Author: Nat Pernick, M.D. (see Authors page)

Revised: 4 September 2015, last major update July 2013

Copyright: (c) 2003-2015,, Inc.

PubMed Search: 45M1
  • Antibody against MUC5AC, a gastric mucin, with epitope located in the C-terminal cysteine-rich part (FEBS J 2008;275:481)
Uses by Pathologists
  • To detect gastric mucins
Case Reports
  • 58 year old man with recurrence of gastric cancer with mucin phenotype (Surg Today 2007;37:325)
  • 78 year old man with 45M1+ ampullary signet-ring cell carcinoma and ampullary adenocarcinoma (JOP 2011;12:162)
Micro Images

Ampulla of Vater: coexisting signet-ring cell carcinoma and adenocarcinoma (45M1+, fig 4)


Pancreas: mucous gland hyperplasia (45M1+)

Stomach (distal): < 1 mm lesions of well-differentiated adenocarcinoma (45M1+)

Positive Staining - Normal
  • Gastric epithelium
Positive Staining - Disease
Negative Staining
  • Mature small intestinal goblet cells