title: Immunohistochemical staining for c-Kit (CD117) is a rare event in human colorectal carcinoma.
abstract: Recent studies have suggested that the presence of a c-Kit/c-Kit ligand autocrine loop may be an important regulator of proliferation and progression of human colorectal cancer, capable of affecting the prognosis of these patients. If present, the c-Kit alteration may provide a suitable target for therapy, similar to what has been observed in gastrointestinal stromal tumors. To determine the incidence of c-Kit expression in human colorectal carcinomas, we studied the immunohistochemical c-Kit expression in a selection of 126 colorectal carcinomas of different stage, using stage-oriented human cancer tissue microarrays. Formalin-fixed, paraffin-embedded tissues of each case were immunostained using the avidin-biotin-peroxidase method and the antihuman c-Kit (CD117) rabbit polyclonal antibody. High cytoplasmic c-Kit staining (Allred score of 7-8) was observed in 1.6% of the colon carcinoma patients evaluated. The c-Kit-positive tumors were poorly differentiated carcinomas arising at the anorectal junction. The remaining tumors revealed no detectable expression of c-Kit. Twenty-seven non-neoplastic tissues, normal colonic mucosa, and adenomas were also CD117 negative. We show the rare expression of c-Kit in normal and neoplastic colorectal tissues, suggesting that routine screening for c-Kit by immunohistochemistry to identify c-Kit-positive carcinomas may be cost ineffective. However, further study of c-Kit expression in poorly differentiated colon cancers may be useful since these generally chemoresistant tumors may respond to therapy with inhibitor compounds directed against c-Kit.
authors.affiliation: Department of Pathology, University of South Florida College of Medicine, Tampa, FL, USA.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Reed
authors.forename: Abderrahman
authors.initials: A
authors.lastname: Ouban
authors.forename: Frank K
authors.initials: FK
authors.lastname: Schickor
authors.forename: Patrick
authors.initials: P
authors.lastname: Muraca
authors.forename: Timothy
authors.initials: T
authors.lastname: Yeatman
authors.forename: Domenico
authors.initials: D
authors.lastname: Coppola
mesh_terms: D000230:Adenocarcinoma / Q000235:genetics* / Q000473:pathology*; D000328:Adult; D000368:Aged; D014408:Biomarkers, Tumor / Q000032:analysis; D015179:Colorectal Neoplasms / Q000235:genetics* / Q000473:pathology*; D046508:Culture Techniques; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D007413:Intestinal Mucosa / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D011379:Prognosis; D019009:Proto-Oncogene Proteins c-kit / Q000235:genetics*; D012680:Sensitivity and Specificity
chemical_list: D014408:Biomarkers, Tumor; D019009:Proto-Oncogene Proteins c-kit