Associations between ABO blood groups and pancreatic ductal adenocarcinoma: influence on resection status and survival

Abstract

Both serology-based and genetic studies have reported an association between pancreatic cancer risk and ABO blood groups. We have investigated this relationship in a cohort of pancreatic cancer patients from Western Norway (n = 237) and two control materials (healthy blood donors, n = 379; unselected hospitalized patients, n = 6149). When comparing patient and blood donor ABO allele frequencies, we found only the A₁ allele to be associated with significantly higher risk for pancreatic ductal adenocarcinoma (PDAC) (23.8% vs. 17.9%; OR = 1.43, P = 0.018). Analyzing phenotypes, blood group A was more frequent among PDAC cases than blood donors (50.8% vs. 40.6%; OR = 1.51, P = 0.021), an enrichment fully explained by the A₁ subgroup. Blood group O frequency was lower in cases than in blood donors (33.8% vs. 42.7%; OR = 0.69, P = 0.039). This lower frequency was confirmed when cases were compared to hospitalized patients (33.8% vs. 42.9%; OR = 0.68, P = 0.012). Results for blood group B varied according to which control cohort was used for comparison. When patients were classified according to surgical treatment, the enrichment of blood group A was most prominent among unresected cases (54.0%), who also had the lowest prevalence of O (28.7%). There was a statistically significant better survival (P = 0.04) for blood group O cases than non-O cases among unresected but not among resected patients. Secretor status did not show an association with PDAC or survival. Our study demonstrates that pancreatic cancer risk is influenced by ABO status, in particular blood groups O and A₁ , and that this association may reflect also in tumor resectability and survival.

Keywords: ABO; FUT2; blood group; glycosyltransferase; pancreatic ductal adenocarcinoma; risk factor.

Figure 1

Cumulative proportion survival (Kaplan–Meier) plot for the 195 pancreatic ductal adenocarcinomas according to breakdown by resection status and blood group phenotype. (A)‐(F) Pairwise comparison of subgroups as specified in the heading of each panel. The observed survival times (months along the X‐axis) are indicated by circles (complete) or crosses (censored observations). In panel A, survival curves for resected and unresected cases are shown by a blue and a red line, respectively. In all other panels, survival curves for blood group O and the comparison group are shown by a red and blue line, respectively.