Subtyping of intraductal papillary mucinous neoplasms – pitfalls of MUC1 immunohistochemistry

Intraductal papillary mucinous neoplasms (IPMNs) are precursor lesions of pancreatic ductal adenocarcinoma (PDAC). Current edition of WHO Classification of Tumors of the Digestive System recognizes four different subtypes (gastric, intestinal, pancreatobiliary, and oncocytic) and recommends analysis of mucin expression (MUC1, MUC2, MUC5AC, MUC6) as well as evaluation of architectural and cell differentiation patterns for correct classification. However, there is no consensus on MUC1 expression of IPMN ‐lesions in the literature. Current recommendations are based on studies where antibodies against the core MUC1 protein or sialylated MUC1 (tumor associated MUC1), not the fully glycosylated MUC1 were used. We have recently reported that MUC1 is strongly expressed in both gastric and intestinal ty pes IPMN specimens from the cystic wall, obtained by endoscopic ultrasound guided microbiopsy procedure. We have used a commercial MUC1 antibody, validated and recommended for diagnostic use, which recognizes fully glycosylated MUC1. Based on the above, we propose a revision of the WHO Classificatio n, specifying that antibodies against tumor associated MUC1 should be used for IPMN subtyping.

Source: APMIS - November 22, 2018 Category: Research Authors: Pia Klausen, Bojan Kovacevic, Anders Toxv ærd, Evangelos Kalaitzakis, John Gásdal Karstensen, Charlotte Vestrup Rift, Carsten Palnæs Hansen, Jan Storkholm, Peter Vilmann, Jane Preuss Hasselby Tags: Letter to the Editor Source Type: research