One of the Holy Grails for cancer clinicians is diagnosing prostate cancer spread through a non-invasive blood test. Now researchers at the Barts Cancer Institute at Queen Mary University have moved the needle a little closer. They have identifiedcertain tumor cells circulating in the blood of prostate cancer patients which may be markers for the disease.
The study suggests that tests of circulating tumor cells expressing the mesenchymal marker vimentin may aid in predicting and monitoring prostate cancer progression.
Traditional screening for prostate cancer now relies principally on PSA tests and digital rectal exams, followed by prostate biopsies. But better approaches are needed, particularly in the light of some health authorities recommending against PSA tests to detect this cancer. Reports that men with low PSA levels may also have prostate cancer are clearly not helpful.
“There’s a need to develop better tests to identify and monitor men with aggressive prostate cancer,” said Dr. Chris Parker, chair of the National Cancer Research Institute’s Prostate Cancer Clinical Studies Group. “This research has found a promising new marker that could one day make it to the clinic to guide treatment decisions.”
The Queen Mary team examined blood samples from 80 men with prostate cancer. They specifically looking for cancer cells that had undergone epithelial-to-mesenchymal transition, meaning that they now had the ability to migrate and invade organs elsewhere in the body.
Their final data show that blood samples with high numbers of such cells, identified by the expression of the vimentin protein, were more likely in samples taken from patients with more aggressive cancers, that is, those whose cancer had spread.
Dr Yong-Jie Lu, lead author from QMUL's Barts Cancer Institute, said: "Our research shows that the number of these specific cells in a patient's sample is a good indicator of prostate cancer spreading. By identifying these cells, which have gained the ability to move through the body, we have found a potential new way to monitor the disease.
This suggests that these cells may one day be combined with other monitoring techniques to monitor prostate cancer patients, and identify those at risk of metastasis.
“If we’re able to replicate these studies in larger groups of people, we may be able to one day predict the risk of someone’s cancer spreading so they can make more informed treatment decisions,” Parker said.
The study was presented at the recent National Cancer Research Institute Cancer Conference, held in Liverpool.