Pancreatic cancer often has a poor prognosis, even when diagnosed early. It is typically spreads rapidly and is seldom detected in its early stages, which is a major reason why it's a leading cause of cancer death. Signs and symptoms may not appear until the cancer is quite advanced and complete surgical removal isn't possible.
Now scientists have discovered a sign of the early development of pancreatic cancer, an upsurge in certain amino acids that occurs before the disease is diagnosed and symptoms appear. The research is being published online today by the journal Nature Medicine.
Although the increase isn't large enough to be the basis of a new test for early detection of the disease, the findings will help researchers better understand how pancreatic cancer affects the rest of the body, particularly how it can trigger the sometimes deadly muscle-wasting disease known as cachexia.
The researchers utilized blood samples collected years earlier from 1,500 people participating in large health-tracking studies. They analyzed the samples for more than 100 different metabolites, substances produced by the metabolic process, and compared the results from participants who had gone on to develop pancreatic cancer and those who had not. The amount of time that would elapse before those individuals were diagnosed with pancreatic cancer ranged from two to 25 years, although the highest risk was in the several years before diagnosis, the researchers found.
These findings led the researchers to hypothesize that the increase in branched chain amino acids was due to the presence of an early pancreatic tumor, which was confirmed in laboratory experiments performed by a group at MIT. Their experiments showed that mice with newly formed pancreatic tumors had above-normal blood levels of these amino acids. The researchers found the increase was due to a breakdown of muscle tissue, which caused branched amino acids to be released into the bloodstream. This process is similar to what occurs in patients with cancer cachexia.
The findings provide an important lead to scientists studying how pancreatic tumors interact with patients' normal tissues.