Dr. John Lewis
Medical researchers at the University of Alberta and their American colleagues have discovered a biomarker that accurately predicts which prostate cancer patients will have their cancer recur or spread.
Faculty of Medicine & Dentistry researcher John Lewis and his team collaborated with a group led by Andries Zijlstra of Vanderbilt University in the United States. Their findings were published last week in the peer-reviewed journal, Cancer Research. Zijlstra was the principal investigator, while Lewis was the co-investigator.
Prostate cancer is the second leading cause of cancer-related deaths in North America among men and the most commonly diagnosed cancer in North American males. Most prostate cancer-related deaths are due to advanced disease that has spread (metastasized) throughout the body. In this study, the team discovered that an antibody specific for a biomarker called CD151free was able to detect cancer cells that can escape from the primary tumour and metastasize.
The team wanted to know whether cancer spread earlier or recurred earlier in patients who tested positive for this antibody.
"The answer in both cases was yes," said Lewis. "If the antibody detected the biomarker in patients' tissues, their cancer recurred earlier after surgery. Patients who tested positive for the biomarker developed metastasis an average of 10 years earlier than those who tested negative."
Zijlstra added: "The antibody is able to recognize a molecular change that reflects a switch in the metastatic ability of tumour cells. Therefore the detection of CD151free in prostate cancer should predict whether a tumour would remain dormant or progress rapidly."
To see whether this discovery could be used as a diagnostic test in the clinic, the team looked at tissue samples from 138 patients who received prostate cancer treatment in Canada over the past 12 years.
"This translational research project really benefited from our multi-institutional team-based approach," said Lewis, who works in the Faculty's Department of Oncology as the Alberta Cancer Foundation's Frank and Carla Sojonky Chair in Prostate Cancer Research. "The contribution of basic scientists, urologists, pathologists, trainees and clinical fellows from both institutions was essential to successfully answering our translational research questions."
Lewis and his U of A and American colleagues now want to validate their findings in a larger group of patients throughout Alberta. To do this, they recently formed a province-wide translational team called the Alberta Prostate Cancer Research Initiative. If all goes well, the test could be integrated into clinical practice in two to three years.
"Ideally this test could identify a subset of patients that may be followed without treatment, and equally important, identify those who need to be treated earlier and more aggressively," said Peter Venner, an oncologist at the Cross Cancer Institute in Edmonton, and a member of the research team. "This test could improve quality of life for those with prostate cancer who don't have this marker - they could avoid invasive treatments such as surgery or radiation."
The research that led to the discovery of this biomarker was funded by the the National Institutes of Health, the Canadian Cancer Society Research Institute and the Alberta Cancer Foundation/The Motorcycle Ride for Dad.
"These findings have the potential to improve outcomes for prostate cancer patients," saids Siân Bevan, the director of research for the Canadian Cancer Society. "By identifying the role of the CD151 protein in cancer progression, Dr. Lewis' work suggests a new way to monitor patients and deliver more accurate prognoses of their disease. The society is delighted to support studies like this that advance our understanding of cancers and their treatment."
Myka Osinchuk, CEO of the Alberta Cancer Foundation, added: "We are privileged to have invested our donor dollars in this type of research that will have a transformational impact on things that matter to Albertans. With this discovery, better screening will lead to improved treatment for those facing cancer."
Alberta Innovates - Health Solutions and the Alberta Cancer Foundation are funding the next stage of research, developing a simple test to detect the biomarker in the blood.