American Society Of Clinical Oncology/College Of American Pathologists Research Articles

Comparison of the Response to Neoadjuvant Therapy Between Immunohistochemistry HER2 (3+) and HER2 (2+)/ISH+ Early-Stage Breast Cancer: A Retrospective Multicenter Cohort Study.

According to the American Society of Clinical Oncology/College of American Pathologists (ASCO/CAP) criteria, both immunohistochemical HER2 (3+) and HER2 (2+)/in situ hybridization (ISH) amplified [HER2 (2+)/ISH+] breast cancers (BCs) fall under the HER2-positive BC category. However, there is a lack of studies exploring the difference of neoadjuvant therapeutic response between patients with HER2 (3+) and HER2 (2+)/ISH+ early BC. We aimed to evaluate the neoadjuvant therapeutic response, long-term outcome, and intrinsic subtype heterogeneity between HER2 (3+) and HER2 (2+)/ISH+ BC. We examined 2 distinct cohorts. Cohort 1 (C1) encompassed 2648 patients with HER2-positive early BC diagnoses, and they received neoadjuvant therapy (NT) and surgery between January 1, 2009 and December 31, 2022, from the Shanghai Jiao Tong University Breast Cancer Data Base. Cohort 2 (C2) comprised 135 patients with early-stage HER2-positive BC who underwent NT and surgery at Henan Cancer Hospital from January 1, 2021, to December 31, 2022. These patients had available genomic and transcriptomic data at their disposal. C1 and C2 were further categorized into 2 patient cohorts as follows: (1) patients with IHC HER2 (3+) early BC [HER2 (3+) group], (2) patients with HER2 (2+)/ISH+ early BC [HER2 (2+)/ISH+ group]. Among those excluded from the analysis were patients < 18 years or >80 years of age. Clinicopathological parameters, long-term outcomes, and intrinsic subtypes were analyzed. In the C1 population, 83.7% had HER2 (3+) BC, while 16.3% had HER2 (2+)/ISH+ BC. Patients with HER2 (3+) had a significantly higher pathological complete response (PCR) rate (38.9%) than patients with HER2 (2+)/ISH+ (18.1%; P < .001), but the disease-free survival (DFS) was comparable after a median follow-up of 29 months (P = .556). The addition of trastuzumab or trastuzumab plus pertuzumab to neoadjuvant chemotherapy (NAC) improved PCR rates and DFS in HER2 (3+) BC but not in HER2 (2+)/ISH+ BC. In the C2 population, 97.75% HER2 (3+) and 52.17% HER2 (2+)/ISH+ were HER2 enriched (HER2E) subtype (P < .001). HER2E showed increased PCR rates compared to non-HER2E (P = .004). Compared to HER2 (3+) BC, the limited effectiveness of neoadjuvant trastuzumab and pertuzumab therapy for HER2 (2+)/ISH+ BC is due to subtype heterogeneity. Reassessment of targeted therapy efficacy in patients with HER2 (2+)/ISH+ BC is essential.

Interpretable HER2 scoring by evaluating clinical guidelines through a weakly supervised, constrained deep learning approach.

The evaluation of the Human Epidermal growth factor Receptor-2 (HER2) expression is an important prognostic biomarker for breast cancer treatment selection. However, HER2 scoring has notoriously high interobserver variability due to stain variations between centers and the need to estimate visually the staining intensity in specific percentages of tumor area. In this paper, focusing on the interpretability of HER2 scoring by a pathologist, we propose a semi-automatic, two-stage deep learning approach that directly evaluates the clinical HER2 guidelines defined by the American Society of Clinical Oncology/ College of American Pathologists (ASCO/CAP). In the first stage, we segment the invasive tumor over the user-indicated Region of Interest (ROI). Then, in the second stage, we classify the tumor tissue into four HER2 classes. For the classification stage, we use weakly supervised, constrained optimization to find a model that classifies cancerous patches such that the tumor surface percentage meets the guidelines specification of each HER2 class. We end the second stage by freezing the model and refining its output logits in a supervised way to all slide labels in the training set. To ensure the quality of our dataset's labels, we conducted a multi-pathologist HER2 scoring consensus. For the assessment of doubtful cases where no consensus was found, our model can help by interpreting its HER2 class percentages output. We achieve a performance of 0.78 in F1-score on the test set while keeping our model interpretable for the pathologist, hopefully contributing to interpretable AI models in digital pathology.

The Significance of Recognition of Human Epidermal Growth Factor 2 Low in Breast Cancer Therapy.

In response to recent clinical trials that demonstrate the clinical benefit of antibody-drug conjugate drug therapy in breast cancer (BC) with human epidermal growth factor 2 (HER2) immunohistochemical scores of 1+ or 2+ and negative in situ hybridization results, a new concept of "HER2-low BC" has emerged to describe this newly relevant therapeutic category of BC. Clinical recognition of HER2-low BC has caused a paradigm shift in the therapeutic landscape and management of patients with BC and resulted in rapid changes in clinical practice guidelines. In addition the American Society of Clinical Oncology-College of American Pathologists (ASCO-CAP) recently updated their HER2 Guidelines Recommendations to specifically address HER2-low BC. A literature search in PubMed of peer-reviewed articles, regulatory communications, and relevant practice guidelines pertaining to HER2-low BC was conducted. In this review, we have summarized current published knowledge regarding the clinicopathologic and molecular features, diagnostic criteria, and most current guideline recommendations regarding HER2-low BC, and also highlight ongoing practical and diagnostic challenges when identifying HER2-low BC in routine clinical practice.

Prevalence and clinicopathological associations of HER2 expression in non-small cell lung cancer: a retrospective study in Jordanian patients

BackgroundHuman epidermal growth factor receptor 2 (HER2), a promising therapeutic target, can be mutated, amplified, or overexpressed in different malignancies, including non-small cell lung cancer (NSCLC). Although these alterations showed adverse prognostic effects in many cancers, their clinical significance in NSCLC is controversial. This study primarily assessed the prevalence of HER2 protein expression in NSCLC among Jordanian patients. In addition, the possible association between HER2 protein expression and clinicopathological variables was evaluated.MethodsA total of 100 surgically resected NSCLC cases treated at King Hussein Cancer Center (KHCC) between 2009 and 2021 were examined for HER2 protein expression using immunohistochemistry (IHC). The American Society of Clinical Oncology/College of American Pathologists (ASCO/CAP) guidelines for breast cancer were applied to interpret the results with a final score ranging from 0 to 3+, considering a score of 3 + as overexpression. Additionally, a separate subset of patients was tested for HER2 gene mutation. Fisher’s exact test was used to assess the association between HER2 scores and the other variables. Kaplan-Meier method was used to calculate survival.ResultsOf the 100 cases, Her2 overexpression (score 3+) was detected in 2 cases (2%), score 2 + in 10 cases (10%), score 1 + in 12 cases (12%), and score 0 in 76 cases (76%). The two positive cases were one adenocarcinoma and one squamous cell carcinoma; both patients were elderly male smokers. No significant association was identified between Her2 expression and age, gender, smoking, histological subtype, grade, stage, tumor size, and lymph node status. Our findings also showed no association between Her2 expression and survival; however, advanced tumor stages and positive lymph node metastasis were significantly associated with poor overall survival. All cases tested for the Her2 mutation were negative.ConclusionsHer2 overexpression is uncommon in NSCLC among the Jordanian population. However, when the same scoring criteria are used, the rates are similar to other results found in Asian cohorts. Due to our study’s relatively small sample size, a larger one is required to investigate the prognostic value and the molecular associations between the different Her2 alterations.

Human Epidermal Growth Factor Receptor 2 Testing in Breast Cancer.

To update the American Society of Clinical Oncology-College of American Pathologists (ASCO-CAP) recommendations for human epidermal growth factor receptor 2 (HER2) testing in breast cancer. An Update Panel is aware that a new generation of antibody-drug conjugates targeting the HER2 protein is active against breast cancers that lack protein overexpression or gene amplification. The Update Panel conducted a systematic literature review to identify signals for updating recommendations. The search identified 173 abstracts. Of 5 potential publications reviewed, none constituted a signal for revising existing recommendations. The 2018 ASCO-CAP recommendations for HER2 testing are affirmed. HER2 testing guidelines have focused on identifying HER2 protein overexpression or gene amplification in breast cancer to identify patients for therapies that disrupt HER2 signaling. This update acknowledges a new indication for trastuzumab deruxtecan when HER2 is not overexpressed or amplified but is immunohistochemistry (IHC) 1+ or 2+ without amplification by in situ hybridization. Clinical trial data on tumors that tested IHC 0 are limited (excluded from DESTINY-Breast04), and evidence is lacking that these cancers behave differently or do not respond similarly to newer HER2 antibody-drug conjugates. Although current data do not support a new IHC 0 versus 1+ prognostic or predictive threshold for response to trastuzumab deruxtecan, this threshold is now relevant because of the trial entry criteria that supported its new regulatory approval. Therefore, although it is premature to create new result categories of HER2 expression (eg, HER2-Low, HER2-Ultra-Low), best practices to distinguish IHC 0 from 1+ are now clinically relevant. This update affirms prior HER2 reporting recommendations and offers a new HER2 testing reporting comment to highlight the current relevance of IHC 0 versus 1+ results and best practice recommendations to distinguish these often subtle differences. Additional information is available at www.asco.org/breast-cancer-guidelines.

ERBB2 Amplification as a Predictive and Prognostic Biomarker in Upper Tract Urothelial Carcinoma.

Upper tract urothelial carcinomas (UTUCs) occur in about 5-10% of all urothelial carcinomas and are frequently discovered in high-stage disease. We aimed to evaluate human epidermal growth factor receptor 2 (ERBB2) protein expression immunohistochemically and ERBB2 amplification in UTUCs by fluorescence in situ hybridization, applying a tissue microarray technique. ERBB2 overexpression and ERBB2 amplification were defined according to the recommendations of the American Society of Clinical Oncology/College of American Pathologists (ASCO/CAP) for breast cancer and gastric carcinoma (GC), revealing scores of 2+ and 3+ in 10.2% and 41.8% of UTUCs, respectively. The performance parameters showed obviously higher sensitivity of ERBB2 immunoscoring according to the ASCO/CAP criteria for GC. ERBB2 amplification was detected in 10.5% of UTUCs. ERBB2 overexpression was more likely to be found in high-grade tumors and was associated with tumor progression. Univariable Cox regression analysis revealed a significantly lower progression-free survival (PFS) in cases with ERBB2 immunoscores of 2+ or 3+ according to the ASCO/CAP guidelines for GC. UTUCs with ERBB2 amplification showed a significantly shorter PFS in the multivariable Cox regression analysis. Irrespective of their ERBB2 status, patients with UTUC treated with platin showed a significantly lower PFS than UTUC patients who had not received any platin-based therapy. In addition, UTUC patients with a normal ERBB2 gene status who had not received platin-based therapy showed significantly longer overall survival. The results suggest that ERBB2 is a biomarker for progression in UTUCs and may define a distinct subgroup of UTUCs. As previously shown, ERBB2 amplification is infrequent. However, the small number of patients diagnosed with ERBB2-amplified UTUC might benefit from ERBB2-targeted cancer therapy. In clinical-pathological routine diagnostics, the determination of ERBB2 amplification is an established method in some defined entities and also successful in small samples. Still, the simultaneous use of ERBB2 immunohistochemistry and ERBB2 in situ hybridization would be important in order to record the low rate of amplified UTUC cases as completely as possible.

HER2 IHC Expression and Gene Amplification in p53-aberrant High-grade Endometrial Endometrioid Carcinoma Suggests That This Population May Benefit From HER2 Testing and Targeted Therapy.

Among gynecologic cancers, uterine serous carcinoma (USC) has been shown to be human epidermal growth factor receptor 2 (HER2) amplified and trastuzumab has been included in the recent National Comprehensive Cancer Network (NCCN) guidelines for treatment of advanced stage or recurrent USC with HER2 overexpression/amplification. There is limited literature suggesting that a subset of high-grade endometrioid carcinomas with aberrant p53 expression may also be HER2 amplified and these patients could benefit from the addition of targeted therapy. We identified 59 p53-aberrant (mismatch repair proficient) FIGO 3 endometrioid carcinomas of the uterus. HER2 immunohistochemistry was performed in all 59 tumors and HER2 fluorescence in situ hybridization (FISH) was performed in 52 of the 59 cases. Four of the 59 cases were HER2 3+ by immunohistochemistry (6.7%), using the American Society of Clinical Oncology/College of American Pathologists (ASCO/CAP) 2007, 2013, and 2018 criteria. HER2 FISH was performed in 3 of the 4 cases and was amplified in all 3. Nine, 8, and 7 tumors showed 2+ HER2 staining when applying 2018, 2013, and 2007 criteria, respectively, FISH was performed in 7 tumors and none were amplified. An additional 4 cases did not perfectly meet the 2018 ASCO/CAP criteria but were assigned a score of 2+, none were amplified by HER2 FISH. The remaining 42 cases showed 1+ or no staining for HER2, FISH was successfully performed in 38 tumors and none showed amplification. Approximately half of the tumors fulfilled criteria for HER2-low or HER2-very low (10 HER2-low and 20 HER2-very low). Our data shows that a subset of p53-aberrant high-grade endometrial endometrioid carcinoma express HER2 and these patients may benefit from the addition of targeted therapy. The role of targeted therapy in HER2-low gynecologic carcinoma is currently unexplored.

Quantitative Imaging Analysis Fluorescence In Situ Hybridization Validation for Clinical HER2 Testing in Breast Cancer.

Quantitative imaging is a promising tool that is gaining wide use across several areas of pathology. Although there has been increasing adoption of morphologic and immunohistochemical analysis, the adoption of evaluation of fluorescence in situ hybridization (FISH) on formalin-fixed, paraffin-embedded tissue has been limited because of complexity and lack of practice guidelines. To perform human epidermal growth factor receptor 2 (HER2) FISH validation in breast carcinoma in accordance with the American Society of Clinical Oncology/College of American Pathologists (ASCO/CAP) 2018 guideline. Clinical validation of HER2 FISH was performed using the US Food and Drug Administration-approved dual-probe HER2 IQFISH (Dako, Carpinteria, California) with digital scanning performed on a PathFusion (Applied Spectral Imaging, Carlsbad, California) system. Validation parameters evaluated included z-stacking, classifier, accuracy, precision, software, and hardware settings. Finally, we evaluated the performance of digital enumeration on clinical samples in a real-world setting. The accuracy samples showed a final concordance of 95.3% to 100% across HER2 groups 1 to 5. During clinical implementation for HER2 groups 2, 3, and 4, we achieved a final concordance of 76% (95 of 125). Of these cases, only 8% (10 of 125) had discordances with clinical impact that could be identified algorithmically and triaged for manual review. Digital FISH enumeration is a useful tool to improve the efficacy of HER2 FISH enumeration and capture genetic heterogeneity across HER2 signals. Excluding cases with high background or poor image quality and manual review of cases with ASCO/CAP group discordances can further improve the efficiency of digital HER2 FISH enumeration.

ELISA-like QDB method to meet the emerging need of Her2 assessment for breast cancer patients.

Inherent issues of subjectivity and inconsistency have long plagued immunohistochemistry (IHC)-based Her2 assessment, leading to the repeated issuance of guidelines by the American Society of Clinical Oncology/College of American Pathologists (ASCO/CAP) for its standardization for breast cancer patients. Yet, all these efforts may prove insufficient with the advent of Trastuzumab deruxtecan (T-Dxd), a drug with the promise to expand to tumors traditionally defined as Her2 negative (Her2-). In this study, we attempted to address these issues by exploring an ELISA-like quantitative dot blot (QDB) method as an alternative to IHC. The QDB method has been used to measure multiple protein biomarkers including ER, PR, Ki67, and cyclin D1 in breast cancer specimens. Using an independent cohort (cohort 2) of breast cancer formalin-fixed paraffin-embedded (FFPE) specimens, we validated cutoffs developed in cohort 1 (Yu etal., Scientific Reports 2020 10:10502) with overall 100% specificity (95% CI: 100-100) and 97.56% sensitivity (95% CI: 92.68-100) in cohort 2 against standard practice with the dichotomized absolutely quantitated values. Using the limit of detection (LOD) of the QDB method as the putative cutoff point, tumors with no Her2 expression were identified with the number comparable to those of IHC 0. Our results support further evaluation of the QDB method as an alternative to IHC to meet the emerging need of identifying tumors with low Her2 expression (Her2-low) in daily clinical practice.

Abstract HER2-18: HER2-18 Determination of HER2-low status in tumors of patients with unresectable and/or metastatic breast cancer in DESTINY-Breast04

Abstract Background In DESTINY-Breast04, the HER2-targeted antibody drug conjugate trastuzumab deruxtecan (T-DXd) demonstrated significant survival benefit vs treatment of physician’s choice (TPC) in patients (pts) with HER2-low unresectable or metastatic breast cancer (mBC) (Modi et al. N Engl J Med 2022). These results emphasize the importance of accurately identifying HER2 expression in breast tumor tissue. Here, we describe concordance between previously determined (historical) HER2 scores and central HER2 scores, and tumor sample characteristics for pts with mBC screened and enrolled in DESTINY-Breast04. Methods DESTINY-Breast04 was a randomized, open-label, phase 3 study in pts with centrally determined HER2-low (immunohistochemistry [IHC] 1+ or IHC 2+ with negative in situ hybridization [ISH]) mBC who had previously received 1-2 lines of chemotherapy. Pts were randomized 2:1 to T-DXd or TPC. HER2 scores were determined via central testing of tumor specimens by the investigational Ventana PATHWAY 4B5 IHC assay, using the 2018 American Society of Clinical Oncology/College of American Pathologists (ASCO/CAP) testing guidelines HER2 scoring algorithm, and Ventana INFORM HER2 dual ISH assay (as applicable). Results 1340 pts identified as having HER2-low mBC per historical data submitted tumor samples for central HER2-low testing. Of those, 557 pts met all eligibility criteria and were enrolled in DESTINY-Breast04. The proportion of samples from metastatic vs primary tumors was 59% vs 41% for all submitted tumor samples and 65% vs 35% for enrolled patients. Of those with available data, most were biopsy specimens (995 [74%] vs 344 [26%] resection/excisions) and were submitted as archived formalin-fixed, paraffin-embedded tissue (1183 [88%] vs 157 [12%] freshly collected samples); historical testing dates ranged from 2000-2020. Of samples with data on the historical HER2 IHC test used (31%), most were scored using local Ventana 4B5 (63%) or Agilent HercepTest (32%) assays. Tumor distribution characteristics were similar between screened and enrolled pts. For samples with historical and central HER2 results (N = 1108), 849/1108 (77%) were centrally scored as HER2-low. Of the samples that were not centrally scored as HER2-low, 88% were scored as HER2 IHC 0. Historical and central HER2 score concordance was assessed by sample region of origin (North America, Europe, China, or Asia without China) and collection date (2013 or earlier, 2104-2018, or 2019 or after) and scoring agreement was associated with these factors. Efficacy of T-DXd vs TPC for pts in DESTINY-Breast04 was consistent across all tumor sample characteristics (primary vs metastatic, specimen type, archival vs fresh, and tissue collection date). Conclusions Despite the lack of prior clinical utility and training in distinguishing HER2 IHC 0 from HER2-low (IHC 1+, 2+/ISH–), evolving guidelines since historical HER2 status provision, differences in local testing methods, and differences in key sample characteristics (primary vs metastatic; archived vs fresh; widely variable sample biopsy and testing dates), there was a 77% agreement between historical and central HER2-low status using the Ventana PATHWAY 4B5 IHC assay and Ventana INFORM HER2 Dual ISH assay. This rate is comparable to the reported initial concordance rates for HER2 overexpression IHC testing (range 74-82%; Roche J. Natl Cancer Inst 2002, Perez. J Clin Oncol 2006). Moreover, consistent benefit of T-DXd vs TPC was generally seen across patient groups with various tumor sample characteristics in DESTINY-Breast04. Determination of HER2-low status using the Ventana PATHWAY 4B5 IHC assay (and ISH when applicable) demonstrated the ability of the test, analyzed by pathologists using current ASCO/CAP guidelines, to identify pts who benefit from T-DXd. Funding This study was funded by Daiichi Sankyo and AstraZeneca. Citation Format: Aleix Prat, Shanu Modi, Junji Tsurutani, David Cameron, Nadia Harbeck, Charo Garrido, Maha Karnoub, Ching Hsu, Wenquin Feng, Lotus Yung, Yibin Wang, Dhiraj Gambhire, Shirin K. Ford, Patrik Vitazka, Naoto T. Ueno. HER2-18 Determination of HER2-low status in tumors of patients with unresectable and/or metastatic breast cancer in DESTINY-Breast04 [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr HER2-18.

Comparison of breast cancer HER-2 receptor testing with immunohistochemistry and in situ hybridization.

Human epidermal growth factor receptor-2 (HER2) status can be tested with immunohistochemistry (IHC) and in situ hybridization (ISH). The 2018 American Society of Clinical Oncology/College of American Pathologists (ASCO/CAP) HER2 testing guidelines suggest initial HER2 testing using IHC and further testing IHC equivocal cases with ISH. However, many institutions perform both IHC and ISH on the same specimen. This study aims to analyze the concordance between HER2 IHC and ISH in order to evaluate the benefit of repeating HER2 testing on the same breast cancer specimens. Patients diagnosed with invasive breast cancer through BreastScreen NSW Sydney West program between January 2018 and December 2020 were identified and their HER2 IHC and HER2 ISH results on core needle biopsy (CNB) and surgical excisions (SE) were retrospectively collected. Specimens with both IHC and ISH results were then analyzed for agreement and concordance using unweighted kappa values. Equivocal IHC (2+) cases were excluded from concordance analysis. Overall, there were 240 invasive breast cancer specimens (CNB and SE) with both IHC and ISH recorded. Concordance between HER2 IHC and ISH was 100% (95% CI: 96.2-100%; κ=1.00 (P<0.001)). Of the IHC equivocal cases (n=146), 94.5% were ISH negative. There was perfect positive concordance and agreement between non-equivocal IHC and ISH results. This reinforces that IHC alone can be utilized reliably for testing HER2 status of non-equivocal cases consistent with the 2018 ASCO/CAP guidelines.

Interobserver Variation in the Assessment of Immunohistochemistry Expression Levels in HER2-Negative Breast Cancer: Can We Improve the Identification of Low Levels of HER2 Expression by Adjusting the Criteria? An International Interobserver Study

The classification of human epidermal growth factor receptor 2 (HER2) expression is optimized to detect HER2-amplified breast cancer (BC). However, novel HER2-targeting agents are also effective for BCs with low levels of HER2. This raises the question whether the current guidelines for HER2 testing are sufficiently reproducible to identify HER2-low BC. The aim of this multicenter international study was to assess the interobserver agreement of specific HER2 immunohistochemistry scores in cases with negative HER2 results (0, 1+, or 2+/in situ hybridization negative) according to the current American Society of Clinical Oncology/College of American Pathologists (ASCO/CAP) guidelines. Furthermore, we evaluated whether the agreement improved by redefining immunohistochemistry (IHC) scoring criteria or by adding fluorescent in situ hybridization (FISH).We conducted a 2-round study of 105 nonamplified BCs. During the first assessment, 16 pathologists used the latest version of the ASCO/CAP guidelines. After a consensus meeting, the same pathologists scored the same digital slides using modified IHC scoring criteria based on the 2007 ASCO/CAP guidelines, and an extra “ultralow” category was added.Overall, the interobserver agreement was limited (4.7% of cases with 100% agreement) in the first round, but this was improved by clustering IHC categories. In the second round, the highest reproducibility was observed when comparing IHC 0 with the ultralow/1+/2+ grouped cluster (74.3% of cases with 100% agreement). The FISH results were not statistically different between HER2-0 and HER2-low cases, regardless of the IHC criteria used.In conclusion, our study suggests that the modified 2007 ASCO/CAP criteria were more reproducible in distinguishing HER2-0 from HER2-low cases than the 2018 ASCO/CAP criteria. However, the reproducibility was still moderate, which was not improved by adding FISH. This could lead to a suboptimal selection of patients eligible for novel HER2-targeting agents. If the threshold between HER2 IHC 0 and 1+ is to be clinically actionable, there is a need for clearer, more reproducible IHC definitions, training, and/or development of more accurate methods to detect this subtle difference in protein expression levels.

264 (PB-088) Poster - Interobserver variation in the assessment of HER2 low expression in breast cancer: can we improve by adjusting criteria? An international interobserver study

The immunohistochemical classification of Human Epidermal Growth Factor Receptor 2 (HER2) expression is optimized to detect HER2-amplified breast cancer (BC). However, novel HER2 targeting agents are also effective for BCs with low levels of HER2 expression. This raises the question whether the current guidelines for HER2-testing are sufficiently reproducible to identify HER2 low BC. The aim of this multicenter international study was to assess the interobserver agreement of HER2 low scoring according to the current American Society of Clinical Oncology/College of American Pathologists (ASCO/CAP) guidelines.

Characteristics of HER2 Gene Amplification by Fluorescence In Situ Hybridization in Endometrial Serous Carcinoma.

Targeted anti-human epidermal growth factor receptor 2 (HER2) therapy has recently become the standard for advanced-stage and recurrent HER2-positive endometrial serous carcinoma (ESC) in the United States, and an endometrial carcinoma-specific HER2 testing algorithm has been proposed. However, comprehensive studies on the specific features of HER2 gene amplification in these tumors are lacking. To evaluate the characteristics of HER2 amplification in ESC in the context of breast and gastric HER2 fluorescence in situ hybridization (FISH) guidelines. Ninety-four ESCs with available HER2 immunohistochemistry (IHC) and FISH were included. HER2 IHC was scored according to the proposed endometrial carcinoma-specific algorithm and FISH was evaluated by using the 2018 ESC clinical trial criteria, the American Society of Clinical Oncology/College of American Pathologists (ASCO/CAP) 2016 gastric criteria, and ASCO/CAP 2013 and 2018 breast criteria. Most tumors (90.4%; 85 of 94) had a 2+ HER2 IHC score. Polysomy of chromosome 17 was present in 16% (15 of 94) and monosomy 17 was seen in 2% (2 of 94) of tumors. HER2 FISH interpretation per the clinical trial criteria (HER2/CEP17 ratio ≥ 2.0) showed 99% concordance with the current gastric and breast HER2 FISH interpretations. Our results support the clinical trial criteria for HER2 FISH in ESC with a modification to include HER2 IHC 2+ and HER2/CEP17 ratio less than 2.0 and average HER2 copy number of 6.0 or greater in the HER2-positive category. Future prospective clinical investigations are necessary to assess the correlation between specific HER2 FISH result categories and therapeutic response.

The concordance between IHC and ISH for HER-2 testing in breast cancer in Nakhon Pathom Hospital, Thailand, based on the ASCO/CAP 2018 guidelines: a retrospective study.

Human epidermal growth factor receptor 2 (HER-2) is the prognostic and predictive biomarker for breast cancer found in a quarter of all breast cancer cases. Precise testing of HER-2 will impact treatment response.Based on the updated American Society of Clinical Oncology/College of American Pathologists (ASCO/CAP) HER-2 testing guidelines, we report 141 cases of positive concordance rate between HER-2 IHC stain and dual-probe ISH for HER-2 testing classified in equivocal (2+) and positive (3+) IHC groups in Nakhon Pathom Hospital, Thailand. Our study showed statistical significance in the relationship between positive (3+) IHC and dual-probe ISH for HER-2 testing with a correlation rate of 91.76% (rs = 0.38031, p < 0.0001) and 37.50% in equivocal (2+) IHC groups.This is the first report of a positive concordance rate between equivocal and positive HER-2 IHC and dual-probe ISH for HER-2 based on the ASCO/CAP 2018 guidelines in Thailand. Our study confirmed a statistically significant relationship in the positive IHC (3+) group. In addition, we suggested reflexing ISH testing only in equivocal IHC (2+) cases to decrease the waiting time and economical approach.

Impact of the updated 2018 American Society of Clinical Oncology/College of American Pathologists (ASCO/CAP) guidelines on Human Epidermal Growth Factor Receptor 2 (HER2) gene testing in invasive breast cancers: A single center study

The study aimed to evaluate the impact of the updated 2018 American Society of Clinical Oncology/College of American Pathologists (ASCO/CAP) guidelines on Human Epidermal Growth Factor Receptor 2 (HER2) testing in invasive breast cancer compared with previous 2013 guidelines. Between Jan 2014 and May 2020, 3364 consecutive invasive breast carcinomas with concurrent HER2 immunohistochemistry (IHC) and fluorescence in-situ hybridization (FISH) results were retrospectively reviewed for HER2 status. Both 2013 and 2018 testing criteria were applied to establish the HER2 status. The testing algorithms involved testing of invasive breast carcinomas by IHC, with equivocal results being reflexed to FISH assays. Concordance rate improved from 92.7% to 94.1% in the non-equivocal IHC cases with the 2018 guidelines. Comparing 2013 versus 2018 criteria, HER2 non-amplified cases increased significantly from 73.7% (n = 2478) to 76.8% (n = 2585), HER2 amplified cases remained similar from 23.4% (n = 789) to 23.2% (n = 779) while equivocal cases decreased from 2.9% (n = 97) to 0% with the new guidelines. Thus, 107 cases (3.2%) were reclassified from HER2 equivocal (n = 97) and amplified (n = 10) to non-amplified with the updated 2018 guidelines. Under the 2018 criteria, a total of 259 cases (7.7%) belonged to the uncommon categories (groups 2 to 4), with group 3 being the most frequent (4.6%), followed by group 4 (2.9%) and group 2 (0.2%). Implementation of 2018 guidelines resulted in a significant increase in HER2 non-amplified cases, mainly due to the abolishment of the equivocal FISH group. This has helped resolve the clinical practice dilemma by providing a more definitive HER2 gene status.

Comparing the 2017 ASCO/CAP guideline for gastroesophageal adenocarcinoma surgical specimen to the 2018 ASCO/CAP guideline for breast cancer in assessing the HER2 status in primary mucinous ovarian carcinoma.

The successful experiences of HER2 inhibitors in patients with HER2 ( +) breast cancer (BC) and advanced gastroesophageal adenocarcinoma (GEA) have encouraged us to continuously explore the HER2 status and its potential as a therapeutic target in primary mucinous ovarian carcinoma (mOC). Using 49 primary mOC samples, we compared the assay characteristics of HER2 status between both 2017 American Society of Clinical Oncology/College of American Pathologists (ASCO/CAP) for GEA and 2018 ASCO/CAP for BC guideline recommendations. We demonstrated moderate to strong agreement between their HER2 IHC results (Weighted Kappa = 0.78) and perfect agreement between their HER2 FISH results (Kappa = 1.00). The overall concordance of non-equivocal HER2 IHC and HER2 FISH results was 97.56% (kappa = 0.93) by 2017 ASCO/CAP for GEA criteria and 100% (kappa = 1.00) by 2018 ASCO/CAP for BC criteria. The number (n = 8; 16.32%) of HER2 IHC equivocal (score + 2) by 2017 ASCO/CAP for GEA criteria was twofold higher than that (n = 4; 8.16%) by 2018 ASCO/CAP for BC criteria. Additionally, we identified one false-positive (FP) case (n = 1; 2.04%) that was HER2 IHC positive (score + 3), but HER2 FISH non-amplified result by the 2017 ASCO/CAP for GEA criteria. In conclusion, owing to the absence of FP/ FN and fewer equivocal cases of HER2 IHC, we recommend that the 2018 ASCO/CAP for BC are more appropriate than 2017 ASCO/CAP for GEA criteria in appraising the HER2 status in mOC and justifying the inclusion of eligible subjects for basket clinical trials of the newly developmental anti-HER2 treatments.

The prognostic and predictive impact of low estrogen receptor expression in early breast cancer: a systematic review and meta-analysis

IntroductionTraditionally, estrogen receptor (ER)-positive breast cancer has been defined as tumors with ≥1% positive for ER. The updated American Society of Clinical Oncology/College of American Pathologists (ASCO/CAP) guidelines recommend that tumors with ER expression of 1%-10% should be classified as ER-low-positive, recognizing the limited clinical evidence on the prognostic and predictive role of low ER expression. We aimed to investigate the predictive role of ER-low expression to neoadjuvant chemotherapy (NeoCT) and the prognostic significance of ER-low expressing breast tumors compared with ER-positive or ER-negative breast tumors.MethodsA meta-analysis was conducted using the Meta-analyses Of Observational Studies in Epidemiology (MOOSE) guidelines and eligible articles were identified on PubMed and ISI Web of Science databases. The primary outcome was pathologic complete response and secondary outcomes were disease-free survival (DFS) and overall survival (OS). Twelve retrospective cohort studies were included in the meta-analysis. NeoCT resulted in higher pathologic complete response among patients with ER-low expression compared with ER-positive and comparable to ER-negative. Patients with ER-low breast cancer had a statistically significant worse DFS and OS compared with patients with ER-positive breast cancer, whereas no difference in DFS or OS was observed between ER-low and ER-negative subgroups.DiscussionThe current evidence suggests that ER-low breast cancer has a more similar outcome to ER-negative than to ER-positive breast cancer in terms of DFS and OS. ER-low expression seems also to have a predictive role regarding NeoCT. Considering the certainty of current evidence categorized as low to moderate, our results urge the need for well-designed prospective studies investigating the molecular background and the most appropriate treatment strategy for ER-low expressing breast cancer.

Prevalence of HER2 overexpression and amplification in cervical cancer: A systematic review and meta-analysis.

The reported rates of HER2 positivity in cervical cancer (CC) range from 0% to 87%. The importance of HER2 as an actionable target in CC would depend on HER2 positivity prevalence. Our aim was to provide precise estimates of HER2 overexpression and amplification in CC, globally and by relevant subgroups. We conducted a PRISMA compliant meta-analytic systematic review. We searched Medline, EMBASE, Cochrane database, and grey literature for articles reporting the proportion of HER2 positivity in CC. Studies assessing HER2 status by immunohistochemistry or in situ hybridization in invasive disease were eligible. We performed descriptive analyses of all 65 included studies. Out of these, we selected 26 studies that used standardized American Society of Clinical Oncology / College of American Pathologists (ASCO/CAP) Guidelines compliant methodology. We conducted several meta-analyses of proportions to estimate the pooled prevalence of HER2 positivity and subgroup analyses using geographic region, histology, tumor stage, primary antibody brand, study size, and publication year as moderators. The estimated pooled prevalence of HER2 overexpression was 5.7% (CI 95%: 1.5% to 11.7%) I2 = 87% in ASCO/CAP compliant studies and 27.0%, (CI 95%: 19.9% to 34.8%) I2 = 96% in ASCO/CAP non-compliant ones, p < 0.001. The estimated pooled prevalence of HER2 amplification was 1.2% (CI 95%: 0.0% to 5.8%) I2 = 0% and 24.9% (CI 95%: 12.6% to 39.6%) I2 = 86%, respectively, p = 0.004. No other factor was significantly associated with HER2 positivity rates. Our results suggest that a small, but still meaningful proportion of CC is expected to be HER2-positive. High heterogeneity was the main limitation of the study. Variations in previously reported HER2 positivity rates are mainly related to methodological issues.

Clinicopathological Features of Breast Cancer with Polysomy 17 and Its Response to Neoadjuvant Chemotherapy.

The interpretation of human epidermal growth factor receptor 2 (HER2) fluorescence in situ hybridization (FISH) results may be challenging in tumors with polysomy 17, which is defined as increased signals of chromosome enumeration probe 17 (CEP17). The effect of polysomy 17 on HER2 protein expression and tumor treatment response has not been established. In this retrospective study, we investigated the clinicopathological features of breast cancer with polysomy 17 and determined the tumors' response to neoadjuvant chemotherapy (NACT). The study included 366 patients with primary breast cancer whose tumors had a CEP17 count of ≥ three/nucleus based on HER2 FISH studies. These cases were categorized according to HER2/CEP17 ratio and HER2 signals/nucleus using the American Society of Clinical Oncology/College of American Pathologists (ASCO/CAP) guidelines. We compared the clinicopathological characteristics and tumor response to NACT among different groups. There was a statistically significant difference in patients' age at diagnosis, tumor pathological grade, estrogen and progesterone receptor status, and NACT response among different HER2 FISH groups. Polysomy 17 tumors in group 1 had a higher rate of response (pathological complete response and residual cancer burden class I) to NACT containing anti-HER2 reagent than did those in other groups (p = 0.004), whereas polysomy 17 tumors in group 3 did not show a significant response to anti-HER2 treatment. Polysomy 17 tumors in different HER2 FISH groups have different pathological features and respond to NACT differently. These results may help us identify patients who will benefit from anti-HER2 therapy.