Tampa, FL– Scientists have located a region of DNA that – when altered – can increase the risk of ovarian cancer, according to research published in Nature Genetics on Sunday.
An international research group, including scientists from Moffitt Cancer Center, searched through the genomes of 1,817 women with ovarian cancer and 2,353 women without the disease from across the UK. They analyzed 2.5 million variations in DNA base pairs – the letters that spell out the genetic code – to identify common spelling “errors” linked to ovarian cancer risk. Scientists at the Cancer Research UK Genetics Epidemiology Unit, at the University of Cambridge and the University College London led the study.
The scientists identified the genetic “letters,” called single nucleotide polymorphisms (SNPs), which when spelt slightly differently increase ovarian cancer risk in some women. This is the first time scientists have found an SNP linked uniquely to risk of ovarian cancer and is the result of eight years of investigations. With the help of the international Ovarian Cancer Association Consortium, they then looked at more than 7,000 additional women with ovarian cancer and 10,000 women without disease from around the world to confirm this finding.
The region of risk DNA is located on chromosome 9 – there are 23 pairs of each chromosome in humans, one of each pair inherited from each parent. The scientists estimate that there is a 40 percent increase in lifetime risk for women carrying the DNA variation on both copies of chromosome 9 compared with someone who doesn’t carry it on either chromosome. The lifetime risk for a woman carrying the DNA variant on one copy of chromosome is increased by 20 percent.
“Given that ovarian cancer has few signs and symptoms, it is often called a silent killer. Since there are ways to lower risk, it is important to identify high-risk women so that the interventions can be tailored to create an optimal risk-to-benefit profile,” said Thomas Sellers, Ph.D. a genetic epidemiologist at Moffitt Cancer Center. “That’s exactly what Moffitt’s Total Cancer Care initiative is all about. We’re close to identifying other gene variants that influence risk for ovarian cancer and fully expect the profile of susceptibility genes will help us in our fight against this terrible disease.”
Ovarian cancer is the ninth most common cancer in women in the United States with around 21,550 new cases diagnosed each year – 414 women every week. It is the fifth most common cause of cancer death in women in the United States with around 14,600 deaths from the disease.*
*source: American Cancer Society, Cancer Facts & Figures 2009
About H. Lee Moffitt Cancer Center & Research Institute
Located in Tampa, Florida, Moffitt Cancer Center is an NCI Comprehensive Cancer Center - a designation that recognizes Moffitt’s excellence in research and contributions to clinical trials, prevention and cancer control. Moffitt currently has 15 affiliates in Florida, one in Georgia and two in Puerto Rico. Additionally, Moffitt is 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. Moffitt’s sole mission is to contribute to the prevention and cure of cancer.
About the Ovarian Cancer Association Consortium (OCAC)
The Ovarian Cancer Association Consortium (OCAC) was founded in 2005 and its activities are supported by the Ovarian Cancer Research Fund (OCRF) in New York City (www.ocrf.org). OCAC comprises over twenty groups of investigators from around the world who are conducting genetic epidemiology studies of ovarian cancer. The group meets biannually and is working together to discover common genetic polymorphisms that affect a woman's risk of developing ovarian cancer.
The ability to inform women whether they are more or less likely to develop the disease is an important first step towards an indivualized approach to decreasing ovarian cancer deaths. Those at increased risk due to genetic factors, as well as reproductive risk factors such as not having had children or used oral contraceptives, would be the best candidates for screening and prevention strategies. This potentially includes interventions such as screening with CA125 and/or ultrasound, as is being examined in the randomized UK Trial of Ovarian Cancer Screening (UKTOCS). Other approaches include prophylactic removal of the ovaries and fallopian tubes or chemoprevention with oral contraceptives.