Investigating the Genetic Link Between Breast Cancer and Prostate Cancer
In many families, both prostate cancer and breast cancer are diagnosed among close relatives. However, the major breast cancer genes (BRCA1 and BRCA2) do not appear to explain the clustering of these two cancers within most of these families. Dr. Kathy Cooney and I, along with our research team, are beginning a study to identify new genes associated with the clustering of prostate and breast cancer in families.
Researchers have identified very few genes that increase a man’s risk of developing prostate cancer. However, a positive family history of prostate cancer, particularly when a man’s relatives are diagnosed with prostate cancer at a younger age, is an important risk factor and suggests that genetics play an important role.
We have discovered a specific region on chromosome 16 that we believe contains one or more genes that increase risk for both prostate cancer and breast cancer. We plan to work with the International Consortium of Prostate Cancer Genetics (ICPCG) to learn more about these potential genetic variants. The ICPCG is a large group of scientists who collect information and DNA specimens on families with multiple cases of prostate cancer. The group will help us identify which of these families also have breast cancer diagnosed in a close relative (often mothers, sisters or daughters).
In 2000, Dr. Catalona’s research team was among the first to report the connection between the genetic locus on chromosome 16 and prostate cancer in a study of siblings with prostate cancer.
We will study the DNA of the family members diagnosed with prostate and breast cancer to find new genetic mutations. Once the gene mutations are identified, we will verify that they are associated with prostate cancer in a large, clinical population by studying whether or not these mutations occur more frequently in men with prostate cancer compared to men without prostate cancer.
Understanding the function of these genes will help us to understand the underlying biology of both cancers and importantly why these cancers occur in some families and not others.
Genetic variants as a screening tool
The importance of this research lies in the identification of new genes that increase risk for both prostate cancer and breast cancer. If we can verify that these genes cause clustering of breast and prostate cancers within families, eventually individuals with a family history of these cancers could undergo testing for the genetic mutation. This information would be valuable for both the physician and patient to determine individualized risk for cancer and dictate how closely the patient should monitored (or screened via testing of PSA or mammogram) for development of prostate or breast cancer.
“The proposed study has the potential to make an important contribution to prostate cancer research by identifying new cancer genes which may be used to screen individuals based upon their family history of prostate and breast cancer.”
If you are currently involved in Dr. Catalona’s Genetics of Prostate Cancer research study, you may be eligible to participate in the new study. We are looking for families in which two first-degree relatives (e.g. brothers, or father-son) are affected with prostate cancer and another first-degree relative (e.g. sister, mother) is affected with breast cancer. Contact Dr. Catalona’s research coordinator at 312-695-0912 to update your family history of breast cancer and learn how to submit a blood sample for DNA testing.