title: Determining HER2 (ERBB2) amplification status in women with breast cancer: final results from the Australian in situ hybridisation program.
abstract: Appropriate and accurate determination of HER2 status in women with breast cancer is critical for stratifying anti-HER2 therapies, and for access to subsidised treatment in the Australian setting. We conducted a regulated, nationwide program providing HER2 in situ hybridisation (ISH) testing for patients with newly diagnosed breast cancer. Cases with equivocal or non-diagnostic ISH test results at the local laboratory were sent to a high volume central testing laboratory for analysis using fluorescence ISH (FISH). We tested 78,408 early breast cancers and 3469 metastatic cancers using ISH. Of these, 12,405 early breast cancers (15.8%) and 798 metastatic cancers (23.0%) were HER2 positive. During the testing period, the proportion of core biopsy samples increased, the number of repeat tests remained stable and testing turnaround time declined. Discordant 3+ IHC, ISH negative results dropped from 20% to 13% in early breast cancers and from 35% to 8% among metastatic breast cancers. Following central laboratory FISH testing only 87 samples remained non-diagnostic (1.9% of FISH-tested samples, 0.1% of the whole cohort), most being decalcified specimens. This is a successful story of a cohesive service determining HER2 status in women with breast cancer in a 'real-world' setting.
authors: SydPath St Vincent's Hospital, Sydney, NSW, Australia. Electronic address: Adrienne.Morey@act.gov.au.
authors: Adrienne L
authors: AL
authors: Morey
authors: SydPath St Vincent's Hospital, Sydney, NSW, Australia.
authors: Belinda
authors: B
authors: Brown
authors: Divisions of Surgical Pathology and Cytopathology, SA Pathology, Adelaide, Australia; BreastScreen SA, Australia; Discipline of Medicine, Adelaide University, SA, Australia.
authors: Gelareh
authors: G
authors: Farshid
authors: The Peter MacCallum Cancer Centre and University of Melbourne, East Melbourne, Vic, Australia.
authors: Stephen B
authors: SB
authors: Fox
authors: Griffith University, Gold Coast, Australia; University of Queensland, St Lucia, Qld, Australia.
authors: Glenn D
authors: GD
authors: Francis
authors: Woolomin Consulting, Wheeo, NSW, Australia.
authors: Glenda
authors: G
authors: McCue
authors: Roche Products Pty Ltd, Dee Why, NSW, Australia.
authors: Vita
authors: V
authors: von Neumann-Cosel
authors: Healthscope Pathology, Norwest Private Hospital, Bella Vista, NSW, Australia; Western Sydney University, Sydney, NSW, Australia.
authors: Michael
authors: M
authors: Bilous
mesh_terms: D001315:Australia; D014408:Biomarkers, Tumor / Q000032:analysis*; D001943:Breast Neoplasms / Q000145:classification*; D005260:Female; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000032:analysis*
chemical_list: D014408:Biomarkers, Tumor; D018719:Erb-b2 Receptor Tyrosine Kinases; C508053:ERBB2 protein, human
keywords: Breast cancer; HER2 genes; clinical laboratory techniques; immunohistochemistry; in situ hybridisation