Up to a third of women with ovarian cancer could one day benefit from a drug which is showing early promise.
There are around 7,000 cases of ovarian cancer in the UK each year
A team from the Institute of Cancer Research say PARP inhibitors have already been shown to shrink tumours in women with an inherited gene flaw.
But lab tests suggest that some cancers in women without the fault could also be treated.
The research is set to be discussed at an Ovarian Cancer Action conference in London this weekend.
Ovarian cancer is known as a "silent killer".
Women tend not to know they have the disease until it is advanced.
Symptoms including a swollen tummy, difficulty eating and needing to urinate more often - all of which can be signs of other conditions or things women put down to ageing.
It is the fourth most common women's cancer after breast, bowel and lung, with around 7,000 new cases each year.
If it is detected while it is contained in the ovaries, the cure rate is around 90%, but once it has spread elsewhere in the body, this falls to around 20-30%
The PARP inhibitor has already been shown to shrink tumours in those who have inherited a faulty BRCA1 gene, and therefore have a family risk of the disease.
Around 15% of women with the cancer have a genetic fault.
But lab tests have shown that women without this genetic flaw - those with so-called sporadic cancers which occur without any known family risk - may also benefit from the drug because their tumours behave in a similar way, potentially doubling the number who could benefit.
Further work is now needed to see if these lab tests translate into real-life benefits.
Professor Stan Kaye of the drug development unit at the Institute of Cancer, who is leading the research, said: "It is too soon to say exactly how many women could be treated with this drug, but it could be around a third.
"Over the next few years, we're aiming to get better at developing selective treatment.
"So rather than treat all women with ovarian cancer the same radiotherapy or drugs, we will be able to tailor treatments to work on specific defects in the cell."
A second team of UK researchers, based at University College London is looking at developing a blood test to screen for the disease.
The researchers led by Professor Ian Jacobs, are investigating whether checking levels of a chemical called CA215, which rise as a tumour grows, could improve the detection of ovarian cancer.
The test is already used to diagnose cancers in women with symptoms, but the team have found evidence it can also detect tumours at an earlier, and therefore more treatable, stage.
The study is due to finish in 2011, but preliminary results are expected to be released this year.
Professor Bob Bast, of the University of Texas who developed the test 25 years ago, said: "If this work is successful, it would be the first evidence that screening for ovarian cancer in healthy women is effective."
But he said it would not be enough to use the CA125 test alone. "It will probably detect around 80% of cases. Teams including our group in Houston, plus others in Boston, Seattle and London are trying to develop other blood tests to use alongside it."
Annwen Jones, chief executive of Ovarian Cancer Action, said: "Ovarian cancer has been a difficult disease to treat, particularly because of the development of drug resistance, the way the cancer spreads, and because of late detection.
"Scientific and laboratory understanding has made significant progress in very recent years, and we are now at the point where this has promising potential for more effective and targeted treatments."