title: Immunohistochemical expression of E-cadherin does not distinguish canine cutaneous histiocytoma from other canine round cell tumors.
abstract: Immunohistochemistry for E-cadherin (ECAD) has been used to distinguish canine cutaneous histiocytoma from other leukocytic neoplasms ("round cell tumors"). To determine the specificity of this test, 5 types of canine cutaneous round cell tumors were evaluated for immunohistochemical expression of ECAD. Tumors of all 5 types had variable cytoplasmic, plasma membrane, and/or paranuclear ECAD expression: All 13 cutaneous histiocytomas were ECAD+; all but 1 of 14 mast cell tumors expressed ECAD; 10 of 12 epitheliotropic lymphomas reacted with E-cadherin antibody; of 72 plasmacytomas, 54 were ECAD+; and 5 of 5 histiocytic sarcomas were positive. Conclusions based on these results include the following: First, immunoreactivity for ECAD is not limited to leukocytes of cutaneous histiocytoma; second, antibody to ECAD also labels neoplastic cells in most mast cell tumors, plasmacytomas, cutaneous histiocytic sarcomas, and epitheliotropic lymphomas; third, although most histiocytomas have membranous ECAD expression, the immunoreactivity varies among round cell tumors and is frequently concurrent in different cellular compartments; fourth, the distinctively paranuclear ECAD expression pattern in epitheliotropic lymphomas might distinguish them from other round cell tumors; and, fifth, ECAD should be used with other markers (eg, MUM1 for plasmacytomas, KIT for mast cell tumors, CD3 and CD79a for lymphomas) to distinguish among canine round cell tumors.
authors.affiliation: Department of Comparative Pathobiology, Purdue University, West Lafayette, IN 47907, USA. ramosja@purdue.edu
authors.forename: J A
authors.initials: JA
authors.lastname: Ramos-Vara
authors.forename: M A
authors.initials: MA
authors.lastname: Miller
mesh_terms: D000818:Animals; D015820:Cadherins / Q000235:genetics / Q000378:metabolism*; D003937:Diagnosis, Differential; D004283:Dog Diseases / Q000378:metabolism* / Q000473:pathology; D004285:Dogs; D015972:Gene Expression Regulation, Neoplastic / Q000502:physiology*; D054747:Histiocytic Sarcoma / Q000378:metabolism / Q000662:veterinary; D018219:Histiocytoma, Benign Fibrous / Q000378:metabolism / Q000473:pathology / Q000662:veterinary*; D007150:Immunohistochemistry / Q000662:veterinary*; D008223:Lymphoma / Q000378:metabolism / Q000662:veterinary; D034801:Mastocytoma / Q000378:metabolism / Q000662:veterinary*; D010954:Plasmacytoma / Q000378:metabolism / Q000662:veterinary
chemical_list: D015820:Cadherins