title: C-kit expression in canine mucosal melanomas.
abstract: The c-kit receptor is responsible for transmission of promigration signals to melanocytes; its downregulation may be involved in malignant progression of human melanocytic neoplasms. Expression of this receptor has not been examined in normal or neoplastic melanocytes from dogs. In this study, 14 benign dermal and 61 malignant mucosal melanocytic tumors were examined for c-kit (KIT) expression. Sites of the mucosal melanomas were gingiva (not further specified; n = 30), buccal gingiva (n = 6), soft palate (n = 4), hard palate (n = 5), tongue (n = 7), lip (n = 6), and conjunctiva (n = 3). Melan A was expressed in all 14 dermal melanocytomas and in 59 of 61 (96.7%) tumors from oral or conjunctival mucosa, confirming melanocytic origin. C-kit receptor expression was strong and diffuse throughout the cytoplasm in all 14 dermal melanocytomas and was identified in basilar mucosal melanocytes over submucosal neoplasms (27 of 61, 44.3%), junctional (neoplastic) melanocytes (17 of 61, 27.9%), and, less commonly, neoplastic melanocytes of the subepithelial tumors (6 of 61, 9.8%). KIT expression anywhere within the resected melanomas correlated with significantly longer survival. These results suggest that c-kit receptor expression may be altered in canine melanomas and may have potential as a prognostic indicator for mucosal melanomas.
authors.affiliation: Department of Pathobiology, College of Veterinary Medicine, University of Tennessee, 2407 River Drive, Knoxville, TN 37996-4542, USA. snewman4@utk.edu
authors.forename: S J
authors.initials: SJ
authors.lastname: Newman
authors.forename: J M
authors.initials: JM
authors.lastname: Jankovsky
authors.forename: B W
authors.initials: BW
authors.lastname: Rohrbach
authors.forename: A K
authors.initials: AK
authors.lastname: LeBlanc
mesh_terms: D000818:Animals; D014408:Biomarkers, Tumor / Q000378:metabolism*; D003230:Conjunctival Neoplasms / Q000378:metabolism / Q000473:pathology / Q000662:veterinary*; D018450:Disease Progression; D004283:Dog Diseases / Q000378:metabolism* / Q000401:mortality / Q000473:pathology; D004285:Dogs; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D007150:Immunohistochemistry / Q000662:veterinary; D058965:MART-1 Antigen / Q000378:metabolism; D008297:Male; D008544:Melanocytes / Q000378:metabolism / Q000473:pathology; D008545:Melanoma / Q000378:metabolism / Q000473:pathology / Q000662:veterinary*; D009062:Mouth Neoplasms / Q000378:metabolism / Q000473:pathology / Q000662:veterinary*; D011379:Prognosis; D019009:Proto-Oncogene Proteins c-kit / Q000378:metabolism*; D020794:Receptor Protein-Tyrosine Kinases / Q000378:metabolism; D009418:S100 Proteins / Q000378:metabolism; D012878:Skin Neoplasms / Q000378:metabolism / Q000473:pathology / Q000662:veterinary; D016019:Survival Analysis
chemical_list: D014408:Biomarkers, Tumor; D058965:MART-1 Antigen; D009418:S100 Proteins; D019009:Proto-Oncogene Proteins c-kit; D020794:Receptor Protein-Tyrosine Kinases