Cancer Research UK scientists hope to use a simple blood test to discover which ovarian cancer patients become resistant to chemotherapy – says a leading researcher at the charity’s conference in Harrogate, Yorkshire.
In a study led by Professor Robert Brown, at Glasgow University, researchers found that important genes – which allow chemotherapy to trigger cancer cell death – can be ‘switched off’ if the tumour recurs after initial treatment.
This process, known as gene methylation, means that when chemotherapy is given a second time it may not be as efficient at killing cells in the tumour.
Prof Brown says that tumours release DNA into the bloodstream and it is possible to identify gene methylation in patients by taking a blood sample.
“This is far less invasive than doing a biopsy on a tumour,” he says. “Patients who do not acquire methylation of a particular gene survive longer.”
As part of Cancer Research UK’s work into ovarian cancer Prof Brown’s team is also working on early clinical trials of a drug that can reverse the process of gene methylation.
This is still at a very early stage but scientists are investigating a drug that can switch back on the genes that methylation has switched off.
This drug would allow chemotherapy to activate cell death in the tumour and be more effective in tumours that have become resistant to chemotherapy.
Prof Brown says: “Early clinical trials of these drugs, known as demethylating agents, are reducing methylation in patients.
“We now need to do further trials to examine the value of doing a blood test which could allow us to target the drugs to the most appropriate patients.
“This is turn would give us a chance to measure whether the demethylating drugs in these patients gives an improvement in survival which is always the ultimate goal.”
Professor Robert Souhami, Cancer Research UK’s Director of Clinical and External Affairs, says: “Failure to respond to chemotherapy is one of the major reasons people die from cancer. Professor Brown’s pioneering work shows the potential for reversing this and this may increase the effectiveness of drug treatments.”
Ovarian cancer is the most common gynaecological cancer in UK women. It is the fourth most common cause of cancer death in women.
Each year around 6,700 women in the UK are diagnosed with ovarian cancer. More statistics.
The majority of cases are diagnosed at a late stage and five year survival rates are correspondingly low. More statistics.
Ovarian cancer is predominantly found in older, post-menopausal women with 80 per cent of cases diagnosed in women over 50 and the highest incidence occurs in women over 70. More statistics.