American Society of Clinical Oncology/College of American Pathologists 2018 Focused Update of Breast Cancer HER2 FISH Testing GuidelinesResults From a National Reference Laboratory

2019 ◽  
Vol 152 (4) ◽  
pp. 479-485 ◽  
Author(s):  
Leo Lin ◽  
Deepika Sirohi ◽  
Joshua F Coleman ◽  
H Evin Gulbahce
Keyword(s):  
Breast Cancer ◽  
Metastatic Breast ◽  
Reference Laboratory ◽  
National Reference Laboratory ◽  
Breast Cancers ◽  
National Reference ◽  
American Society ◽  
New Guidelines ◽  
Her2 Positivity

Abstract Objectives To review impact of the ASCO/CAP 2018 update on HER2 testing. Methods HER2 fluorescence in situ hybridization (FISH) test requests from primary and metastatic breast cancers between August 2018 and January 2019 were included. FISH results requiring a changed algorithm under the new guidelines (groups 2, 3, and 4) were identified and HER2:CEN17 ratios, average HER2, CEN17 signals/cell, and HER2 immunohistochemistry (IHC) results were recorded. Results Of the HER2 FISH cases 176/812(21.7%) fell within groups 2, 3, or 4; 0/12, 1/12, and 2/152 cases were positive (3+) by IHC, and 1/12, 2/12, and 6/152 cases were positive after targeted scoring from groups 2, 3, and 4, respectively. Following 2018 updates, 8.3%, 25%, and 5.3% of the groups 2, 3, and 4 were positive, respectively. Conclusions Groups 2, 3, and 4 constituted over 20% of HER2 FISH tests in a reference laboratory. The 2018 ASCO/CAP update significantly decreased the HER2 positivity rate.

Reassignment of HER2 status for subgroups of breast cancer according to the 2018 updated American Society of Clinical Oncology and College of American Pathologists guidelines: The impact of combined immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH) reflex testing in a large national reference laboratory.

2019 ◽  
Vol 37 (15_suppl) ◽  
pp. 3144-3144
Author(s):  
Katherine Geiersbach ◽  
Reid G. Meyer ◽  
Sara M. Kloft-Nelson ◽  
Darlene L. Knutson ◽  
Ryan A. Knudson ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Her2 Status ◽  
Reference Laboratory ◽  
National Reference Laboratory ◽  
National Reference ◽  
Group 4 ◽  
Reflex Testing ◽  
Group 3 ◽  
Group 2 ◽  
The Impact

3144 Background: Updated ASCO/CAP Guidelines for HER2 testing in breast cancer have been most impactful on the resolution of certain challenging groups of FISH results. We review the change in assignment of HER2 status in a large series of breast cancers referred to a large national reference laboratory for FISH testing since the introduction of the 2018 updated guidelines. Methods: Patient samples submitted to the Mayo Clinic Cytogenetics Laboratory (N = 2208) were analyzed by FISH. Samples with Group 2, Group 3, or Group 4 FISH results were reflexed to immunohistochemistry (IHC) in our central laboratory; FISH slides for those cases with equivocal 2+ IHC results were re-scored in the regions of invasive cancer showing more intense membranous staining. A subset of 202 samples with Group 4 FISH results were also reflexed to the previously employed reflex FISH assay (HER2/D17S122), and these were also re-analyzed according to the new reflex IHC/FISH process. Results: 382 of 2208 breast cancer samples tested (17.3%) had FISH results categorized as Group 2 (N = 17, 0.8%), Group 3 (N = 34, 1.5%), or Group 4 (N = 331, 15%) and required reflex IHC testing, and of those, 75% were 2+ equivocal and required targeted re-analysis of the FISH slide according to the 2018 updated guidelines. Re-analysis of the FISH slide resulted in switching between Groups 1-5 in 19.4% of cases, but HER2 status was changed by FISH re-scoring in only 7.7% of cases re-scored (1.0% of all samples), generally due to only minor shifts in HER2 copy number and HER2/control ratios between the initial and IHC-guided reflex FISH scores. In the subset of 202 cases tested by both reflex methods, the previously employed HER2/D17S122 reflex probe set was positive in 123 cases (60.9%), whereas reflex IHC/FISH was positive in only 10 cases (7.9%). Including positive reflex IHC (0.4%) and positive reflex FISH results (2.1%), the overall assignment of positive HER2 status on our series of 2208 cases was 11.5%. Conclusions: Overall rates of HER2 positive FISH results have declined under the most recent ASCO/CAP guideline update as a consequence of new recommendations for reflex testing for Groups 2-4. This change is largely due to reassignment of Group 2 and Group 4 results as negative in the absence of positive IHC.

scholarly journals Impact of the 2018 American Society of Clinical Oncology/College of American Pathologists HER2 Guideline Updates on HER2 Assessment in Breast Cancer With Equivocal HER2 Immunohistochemistry Results With Focus on Cases With HER2/CEP17 Ratio <2.0 and Average HER2 Copy Number ≥4.0 and <6.0

2019 ◽  
Vol 144 (5) ◽  
pp. 597-601 ◽  
Author(s):  
Raza S. Hoda ◽  
Edi Brogi ◽  
Jin Xu ◽  
Katia Ventura ◽  
Dara S. Ross ◽  
...  
Keyword(s):  
Breast Cancer ◽  
In Situ Hybridization ◽  
Clinical Oncology ◽  
Copy Number ◽  
Her2 Overexpression ◽  
Breast Cancers ◽  
American Society ◽  
Dual Probe

Context.— The American Society of Clinical Oncology/College of American Pathologists HER2 testing guideline in breast cancer was updated in 2018 to address issues on interpretation of uncommon results using dual-probe in situ hybridization according to the 2013 guideline. Objective.— To assess impact of the 2018 guideline on breast cancer with equivocal HER2 immunohistochemistry results. Design.— We retrospectively reviewed HER2 fluorescence in situ hybridization (FISH) data (HER2/CEP17 ratio and average HER2 copy number per cell) of HER2 immunohistochemistry–equivocal (2+ or 1+ to 2+) breast cancers at our center between January 2014 and May 2018 and compared HER2 FISH results according to 2013 and 2018 guidelines. Results.— A total of 1666 HER2 FISH results from 1421 patients with equivocal HER2 immunohistochemistry were reviewed. Based on the 2013 guideline, HER2 FISH results were amplified in 346 cases (20.8%), equivocal in 242 (14.5%), and nonamplified in 1078 (64.7%). Using the 2018 guideline, 258 cases (16%) were reclassified, including 242 previously equivocal test results (15%) and 16 previously positive results (1%) reclassified as negative. The subset of 2013 HER2-equivocal and 2018 HER2-nonamplified cases with HER2/CEP17 ratio lower than 2.0 and average HER2 copy number 4.0 or higher and lower than 6.0 showed higher incidence of micropapillary morphology compared with HER2-amplified cases. Despite most patients in this group not receiving HER2-targeted treatment, 96% had no evidence of disease at follow-up. Conclusions.— The 2018 guideline eliminated HER2 FISH–equivocal cases by reclassifying HER2-equivocal cases and cases with nonclassical amplification without HER2 overexpression as HER2 negative. As a consequence, we observed a considerable increase in HER2 FISH–negative cases and a slight decrease in HER2 FISH–positive cases.

scholarly journals Impact of the 2018 ASCO/CAP guidelines on HER2 fluorescence in situ hybridization interpretation in invasive breast cancers with immunohistochemically equivocal results

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Bo Wang ◽  
Wei Ding ◽  
Ke Sun ◽  
Xiaoling Wang ◽  
Liming Xu ◽  
...  
Keyword(s):  
Growth Factor Receptor ◽  
Breast Cancers ◽  
Her2 Gene ◽  
Her2 Positive ◽  
Group 2 ◽  
Gene Status ◽  
American Society ◽  
New Guidelines ◽  
The Impact

Abstract The American Society of Clinical Oncology (ASCO)/College of American Pathologists (CAP) recently issued updated guidelines on human epidermal growth factor receptor 2 (HER2) testing by fluorescence in situ hybridization (FISH) in invasive breast cancers. In this study, we aimed to investigate the impact of the new recommendations on HER2 FISH interpretation in invasive breast cancers with immunohistochemically (IHC) equivocal results. 1810 breast cancer cases with IHC equivocal results were enrolled in this study between January 2012 and May 2019. Concomitant IHC was performed on the same tissue blocks detected by FISH testing. According to the 2018 guidelines, all the cases in ISH group 2 were categorized as HER2 negative; three of four cases in ISH group 3 were considered as HER2 positive, while the one scored IHC 1+ was reclassified as HER2 negative; Fifty-three previously ISH equivocal cases were redistributed into ten HER2-positive cases and forty-three HER2-negative cases. In conclusion, the utility of 2018 ASCO/CAP guidelines resulted in a slight decrease in HER2 positive rate, due to the reclassification of cases in ISH group 2 and group 4. The implementation of the new guidelines can reduce reflex FISH test and make the diagnosis of HER2 gene status more definitive.

Impact of 2013 American Society of Clinical Oncology/College of American Pathologists (ASCO/CAP) guidelines on HER2 fluorescent in situ hybridization (FISH) testing in breast cancers: Experience from a national reference laboratory.

2017 ◽  
Vol 35 (15_suppl) ◽  
pp. e23188-e23188
Author(s):  
Eric Johnson ◽  
Evin H Gulbahce
Keyword(s):  
False Negative ◽  
Gene Copy ◽  
Her2 Status ◽  
Reference Laboratory ◽  
National Reference Laboratory ◽  
National Reference ◽  
Control Probe ◽  
Copy Numbers ◽  
Additional Testing ◽  
Her2 Positivity

e23188 Background: Accurate HER2 testing is expected to identify patients who will benefit from HER2 directed therapy (HDT) minimizing false positive and negatives. Like many biologic processes, HER2 protein expression and gene copy numbers are a continuum, however these tests are expected to be reported dichotomously. In 2013, ASCO/CAP revised the guidelines in an attempt to decrease false negative results and reverted to FDA approved ratio of ≥ 2.0 for HER2 positivity. We reviewed HER2 FISH testing results after the implementation of 2013 ASCO/CAP guidelines to determine the effects on HER2 reporting from our national reference laboratory. Methods: HER2 FISH testing performed between 5/2015-4/2016 at ARUP Labs following current 2013 ASCO/CAP guidelines was included. HER2 to control probe ratios, mean HER2 and control probe copy numbers were used to reassign HER2 status using 2007 ASCO/CAP, and FDA guidelines for each case. Results: HER2 FISH results were available in 2,017 cases. 342 (17.0%) cases were amplified, 301 (14.9%) were equivocal, and 1374 (68.1%) were non-amplified. After additional testing with alternate probe, 93 (31.2%) of the equivocal cases were reclassified as amplified increasing amplified cases to 21.6%. All of the equivocal cases which were reinterpreted as amplified with alternate probe showed low level amplification (range: 2.0-3.6; mean: 2.3). HER2 positivity rates following 2013 ASCO/CAP guidelines, both at initial testing and after additional testing to resolve equivocal results were significantly higher compared to 2007 ASCO/CAP guidelines and FDA criteria. Conclusions: 2013 ASCO/CAP guidelines lead to higher number of HER2 FISH positive and equivocal cases. In a reference laboratory setting where alternative control probe was used to resolves equivocal FISH cases, 31.2% of patients with initial equivocal results become HER2 positive. However, it is not known if these patients benefit from targeted therapies as they would not be included in the original adjuvant or metastatic trials.

scholarly journals RAI1 Alternate Probe Identifies Additional Breast Cancer Cases as Amplified Following Equivocal HER2 Fluorescence In Situ Hybridization Testing: Experience From a National Reference Laboratory

2016 ◽  
Vol 141 (2) ◽  
pp. 274-278 ◽  
Author(s):  
Ling Hui ◽  
Katherine B. Geiersbach ◽  
Erinn Downs-Kelly ◽  
H. Evin Gulbahce
Keyword(s):  
In Situ Hybridization ◽  
Fluorescence In Situ Hybridization ◽  
False Negative ◽  
Metastatic Breast ◽  
Her2 Status ◽  
Reference Laboratory ◽  
Breast Cancers ◽  
Negative Results ◽  
Control Probe

Context.—In 2013 the American Society of Clinical Oncology and College of American Pathologists updated the HER2 guidelines and changed the equivocal category for HER2 in situ hybridization testing to an average HER2 copy number of 4.0 to 5.9 with a HER2:CEP17 ratio of less than 2.0 and proposed retesting, with an option of using another control probe to avoid false-negative results. RAI1, located at band position 17p11.2, is a popular alternate probe locus for retesting equivocal changes. Objective.—To review experience with the RAI1 alternate probe in HER2 fluorescence in situ hybridization equivocal breast cancers. Design.—Primary and metastatic breast cancers with equivocal HER2 fluorescence in situ hybridization, retested with an alternate (RAI1) probe, were identified. HER2, RAI1, and CEP17 copy numbers, HER2 to control probe ratios, and genetic heterogeneity were recorded. Hematoxylin-eosin–stained slides were reviewed for type and grade of cancer. Results.—Of 876 cases tested with CEP17 as the reference probe, 97 (11.1%) had equivocal HER2 fluorescence in situ hybridization results. Additional testing with the RAI1 probe classified 39.2% cases (38 of 97) as amplified with a HER2:RAI1 ratio ranging from 2.0 to 3.2 (mean, 2.37); 3.1% (3 of 97) were still unclassifiable because of a deletion of RAI1. Conclusions.—RAI1 identified close to 40% of original HER2 fluorescence in situ hybridization equivocal cases as amplified, making these patients eligible for targeted therapies. It is not known whether guidelines for US Food and Drug Administration–approved probes can be extrapolated to alternate probes when an alternate control probe shows losses or gains. Because of the lack of guidelines for reporting HER2 status with alternate probes, laboratories face challenges in interpreting results.

HER2 testing in metastatic breast cancer – is reflex in situ hybridization necessary in cases that are equivocal by immunohistochemistry?

2021 ◽  
Vol 156 (Supplement_1) ◽  
pp. S27-S28
Author(s):  
C R Liwski ◽  
M Castonguay ◽  
P Barnes ◽  
G Bethune ◽  
D Rayson
Keyword(s):  
Breast Cancer ◽  
In Situ Hybridization ◽  
Metastatic Breast ◽  
Moderate Intensity ◽  
Breast Cancers ◽  
Metastatic Tumors ◽  
Primary Tumors ◽  
Her2 Testing ◽  
Metastatic Lesions

Abstract Introduction/Objective Current guidelines recommend HER2 testing on all primary invasive breast cancers and at least one metastatic lesion. Typical HER2 testing involves immunohistochemistry (IHC), with reflex in situ hybridization (ISH) in the event of equivocal (2+) IHC. ISH testing is time consuming and resource intensive, and there may be situations where it is unnecessary. The incidence of discordance between HER2 negative primary tumors and HER2 IHC2+ metastases that are ISH positive is unknown. We hypothesize that the majority of such cases are non- amplified. Methods/Case Report A retrospective review of IHC2+ metastatic lesions further assessed with ISH at our center from 2013-2021 was undertaken. A total of 105 cases were identified after exclusion of cases missing HER2 results, with primaries of unconfirmed origin, and cases of synchronous primary and metastatic disease. IHC and ISH results were recorded, with a detailed slide review of discordant cases. Results (if a Case Study enter NA) 91/105 metastases had HER2 negative primaries (87%). A metastasis was significantly more likely to be HER2 negative when the primary was HER2 negative (93%) versus positive (43%) (p &lt; 0.0001). 54/91 primaries were IHC2+/ISH negative, and 50/54 (93%) corresponding metastases had identical results. Of the 37 HER2 negative primaries that were IHC0/1+, 35 (95%) corresponding metastatic tumors were ISH negative. Six metastatic lesions in cases with HER2 negative primaries were discordant and slides were reviewed. Characteristics of metastatic tumors suggesting ISH testing was warranted to assess for discordance included IHC heterogeneity, morphological discordance, and increased staining of moderate intensity. These factors were present in all six discordant metastases. Conclusion Our results suggest that selective rather than reflex ISH testing on HER2 IHC2+ breast cancer metastases in the context of HER2 negative primary disease may be appropriate when there is careful review of the IHC. Validation of our findings await further studies with larger sample sizes.

scholarly journals Assessing the New American Society of Clinical Oncology/College of American Pathologists Guidelines for HER2 Testing by Fluorescence In Situ Hybridization: Experience of an Academic Consultation Practice

2016 ◽  
Vol 140 (11) ◽  
pp. 1250-1258 ◽  
Author(s):  
Michael F. Press ◽  
Ivonne Villalobos ◽  
Angela Santiago ◽  
Roberta Guzman ◽  
Monica Cervantes ◽  
...  
Keyword(s):  
In Situ Hybridization ◽  
Fluorescence In Situ Hybridization ◽  
Breast Cancers ◽  
Her2 Gene ◽  
Her2 Protein ◽  
Her2 Gene Amplification ◽  
Group 3 ◽  
American Society ◽  
New Guidelines

Context.— Evaluation of HER2 gene amplification by fluorescence in situ hybridization (FISH) was changed by recent American Society of Clinical Oncology/College of American Pathologists (ASCO-CAP) guidelines. Objective.— To determine frequencies and assess patterns of HER2 protein expression for each ASCO-CAP guideline FISH category among 7526 breast cancers accrued to our consultation practice. Design.— We retrospectively reevaluated the HER2 FISH status of breast cancers in our consultation practice according to ASCO-CAP FISH guidelines, and documented HER2 protein levels in each category. Results.— —According to new guidelines, 17.7% of our consultation breast cancers were “ISH-positive” with HER2:CEP17 FISH ratios ≥2.0 and average HER2 gene copies per cell ≥4.0 (group 1); 0.4% were “ISH-positive” with ratios ≥2.0 and average copies &lt;4.0 (group 2); 0.6% were “ISH-positive” with ratios &lt;2.0 and average copies ≥6.0 (group 3); 4.6% were “ISH-equivocal” with ratios &lt;2.0 and average copies ≥4.0 and &lt;6.0 (group 4); and 76.7% were “ISH-negative” with ratios &lt;2.0 and average copies &lt;4.0 (group 5). However, only groups 1 (HER2 amplified) and 5 (HER2 not amplified) agreed with our previously reported status, and only these groups demonstrated the expected immunohistochemistry status, overexpression and low expression, respectively. Groups 2 and 4 breast cancers lacked overexpression, whereas group 3 was not significantly associated with either increased or decreased HER2 expression. Conclusions.— Although the status of approximately 95% of our cases (groups 1 and 5) is not affected by the new guidelines, those of the other 5% (groups 2–4) conflict with previous HER2 gene amplification status and with HER2 status by immunohistochemistry.

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