Avaliação do HER2 em câncer de mama: estudo das fases pré-analítica, analítica e pós-analítica das técnicas de imuno-histoquímica e hibridização in situ pela prata usando microarranjos de tecido

Abstract

AIMS: To investigate the influence of preanalytical phase control (PAPC) for assessment of immunohistochemistry (IHC) HER2 expression against in situ hybridization (DDISH); to compare automated and manual IHC methodologies, and visual evaluations of the IHC assays through optical microscopy (OM) and whole slide imaging (WSI), for HER2 expression in breast cancer. MATERIALS AND METHODS: TMAs containing 200 breast carcinomas (100 with and 100 without PAPC) were submitted to DDISH and IHC (five anti-HER2 antibodies: SP3, CB11 4B5, HercepTestTM and A0485) applying manual (Novolink Polymer) and automated (Benchmark®) methods. Slides were scanned (3DHISTECH) and evaluated visually using OM and WSI on computer screen (Pannoramic MIDI and Viewer) following ASCO/CAP guidelines. RESULTS: 184 cases were assessed by IHC and DDISH. Cases with PAPC showed higher sensitivity and specificity of the antibodies. Sensitivity and specificity of cases with PAPC versus cases without PAPC ranged from 88.5 vs 87.2 (CB11), to 100 vs 94.7 (A0485); and 95.2 vs 95.1 (A0485), to 98.1 vs 95.8 (CB11). 4B5 antibody showed higher sensitivity in cases without PAPC (96.1 vs 97.4). The concordance among antibodies was very good (k=0.82 to 0.9). The overall concordance between IHC and DDISH was 94.1% (CB11) to 96.6% (A0485). A0485, HercepTestTM, SP3 and 4B5 were over 95% sensitive and specific. CB11 was the most specific antibody (97.1%). 60% (CB11) to 83.3% (SP3) of the 2+ cases showed no gene amplification. False negative cases varied from 0.5% (A0485) to 3.8% (CB11), and false positive from 1.6% (CB11) to 2.7% (HercepTest, SP3 and 4B5). The concordance of the antibodies applying both IHC methods was good (A0485, k=0.73) to very good (SP3, k=0.89 and CB11, k=0.85). Comparing automated (A) and manual (M) methodologies, there was a higher sensitivity of A0485 (M=85.0 vs A=98.4) and SP3 (M=92.3 vs A=97.0) and a lower specificity (A0485, M=96,4 vs A=95,3 e SP3, M=96,4 vs A=95,2). CB11 showed higher sensitivity (M=94.1 vs A=89.0) by applying the M methodology and a higher specificity by applying the A methodology (M=92.3 vs A=97.1). Assessment of WSI and OM agreement was good (SP3, k=0.80) to very good (CB11 and HercepTestTM, k=0.81). WSI evaluation led to a higher sensitivity (100-SP3-HercepTestTM to 97-CB11), and a lower specificity (86.4-SP3 to 89.4-HercepTestTM) compared to OM evaluation (sensitivity 92.1-CB11 to 98-SP3; specificity 95.2-SP3-HercepTestTM to 97.1-CB11-SP3). CONCLUSIONS: Cases with PAPC showed a higher sensitivity and specificity for all antibodies, but 4B5. There was a very good agreement among the five anti-HER2 antibodies. CB11 was the most specific antibody, but showed more false negative cases. A0485, SP3, 4B5 and HercepTest were highly sensitive and specific, but showed more false positive cases. The agreement between both IHC methods and between WSI and OM analysis was good to very good. The antibodies were highly sensitive and specific using both methods of evaluation.