A dozen new genetic variants that have the potential to increase the risk of women developing ovarian cancer have been identified by a team of international scientists, in a study of nearly 100,000 people.

"We know that a woman's genetic make-up accounts for about one-third of her risk of developing ovarian cancer. This is the inherited component of disease risk," said Paul Pharoah, Professor at the University of Cambridge in Britain. Inherited faults in genes such as the BRCA1 and BRCA2 gene mutations -- also known to increase the risk of breast cancer -- account for about 40 per cent of the genetic risk. 

For the study, published in the journal Nature Genetics, the team conducted a genetic trawl through the DNA of almost 100,000 people, including 17,000 patients with the most common type of ovarian cancer. The findings revealed 12 new genetic variants, while confirming the association of 18 of the previously published variants.

In total, there are now known to be 30 risk variants, accounting for 6.5 per cent of the inherited component of risk, in addition to the BRCA1 or BRCA2 genes, the researchers said. 

"We really have little idea of the functional effect these variants have at the molecular or cellular level and so there are few clues as to how they might affect risk. If we can understand how they work, we will be in a better position to treat, and possibly prevent ovarian cancer," noted Simon Gayther from Cedars-Sinai Medical Center in Los Angeles, US.

Factors such as taking the oral contraceptive pill, undergoing invasive surgery to remove ovaries and fallopian tubes as well as having children may help reduce the risk of ovarian cancer, the researchers said.