Hereditary Cancer & Genetics: Overview

Everyone has some chance of developing cancer. Most cancer cases occur sporadically or by chance. However, some people may develop cancer due to alterations in hereditary factors called genes.

Genes are present in every cell in our body, contained in structures called chromosomes, which are found in the nucleus of a cell. We have 46 chromosomes that come in 23 pairs. One chromosome in each pair comes from our father, and the other comes from our mother. Each chromosome, in turn, is made up of thousands of genes. Genes are coded segments of DNA that, like chromosomes, come in pairs. DNA contains instructions for making the substances that help our bodies to function properly. A change in the sequence of the DNA that makes up the gene can cause the gene to stop functioning. These genetic changes are called mutations.

Hereditary cancer is the development of cancer due to an inherited gene mutation that has been passed from a parent to a child upon conception. People who have inherited such a gene mutation have also inherited an increased risk to develop cancer in their lifetime that is higher than the cancer risk of someone in the general population.

Over the past decade, scientists have discovered specific genes that can contribute to the development of hereditary breast, ovarian, colorectal, and other less common cancers. Genetic testing is now available for some of these types of hereditary cancers. People who are interested in learning whether or not they have an increased likelihood of developing certain cancers or whether they inherited a gene that contributed to their own or a family member's cancer should consult with a specialist who has experience in the area of hereditary cancer, cancer risk assessment, and genetic counseling and testing.

Genetic Counseling

Genetic counseling involves a discussion of your personal and/or family history of cancer. Genetic counselors will simplify complex scientific concepts into terms you can understand. The goal of cancer genetic counseling is to provide clear and clinically relevant information about genetic risk factors in an atmosphere that is supportive and educational.

Genetic counseling is typically recommended for individuals or families with multiple cases of cancer diagnosed at unusually young ages.

Genetic Testing

Genetic testing involves the use of laboratory methods to obtain a more precise estimate of your cancer risk. Although a cancer risk assessment can be provided without genetic testing, in some cases testing may help you and your physician make important decisions about your medical care. Deciding whether or not to undergo genetic testing is a personal choice that can be made at the time of the counseling session or at a future date.

Genetic counseling does not require genetic testing. Genetic testing may not be useful for everyone receiving genetic counseling.