Genetics is the field of science that looks at how traits (such as eye color) are passed down from parents to their children through genes. It also looks at the reasons related organisms (or living things) are alike or different.

Genes are pieces of DNA that have instructions on how to make the proteins the body needs to function. Genes affect inherited (hereditary) traits, or those that are passed on from a parent to a child, such as hair color, eye color, and height. They also affect whether a person is likely to develop certain diseases, such as cancer.

In humans, genes are located on 23 pairs of chromosomes. One of each chromosome pair comes from the mother, the other from the father. Each chromosome can contain hundreds or thousands of genes that are passed from the parents to the child. The genes you were born with are in every cell of your body.

Genes play an important role in the development of cancer. Changes in genes are called mutations. Mutations can cause cells to grow out of control, which can lead to cancer. Usually several gene changes are needed before a cell becomes cancer. Some of these changes may be inherited from a parent. Only about 5% to 10% of all cancers are thought to have an inherited component that strongly affects a person's risk for a certain type of cancer. To learn more about cancer-related genes, please see our document Oncogenes and Tumor Suppressor Genes.

In other cases, mutations start in one gene during a person's lifetime. These are the most common types of' mutations that result in cancer. These mutations only affect the cells that grow from the mutated cell, and not the rest of the cells in the person's body. For instance, a cancer tumor will have mutations in all of the tumor cells, but the non-cancerous cells of the body will not have those gene changes.

Here we offer basic information about genetic testing and how it is used in cancer. It will help you understand what genetic testing is, but it won't give you specific information or advice on genetic testing for any particular disease. A doctor or a genetic counselor who knows about the diseases in your family is better able to talk with you about your risks and what you might gain from genetic testing.

What is genetic testing?

Genetic tests are done for 2 main reasons:

• to see if a person has a certain gene change (mutation) known to increase the risk for a certain condition or disease (such as cancer)

• to confirm a suspected mutation in an individual or family

Everyone does not need these tests but they can be useful for people with certain types of disease that seem to run in their families.

Uses of genetic testing

• Predictive gene testing is used to look for gene mutations that might put a person at risk of getting a disease. It is usually done in those families with a disease that may be inherited. An example is testing for changes in the BRCA1 and BRCA2 genes in a woman whose mother and sister had breast cancer.

• Carrier testing can be used to help couples learn if they carry a gene mutation for a disorder they might pass on to a child, such as cystic fibrosis, sickle-cell anemia, or Tay-Sachs disease.

• Prenatal screening can be used to diagnose some conditions in babies before they are even born, such as Down syndrome.

• Newborn screening is the most widespread form of genetic testing. Newborns may be screened for a variety of inherited conditions such as phenylketonuria (PKU), cystic fibrosis, sickle cell disease, etc. Laws requiring these tests vary from state to state.

These forms of genetic testing all look for gene changes that are passed from one generation to the next and are present in every cell in the body.

Genetic or DNA testing of cancer cells

There are also other types of tests that look at DNA changes in cancer, but these tests look for the changes only in the cancer cells that are taken from the patient. The genetic tests that are used to check cancer tissue are not the same as those used to find out about inherited cancer risk. They only look for DNA mutations that started in a single cell in the body and are present only in those cells that arose from the mutated cell. These tests can give information on a person's outlook (prognosis) or even on how much he or she might benefit from certain types of treatment. Here, we will not be talking about the type of DNA testing that is done on tumors or cancer cells. For more information about this kind of testing and its use in cancer treatment, see our information on each type of cancer.

The rest of this document focuses on predictive genetic testing for inherited mutations, especially as they relate to cancer.

Who should have genetic testing?

Predictive genetic testing is done only if you choose to do it. If you are concerned about your family's pattern of disease, cancer you've had in the past, or other cancer risk factors, you may want to talk to your doctor about the possibility of having genetic testing.

Doctors will sometimes suggest patients have genetic testing if others in their family have had a certain disease. If you have any of the following, you might consider genetic testing for yourself:

• several first-degree relatives (mother, father, sister, brother) with cancer, especially the same type of cancer
• family members who developed cancer at a young age
• close relatives with rare cancers
• a known genetic mutation in the family (from one or more family members who had genetic testing)

It's important to know what tests may be available. For some types of cancer, there are no mutations that are known to increase risk (at least they are not known yet). Some other cancer types may have known mutations, but genetic tests are not yet available for them. For more information on the types of cancers for which inherited genes may be important, please see our document, Heredity and Cancer.

You will want to think about what the results of testing may tell you before you decide to be tested. It's important to find out how useful testing may be for you before you do it. Before the actual testing, a session with a genetic counselor -- someone who is trained to interpret and explain the results of testing -- can help you know what to expect. Testing does not always give you black-and-white answers. Before having the testing done, you may want to think about how the results might affect you and your family members.

Who pays for genetic testing?

Genetic testing is complicated, and it can cost a lot. Some tests cost more than others, but the final bill can be thousands of dollars. Be sure you have an idea of how much it may cost before you have testing done.

If you have health insurance, you must decide if you're going to ask your insurance company to pay for it. For the most part, state and federal laws do not require insurance companies to pay for predictive testing. And some companies may cover the testing, while others may not. Companies that do pay for testing may then have access to the results. There has been concern that companies might use the test results to deny coverage. Federal law does not allow nationally-regulated health plans that cover more than 50 people to deny insurance coverage based on the results of genetic testing. But, some health plans may charge you higher premiums, put a limit on your health coverage, or restrict it in other ways. Existing state laws differ on this matter. But this is changing due to the 2008 passage of a new federal law called the Genetic Information Nondiscrimination Act or GINA. (See the section, "National law prohibits discrimination by employers and health insurers" under "Privacy issues.")

How the results might be used by others, employers, for example, is another concern. Many states have passed laws to restrict the use of genetic information in employment decisions, but these laws also vary by state. Again, the new GINA law will help change this when it goes into effect. Federal employees (U.S. government workers) are protected from discrimination based on genetics based on a 2000 executive order.

If you are not sure that your genetic information will be kept confidential, you may choose to pay for the tests yourself so that others will not have access to the test results.

What happens during the genetic testing process?

Genetic testing is done only after you and your health care team feel sure that it is the best thing for you and your family. There are several steps before the actual testing is completed.

Risk assessment

The first step in genetic testing is to find out how likely you are to develop a certain disease. This risk is based on the pattern of disease in your family (called a family history) and other factors. Your risk may be looked at by a doctor, nurse, or trained genetic counselor.

You will talk about your reasons for wanting genetic testing. Your family history (as far back as possible) will be reviewed in depth. The patterns of the disease in your family will be identified. It is important to confirm the illnesses in your family by medical records and/or death certificates when possible. If the genetic testing is for a certain type of cancer, you may also be asked for a thorough personal medical history. This may include early detection practices, gynecologic history (for women), lifestyle factors, and exposure to things that may cause cancer (carcinogens).

You may also have a physical exam that focuses on the family cancer of concern.

It is often helpful to look at your family's attitudes about cancer and the possibility of a family member being "blamed" for the cancer. Cultural beliefs, support systems, and finances may also play a role in how your family views cancer. These topics may be discussed, too.

Genetic counseling

Genetic counselors have special training or master's degrees in their field. Some doctors and advanced practice oncology nurses with special training may also do genetic counseling.

The philosophy of genetic counseling is to give you information in an unbiased or neutral way so that you or you and your family can make your own decisions about whether or not to test. But sometimes the need for testing is clear and a doctor will recommend testing and follow-up care.

The counselor will discuss how families inherit cancers and how genes are passed to children, as well as the types of cancer seen in the family and estimates of the person's cancer risk. The pros and cons, cost, and limitations of testing are discussed, as well as who in the family should be tested. (More than one person may be tested.) If the risk is found to be high, the counselor may also talk about the best ways to manage it. These may include lifestyle changes, early detection, watching for signs and symptoms of cancer, medicines to reduce cancer risk, or even preventive surgery.

Many issues require an expert counselor. The risk of disease for children and the potential for discrimination can be frightening. The counselor will explore ways to cope, as well as your specific fears and concerns. How to discuss the test results and what they mean with other family members is another key topic.

Your doctor can probably refer you to a genetic counselor in your area. If not, you can find a list of certified genetic counselors on the Web sites of the National Society of Genetic Counseling or the National Cancer Institute. (See the "Additional Resources" section at the end of this document for more information.)

Informed consent

Once all of these issues have been addressed, you will be asked to give your written consent for the testing itself. Information that should be covered in the process of informing you and your family about testing includes:

• the purpose of the genetic test
• the reason for offering the test
• the type and nature of the genetic condition being tested for
• test accuracy
• pros and cons of testing
• other testing options you could use
• treatment options that might be available depending on the test results (if this applies to you)
• further decisions that may need to be made once the results are back
• the possible consent to use patient's DNA results for research purposes after the test
• availability of counseling and support services
• your right to refuse testing

For more information, please see our document, Informed Consent.

Specimen collection and lab testing

Once you have signed the consent form, lab tests are done to look at the genetic area of interest. Genetic tests may be done on a sample of blood, hair, skin, amniotic fluid (the fluid that surrounds a fetus during pregnancy), or other tissue. Genetic tests for cancer usually mean taking several blood samples.

Getting test results

Once the testing is complete, the lab reports the test results in writing to the doctor or genetic counselor. At this time another counseling session (or more than one) will be scheduled. This may not happen until several weeks after the samples are taken. The accuracy of the test and the meaning of the results will be carefully reviewed.

Positive result

If the results of the test are positive, you have the mutated gene that may place you at risk. Your risk of developing the cancer will be discussed in light of the fact that you have the gene. Fear and anxiety are a normal part of learning about increased cancer risk. There may be a strain in family relationships as a result. Concern about being treated differently may become more real. Even after the testing is complete there is often a great deal of uncertainty. Most likely you still will not know for sure when or even if the disease will develop.

Negative result

If the test result is negative (no mutated gene is found), you will likely feel relieved that you are not at increased risk. But a negative result can also be hard to interpret. There may still be the chance that you have a mutation that was not tested for. (Genes may have more than one kind of mutation.) Rarely, the test result may be a "false negative." This means the test reads negative but the mutation is actually there. But even a result that is truly negative does not mean your risk is zero -- it just means you have the same average risk as most other people. Family members whose test results are negative may feel guilty if other family members test positive.

Inconclusive result

If there is not enough information to know whether the genetic changes are present, the test result is said to be inconclusive. The person (and family) may still be at a higher risk of developing cancer. Taking steps to have some control over one's health can be helpful for family members, but not having a sure result can cause anxiety.

Variance of unknown or uncertain significance

This result can happen when genetic tests show that a person has an unusual gene, but its meaning is unclear. It can be a normal variant, simply a different gene that isn't seen often enough to be sure, or there may be some other explanation. For some, a variance of unknown or uncertain significance (VUS) result can cause anxiety, frustration, and even anger because this result gives no information to guide future decisions. You may want to talk this over with the genetic counselor.

What if testing shows an increased risk of getting cancer?

If the test result is positive or inconclusive, managing the risk should become a priority. Early detection testing, using medicines to reduce risk (this is called chemoprevention), and preventive (or prophylactic) surgery are some of the ways to manage cancer risk.

Early detection tests may be done more often, or special tests may be needed if you have a positive test result. For example, a woman with a genetic mutation raising her risk of breast cancer may need breast MRI scans along with her mammograms to look for early signs of the cancer.

Chemoprevention is the use of medicines to prevent cells from developing into certain types of cancer. Several medicines are being studied and used to help prevent cancer in patients at high risk for certain cancers. For example, tamoxifen and raloxifene are used to reduce breast cancer risk. Some pain relievers, such as aspirin, may be used to help reduce the risk of colon cancer for those at high risk. Each person's risk and medical situation must be carefully considered so that any harmful effects of the drug do not outweigh the benefits. As we learn more about genetic diseases, we should find out more about using medicines to prevent cancer.

Prophylactic (preventive) surgery is another option in some cases. For example, some women at high risk for getting ovarian cancer may decide to have their ovaries removed once they've had their children.

Your doctor may recommend one or more of these approaches, but it is important to understand how much they may affect your risk before you decide on a course of action. You will also want to be sure you understand any risks or downside to your plan.

Changes in lifestyle factors that could affect risk may also be considered, such as exercising to lower your risk of colon or breast cancer. In some cases the effect on risk may be small to offset the mutation, but you may still want to ask your doctor what you can do.

If you have a gene mutation that raises your risk, there may be other factors to think about as well, like whether to tell other family members who might also be at increased risk. Telling them might help them decide if they should get tested or adopt some of the approaches to try to lower their risk. On the other hand, some test results may cause more anxiety than anything else, and some family members may not want to know their own risk. This is especially true if there's not much they can do with the results. You may want to speak with family members before you get tested to find out if they want to know your results.

What are the benefits of genetic testing?

The obvious benefit of genetic testing is a better understanding of your risk for a certain disease. Although testing is not perfect, it can help you make decisions about your health.

A negative result on a genetic test in families at risk for a specific cancer may relieve uncertainty. In the same way, a positive result can help you make important decisions about your future. A positive result may lead to finding disease earlier and preventing deaths.

As scientists continue to learn more about the genes that contribute to cancer, genetic testing will probably become more helpful in determining a person's risk for a disease. In some cases, testing can already help learn the prognosis (outlook) for a person diagnosed with cancer, and can even help with deciding which treatments are most likely to work.

What are the drawbacks of genetic testing?

Genetic tests have several potential problems you must think about before being tested:

Limited answers

Genetic tests do not give perfect answers for those concerned about inherited diseases, especially for those concerned about breast and colon cancer. A positive test result does not always mean you will get the disease. The test can tell what might happen, but it cannot tell what will happen. On the other hand, a negative result does not mean you have no risk of getting the disease.

A test may also be flawed, or test results may be read wrong. Genetic testing is not tightly regulated at this time, and different labs may have different ways of looking for a certain mutation.

Sometimes a genetic test may be done even though the result has little chance of helping the patient. When this happens, the test may create anxiety when the original intent was to relieve it. That is why counseling before you get the test is so important -- you'll want to know exactly how the result will help you, and if it will help enough to make up for the stress it can cause.

Psychological or emotional impact

Learning that you have or might develop a serious disease is frightening. The person being tested may become quite upset if family members have already died of the disease in question.

A positive genetic test can also impact other family members. More family members may need to be tested. Sometimes family secrets are revealed as a result -- paternity, adoptions, or other difficult issues may come up.

Having a gene or passing a gene on to children can bring out feelings of guilt or anger. The test result can have implications on future relationships with a spouse or other family members, which can be upsetting, too.

In some cases, more medical tests or procedures may have to be done as a result of genetic testing. For example, if a gene mutation for colorectal cancer is found, more tests such as colonoscopy may be recommended. Waiting for results can lead to more stress and anxiety.

Privacy issues

Most people who are concerned about privacy issues and genetic information are concerned about how the information may be used to harm them. Most Americans are afraid that employers and insurance companies might have access to and use their genetic information. They fear an employer could find out and discriminate against hiring or promoting them, although the new GINA law is changing this. (See the next section, "National law prohibits discrimination by employers and health insurers.") Some people are even concerned that adoption efforts could be stopped based on this type of sensitive information.

On the other side, some companies and researchers are concerned about there being too many restrictions on this information. The privacy issue becomes even more complicated when so many family members may be influenced by a single positive genetic test result.

For these reasons, it's important to understand who might learn about your results before you decide on testing.

National law prohibits discrimination by employers and health insurers

The Genetic Information Nondiscrimination Act (GINA) was signed by President George W. Bush on May 21, 2008. The law went into effect on May 21, 2009 for insurers and will go into effect on November 21, 2009 for employers. It bars discrimination based on genetics by employers and health insurers:

Employers: GINA bars employers from discriminating based on genetic test results or genetic information. GINA states that employers must not discriminate on the basis of genetic information in hiring, termination (firing or layoffs), pay, or other personnel actions such as promotions, classifications, or assignments. The law applies no matter how they got the information. Employers may not require genetic testing and may not collect genetic information except for very limited exceptions (such as when information is needed to meet the requirements of family and medical leave laws or to watch for harmful effects from hazardous workplace exposures). Employers must keep genetic information confidential. They may not release or share genetic information except for when:

• the employee asks them to;
• fulfilling a request from a health researcher;
• complying with medical leave laws; or
• disclosing or reporting to a public health agency.

This part of the law takes effect November 21, 2009.

Health insurers: GINA bars health insurers from turning down people or charging higher premiums for health insurance based on genetic information or the use of genetic services. This includes genetic counseling and testing. GINA bars group health plans, individual plans, and Medicare supplemental plans from using genetic information to limit enrollment or to change premiums. It also bars these insurers from asking for or requiring genetic tests. GINA applies to all health insurance plans (including federally regulated ERISA plans, state-regulated plans, and private individual plans). This part of the law took effect May 21, 2009.

GINA defines genetic information as (1) an individual's own genetic tests; (2) the genetic tests of family members; and (3) one or more family members with a genetic disease or disorder.

Do all health professionals know about genetic testing?

Genetic tests should be ordered by doctors who know about genetic illnesses, the genetic tests available, the usefulness of these tests, and follow-up care. Other health care workers should be involved in the process of giving information and support throughout the testing process.

Health care professionals often need to learn about genetic testing. Few nurses have been taught more than basic genetic concepts. In much the same way, few doctors have specific training in cancer genetics. Though genetic counselors are available, not all of them have specialized training in cancer genetics, either. One way to ensure that these health care workers know about genetics and cancer is to require them to have a minimal standard of education or training.

The National Coalition for Health Professional Education in Genetics (NCHPEG) is a group of health care professionals whose mission is to be sure members know about new genetic knowledge and technology. Such knowledge will probably become more important in the future. NCHPEG has also identified core competencies in genetics that they recommend all health professionals should have in order to use information about genetics when teaching and caring for patients.

Who else has interests in genetic information?

Medical and pharmaceutical researchers are interested in low-cost access to genetic information and materials. Because of this, the pharmaceutical industry (companies that make medicines) has opposed donor ownership of genetic material. If a person owns their genetic information, the pharmaceutical companies might have to pay the donor for access to the information. Members of the pharmaceutical lobby have argued against people owning their own genetic information, stating it would drive up drug costs, which would be passed on to the consumer.

Medical researchers must get the individual's informed consent before any studies of tissue samples and DNA can be done.

Insurers also could benefit from access to genetic information. But the entire industry may change as health insurers will be required to cover people who are tested and found to be more likely to get a disease, as well as those who are less likely to get the disease. This will happen when the new GINA law takes full effect in late 2009. Note that GINA does not affect life insurance, disability insurance, or long-term care insurance. It also does not say that health insurers must pay for any particular genetic test or treatment.

Employers differ from state to state on whether or not they may ask a job applicant if they have had genetic testing, what the results are, or if they are willing to have genetic testing. Some states allow employers to ask based on the exposure to potentially toxic chemicals and substances in the workplace. But most states prohibit discrimination and employment decisions based on genetic information. For more information about state laws governing genetics, go to the National Conference of State Legislatures Web site at www.ncsl.org/default.aspx?tabid=14408 (where you can find the laws for your state) or www.ncsl.org/default.aspx?tabid=14280 (a chart of genetic employment laws). The federal law called GINA will prohibit the use of genetic testing in the workplace in non-governmental organizations, but it doesn't go into effect until November 2009.

What is the future of genetic testing?

Without question, genetic testing will play a larger role in cancer risk assessment, detection, and treatment in the future.

The Human Genome Project and The Cancer Genome Atlas

The Human Genome Project was a huge undertaking in which government and private researchers mapped the entire sequence of human DNA (known as the genome). The project took more than 10 years and was completed in 2003. Scientists now estimate that the 3 billion or so "letters" that make up the human genome contain about 25,000 genes. The next step is to identify these genes and learn what each one does. The basic genome map will allow researchers to identify cancer-related genes more quickly.

An even larger undertaking, The Cancer Genome Atlas (TCGA), has now begun. Researchers are proposing to map the genomes of many people with the same types of cancer to try to learn which of their genes are different from those in people without these cancers. Not all researchers agree this project is worthwhile because of the huge time and expense involved. Still, the National Cancer Institute (NCI) and the National Human Genome Research Institute (NHGRI) are evaluating a smaller version of the project. The purpose of this pilot project is to find out if there is value in collecting information on the genetic basis of cancer.

These projects will further our understanding of the genetic basis of cancer, making genetic testing more useful in the future.

Better technology

At this time, genetic testing can be quite costly, and it can take several weeks to get the results. As better technologies are developed, tests will become more accurate and will be able to look at more than one gene at a time.

DNA chip technology is one exciting area of genetic research. These chips are able to pick out gene fragments for specific diseases. The p53 DNA chip is now being marketed as a way to detect this genetic mutation, which is often linked to cancer.

Laboratory researchers are now able to put DNA from cells in a DNA chip scanner and analyze which genes are active. In the future, this type of DNA testing may help doctors learn a person's risk of developing different diseases. This could make it easier to customize treatment for that person.

Other areas of research may impact how important genetic testing will become. One is the field known as epigenetics, which looks at how genes are turned on and off. Another is the field of proteomics, which looks at patterns of proteins in the body. (Genes are the blueprints for making proteins.) Researchers in these fields are developing tests that may someday be used along with or instead of standard genetic tests.

Dealing with genetic information

Managing the information we get from genetic testing continues to be an important issue. Many questions about patient rights and privacy still need to be resolved, and will probably become even more complicated in the future. Other gray areas include genetic testing of children up for adoption, testing children for diseases they may develop as adults, and prenatal testing. Both national and international legislation are needed to address these concerns.

Additional resources

More information from your American Cancer Society

We have selected some related information that may also be helpful to you. These materials may be ordered from our toll-free number, 1-800-277-2345.

• Genetic Testing: Patient Privacy and Discrimination Considerations -- ACS Position Statement

• Heredity and Cancer

• Oncogenes and Tumor Suppressor Genes

• Gene Therapy

National organizations and Web sites*

Along with the American Cancer Society, other sources of information and support include:

National Society of Genetic Counselors
Web site: www.nsgc.org
"Consumer Information" link on the Web site offers detailed information on genetic counseling, questions to ask before genetic testing, a guide to collecting family history, info on genetic testing and genetic counselors, and a directory of genetic counselors.

National Cancer Institute
Toll-free number: 1-800-422-6237 (1-800-4-CANCER)
Web site: www.cancer.gov
A listing to find professionals who offer services related to cancer genetics (cancer risk assessment, genetic counseling, genetic susceptibility testing, and others) can be found at: www.cancer.gov/search/geneticsservices.

Centers for Disease Control and Prevention (CDC)
Toll-free number: 1-800-232-4636 (1-800-CDC-INFO)
Web site: www.cdc.gov
Offers information on a wide range of topics, including genetics and disease prevention.

A-T Children's Project (Ataxia Telangiectasia Children's Project)
Toll-free number: 1-800-543-5728 (1-800-5-HELP-A-T)
Web site: www.atcp.org
Group focused on finding a cure for Ataxia Telangiectasia, a lethal genetic disease in children that causes loss of muscle control, cancer, and immune system problems.

Children's Tumor Foundation (CTF)
Toll-free number: 1-800-323-7938
Web site: www.ctf.org
Offers information about the genetic disorder neurofibromatosis, and help finding medical, social, and genetic counseling.

Colon Cancer Alliance
Telephone: 877-422-3030
Web site: www.ccalliance.org
Provides information on colorectal cancer, including the Colorectal Cancer Screening Study, genetics, symptoms, treatment, and more.

David G. Jagelman Inherited Colorectal Cancer Registries
Toll-free number: 1-800-223-2273, ext. 46470
Web site: www.clevelandclinic.org/registries
Information on the colorectal cancer registries and how to join. Also, info on familial adenomatous polyposis (FAP), hereditary non-polyposis colorectal cancer (HNPCC), juvenile polyposis (JP), Puetz-Jegher's Syndrome (PJS) and other inherited colon and rectum problems, as well as risk assessment, prevention, screening, treatment, and research.

* Inclusion on this list does not imply endorsement by the American Cancer Society.

No matter who you are, we can help. Contact us anytime, day or night, for information and support. Call us at 1-800-227-2345 or visit www.cancer.org.

References

American Society of Clinical Oncology. American Society of Clinical Oncology policy statement update: Genetic testing for cancer susceptibility. J ClinOncol. 2003;21:2397-2406.

Cameron LD, Sherman KA, Marteau TM, Brown PM. Impact of genetic risk information and type of disease on perceived risk, anticipated affect, and expected consequences of genetic tests. Health Psychology. 2009;28:307-316.

Cancer Genome Atlas Web Site. The Cancer Genome Atlas Awards Funds for Technology Development (News Release, 7/2/07). Accessed at http://cancergenome.nih.gov/media/news_7_2_2007.asp on July 28, 2009.

Department of Health and Human Services. "GINA" The Genetic Information Nondiscrimination Act of 2008 Information for Researchers and Health Care Professionals. April 6, 2009. Accessed at www.genome.gov/Pages/PolicyEthics/GeneticDiscrimination/GINAInfoDoc.pdf on July 29, 2009.

Giarelli E, Jacobs, LA. Issues related to the use of genetic material and information. Oncol Nurs Forum. 2000;27:459-467.

Hudson KL, Holohan MK, Collins FS. Keeping Pace with the Times -- The Genetic Information Nondiscrimination Act of 2008. New Engl J Med 2008;358:2661-2663.

Johnson A. National Conference of State Legislatures. Plunging Into the Gene Pool. March 2007. Accessed at www.ncsl.org/default.aspx?tabid=13790 on July 29, 2009.

Johnson KA, Rosenblum-Vos L, Petersen GM, Brensinger JD, Giardiello FM, Griffin CA. Response to genetic counseling and testing for the APC I1307K mutation. Am J Med Genet. 2000;91:207-211.

Library of Congress. H.R.493. Genetic Information Nondiscrimination Act of 2008 (Enrolled as Agreed to or Passed by Both House and Senate). Accessed at www.thomas.gov/cgi-bin/query/D?c110:6:./temp/~c110QF8FiN on July 29, 2009.

Matloff ET. Genetic counseling. In: DeVita VT, Hellman S, Rosenberg SA, eds. Cancer: Principles & Practice of Oncology. 7th ed. Philadelphia, Pa: Lippincott Williams & Wilkins;2005:2676-2683.

National Coalition for Health Professional Education in Genetics. Core Competencies in Genetics For Health Professionals. September 2007. Accessed at www.nchpeg.org/core/Core_Comps_English_2007.pdf on July 29, 2009.

National Conference of State Legislatures. Genetics and Health Insurance State Anti-Discrimination Laws. January 2008. Accessed at www.ncsl.org/default.aspx?tabid=14374 on July 29, 2009.

Saslow D, Boetes C, Burke W, et al. American Cancer Society Guidelines for Breast Screening with MRI as an Adjunct to Mammography. CA Cancer J Clin. 2007; 57:75-89.

U.S. Department of Energy Office of Science. Human Genome Project Information. 2008. Accessed at www.ornl.gov/sci/techresources/Human_Genome/home.shtml on July 29, 2009.

Last Medical Review: 08/24/2009
Last Revised: 08/24/2009