Re: ABO Blood Group and the Risk of Pancreatic Cancer

Extract

Wolpin et al. ( 1 ) reported on the association between ABO blood type and the risk of incidental pancreatic cancer in two large US cohorts: the Nurses’ Health Study and the Health Professionals Follow-up Study. They found, in agreement with previous reports, that participants with non-O blood group had an increased risk of developing pancreatic cancer (hazard ratio = 1.44; 95% confidence interval = 1.14 to 1.82). Although the authors mentioned the possibility that the blood group antigen may alter the systemic inflammatory response, they concluded that the potential mechanisms by which ABO antigen may influence the risk of pancreatic cancer risk are unknown ( 1 ).

Interestingly, both individuals with non-O blood type and patients with pancreatic cancer have a markedly increased risk of venous thrombosis ( 2 , 3 ). The relationship of ABO genotype with venous thrombosis appears to be mediated in part through von Willebrand factor (vWF), which carries factor VII (FVII) and protects it from degradation and also has the A and/or B or H (O) antigens on its surface. As a consequence, individuals with the A1 and B alleles have higher levels of vWF and factor VIII plasma levels ( 2 ), thus also activating the coagulation system from the other (plasmatic) side. The association between thrombosis and visceral cancer was suggested in 1865 by French internist Armand Trousseau. Thrombosis is not only a major complication of pancreatic cancer ( 3 ), but may appear as an early manifestation of the disease. Development of an idiopathic venous thromboembolic event, by itself, has been associated with a markedly increased risk of occult pancreatic cancer ( 4 ). Activation of coagulation and tissue factor (TF), the prime initiator of coagulation, have been described as important factors in pancreatic cancer ( 5 , 6 ), being associated with poor prognosis and increased angiogenesis. Therefore, aberrant coagulation could be caused from the TF/FVII activation coming from the tumor cell itself or be promoted from the other side of the pathway of the coagulation system in those with a certain ABO genotype ( 2 ).