Development of automated brightfield double In Situ hybridization (BDISH) application for HER2 gene and chromosome 17 centromere (CEN 17) for breast carcinomas and an assay performance comparison to manual dual color HER2 fluorescence In Situ hybridization (FISH)

Office of Medical Affairs, Ventana Medical Systems Inc., Tucson, AZ, USA.
Diagnostic Pathology (Impact Factor: 2.6). 11/2008; 3(1):41. DOI: 10.1186/1746-1596-3-41
Source: PubMed


Human epidermal growth factor receptor 2 (HER2) fluorescence in situ hybridization (FISH) is a quantitative assay for selecting breast cancer patients for trastuzumab therapy. However, current HER2 FISH procedures are labor intensive, manual methods that require skilled technologists and specialized fluorescence microscopy. Furthermore, FISH slides cannot be archived for long term storage and review. Our objective was to develop an automated brightfield double in situ hybridization (BDISH) application for HER2 gene and chromosome 17 centromere (CEN 17) and test the assay performance with dual color HER2 FISH evaluated breast carcinomas.
The BDISH assay was developed with the nick translated dinitrophenyl (DNP)-labeled HER2 DNA probe and DNP-labeled CEN 17 oligoprobe on the Ventana BenchMark(R) XT slide processing system. Detection of HER2 and CEN 17 signals was accomplished with the silver acetate, hydroquinone, and H2O2 reaction with horseradish peroxidase (HRP) and the fast red and naphthol phosphate reaction with alkaline phosphatase (AP), respectively. The BDISH specificity was optimized with formalin-fixed, paraffin-embedded xenograft tumors, MCF7 (non-amplified HER2 gene) and BT-474 (amplified HER2 gene). Then, the BDISH performance was evaluated with 94 routinely processed breast cancer tissues. Interpretation of HER2 and CEN 17 BDISH slides was conducted by 4 observers using a conventional brightfield microscope without oil immersion objectives.
Sequential hybridization and signal detection for HER2 and CEN 17 ISH demonstrated both DNA targets in the same cells. HER2 signals were visualized as discrete black metallic silver dots while CEN 17 signals were detected as slightly larger red dots. Our study demonstrated a high consensus concordance between HER2 FISH and BDISH results of clinical breast carcinoma cases based on the historical scoring method (98.9%, Simple Kappa = 0.9736, 95% CI = 0.9222 - 1.0000) and the ASCO/CAP scoring method with the FISH equivocal cases (95.7%, Simple Kappa = 0.8993%, 95% CI = 0.8068 - 0.9919) and without the FISH equivocal cases (100%, Simple Kappa = 1.0000%, 95% CI = 1.0000 - 1.0000).
Automated BDISH applications for HER2 and CEN 17 targets were successfully developed and it might be able to replace manual two-color HER2 FISH methods. The application also has the potential to be used for other gene targets. The use of BDISH technology allows the simultaneous analyses of two DNA targets within the context of tissue morphological observation.

Download full-text


Available from: Eric Walk, Oct 01, 2015
1 Follower
212 Reads
  • Source
    • "As such, they are offered only to those patients for whom there is definitive molecular proof that they harbour the associated specific mutation. Human epidermal growth factor 2 status in breast cancer is one such example and is used as a predictive therapy-selection factor for the humanised monoclonal antibody trastuzumab (Herceptin, Genentech) [110]. Current diagnostic methods, including fluorescent in situ hybridisation and immunohistochemistry, can be subjective and insensitive. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Reverse transcription quantitative PCR is an established, simple and effective method for RNA measurement. However, technical standardisation challenges combined with frequent insufficient experimental detail render replication of many published findings challenging. Consequently, without adequate consideration of experimental standardisation, such findings may be sufficient for a given publication but cannot be translated to wider clinical application. This article builds on earlier standardisation work and the MIQE guidelines, discussing processes that need consideration for accurate, reproducible analysis when dealing with patient samples. By applying considerations common to the science of measurement (metrology), one can maximise the impact of gene expression studies, increasing the likelihood of their translation to clinical tools. ᅟ
    Analytical and Bioanalytical Chemistry 05/2014; 406(26). DOI:10.1007/s00216-014-7857-x · 3.44 Impact Factor
  • Source
    • "HER2 gene amplification and protein overexpression, which occur in 20% to 25% of breast cancer patients, have been recognized as prognostic and predictive markers for treatment [4]. Multiple detection methods have been established to examine HER2 gene status and protein expression [5-8]. Trastuzumab, a recombinant monoclonal antibody targeting HER2 protein, is now being applied not only in metastatic breast cancer cases but also to localized cases as adjuvant therapy [9,10]. "
    [Show abstract] [Hide abstract]
    ABSTRACT: With varied immunohistochemistry scoring criteria and patient cohorts, HER2-positivity rates in gastric cancer (GC) and gastroesophageal junction (GEJ) adenocarcinoma have been reported with a wide range. Recently standardized scoring criteria for GC and GEJ cancer has been established and recommended. In this study, the frequency of HER2 expression and the relationship between HER2 expression and clinicopathological features were examined in a large cohort of Chinese GC and GEJ cancer patients. A total of 1463 patients, including 929 primary GCs and 534 primary GEJ adenocarcinomas, was retrospectively analyzed for HER2 overexpression by immunohistochemistry (IHC). Fluorescence in situ hybridization (FISH) analysis was used in 308 GCs and GEJ adenocarcinoma cases to assess HER2 gene amplification. HER2 overexpression (3+) was detected in 9.8% of carcinomas and more frequently observed in GEJ cancer cases, in the intestinal type, and in the well or moderately differentiated type (P=0.003, 0.000, and 0.000, respectively). HER2 equivocal (2+) was detected in 14.4% of cases. As for the 308 cases analyzed by FISH, 39 (of 40, 97.5%) IHC 3+ cases, 11 (of 38, 28.9%) IHC 2+ cases, and 3 (of 230, 1.3%) IHC 1+/0 cases showed HER2 gene amplification. A high concordance rate (98.5%) between IHC and FISH was demonstrated. Approximately 10% of Chinese patients with primary GC and GEJ adenocarcinoma were HER2-positive on IHC. HER2 overexpression was associated with GEJ site, intestinal cancer subtype, and well or moderately differentiated carcinomas. Virtual slides The virtual slide(s) for this article can be found here:
    Diagnostic Pathology 05/2013; 8(1):76. DOI:10.1186/1746-1596-8-76 · 2.60 Impact Factor
  • Source
    • "Breast tumor heterogeneity is a major cause of discordance between HER2 IHC and HER2 FISH assay results [16,17] and approximately 5-30% of HER2 positive breast cancer cases exhibit intratumoral genetic heterogeneity [18]. Subtle HER2 genetic heterogeneity of tumor cells has been reported among equivocal cases [17,19]. An alternative method for determining HER2 status from FFPE breast cancer samples based on the quantitative reverse transcription-polymerase chain reaction (qRT-PCR) has been proposed, but has not been approved by the FDA. "
    [Show abstract] [Hide abstract]
    ABSTRACT: The eligibility of breast cancer patients for human epidermal growth factor receptor 2 (HER2)-directed therapies is determined by the HER2 gene amplification and/or HER2 protein overexpression status of the breast tumor as determined by in situ hybridization (ISH) or immunohistochemistry (IHC), respectively. Our objective was to combine the US Food and Drug Administration (FDA)-approved HER2 & chromosome 17 centromere (CEN17) brightfield ISH (BISH) and HER2 IHC assays into a single automated HER2 gene-protein assay allowing simultaneous detection of all three targets in a single tissue section. The HER2 gene-protein assay was optimized using formalin-fixed, paraffin-embedded (FFPE) samples of the xenograft tumors MCF7 [HER2 negative (non-amplified gene, protein negative)] and Calu-3 [HER2 positive (amplified gene, protein positive)]. HER2 IHC was performed using a rabbit monoclonal anti-HER2 antibody (clone 4B5) and a conventional 3,3'-diaminobenzidine IHC detection. The HER2 & CEN17 BISH signals were visualized using horseradish peroxidase-based silver and alkaline phosphatase-based red detection systems, respectively with a cocktail of 2,4-dinitrophenyl-labeled HER2 and digoxigenin-labeled CEN17 probes. The performance of the gene-protein assay on tissue microarray slides containing 189 randomly selected FFPE clinical breast cancer tissue cores was compared to that of the separate HER2 IHC and HER2 & CEN17 BISH assays. HER2 protein detection was optimal when the HER2 IHC protocol was used before (rather than after) the BISH protocol. The sequential use of HER2 IHC and HER2 & CEN17 BISH detection steps on FFPE xenograft tumor sections appropriately co-localized the HER2 protein, HER2 gene, and CEN17 signals after mitigating the silver background staining by using a naphthol phosphate-containing hybridization buffer for the hybridization step. The HER2 protein and HER2 gene status obtained using the multiplex HER2 gene-protein assay demonstrated high concordance with those obtained using the separate HER2 IHC and HER2 & CEN17 BISH assays, respectively. We have developed a protocol that allows simultaneous visualization of the HER2 IHC and HER2 & CEN17 BISH targets. This automated protocol facilitated the determination of HER2 protein and HER2 gene status in randomly selected breast cancer samples, particularly in cases that were equivocal or exhibited tumor heterogeneity. The HER2 gene-protein assay produced results virtually equivalent to those of the single FDA-approved HER2 IHC and HER2 & CEN17 BISH assays. Virtual slides The virtual slides for this article can be found here:
    Diagnostic Pathology 05/2012; 7(1):60. DOI:10.1186/1746-1596-7-60 · 2.60 Impact Factor
Show more