A huge international research effort has pinpointed an area of genetic variation that is linked to developing both breast and ovarian cancer.
Two studies published today in Nature Genetics separately found that changes in a stretch of chromosome 19 are associated with developing the cancers.
Breast and ovarian cancer have long been related and their genetic link was confirmed in the 1990s when mutations in the BRCA1 and BRCA2 genes were found to increase the risk of both types of cancer.
In this latest research, the DNA of thousands of women from around the world, including Australia, was scanned to look for 'typos' called single nucleotide polymorphisms (SNPs). By comparing women with and without cancer, researchers learn which SNPs are associated with disease.
While studies like this don't necessarily find the mutations that cause disease, they act as 'signposts' for areas of the genome that should be looked at more closely.
One study found that an area of chromosome 19 called 19p13 - near a gene that is known to interact with BRCA1 - was associated with an increased risk of a particular type of breast cancer in the general population, as well as breast cancer in women with BRCA1 mutations. The second study found the same area was associated with ovarian cancer.
Professor Georgia Chenevix-Trench, head of the Cancer Genetics Laboratory at the Queensland Institute of Medical Research and a researcher on both studies, says the findings help scientists to understand more about how breast and ovarian tumours develop. But she admits it's too early to use the information in any kind of genetic test.
Associate Professor Jennifer Byrne, an oncology researcher at the University of Sydney Medical School, says the research is interesting "because it's leading us to a gene that probably cooperates with BRCA1 in some way and BRCA1 is a very important gene".
A third study published the same issue found that SNPs located on chromosomes 2 and 8 are associated with developing a particular type of ovarian cancer. The region of chromosome 8 is also linked with prostate, colorectal and breast cancer, says Byrne.
"It's another example of how a common gene might affect susceptibility to a number of different tumours," she says.
Professor John Hopper from the University of Melbourne and an author on one of the studies, says the next step is to 'zoom in' on the areas found in these studies with detailed DNA sequencing.
"Instead of looking at large numbers of people for common variants we now need to look at particular people and particular regions that have been identified by studies like these."