UCSF Cancer Genetics and Prevention Program

Cancer Genetics and Prevention Program

 What is genetic counseling and why was I referred?

Cancer genetic counseling can help an individual determine whether or not they have inherited an increased risk for cancer.  People who see a genetic counselor include individuals with a personal or family history of:

  • Cancer, such as breast or colon cancer, under the age of 50
  • Two or more first-degree relatives on the same side of their family who have been diagnosed with cancer
  • More than one primary cancer in the same individual (such as two primary breast cancers, or primary colon cancer and primary stomach cancer)
  • More than one type of cancer in the same individual
  • A rare type of cancer or tumor pathology
  • A known genetic mutation in a cancer susceptibility gene in their family
  • An ethnicity associated with a higher frequency of hereditary cancer syndromes (e.g. Ashkenazi or Eastern European Jewish descent)

Who are genetic counselors?

UCSF genetic counselors are trained professionals who can provide you and your family risk assessment for hereditary cancer syndromes (along with other genetic conditions), education about a particular hereditary cancer syndrome, genetic testing (if indicated), screening recommendations and referrals and resources if you are found to have a hereditary cancer syndrome. To see a list of UCSF Genetic Counselors click here.

You can also contact the UCSF genetic counselors through Kintalk at by clicking here.

What you need for your genetic counseling appointment:

- Information about family members who have had cancer
- Specific cancer diagnoses (second primary cancer, recurrent cancer, etc.)
- Age at cancer diagnosis
- Copies of any medical reports available (pathology reports, genetic test results, death certificates, etc.)
- Information about family members who have not had cancer
- Current age or age of death in family members diagnosed with cancer
- Screening practices (mammography, colonoscopy, ect.)
- Insurance card- most insurances will pay for genetic counseling and genetic testing
- Relatives positive genetic test result*

*If a family member has had a genetic test and has tested positive for a hereditary cancer syndrome
you will need to bring a copy of their genetic test result to your genetic counseling appointment. These results are very important in ensuring that your genetic counselor orders the correct genetic test for you.

Click HERE to print a list of the things you will need for your appointment with your UCSF genetic counselor. (Add a link)

What to expect at a genetic counseling appointment

Genetic counseling usually requires at least one face-to-face visit with a trained genetic counselor. The first session often involves:

- reviewing your personal and family history,
- reviewing medical records
- education on cancer and hereditary cancer syndromes like Hereditary Breast and Ovarian Cancer Syndrome or Lynch syndrome
- a risk assessment for a potential hereditary cancer predisposition in you and your family.

The genetic counselor may request tumor tissue from you if you have had a cancer or from an affected relative. Click here to read more about the tumor testing done in Lynch syndrome. Genetic testing may be offered to you at the first appointment or more information may need to be gathered.  Sometimes a genetic counselor will recommend that a relative who has been diagnosed with cancer be tested instead of you as there is a higher chance of finding a genetic mutation in a person affected with cancer than a person without a cancer diagnosis. If you do undergo genetic testing then you will be asked to come back for a results visits to discuss your genetic test results and their interpretation.

To find out more about genetic counselors and genetic counseling click here.

The genes we inherit from our biological parents explain many things about our bodies, from our hair and eye color to the length of our toes. In the case of hereditary cancer syndromes, inherited genetic changes, called mutations, increase our risk of certain types of cancer. But what is a gene? And how are genetic traits passed down from one generation to the next?

DNA, Chromosomes, and Genes

The genes we inherit from our biological parents explain many things about our bodies, from our hair and eye color to the length of our toes. In the case of hereditary cancer syndromes, inherited genetic changes, called mutations, increase our risk of certain types of cancer. But what is a gene? And how are genetic traits passed down from one generation to the next?

Every cell in our body contains hereditary material known as deoxyribonucleic acid (DNA). This DNA gets packaged into structures known as chromosomes.

Our cells typically contain 23 pairs of chromosomes. For each pair, we inherit one from our father and one from our mother.

Cells and chromosome and DNA

Each chromosome consists of many genes. And since we have two copies of each chromosome—one from each parent—we also have two copies of each gene. An exception to this involves what are known as the “sex chromosomes” (the X and Y chromosomes). Women normally have two X chromosomes and men normally have one X chromosome and one Y chromosome. This means that for genes on the X chromosome, women have two copies but men have only one.

Genes contain the instructions necessary to build and maintain our bodies. These instructions are provided by the DNA within each gene. Based on the underlying DNA “code,” genes tell our bodies what proteins to produce. Proteins, in turn, provide the structure of our bodies and play key roles in regulating bodily function.

Gene Mutations

A mutation in a gene refers to a change in the underlying DNA code that makes the gene not function properly. If you think of DNA as spelling out a word, a mutation involves a change in the letters of the word. This change may involve a substitution of letters, or an addition or loss of letters.

When the underlying DNA code changes, protein production can also change. A gene may create a different protein than it’s supposed to, it may create the wrong amount of protein, or it may not make a protein at all. Any of these changes can affect how the body functions.

Gene mutations are either germline or somatic. Germline mutations are present in the egg or sperm cells that make us. These mutations are often inherited from our parents, but can also occur for the first time in us. Germline mutations are present in every cell in our body, and we can pass them on to our children. Somatic mutations, in contrast, develop in body cells over the course of life, but do not involve the egg or sperm cells. These mutations may cause us to develop health problems such as cancer, but we will not pass the mutation on to our children.

Lynch Syndrome involves inherited (germline) mutations.

Cancer Genetics

Cancer is caused by DNA damage (i.e., mutations) in genes that regulate cell growth and division.
Some mutations are inherited, while others are caused by exposure to radiation or to mutation-inducing chemicals such as those found in cigarette smoke. Mutations also can occur spontaneously as a result of mistakes that are made when a cell duplicates its DNA molecules prior to cell division.
When cells acquire mutations in specific genes, like those associated with Lynch syndrome, that control proliferation, such as proto-oncogenes or tumor suppressor genes, these changes are copied with each new generation of cells. Later, more mutations in these altered cells can lead to uncontrolled cell replication and the onset of cancer.

cancers cells

Patterns of Inheritance

For inherited conditions that can be traced to a single gene, the patterns of inheritance are fairly straightforward. Depending on the gene, common patterns of inheritance are autosomal dominant, autosomal recessive, X-linked and mitochondrial.

Autosomal Dominant Inheritance

With autosomal dominant inheritance, a person only needs to inherit one copy of the abnormal gene in order to develop the condition. Lynch Syndrome is an example of an autosomal dominant condition. A parent with an autosomal dominant disorder has 50/50 chance of passing the disorder to each of his or her children.

autodominant

Autosomal Recessive Inheritance

With autosomal recessive conditions, a person needs to inherit abnormal copies of the gene from both parents in order to develop the condition. If the person inherits the abnormal gene from only one parent, the person is a carrier of the mutation (and can pass it on to their children), but does not develop the health problems associated with the mutation. If two carriers of the same autosomal recessive condition have a child together, there’s a 25 percent chance that their child will have the condition, a 50 percent chance that the child will be a carrier, and a 25 percent chance that the child will not inherit any copies of the abnormal gene. This risk applies to each pregnancy. Examples of autosomal recessive conditions include cystic fibrosis and sickle cell disease.

recessive inheritance

 

Research is Ongoing

For some inherited genetic conditions, the condition has been well defined, tests are available, and there are options to manage disease risk. For many other conditions that appear to have a hereditary basis, however, the underlying genetic causes are still poorly understood. Ongoing research in this area will allow individuals and families to better understand and manage their health.

Reference: Genetics Home Reference. Handbook: Help Me Understand Genetics. Published by the Lister Hill National Center for Biomedical Communications, US National Library of Medicine, National Institutes of Health, Department of Health & Human Services. June 4, 2012.

 

Here is a quick video on Hereditary Cancer