title: Progesterone receptor isoform analysis by quantitative real-time polymerase chain reaction in formalin-fixed, paraffin-embedded canine mammary dysplasias and tumors.
abstract: Cloning and sequencing of the progesterone receptor gene in dogs have revealed 2 isoforms, A and B, transcribed from a single gene. Distribution of isoforms A and B in canine mammary lesions has hitherto been investigated only by Western blot analysis. This study analyzed progesterone receptor and its isoforms in formalin-fixed, paraffin-embedded tissue samples from canine mammary lesions (4 dysplasias, 10 benign tumors, and 46 carcinomas) using 1-step SYBR Green quantitative real-time polymerase chain reaction (RT-qPCR). Progesterone receptor was expressed in 75% of dysplasias, all benign tumors, and 59% of carcinomas. Carcinomas, and particularly simple epithelial-type carcinomas, displayed the lowest levels of expression. A high rate of agreement was recorded between RT-qPCR and immunohistochemical labeling. Isoforms A and B were successfully amplified, with correlation coefficients of 0.99 and amplification efficiencies close to 2, and were expressed in all lesion types analyzed. Predominance of A over B expression was observed in carcinomas and complex adenomas. Low-grade tumors exhibited higher progesterone receptor messenger RNA (mRNA) levels, but no difference was observed in the expression of isoform A versus B. Analysis of progesterone receptor mRNA isoforms by RT-qPCR was successful in routinely formalin-fixed, paraffin-embedded tissue samples and enabled the distribution of isoforms A and B to be identified for the first time in dysplasias, benign tumors, and malignant tumors of the canine mammary gland. These findings will facilitate future research into the role of progesterone receptor isoforms in the progression of canine mammary tumors.
authors.affiliation: Department of Comparative Pathology, Veterinary Faculty, University of Córdoba, Córdoba, Spain v22gulus@uco.es.
authors.forename: S
authors.initials: S
authors.lastname: Guil-Luna
authors.affiliation: Institute of Veterinary Disease Biology, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark.
authors.forename: J
authors.initials: J
authors.lastname: Stenvang
authors.affiliation: Institute of Veterinary Disease Biology, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark.
authors.forename: N
authors.initials: N
authors.lastname: Brünner
authors.affiliation: Department of Comparative Pathology, Veterinary Faculty, University of Córdoba, Córdoba, Spain.
authors.forename: R
authors.initials: R
authors.lastname: Sánchez-Céspedes
authors.affiliation: Department of Comparative Pathology, Veterinary Faculty, University of Córdoba, Córdoba, Spain.
authors.forename: Y
authors.initials: Y
authors.lastname: Millán
authors.affiliation: Department of Comparative Pathology, Veterinary Faculty, University of Córdoba, Córdoba, Spain.
authors.forename: J
authors.initials: J
authors.lastname: Gómez-Laguna
authors.affiliation: Department of Comparative Pathology, Veterinary Faculty, University of Córdoba, Córdoba, Spain.
authors.forename: J Martín
authors.initials: JM
authors.lastname: de las Mulas
mesh_terms: D000236:Adenoma / Q000473:pathology / Q000662:veterinary*; D000818:Animals; D002277:Carcinoma / Q000473:pathology / Q000662:veterinary; D017931:DNA Primers / Q000235:genetics; D004283:Dog Diseases / Q000473:pathology*; D004285:Dogs; D005260:Female; D005557:Formaldehyde; D007150:Immunohistochemistry / Q000662:veterinary; D008321:Mammary Glands, Animal / Q000473:pathology; D015674:Mammary Neoplasms, Animal / Q000473:pathology*; D016612:Paraffin Embedding / Q000662:veterinary; D020033:Protein Isoforms; D012333:RNA, Messenger / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction / Q000662:veterinary*; D011980:Receptors, Progesterone / Q000235:genetics* / Q000378:metabolism
chemical_list: D017931:DNA Primers; D020033:Protein Isoforms; D012333:RNA, Messenger; D011980:Receptors, Progesterone; D005557:Formaldehyde
keywords: dog; immunohistochemistry; isoform A; isoform B; mammary tumors; progesterone receptor; quantitative real-time polymerase chain reaction (RT-qPCR)