The effect of delay in fixation on HER2 expression in invasive carcinoma of the breast assessed with immunohistochemistry and in situ hybridisation. Issue 7 (15th April 2014)

• Record Type: Journal Article
• Authors: Lee, Andrew H S; Key, Heather P; Bell, Jane A; Kumah, Patrick; Hodi, Zsolt; Ellis, Ian O
• Is Part Of: Journal of clinical pathology. Volume 67:Issue 7(2014)
• Page Start: 573
• Page End: 575
• Publication Date: 2014-04-15
• Subjects: Breast -- Immunohistochemistry -- Fixation -- In Situ Hybridisation; Pathology -- Periodicals; Pathology, Molecular -- Periodicals; 616.0705
• DOI: 10.1136/jclinpath-2013-201978
• Languages: English
• ISSNs: 0021-9746

Abstract

Abstract : Aims: Accurate assessment of HER2 status is essential for selection of patients for HER2-targeted treatment such as trastuzumab. This study investigated the hypothesis that delayed fixation impairs HER2 assessment. Methods: 9 carcinomas were received fresh, and samples were fixed immediately or put in fixative at time intervals up to 24 h. All carcinomas were scored as 3+ with immunohistochemistry in properly fixed tissue. Results: 2 of 9 carcinomas (95% CIs 6% to 56%) showed reduced immunohistochemical staining with delays in fixation of 1 and 8 h. One carcinoma showed low-level amplification with fluorescence in situ hybridisation (FISH) when properly fixed and was not amplified after delayed fixation. The other carcinomas were amplified at all time points. Conclusions: Delayed fixation impaired HER2 protein expression assessed using immunohistochemistry in 22% of 3+ carcinomas. HER2 amplification assessed using FISH may be less affected.