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Cancer in the Family

It is not uncommon for more than one member of a family to be affected by cancer in their lifetime.

It is important to know that only a small percentage (up to 5%) of certain cancers are due to a faulty inherited gene. It is also important to know that even if a faulty gene causing an increased chance of cancer is being passed down in your family, it does not mean you will inherit or develop cancer.


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Faulty genes and cancer.

Our bodies are made up of billions of tiny cells. These cells contain a copy of the genetic plan for our growth, development and health.

This genetic plan comes in the form of genes which we inherit from our parents. Our genes decide features such as the colour of our eyes, hair and skin and whether we are tall or short.

Everyone has some faulty genes. Sometimes they have been inherited from our parents. Faults in genes also build up during our life as we age. Usually faulty genes don't cause us any problems.

However, sometimes our faulty genes cause, or make us more prone to, particular health problems.

Over the last 10 years, scientists have made some important discoveries about the role faulty genes play in cancer.

For more information on genes, chromosomes and inheritance the Centre for Genetics Education has produced Genetic Fact Sheets or read our fact sheet on Cancer, Genes and Inherited Predisposition.


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How can I tell if my family history of cancer is of concern?

Look at the family history on both your father’s and your mother’s side of the family. The clues that cancers in the family may be due to an inherited faulty gene include:

  • The number of blood relatives who developed cancer.

    The more blood relatives who have developed cancer, the more likely the cancer is due to an inherited faulty gene.

    • The types of cancer (in particular breast, ovarian and/or bowel cancer)

    The types of cancer and who it affects in the family are important. In some families there are a number of blood relatives who develop the same type of cancer (such as breast cancer or bowel cancer). In other families there are particular cancers running in the family (such as breast and ovarian cancer or bowel cancer and cancer of the uterus). This happens because some faulty genes can cause more than one type of cancer.

    • The age at which cancers in the family developed.

    The younger people were when they developed cancer (compared to what is expected in the general community), the more likely it is to be due to hereditary factors.

    The more clues that are present, the more likely it is that there is an inherited faulty gene in the family causing a higher than usual chance of cancer. However, it is not definite. It is important to know that some people who inherit a faulty gene which causes an increased chance of cancer, never go on to develop cancer.

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    What should I do if I am worried about my family history of cancer?

    Find out what types of cancer have occurred in your family and how old each person was when they got cancer. It is also important to record the family members not affected by cancer. Talk to your doctor who can help you find out if your family history of cancer is of concern. Your family history of cancer can change over time so it is important to keep your doctor updated about any new cancers. For more information on family history the Centre for Genetics Education has produced resources to help you, these can be found in the Family Health History section or in our brochure.

    Brochure: What if I have a Family History of Cancer?

    If necessary, your doctor may refer you to a Family Cancer Clinic or Genetic Counselling Service. These services give people information about their chance of developing cancer based on their family history.

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    What types of cancer can be due to an inherited faulty gene?

    It is thought that up to 5% of these types of cancer may involve an inherited faulty gene.

    In rare cases, there may be a number of people in a family who developed less common cancers in a pattern that suggests an inherited faulty gene is present. It is therefore important to look at all the different types of cancer that have occurred in the family.

    What are Genetic Counselling and Family Cancer Clinics

    Genetic Counselling and Family Cancer Clinics provide counselling and information for families with a history of cancer on:

    • Inheriting cancer
    • Individual's chance of developing cancer
    • Screening
    • Cancer reduction strategies.

    They also provide genetic testing where appropriate.

    The clinics are conducted through the public hospital system and there is no direct cost to the patient for consultation or genetic testing.

    More information on Genetic Counselling.

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    Who attends a Family Cancer Clinic?

    The types of families often referred to a clinic are:

      • Families with three or more individuals with a specific type of cancer - often breast/ovarian or bowel cancer.
      • Individuals with multiple cancers or cancers diagnosed at an unusually young age.


    How can you attend a Family Cancer Clinic?

    There are two ways you can attend:

    1. Your GP, physician or surgeon may refer you to a clinic;
    2. You can call one of the Family Cancer Clinics to discuss an appointment.

    Click Here for a list of Family Cancer Services

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    Last updated: May 08, 2017