Concomitant Detection of HER2 Protein and Gene Alterations by Immunohistochemistry (IHC) and Silver Enhanced In Situ Hybridization (SISH) Identifies HER2 Positive Breast Cancer with and without Gene Amplification

摘要: INTRODUCTION HER2 status assessment became a mandatory test assay in breast cancer, giving prognostic and predictive information including eligibility for adjuvant anti-HER2 therapy. Precise reliable of is therefore utmost importance. In this study we analyzed cancer samples by novel technology concomitant detection the protein gene copy number. METHODS Tissue microarrays containing 589 invasive were with double immunohistochemistry (IHC) silver labeled situ hybridization (SISH) simultaneously detecting number same tumor cells. This bright-field was using scores according to modified ASCO guidelines results correlated patient prognosis. RESULTS Overall concordance rate between expression presence amplification 98%. Fifty-seven 60 tumors (95%) IHC score 3+, 6 10 2+ (60%) only 3 519 (0.6%) 0/1+ amplified SISH. Patients despite had tendency worse overall survival (p = 0.088, reaching nearly statistical significance) compared without amplification. contrast, there no difference 3+/2+ CONCLUSIONS The SISH efficient identification discordant status, especially prognostically relevant groups negative positive Breast among 2+/3+ (10% our cohort) suggests that other mechanisms than contribute overexpression these