title: Immunodiscrimination of colorectal neoplasia using MUC1 antibodies: discrepant findings in tissue versus stool.
abstract: Colorectal tumor-associated antigens are attractive targets for novel stool-screening assays. MUC1, a glycoprotein antigen, is aberrantly expressed in transformed colorectal mucosa and represents a candidate fecal biomarker. In this study, tissue staining and stool testing were performed to further clarify the discriminant potential of MUC1 in markedly different biologic media. One anti-MUC1 monoclonal antibody (MA5) was used for immunohistochemistry and two commercially available MUC1 assay kits (ELSA-CA 15-3 and Truquant BR) were used for stool detection. On tissue staining, MUC1 expression was strong in 40/40 (100%) adenocarcinomas, moderate in 42/55 (76%) adenomas, faint in 8/28 (29%) juxtatumoral mucosa specimens, and absent in 15/15 (0%) nonadjacent mucosa specimens. Conversely MUC1 levels in stool testing did not differ between colorectal cancer cases (N = 14) and controls (N = 14). Based on these results, MUC1 appears to be a functional tumor biomarker in colorectal tissue but not in stool. Bacterial metabolism within stool may unmask the core antigen of MUC1 and account for this discordance in immunoreactivity.
authors.affiliation: Office of Preventive Oncology, Division of Cancer Prevention, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA.
authors.forename: P J
authors.initials: PJ
authors.lastname: Limburg
authors.forename: D A
authors.initials: DA
authors.lastname: Ahlquist
authors.forename: J A
authors.initials: JA
authors.lastname: Gilbert
authors.forename: J J
authors.initials: JJ
authors.lastname: Harrington
authors.forename: G G
authors.initials: GG
authors.lastname: Klee
authors.forename: P C
authors.initials: PC
authors.lastname: Roche
mesh_terms: D000230:Adenocarcinoma / Q000175:diagnosis; D000236:Adenoma / Q000175:diagnosis; D000906:Antibodies / Q000032:analysis; D015295:Antigens, Tumor-Associated, Carbohydrate / Q000032:analysis / Q000276:immunology*; D014408:Biomarkers, Tumor; D015179:Colorectal Neoplasms / Q000175:diagnosis*; D005243:Feces / Q000737:chemistry; D006801:Humans; D007150:Immunohistochemistry; D007413:Intestinal Mucosa / Q000276:immunology; D018396:Mucin-1 / Q000032:analysis / Q000276:immunology*; D009077:Mucins / Q000032:analysis / Q000276:immunology*
chemical_list: D000906:Antibodies; D015295:Antigens, Tumor-Associated, Carbohydrate; D014408:Biomarkers, Tumor; D018396:Mucin-1; D009077:Mucins