Cancer scientists believe they have found a gene which - when working properly - may have the ability to stop ovarian cancer developing.
The gene tests could eventually help women
Scientists at Cancer Research UK's Edinburgh oncology unit found the gene was not functioning correctly in nine out of 10 cancer tissue samples.
When the gene is turned back on within the cancer cells, further growth is suppressed, suggesting it is influential in the body's defences against the tumour.
However, it will be some time before the findings translate into new drugs or tests for women.
Ovarian cancer is one of the most dangerous for women, as it is often not diagnosed early, making treatment much more difficult.
There are more than 6,000 cases diagnosed each year, and more than 4,000 deaths.
The human body has a variety of defence systems which it uses to carry out repairs when abnormal cells develop.
When these defences fail, or are circumvented, tumours can develop.
One of the ways cancer gets a foothold in the body is to somehow "switch off" genes which would normally prevent such abnormal cells from either growing or dividing.
The scientists involved in this project believe the gene they are investigating - called OPCML - may be one of these.
Their hope is to either find a way to turn the gene back on in human ovarian tumours - or find a drug which mimics the biological effects of the activity of the gene.
Dr Hani Gabra, who led the project, said: "It takes us further in the urgent quest to find a method for earlier diagnosis and treatment of ovarian cancer.
"We now need to work on understanding more about this gene and exactly how it works and what makes it switch off."
Cancer Research UK's medical director Dr John Toy said: "It is always heartening to make headway when investigating a cancer, like ovarian cancer, which is difficult to treat entirely successfully unless caught early.
"This work still has a long way to go in the laboratory before patients could benefit but results so far are promising."
The research was published in the journal Nature Genetics.