A simple blood test that can detect the presence of all cancers is a bit of a holy grail for many medical researchers. While numerous biomarkers are being discovered signaling the presence of different cancers, it's proving a big challenge to find a single easy way to track all kinds of cancer. Remarkable new work from the University of Copenhagen may have finally found a solution, discovering that a protein produced by malaria parasites is perfectly engineered to detect most cancer cells.
Developing a cancer blood test has been tricky, to say the least. The large variety of different cancers make it exceedingly difficult to find single biomarkers that can be used to detect them all. One recent blood test to show promise targeted two biomarkers which seem to be able to detect eight common types of cancer.
More ambitious studies are working on universal cancer blood tests either by trying to track RNA footprints in blood or certain proteins that are common to almost all cancers. Other research has attempted to find ways to detect tumor cells freely circulating in a person's bloodstream. The big challenge with that technique is that these tumor cells are so minute in quantity that it can be nearly impossible to easily identify them in a single blood sample.
Scientists develop "smoke detector" cancer test
The new research reveals that a particular protein produced by malaria parasites is attracted to a very specific sugar molecule found on more than 95 percent of cancer cells. Called VAR2CSA, the protein essentially acts like a tumor cell magnet, gripping onto any cell found to harbor the target sugar molecule.
The experiments have already yielded some exciting early results. One test placed ten single cancer cells into five millilitres of blood. Using the malaria protein the researchers were able to successfully retrieve 9 of those cells.
"We catch the cancer cells in greater numbers than existing methods, which offers the opportunity to detect cancer earlier and thus improve outcome. You can use this method to diagnose broadly, as it's not dependent on cancer type," says Ali Salanti, joint author on the new research.
Another study of patients suffering from pancreatic cancer revealed the process to be incredibly effective in separating patients with positive cancer diagnoses from healthy subjects.
"We found strikingly high numbers of circulating tumor cells in every single patient with pancreatic cancer, but none in the control group," says Christopher Heeschen, joint author on the new research.
Even more impressive, the technique is reportedly precise enough to be able to accurately detect the stages of individual cancers by calculating how many specific cancer cells are found in a blood sample.
"Our method has enabled us to detect cancer at stages one, two, three and four," says Salanti. "Based on the number of circulating tumor cells we find in someone's blood, we'll be able to determine whether it's a relatively aggressive cancer or not so then to adjust the treatment accordingly."
Further clinical studies will be needed before the test can be comprehensively validated, but it certainly is one of the more promising discoveries in the great search for a universal cancer blood test. What's more, the protein is already being investigated as a potential new way to deliver cancer treatments. Finding effective molecules that can zero in on tumors will be key to directly delivering newer therapies straight to cancers in the future and this malaria protein may be the perfect molecule for the job.
