Scientists said they had netted a clutch of tipoffs to help identify women with a higher inherited risk of ovarian and breast cancer, dubbed "silent killers" for the stealthy way they claim lives.
The work gathered experts from the United States, Europe, Canada and Australia, who trawled through the genetic code of tens of thousands of women, looking for single-letter changes found among women with cancer but absent among women who were otherwise healthy.
Their work was published online in the journal Nature Genetics.
One study found telltale DNA on chromosomes 2, 3, 8, 17 and 19 that strongly indicated risk from serious ovarian cancer, the term for the commonest and most aggressive form of this disease.
Another paper found that a variation of DNA on Chromosome 19 amplified the risk of breast cancer associated with a well-known culprit, a faulty copy of the BRCA1 gene, which is located on Chromosome 17.
What role these variants perform in the biology of cancer is unclear, and finding out will probably take many more years of investigation.
Even so, the researchers believe that the clues add powerfully to the basket of genetic telltales for cancer, which thus opens the way to diagnostic tools for women at risk.
"These latest findings raise the possibility that in the future, women in the general population who are at the greatest risk of developing ovarian cancer because they carry these newly discovered DNA variants can be identified and given closer surveillance," said Andrew Berchuck, a professor at Duke University Medical Center in North Carolina, who headed one of the investigations.
"It also suggests that preventive approaches could be targeted towards these women."
Ovarian cancer is the fifth commonest cancer in developed countries and is often detected too late, when the chances of a cure are remote. Each year, about 130,000 women around the world die from the disease.