title: Investigation of HER2 expression in canine mammary tumors by antibody-based, transcriptomic and mass spectrometry analysis: is the dog a suitable animal model for human breast cancer?
abstract: Canine mammary tumors (CMTs) share many features with human breast cancer (HBC), specifically concerning cancer-related pathways. Although the human epidermal growth factor receptor 2 (HER2) plays a significant role as a therapeutic and prognostic biomarker in HBC, its relevance in the pathogenesis and prognosis of CMT is still controversial. The aim of this study was to investigate HER2 expression in canine mammary hyperplasic and neoplastic tissues as well as to evaluate the specificity of the most commonly used polyclonal anti HER2 antibody by multiple molecular approaches. HER2 protein and RNA expression were determined by immunohistochemistry (IHC) and by quantitative real-time (qRT) PCR. A strong cell membrane associated with non-specific cytoplasmic staining was observed in 22% of carcinomas by IHC. Adenomas and carcinomas exhibited a significantly higher HER2 mRNA expression when compared to normal mammary glands, although no significant difference between benign and malignant tumors was noticed by qRT-PCR. The IHC results suggest a lack of specificity of the FDA-approved antibody in CMT samples as further demonstrated by Western immunoblotting (WB) and reverse phase protein arrays (RPPA). Furthemore, HER2 was not detected by mass spectrometry (MS) in a protein-expressing carcinoma at the IHC investigation. This study highlights that caution needs to be used when trying to translate from human to veterinary medicine information concerning cancer-related biomarkers and pathways. Further investigations are necessary to carefully assess the diagnostic and biological role specifically exerted by HER2 in CMTs and the use of canine mammary tumors as a model of HER2 over-expressing breast cancer.
authors.affiliation: Dipartimento di Medicina Veterinaria, Università degli Studi di Sassari, Via Vienna 2, 07100, Sassari, Italy.
authors.forename: G P
authors.initials: GP
authors.lastname: Burrai
authors.affiliation: Porto Conte Ricerche Srl, S.P. 55 Porto Conte/Capo Caccia Km 8.400, Tramariglio, 07041, Alghero, SS, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Tanca
authors.affiliation: Dipartimento di Medicina Clinica e Sperimentale, Università degli Studi di Sassari, Via P. Manzella, 07100, Sassari, Italy.
authors.forename: M R
authors.initials: MR
authors.lastname: De Miglio
authors.affiliation: Porto Conte Ricerche Srl, S.P. 55 Porto Conte/Capo Caccia Km 8.400, Tramariglio, 07041, Alghero, SS, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Abbondio
authors.affiliation: Porto Conte Ricerche Srl, S.P. 55 Porto Conte/Capo Caccia Km 8.400, Tramariglio, 07041, Alghero, SS, Italy.
authors.forename: S
authors.initials: S
authors.lastname: Pisanu
authors.affiliation: Dipartimento di Medicina Veterinaria, Università degli Studi di Sassari, Via Vienna 2, 07100, Sassari, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Polinas
authors.affiliation: Dipartimento di Medicina Veterinaria, Università degli Studi di Sassari, Via Vienna 2, 07100, Sassari, Italy.
authors.forename: S
authors.initials: S
authors.lastname: Pirino
authors.affiliation: Department of Comparative Pathobiology and Purdue University Centre for Cancer Research, Purdue University, 625 Harrison St., West Lafayette, IN, 47907, USA.
authors.forename: S I
authors.initials: SI
authors.lastname: Mohammed
authors.affiliation: Porto Conte Ricerche Srl, S.P. 55 Porto Conte/Capo Caccia Km 8.400, Tramariglio, 07041, Alghero, SS, Italy.
authors.forename: S
authors.initials: S
authors.lastname: Uzzau
authors.affiliation: Porto Conte Ricerche Srl, S.P. 55 Porto Conte/Capo Caccia Km 8.400, Tramariglio, 07041, Alghero, SS, Italy.
authors.forename: M F
authors.initials: MF
authors.lastname: Addis
authors.affiliation: Dipartimento di Medicina Veterinaria, Università degli Studi di Sassari, Via Vienna 2, 07100, Sassari, Italy. eantuofermo@uniss.it.
authors.forename: E
authors.initials: E
authors.lastname: Antuofermo
mesh_terms: D000818:Animals; D000906:Antibodies / Q000276:immunology; D001943:Breast Neoplasms / Q000235:genetics* / Q000473:pathology; D004195:Disease Models, Animal; D004285:Dogs; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D015674:Mammary Neoplasms, Animal / Q000235:genetics* / Q000473:pathology; D011379:Prognosis; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000096:biosynthesis*; D059467:Transcriptome / Q000235:genetics*
chemical_list: D000906:Antibodies; D018719:Erb-b2 Receptor Tyrosine Kinases
keywords: Antibody specificity; Canine mammary tumors; HER2; IHC; Proteomics; RT-PCR