An immunohistochemical study and review of potential markers of human intestinal M cells.
M cells are found in intestinal follicle associated epithelium. Studies into the physiological and pathological roles of human M cells have been hampered by the lack of well-substantiated, specific markers for these cells. A critical literature review suggests the following molecules may potentially serve as such markers: CK7, FcaR (CD89), S100, CD1a, CD21, CD23, sialyl Lewis A, and cathepsin E. Normal ileum, appendix and colorectum were studied using paraffin-embedded, formalin-fixed tissue and immunohistochemistry for these 8 markers. Cathepsin E immunohistochemistry was also performed on cases of colorectal adenocarcinoma, colorectal adenoma, colorectal hyperplastic/metaplastic polyp, lymphocytic colitis, collagenous colitis, pseudomembranous colitis and active ulcerative colitis. Of the 8 markers tested, only cathepsin E appeared to be specific to follicle associated epithelium (expressed by cells with and without M cell morphology) and follicular crypt epithelium; this specificity was limited to the colorectum. Focal epithelial expression of cathepsin E was seen in adenocarcinoma, adenoma, hyperplastic/metaplastic polyp, ulcerative colitis and pseudomembranous colitis. In conclusion, cathepsin E is a specific marker of normal colorectal follicle associated epithelium and follicular crypt epithelium though is not specific to M cells within these compartments. None of the other 7 markers studied is exclusively expressed by human M cells.
Wong
N A C S
NA
Cancer Research UK Cancer and Immunogenetics Laboratory, Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, Headley Way, Oxford OX3 9DS, UK. newton.wong@cancer.org.uk
Herriot
M
M
Rae
F
F
D000230:Adenocarcinoma / Q000378:metabolism / Q000473:pathology; D000236:Adenoma / Q000378:metabolism / Q000473:pathology; D015415:Biomarkers; D018395:CA-19-9 Antigen / Q000032:analysis; D020059:Cathepsin E / Q000032:analysis*; D003092:Colitis / Q000378:metabolism / Q000473:pathology; D015179:Colorectal Neoplasms / Q000378:metabolism / Q000473:pathology; D004847:Epithelial Cells / Q000737:chemistry / Q000166:cytology; D006801:Humans; D007124:Immunoenzyme Techniques; D007413:Intestinal Mucosa / Q000737:chemistry* / Q000166:cytology; D053552:Keratin-7; D007633:Keratins / Q000032:analysis; D041741:Lower Gastrointestinal Tract / Q000166:cytology / Q000378:metabolism; D010581:Peyer's Patches
D015415:Biomarkers; D018395:CA-19-9 Antigen; C507497:KRT7 protein, human; D053552:Keratin-7; D007633:Keratins; D020059:Cathepsin E