Doctors have identified a protein in the blood that they believe could serve as an early warning sign for patients at risk of diabetes and death from cancer.
Researchers in Sweden and China analyzed two decades of health records of more than 4,500 middle-aged adults as part of the Malmö Diet and Cancer Study. They found that those with the highest levels of prostasin, a protein that circulates in the blood, were almost twice as likely to have diabetes as those with the lowest levels.
Some of the people in the study already had diabetes, so the scientists looked at who among those without the disease was diagnosed later. People in the top quarter for prostasin levels were found to be 76% more likely to develop diabetes than those in the bottom quarter.
Dr Xue Bao, first author of the study at the Affiliate Hospital of Nanjing University Medical School in China, said prostasin was a potential new “risk marker” for diabetes, but also death from cancer, especially in people who have high blood sugar.
Prostasin plays several roles in the body, such as regulating blood pressure and blood volume, and it also suppresses the growth of tumors fueled by high blood sugar. While type 2 diabetes is known to increase the risk of certain cancers, including pancreatic, liver, bowel and endometrial tumours, the biological mechanisms are far from clear.
After studying the link between prostasin and diabetes, researchers set out to find out if people with high levels of the protein were at higher risk for cancer.
Writing in Diabetologia, they describe how those in the top quarter for prostasin levels were 43% more likely to die of cancer than those in the bottom quarter.
According to the study, participants with high levels of prostasin and blood sugar had a significantly higher risk of dying from cancer. For each doubling of prostasin concentration, the risk of death from cancer increased by 24% in people without high blood sugar and by 139% in those with high blood sugar. “Special attention should be paid to these people,” write the authors.
It is not known if high prostasin levels play a role in the disease or if it is simply a biological marker that increases as the disease progresses. One possibility, the authors suggest, is that prostasin levels rise in an attempt to suppress high blood sugar levels, but are unable to stop or reverse the damage done.
“The relationship between diabetes and cancer is poorly understood and this protein could provide a possible shared link between the two conditions,” said Professor Gunnar Engström, lead author of the study at Lund University.
“We now need to examine to what extent prostasin is causally linked to these diseases or if it is a valuable marker of increased disease risk,” Engström added.
“It might also be possible to identify people at increased risk of diabetes and cancer, and suggest preventive measures.”
Because the results are drawn from the residents of a city, they may not apply to broader populations. The researchers also point out that prostasin was measured from frozen blood taken at a single time point and the study was unable to distinguish between different types of diabetes.
Jessica Brown, from Diabetes UK, said: “We know there is a link between diabetes and certain types of cancer, and this study suggests that levels of a particular protein, called prostasin, are linked to both conditions.
“Better understanding the changes inside the body that can put people at risk for diabetes and cancer will help scientists find ways to protect people from these serious diseases, but there is still much to discover.
“We need more research to find out if prostasin plays a direct role in the development of type 2 diabetes and poorer cancer outcomes in people with high blood sugar.”