title: CD117 (KIT receptor) expression in Merkel cell carcinoma.
abstract: The KIT receptor tyrosine kinase (CD117 antigen) is found in a variety of normal tissue cell types and in several malignant tumors, including acute myeloid leukemia. We recently encountered two tumors initially suspected as acute myeloid leukemia cutis and expressing CD117 that showed punctate positivity for cytokeratin 20 diagnostic for Merkel cell carcinoma. We evaluated 20 additional cases of MCC and found that 21 of 22 tumors (95%) expressed CD117. Intensity of CD117 expression did not appear to correlate with aggressive behavior. While the function of the KIT receptor in MCC is not known, its pathogenic role in other malignant neoplasms suggests the possibility of a similar role in MCC.
authors.affiliation: Department of Pathology, University of Michigan Medical Center, Ann Arbor, Michigan 48109-5224, U.S.A. lyndonsu@umich.edu
authors.forename: Lyndon D
authors.initials: LD
authors.lastname: Su
authors.forename: Douglas R
authors.initials: DR
authors.lastname: Fullen
authors.forename: Lori
authors.initials: L
authors.lastname: Lowe
authors.forename: Patricia
authors.initials: P
authors.lastname: Uherova
authors.forename: Bertram
authors.initials: B
authors.lastname: Schnitzer
authors.forename: Riccardo
authors.initials: R
authors.lastname: Valdez
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D015266:Carcinoma, Merkel Cell / Q000378:metabolism* / Q000556:secondary; D005260:Female; D019084:Fluorescent Antibody Technique, Indirect; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D019009:Proto-Oncogene Proteins c-kit / Q000096:biosynthesis*; D012878:Skin Neoplasms / Q000378:metabolism* / Q000473:pathology
chemical_list: D019009:Proto-Oncogene Proteins c-kit