer. The connection between cancer progression and inflammation suggests that suppressing inflammation may be a useful method for preventing cancer. However, in some cases inflammation seems to actually help prevent tumorigenesis (Grivennikov, 2010). This makes sense because inflammation and the immune system is how your body normally fights off infections.
Usually the immune system won't attack a cancer cell because it thinks it is part of itself, not an invader. The cancer cell is pretty much a wolf in sheep's clothing. It is easy to understand how beneficial it could be if the immune system could recognize and destroy cancer cells. There appears to be a delicate balance existing between a potentially invasive cancer cell and its host immune system that can be tilted towards cancer progression or cancer elimination. Understanding how we can control this biological seesaw phenomenon and tilt it towards both the prevention and treatment of cancer is an active, promising area of cancer research.