The authors noted that in 2011 there were an estimated 225,500 new cases of ovarian cancer worldwide. Although some women are at greatly elevated risks of ovarian cancer due to inherited mutations in the BRCA1 and BRCA2 genes, these are rare in the population and account for perhaps 10 percent of cases. However, a substantial portion of genetic influence on ovarian cancer risk has been “unexplained” and some of that may be due to common genetic variants. Sellers points out that “the Il1A variant that was most strongly protective is carried by 30 percent of women in the study, so the impact at the population level is not trivial.”
The Follow-Up of Ovarian Cancer Genetic Association and Interaction Studies (FOCI) is funded by the National Cancer Institute and is based at Moffitt. In addition to researchers from Moffitt, researchers from Columbia University, Duke University, the Mayo Clinic College of Medicine, the University of South Florida, Brigham and Women’s Hospital, the University of Cambridge (UK), the University of Southern California and the Institute of Cancer Research (UK) participated in the study.
What role do genes play in ovarian cancer?
Many cancers begin when one or more genes in a cell are mutated (changed), creating an abnormal protein or no protein at all. The information provided by an abnormal protein is different from that of a normal protein, which can cause cells to multiply uncontrollably and become cancerous.
A person may either be born with the genetic mutation in all of their cells (germline mutation) or acquire a genetic mutation in a single cell during his or her lifetime. An acquired mutation is passed on to all cells that develop from that single cell (called a somatic mutation). Somatic mutations can sometimes be caused by environmental factors, such as cigarette smoke. Most ovarian cancers (about 85% to 90%) are considered sporadic, meaning that the damage to the genes occurs by chance after a person is born and there is no risk of passing on the gene to a person’s children. Inherited ovarian cancers are less common (about 10% to 15%) and occur when gene mutations are passed within a family, from one generation to the next.
What are the chances a mutated gene is inherited?
Every cell usually has two copies of each gene: one inherited from a person’s mother and one inherited from a person’s father. Most types of hereditary ovarian cancer follow an autosomal dominant inheritance pattern, in which a mutation needs to happen in only one copy of the gene for the person to have an increased risk of getting the disease. This means that a parent with a gene mutation may pass on a copy of the normal gene or a copy of the gene with a mutation. Therefore, a child who has a parent with a mutation has a 50% chance of inheriting that mutation. A brother, sister, or parent of a person who has a gene mutation also has a 50% chance of having the same mutation.
Located in Tampa, Moffitt Cancer Center is the only Florida-based National Cancer Institute Comprehensive Cancer Center, a designation that recognizes Moffitt’s excellence in research and contributions to clinical trials, prevention and cancer control. Moffitt has 14 affiliates in Florida, one in Georgia, one in Pennsylvania and two in Puerto Rico. Moffitt is also a member of the National Comprehensive Cancer Network, a prestigious alliance of the country’s leading cancer centers, and is listed in U.S. News & World Report as one of “America’s Best Hospitals” for cancer.
Ovarian cancer gene raises risk six-fold
About one woman in 70 is at risk of developing ovarian cancer, which claims more than 4,200 lives a year.
However, for those with a faulty RAD15D gene, the risk is raised to one in 11.
The discovery was made by scientists at the Institute of Cancer Research, which is connected to The Royal Marsden hospital in London.
Professor Nazneen Rahman, head of genetics and epidemiology, said: “At this level of risk, women may wish to consider having their ovaries removed after having children, to prevent ovarian cancer occurring.”
At the moment the discovery, published in the journal Nature Genetics, is limited to the knowledge that faulty copies of this gene raise ovarian cancer risk.
But Prof Rahman said: “There is also real hope on the horizon that drugs specifically targeted to the gene will be available.”
The study was based on comparing the DNA of women from 911 families with ovarian and breast cancer, to that from 1,060 people in the general population.
Cancer Research UK, which helped fund the study, described it as “the most significant ovarian cancer gene discovery for more than a decade”.
By Stephen Adams, Medical Correspondent
Media release by Florida Science Communications
Source: Moffitt Cancer Center