BACKGROUND: There are few data on blood group(BG) types and types of pancreatic cancers. The aims of this study were to study BG types and BG-antigens in pancreatic intraductal papillary mucinous neoplasms(IPMNs). METHODS: BG type and tumor BG-antigen(glycoprotein) expression(studied by immunohistochemistry on tissue microarrays) were analyzed with regard to characteristics of 101 surgically resected pancreatic IPMNs. RESULTS: Non-O BG type predicted invasive carcinoma independently from high serum CA19-9 and male gender. BG type A was observed more frequently in women than in men. Chronic pancreatitis was more frequently seen in patients with BG type B or AB. Aberrant tumor expression(with regard to BG type) of loss of A antigen expression type occurred in 15.0% of IPMNs and of loss of B antigen expression type in 62.5% of IPMNs. Intraneoplasm BG-antigen expression was not related to dysplasia grade or invasion. CONCLUSION: The results of the study suggest that in pancreatic IPMN, non-O BG type predicted invasive carcinoma, whereas for intratumor BG-antigen expression no specific patterns were detected with regard to the progression of glandular epithelial dysplasia or invasion. BACKGROUND: There are few data on blood group (BG) types and types of pancreatic cancers. The aims of this study were to study BG types and BG-antigens in pancreatic intraductal papillary mucinous neoplasms (IPMNs). METHODS: BG type and tumor BG -antigen (glycoprotein) expression (studied by immunohistochemistry on tissue microarrays) were analyzed with regard to the characteristics of 101 surgically resected pancreatic IPMNs. RESULTS: Non-O BG type predicted invasive carcinoma independently from high serum CA19-9 and male gender. BG type Aberrant tumor expression (with regard to BG type) of loss of A antigen expression type occurred in 15.0% of IPMNs and of loss of B antigen expression type in 62.5% of IPMNs. Intraneplasm BG-antigen expression was not related to dysplasia grade or invasion. CONCLUSION: The results of the study suggest that in pancreatic IPMN, non -O BG type predicted invasive carcinoma, for for intratumor BG-antigen expression no specific patterns were detected with regard to the progression of glandular epithelial dysplasia or invasion.