Researchers at the Keck School of Medicine of USC have discovered new genetic variants in five regions of the genome that affect the risk of ovarian cancer in the general population.
The USC researchers are among an international consortium of scientists from the United States, Europe, Canada and Australia that carried out genome-wide association studies comparing 10,283 women with ovarian cancer to 13,185 women without the disease.
The consortium’s results appear in two separate studies published Sept. 19 in the journal Nature Genetics.
The studies built upon previous findings that a stretch of DNA on chromosome 9 containing single DNA letter variations is associated with ovarian cancer risk. The researchers now have found additional stretches of DNA on chromosomes 2, 3, 8, 17 and 19 by grouping patients according to the type of ovarian cancer they had developed. Four out of five of the new DNA variations were more common in women who had developed the most common and aggressive form of the disease, known as serous ovarian cancer.
Simon Gayther, professor of preventive medicine at the Keck School of Medicine, is senior author on one of the studies, which found a region of DNA on chromosome 19 that affects ovarian cancer risk. A third study in the same journal issue found that variation in this same region of chromosome 19 also increases the risk of breast cancer in women who already carry the BRCA1 gene.
“Our study shows that the same genetic region plays a role in both breast and ovarian cancer, suggesting that the same faulty pathway can cause both diseases, just like BRCA1 and BRCA2 do,” said Gayther, who conducted the research at University College London. “This is important because it suggests that women who carry certain versions of this stretch of DNA could benefit from closer monitoring for both breast and ovarian cancers.”
“Since the critical validation of these findings was performed by a large consortium of investigators from around the world, we see this research as a triumph of science without borders for the benefit of women everywhere,” said Andrew Berchuck, professor of gynecologic oncology at Duke University Medical Center and head of the steering committee of the international Ovarian Cancer Association Consortium.
Ovarian cancer is the fifth-most common cancer among women in developed countries, often detected in later stages when the chances of a cure are small. As a result, the disease claims more lives in the United States than all other gynecological cancers combined. Every year, about 13,000 women in the United States and 130,000 worldwide die from the disease.
“These latest findings raise the possibility that we can identify the women in the general population who are at the greatest risk of developing ovarian cancer because they carry these newly discovered DNA variants,” Gayther said. “These women could then be given closer surveillance to either prevent ovarian cancer altogether or look for early signs of the disease when it is most treatable.”