New Haven, Conn. — Yale researchers have discovered that stomach colonization byHelicobacter pylori in people with non-O blood types is associated with a nearly three-fold increased risk of pancreatic cancer. The research, published online February 24 in the Journal of the National Cancer Institute, confirms the role of Helicobacter pylori, bacteria frequently found in the stomach, in the onset of pancreatic cancer.
In the United States, pancreatic cancer is the 4th most frequent cause of
cancer death. Over the lifetime, more than 1% of the population is affected.
Known risk factors for pancreatic cancer include certain uncommon inherited
genetic mutations, chronic pancreatitis, non-O (A, B, and AB) blood type, and
cigarette smoking. Altogether, these factors explain less than 30% of the
disease.
Seven years ago, a research team from the Yale Cancer Center
Prevention and Control Research Program proposed that colonization by the common
stomach bacterium Helicobacter pylori acted to increase risk of
pancreatic cancer by increasing stomach acidity as well as the pancreatic
response to neutralize the acidity. Over the intervening years, the researchers
carried out a large population-based, case-control study of pancreatic cancer in
Connecticut, and found that stomach colonization by strains of Helicobacter
pylori that cause increased gastric acidity is indeed associated with
increased risk. The Helicobacter bacterium attaches to stomach cells
immediately adjacent to non-O ABO blood groups, and these blood groups may
interfere with how the bacterium functions.
“Our results provide
confirmation of the involvement of Helicobacter pylori in the causation
of pancreatic cancer, as well as suggest the pathway, from bacterial
colonization, to excess stomach acidity, to increased pancreatic response, to
enhanced susceptibility to smoking and other carcinogens, and finally to cancer
transformation,” explained lead author and principal investigator Harvey Risch,
MD, PhD, Professor of Epidemiology and Public Health at Yale.
The researcher’s findings provide the first systematic explanation of the etiology of pancreatic cancer, and in addition to allowing the estimation of the risk of developing this disease, provide a foundation for in-depth exploration of the components of the etiological path.
Herbert Yu, Lingeng Lu, and Mark Kidd of Yale are other authors of the study, which was funded by the National Cancer Institute.
J Natl Cancer Inst. 2010 Feb 24.