title: Incorporating microarray assessment of HER2 status in clinical practice supports individualised therapy in early-stage breast cancer.
abstract: Accurate determination of human epidermal growth factor receptor-2 (HER2) status is essential for optimal selection of breast cancer patients for gene targeted therapy. The analytical performance of microarray analysis using TargetPrint for assessment of HER2 status was evaluated in 138 breast tumours, including 41 fresh and 97 formalin-fixed paraffin embedded (FFPE) specimens. Reflex testing using immunohistochemistry/in situ hybridization (IHC/ISH) in four discordant cases confirmed the TargetPrint results, achieving 100% agreement regardless of whether fresh tissue or FFPE specimens were used. One equivocal IHC/ISH case was classified as HER2-positive based on the microarray result. The proven clinical utility in resolving equivocal and borderline cases justifies modification of the testing algorithm under these circumstances, to obtain a definitive positive or negative test result with the use of microarrays. Determination of HER2 status across three assay platforms facilitated improved quality assurance and led to a higher level of confidence on which to base treatment decisions.
authors.affiliation: Division of Anatomical Pathology, Department of Pathology, Faculty of Medicine and Health Sciences, University of Stellenbosch, Tygerberg, South Africa; Department of Biomedical Sciences, Faculty of Health and Wellness, Cape Peninsula University of Technology, Bellville, South Africa.
authors.forename: Kathleen A
authors.initials: KA
authors.lastname: Grant
authors.affiliation: GVI Oncology, Panorama Medi-Clinic, Panorama, South Africa.
authors.forename: Fredrieka M
authors.initials: FM
authors.lastname: Pienaar
authors.affiliation: Pathcare N1-City, Goodwood, South Africa.
authors.forename: Karen
authors.initials: K
authors.lastname: Brundyn
authors.affiliation: Pathcare N1-City, Goodwood, South Africa.
authors.forename: Gillaume
authors.initials: G
authors.lastname: Swart
authors.affiliation: Ampath, Centurion, Pretoria, South Africa.
authors.forename: George S
authors.initials: GS
authors.lastname: Gericke
authors.affiliation: Panorama Medi-Clinic, Panorama, South Africa.
authors.forename: Ettienne J
authors.initials: EJ
authors.lastname: Myburgh
authors.affiliation: Division of Anatomical Pathology, Department of Pathology, Faculty of Medicine and Health Sciences, University of Stellenbosch, Tygerberg, South Africa; National Health Laboratory Service, Port Elizabeth, South Africa.
authors.forename: Colleen A
authors.initials: CA
authors.lastname: Wright
authors.affiliation: Department of Surgery, Faculty of Medicine and Health Sciences, University of Stellenbosch, Tygerberg, South Africa.
authors.forename: Justus P
authors.initials: JP
authors.lastname: Apffelstaedt
authors.affiliation: Division of Anatomical Pathology, Department of Pathology, Faculty of Medicine and Health Sciences, University of Stellenbosch, Tygerberg, South Africa. Electronic address: maritha@sun.ac.za.
authors.forename: Maritha J
authors.initials: MJ
authors.lastname: Kotze
mesh_terms: D000328:Adult; D000465:Algorithms; D014408:Biomarkers, Tumor / Q000378:metabolism*; D001943:Breast Neoplasms / Q000378:metabolism* / Q000473:pathology / Q000628:therapy; D018270:Carcinoma, Ductal, Breast / Q000378:metabolism* / Q000473:pathology / Q000628:therapy; D018275:Carcinoma, Lobular / Q000378:metabolism* / Q000473:pathology / Q000628:therapy; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D008875:Middle Aged; D009367:Neoplasm Staging; D057285:Precision Medicine; D011785:Quality Assurance, Health Care; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000378:metabolism*; D046888:Tissue Array Analysis
chemical_list: D014408:Biomarkers, Tumor; D018719:Erb-b2 Receptor Tyrosine Kinases; C508053:ERBB2 protein, human
keywords: Analytical validation; Breast cancer; HER2 status; MammaPrint prescreen algorithm; Quality assurance; TargetPrint microarray