We also reported that individuals with pancreatic premalignancy, Intraductal Papillary Mucinous Neoplasm (IPMN), had increased circulating levels of MDSC that inversely correlated with spontaneous antibody responses against the pancreatic tumor associated antigen MUC1, abnormally expressed on IPMN.
Positive MUC1 expression in cell block cytology specimens may be associated with progressive dilation of the main and ectatic branches of pancreatic ducts and appearance of a solid mass in patients with intraductal papillary mucinous neoplasm with worrisome features during follow-up.
Furthermore, apomucin immunostains of mucinous nonneoplastic cyst showed MUC1 expressed in 27% (4/15) cases, MUC5AC in 67% (10/15 cases), and MUC2 was were negative in all cases, whereas intraductal papillary mucinous neoplasm (n = 17; 5 main duct type, 12 branch-duct type) showed focal and weak MUC1 positivity in 18% (3/17) cases, MUC2 positivity in 71% (12/17) cases, and all intraductal papillary mucinous neoplasm (17/17) were MUC5AC positive.