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Wendy Kohlmann, M.S. |
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In the last issue of the newsletter,
we talked about what genes are and how they work.
Now we are going to move on to
the role of genes in the development of cancer.
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As we discussed in the last newsletter, our genes are the set of instructions inside each cell that tell our bodies how to develop and function properly. Our cells receive signals and information from the environment, hormones, nearby cells, and other factors, and they respond to this information by turning different genes on and off. If a gene has a mutation and is not working properly, it may not be able to respond to signals that tell the cell how to grow properly. For a cell to become a cancer cell,
many genes need to acquire mutations. The development of cancer
is a process. For example, a polyp is a benign growth in the colon.
Cells that have accumulated some genetic mutations may grow into
a polyp. If polyps go undetected, they may continue to acquire genetic
changes and develop into a cancer. Because cancer is a process, it usually occurs in older individuals. It takes many years for all these genetic changes to accumulate in a single cell, and for that cell to go on to become a cancer. |
The specific cause of genetic changes in most cancers cannot be determined. We do know that some environmental factors such as smoking or severe sunburns can increase the risk for genetic changes in the lungs and skin respectively, but most genetic changes are thought to happen by chance. Much of the research in cancer prevention is looking at ways to prevent these early changes. | |||||
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| The genetic changes that we have been discussing are genetic changes that a person acquires through their lifetime, either by chance or by environmental factors. They happen in one or a few cells in the body. These genetic changes are not present when a person is born, and a person who has had cancer cannot pass the genetic changes that occurred in their cancer cells on to their children. In contrast, the genetic changes associated with HNPCC, FAP, Peutz-Jeghers, and other conditions that predispose individuals to cancer and polyps are different than the spontaneous genetic changes associated with most cancers. Individuals with hereditary cancers or polyps are born with a non-working gene in every cell in their body that increases their risk for developing cancer. The development of cancer is still a process that takes many steps, but these individuals are born one step closer in the process. Unlike the sporadic genetic changes, the inherited genetic changes, present in every body cell including the egg and sperm, can be passed down from parent to child. | ||||||
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