A comparison of the risk of pancreatic adenocarcinoma development between individuals with different ABO blood group phenotypes: A meta-analysis

Abstract

Pancreatic adenocarcinoma aetiology is complex and incompletely understood, and with incidence and mortality rate increasing annually, discovery of associated risk factors is essential. One such risk factor is ABO blood group phenotype; however, conflicting study results make it unclear whether individuals with one ABO phenotype are more at risk than individuals with a different ABO phenotype. Therefore, a meta-analysis was performed comparing the risk of pancreatic cancer development between individuals with different ABO blood group phenotypes. Database searches were conducted using the search terms ABO blood group OR ABO blood type AND pancreatic cancer OR pancreatic adenocarcinoma OR pancreatic carcinoma, and a meta-analysis was then conducted on eligible studies. Twenty-one studies totalling 5,952,008 participants were analysed. The odds ratios (OR) for the comparison of pancreatic cancer development between individuals with different ABO phenotypes were determined; A vs. B (1.20, p=0.0002), AB (1.16, p=0.007), and O (1.38, p<0.00001); B vs. A (0.84, p=0.0002), AB (0.94, p=0.14), and O (1.16, p=0.0005); AB vs. A (0.86, p=0.007), B (1.06, p=0.14), and O (1.20, p=0.001); O vs. A (0.72, p<0.00001), B (0.86, p=0.0005), and AB (0.83, p=0.001). Individuals with blood group A have a significantly increased risk of pancreatic cancer development compared to all other ABO phenotypes, whereas blood group O individuals are significantly less at risk compared to all other ABO phenotypes. These results could influence eligibility of individuals for future pancreatic cancer screening programmes; however, further research is required to determine the mechanism by which ABO phenotypes can promote tumorigenesis.