title: Immunohistochemical studies on cytokeratin 8 and 18 expressions in canine cutaneous adnexus and their tumors.
abstract: The expressions of cytokeratin 8 and 18 (CK8 and CK18) in the normal canine skin (2 cases) and cutaneous adnexal tumors (127 cases) were investigated immunohistochemically. In the normal skin, co-expression of CK8/18 was found in the glandular epithelium of apocrine sweat glands, and single CK8-immunoreactivity was detected occasionally in the external root sheath at the isthmus and suprabulbar regions of the hair follicles. Neoplastic glandular epithelial cells in all apocrine gland tumors (21/21 cases, 100%) had co-expression of CK8/18. In trichoblastomas (27/28 cases, 96%), most neoplastic cells were diffusely positive for CK8, but those were negative for CK18. Single CK8-expression was also observed in basaloid neoplastic cells in several cases of trichoepitheliomas (7/19 cases, 37%) and pilomatricoma (1/7 cases, 14%). In several cases of trichoblastomas (4/28 cases, 14%) and trichoepitheliomas (2/19 cases, 11%), tumor cells forming glandular structures had co-expression of CK8/18. There were no positive reactions for both CK8 and 18 in infundibular keratinizing acanthomas, and sebaceous and hepatoid gland tumors. The present findings indicate that co-expression of CK8/18 is a specific feature of apocrine sweat glands and single CK8-expression represents the natures of external root sheath or pluripotential stem cells. Thus, the combination of CK8- and 18-immunostainings may have the utility to confirm the directions of differentiation in canine cutaneous adnexal tumors providing a reliable hallmark for histopathological diagnoses.
authors.affiliation: Department of Veterinary Pathology, Faculty of Agriculture, Miyazaki University, Japan.
authors.forename: Koichiro
authors.initials: K
authors.lastname: Kato
authors.forename: Kazuyuki
authors.initials: K
authors.lastname: Uchida
authors.forename: Kazumi
authors.initials: K
authors.lastname: Nibe
authors.forename: Susumu
authors.initials: S
authors.lastname: Tateyama
mesh_terms: D000818:Animals; D004283:Dog Diseases / Q000378:metabolism* / Q000473:pathology*; D004285:Dogs; D007150:Immunohistochemistry / Q000662:veterinary; D053538:Keratin-18 / Q000378:metabolism*; D053533:Keratin-8 / Q000378:metabolism*; D018294:Neoplasms, Adnexal and Skin Appendage / Q000378:metabolism / Q000473:pathology / Q000662:veterinary*; D012878:Skin Neoplasms / Q000378:metabolism / Q000473:pathology / Q000662:veterinary*; D013545:Sweat Glands / Q000378:metabolism
chemical_list: D053538:Keratin-18; D053533:Keratin-8