Association between ABO gene polymorphism (rs505922) and cancer risk: a meta-analysis

Previous studies have showed that ABO blood type is associated with multiple gastrointestinal cancers, including pancreatic cancer. Recently, one single nucleotide polymorphism (SNP) rs505922 in ABO gene has been implicated in susceptibility to pancreatic cancer across different populations, but different results were found in other types of cancer. This meta-analysis aimed to clarify the association. All eligible case-control studies were identified by searching through PubMed and Chinese language databases (CNKI and WanFang) up to September 1, 2014. Pooled estimates (odds ratio) were used to assess the strength of associations in fixed-or random-effects models. A total of nine studies with 10,304 cases and 15,564 controls were included. Overall, SNP rs505922 C allele was confirmed as a risk factor for cancer. Additionally, in further stratified analysis by cancer type, C allele carriers were more likely to have higher risk of pancreatic cancer. This study provided evidence of SNP rs505922 C allele as a strong risk factor of cancer susceptibility, specifically for pancreatic cancer.