DNA biomarkers may improve ovarian cancer outcomes

Ovarian cancer is a silent killer--most women present late, and only have a 30% survival rate over 5 years. However, if it is diagnosed early, 90% of these women could survive, and a panel of DNA-based biomarkers could provide the diagnostic solution.

Epigenetic changes are changes to the chromosomes that don't alter the DNA sequence, such as DNA methylation, and can change how genes are expressed. These types of changes are common in cancers. Researchers at the Garvan Institute of Medical Research in Australia sequenced the entire genome of cancer cells from samples of ovarian tumors, looking to find DNA methylation changes that could be used as biomarkers.

"This was one of the first studies that used whole genome techniques to directly profile DNA methylation aberrations in ovarian cancer--with the aim of identifying diagnostic biomarkers," said co-author Brian Gloss. "When we started in 2008, most other research groups were investigating single genes known to be methylated in other cancers. We decided to make use of new whole genome technologies--using DNA methylation profiling and gene expression profiling."

The researchers found 6 altered genes that could be linked to ovarian cancer, including one that had not been connected with cancer before. This new gene was found to be modified in 80% of tumor samples checked by the team.

It's not surprising that ovarian cancer often isn't diagnosed until late--some women don't have any symptoms at all, and for others the symptoms are vague, including stomach pain, bloating, loss of appetite, tiredness and changes in bowel or bladder activity. All these are symptoms that could point to a number of things other than ovarian cancer.

The research is in early stages, and the researchers have said they need to conduct further studies to be sure that their panel of 6 genetic biomarkers will be able to identify enough cancers, as ovarian cancers can vary. However, such a panel, combined with rigorous checking of symptoms, could mean that more women can be diagnosed early and thereby lead to improved outcomes for the patients.

- read the press release
- see the abstract in Cancer Letters