A Belgian and Swedish team tested this new technique on breast and pancreatic cancer cells. The researchers say further tests are needed to determine how the liver responds in producing higher quantities of the protein.
Cancer cells up close
One of the hallmarks of cancer is inflamed cells, and in many cases, this inflammation leads to angiogenesis - the growth of blood vessels - and a moderation of the body's immune defense.
Until now, scientists and medics have worked on the basis that the best way to treat tumors is to starve the vascular supply, thereby cutting off their supply of nutrients.
Now though, a team of researchers from Sweden's Uppsala University and the University of Leuven in Belgium say there might be another way.
In a paper published Friday in the journal Cancer Cell, the scientists showed that by using histidien-rich glycoprotein (HRG), a protein found in blood plasma, it is possible to activate specific immune cells which inhibit tumor growth and reduce the risk of metastasis in secondary organs.
"Our study shows that the regulation of tumor-associated inflammation can be utilized to treat cancer and that there is a great potential to develop HRG into a drug for cancer treatment," said Lena Claesson-Welsh, a professor of genetics at Uppsala University in a written statement.
Although the research is still in its initial phase and no clinical trials have yet been set up, Peter Carmeliet of the Belgian team says the findings are both striking and paradoxical.
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"If you starve the tumor, you risk depriving it of oxygen which creates a hostile micro environment from which the cells try to escape," he told Deutsche Welle. "They will look for other places to go and that is what leads to metastasis, which is what kills most patients."
Against that backdrop, he and his colleagues ran a series of laboratory tests on different types of cancer, including breast and pancreatic. They used HRG to increase oxygen supply to the blood vessels in the tumors.
"You would think they'd grow too big, but what we actually achieve by providing them with more oxygen is to make them feel happier so they don't feel the need to spread," Carmeliet added.
In short, HRG can be used to normalize tumor vessels, which creates a less hostile environment and reduces the subsequent need to metastasize.
Carmeliet also said that the normalization process improves the potential success of chemotherapy, which does not specifically target tumor cells but interferes with cell division.
When the body needs a helping hand
HRG could have beneficial effects on all forms of cancer
But although HRG is circulated around the body in the plasma and deposited in different organs, it is neither abundant nor powerful enough to successfully tackle cancer.
"The tumors progressively try to get rid of the HRG," Carmeliet said. "They are smart, in order to grow, they know they need to get rid of the things that prevent them from doing so."
In order to progress with the research, Sonia Tuges, who co-wrote the paper, told Deutsche Welle that further tests now needed to be done to establish whether the liver, where HRG is generated, responds to cancers by producing higher quantities of the protein.
"It is difficult to modulate the levels," she said, adding that they seem to fall in people with high-degree cancer.
"We think there is a kind of mechanism which down regulates, but we want to know if levels increase when they are trying to stop the formation of new blood vessels, or decrease when they are trying to protect against a tumor."
The team hopes to identify some answers to those questions within the next year.
Author: Tamsin Walker
Editor: Cyrus Farivar