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Objectives: We investigated the impact of our laboratory's reflex testing process for resolving ERBB2 (HER2) status on breast cancer samples that require additional workup after fluorescence in situ hybridization (FISH), per guideline recommendations published in 2018 by the American Society of Clinical Oncology (ASCO) and the College of American Pathologists (CAP).Methods: In total, 500 breast cancer specimens with ERBB2 FISH results in groups 2 through 4 (all reported as immunohistochemistry [IHC] equivocal [2+] at external laboratories) were resubmitted for IHC testing in our laboratory. Per the ASCO/CAP guideline, FISH was rescored when internal IHC was also equivocal (2+), targeted to tumor areas demonstrating more intense IHC staining, if observed.Results: Reflex IHC/FISH testing changed the final reported ERBB2 status in 185 of 500 (37.0%) samples. Result changes included discordant IHC (n = 4 score 0, n = 132 score 1+, and n = 16 score 3+) and discordant FISH (n = 33). Numerical differences in FISH scores were comparable for targeted vs nontargeted FISH rescoring (P = .086 for ERBB2 copy number; P = .49 for ERBB2 ratio). Two cases showed larger differences in FISH scores, suggesting heterogeneity.Conclusions: Retesting of breast cancer samples with equivocal IHC frequently changes IHC results, but targeted reanalysis of borderline FISH results rarely identifies significant differences in ERBB2 copy number or ratio. [ABSTRACT FROM AUTHOR]

Image analysis of the HER2 immunohistochemical IHC) stain can help determine which breast cancer patients may benefit from HER2-targeted therapy. We studied the concordance of HER2 IHC and fluorescence in situ hybridization (FISH) as well reproducibility of surgical pathologist (SP) and cytotechnologist (CT) interpretations using manual and image analysis methodologies on 154 IHC cases. Concordances with FISH were good for IHC negative (0, 1+) cases (range, 97%-100%) and positive (3+) cases (range, 87%-100%). Image analysis had fewer equivocal (2+) results (10.4%) than CT (14.9%) and SP (16.2%) manual methods, with higher concordances to FISH (31%, 26%, and 20% for image analysis, CT manual, and SP manual, respectively). CT manual (κ = 0.747) and image analysis (κ = 0.779) methods had better interobserver reproducibility than SP manual (κ = 0.697). CT image analysis had better intraobserver reproducibility (κ = 0.882) than CT (κ = 0.828) and SP (κ = 0.766) manual methods. HER2 IHC analysis performed by image analysis can produce accurate results with improved reproducibility. [ABSTRACT FROM AUTHOR]

Summary: Accurate assessment of human epidermal growth factor receptor 2 is critical for the management of patients with breast cancer. We set out to study the impact of the 2007 American Society of Clinical Oncology/College of American Pathologists guidelines on the interpretation of human epidermal growth factor receptor 2 IHC results and its correlation with fluorescence in situ hybridization results. Invasive breast carcinomas with IHC HercepTest 3+ were retrieved from the archive of Mayo Clinic Rochester. The human epidermal growth factor receptor 2 slides were rereviewed, and results were recorded as percentage of invasive tumor cells with 3+, 2+, 1+, and 0 staining intensity. Human epidermal growth factor receptor 2 gene amplification by fluorescence in situ hybridization was performed on all tumors with 3+ staining in 70% or less of tumor cells. Of the 141 cases studied, 12 cases showed intense membrane staining in 11% to 30% of the invasive tumor cells and would have been scored as 2+ according to the new American Society of Clinical Oncology/College of American Pathologists guidelines. Of these 12 cases, 6 were positive for human epidermal growth factor receptor 2 gene amplification by fluorescence in situ hybridization (ratio >2.2), 4 cases were negative (HER2/CEP17 ratio of < 1.8), and 2 cases were equivocal (ratio of 1.8-2.2). One human epidermal growth factor receptor 2–positive case showed dramatic intratumoral heterogeneity with high-level amplification (ratio of 12.2) in the IHC 3+ area and no amplification (ratio of 1.0) in the IHC 1+/2+ areas. The 2007 American Society of Clinical Oncology/College of American Pathologists guidelines down-scored 2.8% of tumors from human epidermal growth factor receptor 2–positive (IHC 3+) to human epidermal growth factor receptor 2–negative (IHC 2+ equivocal and fluorescence in situ hybridization negative) in this study. Clinical studies are needed to determine whether the updated guidelines are better at predicting response to anti–human epidermal growth factor receptor 2 therapy. [Copyright &y& Elsevier]

: BackgroundGene amplification is the primary mechanism of HER-2/neu overexpression in breast cancer and is a strong predictor of prognosis. Currently screening for HER-2/neu gene amplification in breast cancer is done by fluorescent in-situ hybridization (FISH), which is accurate but costly and labor intensive. We have evaluated a new PCR (polymerase chain reaction)-based assay for the detection of HER-2/neu gene amplification in human breast cancer.: Study designA total of 15 breast cancer cell lines and 14 breast cancer specimens were evaluated. HER-2/neu status of the tumors was evaluated by FISH and then assessed using a quantitative polymerase chain reaction/ligase detection reaction (PCR/LRD) technique.: ResultsAmplification of the HER-2/neu gene was detected in seven cell lines previously reported to have amplification and no amplification was found in any of the six that had been reported not to have amplification. In the assessment of breast specimens the PCR/LDR and FISH assays were in complete agreement. All 10 tumors with amplification by FISH were also amplified by PCR/LDR.: ConclusionsThe PCR/LDR technique successfully detects HER-2/neu gene amplification in clinical breast cancer specimens and shows 100% concordance with FISH. This technique is an accurate and rapid alternative to FISH with the potential for automation and high throughput analysis of HER-2/neu status in breast cancer. [Copyright &y& Elsevier]

Abstract: Objective: The aim of this study is to examine Her-2/neu gene amplification and protein overexpression in a spectrum of ovarian neoplasms using both immunohistochemical (IHC) and fluorescence in situ hybridization (FISH) techniques that are FDA approved. This study is focused on early stage tumors including both carcinomas and borderline tumors. Methods: FDA-approved IHC and FISH for Her-2/neu were performed on formalin-fixed, paraffin-embedded tissue from 79 ovarian neoplasms representing a broad spectrum of tumor types as well as four normal ovaries. All tumors were either stage I or stage II. Tumor and normal tissue were studied collectively using a tissue microarray (TMA). HercepTest (DAKO) and PathVysion Her-2/neu probe kit (Vysis Inc.) were used for IHC and FISH analysis. Results: FISH analysis of serous carcinomas demonstrated Her-2/neu gene amplification in 3 (18%) of 17 cases. Two of three cases showing Her-2/neu gene amplification were scored 1+ using IHC, while the remaining case was scored as 0. Analysis of endometrioid carcinomas demonstrated Her-2/neu amplification using FISH in 1 of 10 (10%) cases. IHC in this case was scored 2+ (positive). None of the remaining 44 tumors, including clear cell carcinoma (n = 12), transitional cell carcinoma (n = 1), mixed epithelial carcinoma (n = 7), carcinoma not otherwise specified (n = 1), and 31 borderline tumors (mucinous, n = 17; endometrioid, n = 7; serous, n = 7), showed Her-2/neu gene amplification or protein overexpression. Normal ovaries were negative as well. Conclusions: Amplification of Her-2/neu in early stage ovarian neoplasms is infrequent, 6.7% overall. Due to the limited number of informative cases, we were unable to determine the clinical significance of Her-2/neu amplification in this study. Her-2/neu amplification was restricted to carcinomas and was not encountered in ovarian borderline tumors. [Copyright &y& Elsevier]