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. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.
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. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.
Entities:
Keywords:
Breast; Fixation; Immunohistochemistry; In Situ Hybridisation
Authors: Emad A Rakha; Sarah E Pinder; John M S Bartlett; Merdol Ibrahim; Jane Starczynski; Pauline J Carder; Elena Provenzano; Andrew Hanby; Sally Hales; Andrew H S Lee; Ian O Ellis Journal: J Clin Pathol Date: 2014-12-08 Impact factor: 3.411