title: Estrogen Receptor and Signal Transducer and Activator of Transcription 3 Expression in Equine Mammary Tumors.
abstract: Equine mammary tumors are uncommon, and relatively sparse histopathologic and molecular data exist. The present study describes the histopathologic features of 7 such tumors, which exhibited infiltrative growth, intermediate to high mitotic rates, and focally extensive necrosis. The tumors exhibited variably strong staining for vimentin and cytokeratin 14, as well as frequently weak cytoplasmic staining for pan-cytokeratin. E-cadherin expression was strong. Interestingly, a subgroup of the tumors exhibited strong nuclear staining for estrogen receptor α. Three of 7 tumors exhibited nuclear expression of the transcription factor STAT3, suggesting that STAT3 was transcriptionally active. Rare to absent nuclear STAT3 expression was observed in carcinomas exhibiting moderate to intense staining for cytokeratin 14. This investigation confirms previous investigators' assertions that equine mammary tumors have a malignant phenotype. A subset of the equine mammary tumors exhibited estrogen receptor α expression, suggesting that these tumors may potentially have similar molecular characteristics to their feline and canine counterparts.
authors.affiliation: Department of Veterinary Medicine, University of Cambridge, Cambridge, UK kh387@cam.ac.uk.
authors.forename: K
authors.initials: K
authors.lastname: Hughes
authors.affiliation: Bridge Pathology Ltd, Horner Court, Bristol, UK.
authors.forename: T J
authors.initials: TJ
authors.lastname: Scase
authors.affiliation: Beaufort Cottage Laboratories, Newmarket, Suffolk, UK.
authors.forename: A K
authors.initials: AK
authors.lastname: Foote
mesh_terms: D000818:Animals; D014408:Biomarkers, Tumor / Q000378:metabolism*; D015820:Cadherins / Q000378:metabolism; D002277:Carcinoma / Q000378:metabolism / Q000473:pathology / Q000662:veterinary*; D047628:Estrogen Receptor alpha / Q000378:metabolism; D005260:Female; D006734:Horse Diseases / Q000378:metabolism / Q000473:pathology*; D006736:Horses; D007150:Immunohistochemistry / Q000662:veterinary; D053547:Keratin-14 / Q000378:metabolism; D015674:Mammary Neoplasms, Animal / Q000378:metabolism / Q000473:pathology*; D050796:STAT3 Transcription Factor / Q000378:metabolism; D015398:Signal Transduction; D014746:Vimentin / Q000378:metabolism
chemical_list: D014408:Biomarkers, Tumor; D015820:Cadherins; D047628:Estrogen Receptor alpha; D053547:Keratin-14; D050796:STAT3 Transcription Factor; D014746:Vimentin
keywords: STAT3; equine; estrogen receptor; horse; mammary tumor