The team assessed previously collected blood samples from 1,500 people who were part of large health-monitoring studies.
They found that the participants who went on to develop pancreatic cancer had higher blood levels of branched-chain amino acids (BCAAs) - essential nutrients that the body extracts from proteins found in foods - compared with participants who did not develop pancreatic cancer.
These increased BCAA levels were found in patients 2-25 years before they were diagnosed with pancreatic cancer, the researchers say. But they note that patients with high levels of these amino acids several years prior to diagnosis were at highest risk.
Past studies from the team have shown that mice with pancreatic tumors also have increased levels of BCAAs. With that in mind, the researchers hypothesize that these latest findings indicate that early pancreatic tumors in humans increase BCAA levels.