Researchers from the University of Adelaide and Griffith University are celebrating this week after developing a new blood test that can diagnose ovarian cancer in its early stages. The results of their research, published in the Biochemical and Biophysical Research Communications Journal, explained the new test has the potential to “dramatically improve” early detection of the disease, which is notoriously difficult to detect in the early stages.
Ovarian cancer is one of the biggest cancer killers for women in Australia and around the world, and each year more than 150,000 women around the world die as a result of the devastating cancer. It’s the sixth-leading cause of death for Australian women and 60 per cent of those diagnosed are over the age of 60.
Unlike other cancers, there is currently no early detection test for ovarian cancer, meaning many women are often diagnosed with the cancer when it’s too late. What’s worse is many signs and symptoms of the cancer such as bloating, frequent urination and tummy pain are often dismissed as other less serious health issues.
While the blood test requires further testing before it is available for clinicians, researchers have been studying the interactions between a bacterial toxin and an abnormal glycan — a large carbohydrate molecule that is expressed on the surface of cancer cells and released into the blood. Glycosylation is a universal feature of cancer cells, and certain glycans are well-known markers of tumour progression.
The research team has now been able to engineer a harmless portion of the bacterial toxin to enhance its specificity for the glycan and use it to detect glycans in blood samples of women with ovarian cancer.
“Recently we’ve been doing some refining to specific and sensitivity,” researcher James Paton from the University of Adelaide’s Research Centre for Infectious Diseases told Starts at 60. “Now it’s ready for testing in cancer samples and the first ones we did were ovarian cancer. We think this is a test that will pick up a wide range of cancers as a generic screen.”
The results of the research found the new test was able to detect significant levels of the glycan in blood samples from more than 90 per cent of women with stage 1 ovarian cancer. It also found it was detected 100 per cent of samples from later stages of the disease. In promising results, it hadn’t been detected in any of the samples from healthy controls.
Stage 1 or 2 is an early variation of ovarian cancer, while 3 or 4 are more advanced stages. According to the Cancer Council, seven out of 10 women with ovarian cancer are diagnosed at later stages.
“What we need to do now is to test a larger number of serum from healthy people to get a rigorous normal range for age and gender and that sort of thing like environmental factors and use that set a define cut-off and then we’ll be able to get more accurate data from bigger samples,” Paton said. “The problem we’ve got is we’re microbiologists and glycobiologists, we’re not cancer researchers and so the only serum we’ve tested came from the Victorian Cancer Bio Bank. That had limited numbers of serum, particularly from early stage ovarian cancer because so few women get diagnosed at that stage.”
Researchers are now working with specialist ovarian cancer researchers so they can more samples analysed faster.
“We want to understand what the normal ranges are for the glycan in the serum anyway of healthy people and so far the ones we’ve tested, it’s been very low. It’s making sure that trend is still there with bigger data sets,” Paton said. “Then it’s a matter of going through the necessary licensing and that’s going to take a couple of years at least.”
At present, screening tests for ovarian cancer are the most effective way of diagnosing the disease. Transvaginal ultrasounds (TVUS) and CA-125 blood tests are the current screening processes in place, according to the Cancer Council. A TVUS uses sound waves to analyse the uterus, fallopian tubes and ovaries through an ultrasound wand inserted into the vagina. Meanwhile, the CA-125 blood test measures CA-125 protein levels in the blood. This is useful because those with ovarian cancer typically have higher levels of the protein in their system.
Paton explained that the next step is to develop a follow-up cancer test where researchers use the modified bacterial toxin as a pet imaging target.
“We’d put a pet dye on it and the idea is you could do a mass screen with the blood test and anybody who comes up above a threshold, you could subject them to pet imaging and that would tell you exactly where the cancer is and whether it’s spread and all that sort of thing,” he said. “That could have a variety of uses. It could for example give you a 3D map of where the tumour is for surgical intervention so the surgeon knows already exactly how big it is and whether it’s infiltrating the delicate structures and things like that.”