PT - JOURNAL ARTICLE AU - J Zustin AU - K Boddin AU - M C Tsourlakis AU - E Burandt AU - M Mirlacher AU - F Jaenicke AU - J Izbicki AU - W Ruether AU - J M Rueger AU - C Bokemeyer AU - R Simon AU - G Sauter TI - HER-2/neu analysis in breast cancer bone metastases AID - 10.1136/jcp.2008.059717 DP - 2009 Jun 01 TA - Journal of Clinical Pathology PG - 542--546 VI - 62 IP - 6 4099 - http://jcp.bmj.com/content/62/6/542.short 4100 - http://jcp.bmj.com/content/62/6/542.full SO - J Clin Pathol2009 Jun 01; 62 AB - Background: HER-2 is the target for antibody-based treatment of breast cancer (trastuzumab), which is highly successful in both advanced disease and the adjuvant setting. HER-2 can be analysed by fluorescence in situ hybridisation (FISH) for gene amplification or immunohistochemistry (IHC) for protein overexpression.Aim: As both methods are known to be influenced by previous tissue processing, to analyse the applicability of both FISH and IHC to decalcified bone metastases of breast cancer.Methods: A tissue microarray (TMA) was constructed from 149 breast cancer bone metastases. Consecutive TMA sections were analysed by FISH (PathVysion) and IHC (HercepTest).Results: FISH analysis was interpretable in 113 (85.0%) cases. Amplification was seen in 14 (12.4%) interpretable metastases. HER-2 positivity on IHC analysis was 3+ in 9.8% of cases and 2+ in 11.3%. A comparison of the two techniques revealed high concordance. Of the 14 cases of amplification, 10 (71%) showed 3+ IHC staining, two (14%) showed 2+, one (7%) showed 1+, and one (7%) showed 0+. Three of the four amplified cases that did not show 3+ IHC staining had an equivocal FISH result, with a HER-2/centromere 17 ratio of 1.8–2.2. Of the 13 cases that showed IHC 3+ staining, amplification was present in 10 (77%).Conclusions: HER-2 FISH analysis has an excellent success rate in highly standardised EDTA-decalcified bone metastases, suggesting that this method is easily applicable to decalcified tissues. The high concordance between IHC and FISH suggests that HER-2 IHC may be equally applicable to EDTA-treated tissues as to the usual formalin-fixed tissues.