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Friday, July 25, 2014
Cancer is considered a multifactorial condition. Multifactorial means that both genes and environment play an important role.
Most cancers occur due to a combination of both genes and environment. Some forms of cancer, such as lung cancer, are mostly due to environmental factors (i.e., smoking). A few of the known environmental risk factors that can increase a person's risk for cancer include:
We also know that genes play an important role in cancer, since having a close family member (a mother, father, sister or brother) with cancer increases a person's risk for developing cancer. Other forms of cancer, such as retinoblastoma (a rare tumor of the back of the eye), are strongly genetic or hereditary.
While all cancers are genetic, not all cancers are inherited. All cancer cells have mutations in their DNA. It is these mutations that cause a once "normal" cell to behave like a cancer cell--one that grows and divides quickly and does not respond to normal checks on cell growth.
Somatic mutations are mutations that only occur within the tumor itself. Somatic mutations cannot be passed down from a parent to a child.
Germline mutations are mutations that are found in all the cells of the body, including the egg cells of a woman or the sperm cells of a man. Germline mutations can be passed down from a parent to a child. Only those mutations that are present in the eggs or sperm can be passed down through a family.
In some families with a very strong history of cancer there may be a germline mutation that is being passed down through the family. These families usually have some features that are "red flags" or clues that there may be a cancer gene in the family. These red flags include:
Families who have some or all of these features may benefit from meeting with a genetic counselor and/or a geneticist to discuss their family history.
This article is a NetWellness exclusive.
Last Reviewed: Jun 22, 2011
Duane D Culler, PhD, MS
Clinical Instructor of Genetics
School of Medicine
Case Western Reserve University