HER-2 Gene Amplification, HER-2 and Epidermal Growth Factor Receptor mRNA and Protein Expression, and Lapatinib Efficacy in Women with Metastatic Breast Cancer

A comprehensive single-cell breast tumor atlas defines epithelial and immune heterogeneity and interactions predicting anti-PD-1 therapy response

We present an integrated single-cell RNA sequencing atlas of the primary breast tumor microenvironment (TME) containing 236,363 cells from 119 biopsy samples across eight datasets. In this study, we leverage this resource for multiple analyses of immune and cancer epithelial cell heterogeneity. We define natural killer (NK) cell heterogeneity through six subsets in the breast TME. Because NK cell heterogeneity correlates with epithelial cell heterogeneity, we characterize epithelial cells at the level of single-gene expression, molecular subtype, and 10 categories reflecting intratumoral transcriptional heterogeneity. We develop InteractPrint, which considers how cancer epithelial cell heterogeneity influences cancer-immune interactions. We use T cell InteractPrint to predict response to immune checkpoint inhibition (ICI) in two breast cancer clinical trials testing neoadjuvant anti-PD-1 therapy. T cell InteractPrint was predictive of response in both trials versus PD-L1 (AUC = 0.82, 0.83 vs. 0.50, 0.72). This resource enables additional high-resolution investigations of the breast TME.

Proposal to distinguish HER2-low from HER2-normal breast cancer by in situ hybridisation

AIMS

'HER2-low' breast cancer is an emerging issue as the clinical trials for anti-HER2 antibody-drug conjugates (trastuzumab deruxtecan) are making progress. A reliable method to identify HER2-low cancers is needed. This study aimed to evaluate immunohistochemistry (IHC) and in situ hybridisation (ISH) in detecting HER2-low status.

METHODS

We evaluated the HER2 ISH data grouped by the IHC consensus in proficiency tests (PTs), and compared the HER2 ISH results between HER2 IHC scored 0 (IHC-0) and IHC scored 1+ (IHC-1+) tumours from in-house tissue microarrays (TMAs). Since benign/normal glands have HER2 expression and ideally should not be affected by targeted therapy, we evaluated HER2 ISH results in peritumoural benign glands of 52 breast cancers as reference values.

RESULTS

None of the 565 tissue cores in PTs achieved an 80% participant agreement of IHC-1+. In PTs and in-house TMAs, HER2 signals of the IHC-1+cores (median: 2.6 and 2.0, respectively) were significantly higher than those of IHC-0 cores (median: 2.0 and 1.7, respectively). But the ranges of HER2 signals had a considerable overlap between IHC-1+and IHC-0 cores. The HER2 signals and HER2:CEP17 ratios of peritumoural benign glands exhibited normal distributions, and their upper bounds of the 95% reference intervals were 2.10 and 1.30, respectively.

CONCLUSIONS

Current HER2 testing algorithms are unsatisfactory in detecting HER2-low cases. Using ISH to detect tumour with HER2 signals and HER2:CEP17 ratio higher than the upper bound of the benign glands can be an alternative method.

Efficacy and safety of trastuzumab deruxtecan in the treatment of HER2-low/positive advanced breast cancer: a single-arm meta-analysis

Background: Clinical trials have shown that the use of trastuzumab deruxtecan (DS-8201) alone is expected to provide novel therapeutic options for HER2-low/positive patients. Nevertheless, there are some variations in the efficacy of trial results, with potential risks at the safety level. Most DS-8201 trials in HER2 advanced breast cancer (ABC) have been conducted in the form of small-sample nonrandomized controlled studies, resulting in a lack of validated indicators to evaluate the efficacy and safety of DS-8201. Thus, this meta-analysis aimed to pool the results of various trials of DS-8201 alone to explore the efficacy and safety of DS-8201 in patients with HER2-low/positive advanced breast cancer. Methods: Relevant studies were searched in seven databases, including Embase, PubMed, Web of Science, Cochrane Library, CNKI, VIP database and WanFang data, to collect single-arm studies on DS-8201 for HER2-low/positive ABC. MINORS was adopted for quality assessment and STATA 16.0 for data analysis. Results: Ten studies involving 1,108 patients were included in this meta-analysis. As for the tumor response rate, the pooled ORR and DCR of all studies reached 57% (95% CI: 47%-67%) and 92% (95% CI: 89%-96%) respectively, and the pooled ORRs of the HER2-low expression group and the HER2-positive expression group were 46% (95% CI: 35%-56%) and 64% (95% CI: 54%-74%). Only the low expression group achieved median survival time, with a pooled median PFS and median OS of 9.24 (95% CI: 7.54-10.94) months and 23.87 (95% CI: 21.56-26.17) months, respectively. The most common treatment-related adverse events from DS-8201 were nausea (all grades: 62%; ≥ grade III: 5%), fatigue (all grade: 44%; ≥ grade III: 6%), and alopecia (all grades: 38%; ≥ grade III: 0.5%). Drug-related interstitial lung disease or pneumonitis occurred in 13% of the 1,108 patients, with only a 1% incidence of AE ≥ grade III. Conclusion: The present study suggests that DS-8201 is effective and safe in the treatment of ABC with low or positive HER2 expression, providing additional relevant information for its clinical application. However, further strengthening of the pairs is needed, as well as more clinical studies to support individualized treatment. Systematic Review Registration: https://www.crd.york.ac.uk/PROSPERO/, identifier CRD42023390316.

HER2 amplification by next-generation sequencing to identify HER2-positive invasive breast cancer with negative HER2 immunohistochemistry

Background

Human epidermal growth factor receptor 2 (HER2) positive breast carcinomas due to HER2 amplification are associated with aggressive behavior and a poor prognosis. Anti-HER2-targeted therapies are widely used to treat HER2-positive breast carcinomas with excellent outcomes. Accurate identification of HER2 amplification status in breast carcinomas is of important diagnostic and treatment value. Currently, HER2 amplification status is routinely determined by immunohistochemistry (IHC) and/or fluorescence in situ hybridization (FISH) testing. This study will review our past HER2 data to determine and characterize discordant results between HER2 IHC and FISH. It will also determine a potential impact of HER2 amplification status by next-generation sequencing (NGS) on these patients.

Methods

We reviewed a total of 4884 breast carcinomas with coexisting HER2 IHC and HER2 FISH performed at our institution from 2010 to 2022. 57 cases also had a Next-Generation-Sequencing-based (NGS) gene panel performed. Given the advances in biostatic analysis pipelines, NGS methods were utilized to provide results on HER2 amplification status along with somatic mutations.

Results

While the majority (ranging from 98.5% with IHC score of 0 and 93.1% with IHC score of 1 +) of 4884 breast carcinomas had concordant results from HER2 IHC and HER2 FISH testing, a small percentage of patients (ranging from 1.5% in those with IHC score of 0, to 6.9% with IHC score of 1 +) had discordant results, with negative HER2 IHC and positive HER2 FISH results. These patients could be reported as HER2-negative breast carcinomas if only HER2 IHC testing has been performed according to a current cost-effective HER2 test strategy. 57 patients had HER2 amplification status determined by NGS, and all patients had concordant results between HER2 NGS and FISH tests. A HER2-amplified breast carcinoma by NGS had a negative IHC and a positive HER2 FISH result. This case was classified as a HER2-positive breast carcinoma, had anti-HER2-targeted therapy, and achieved a complete clinical response.

Conclusions

A small percentage of HER2-positive breast carcinomas are unidentified because of a negative HER2 IHC based on our current cost-effective HER2 test strategy. It is not feasible and affordable in routine clinical practice to perform HER2 FISH for the cases with negative HER2 IHC (IHC score 0 and 1 +). Therefore, NGS assays capable of simultaneously detecting both somatic mutations and HER2 amplification could provide a more comprehensive genetic profiling for breast carcinomas in a clinical setting. Identification of HER2 amplification by NGS in HER2-positive breast carcinomas with negative HER2 IHC results is important since these cases are concealed by our current cost-effective HER2 test strategy with IHC first (for all cases) and FISH reflex (only for cases with IHC score of 2 +), and would offer the opportunity for potentially beneficial anti-HER2-targeted therapies for these patients.

Clinical, Pathological Complete Response, and Prognosis Characteristics of HER2-Low Breast Cancer in the Neoadjuvant Chemotherapy Setting: A Retrospective Analysis

BACKGROUND

The present study was conducted to evaluate the clinical, pathological response, and prognosis characteristics of human epidermal growth factor receptor 2 (HER2)-low breast cancer in the neoadjuvant chemotherapy setting.

METHODS

Patients with HER2-negative breast cancer who received neoadjuvant chemotherapy from January 2017 to December 2019 were retrospectively analyzed. HER2-negative breast cancer was divided into two groups: HER2-zero (defined as immunohistochemistry [IHC] 0) and HER2-low (defined as IHC 1+, or IHC 2+ and fluorescence in-situ hybridization-negative.

RESULTS

Overall, 314 patients with HER2-negative breast cancer were analyzed. The proportion of HER2-low patients with hormone receptor (HR)-positive disease was higher than in triple-negative breast cancer (TNBC; 75.3% vs. 63.2%, p = 0.032). In HR-positive breast cancer, HER2-low tumors presented less nodal involvement (p = 0.023) and earlier clinical stage (p = 0.015) compared with HER2-zero tumors; however, in TNBC, HER2-low patients had a later clinical stage (p = 0.028). With the pathological complete response (pCR) defined as ypTis/0ypN0, there was no difference in pCR rates among the entire cohort, HR-positive disease, and TNBC. However, with the pCR defined as ypT0ypN0, the pCR rate in HER2-low breast cancer was significantly lower than HER2-zero breast cancer in the entire cohort (24.3% vs. 36.4%, p = 0.032) and the HR-positive subgroup (18.7% vs. 32.1%, p = 0.035), but not for TNBC. Multivariate analysis demonstrated that HER2 status (low vs. zero) was an independent predictive factor for pCR (p = 0.013) in HR-positive breast cancer. There were no statistically significant differences in 3-year disease-free survival and overall survival between HER2-low and HER2-zero breast cancer among the entire cohort, HR-positive disease, and TNBC.

CONCLUSIONS

HER2-low breast cancer exhibits specific clinical features and different response to treatment associated with HR status in the neoadjuvant chemotherapy setting.

Distinct clinical and somatic mutational features of breast tumors with high-, low-, or non-expressing human epidermal growth factor receptor 2 status

BACKGROUND

HER2-low breast cancers were reported to have distinct clinicopathological characteristics from HER2-zero; however, the difference in their genetic features remains unclear. This study investigated the clinical and molecular features of breast tumors according to HER2 status.

METHODS

We analyzed the clinicopathological and genomic data of 523 Chinese women with breast cancer. Genomic data was generated by targeted next-generation sequencing (NGS) of breast tumor samples using a commercial 520 gene panel. The cohort was stratified according to HER2 status as HER2-zero (n = 90), HER2-low (n = 231), and HER2-positive (n = 202) according to their immunohistochemistry and fluorescence in situ hybridization results.

RESULTS

HER2-low breast tumors were enriched with hormone receptor-positive tumors, and who had lower Ki67 expression levels. Genes were differentially mutated across HER2 subgroups. HER2-low tumors had significantly more mutations involved in PI3K-Akt signaling than HER2-positive (p < 0.001) and HER2-zero breast tumors (p < 0.01). HER2-zero tumors had more mutations in checkpoint factors (p < 0.01), Fanconi anemia (p < 0.05), and p53 signaling and cell cycle pathway (p < 0.05) compared to HER2-low breast tumors. Compared with HER2-zero tumors, HER2-low tumors had significantly lower pathological complete response rates after neoadjuvant therapy (15.9% vs. 37.5%, p = 0.042) and proportion of relapsed/progressed patients across follow-up time points (p = 0.031), but had comparable disease-free survival (p = 0.271).

CONCLUSION

Our results demonstrate the distinct clinical and molecular features and clinical outcomes of HER2-low breast tumors.

Value of CT-Based Radiomics in Predicating the Efficacy of Anti-HER2 Therapy for Patients With Liver Metastases From Breast Cancer

Objective

This study aims to assess the performance of machine learning (ML)-based contrast-enhanced CT radiomics analysis for predicating the efficacy of anti-HER2 therapy for patients with liver metastases from breast cancer.

Methods

This retrospective study analyzed 83 patients with breast cancer liver metastases. Radiomics features were extracted from arterial phase, portal venous phase, and delayed phase images, respectively. The intraclass correlation coefficient (ICC) was calculated to quantify the reproducibility of features. The training and validation sets consisted of 58 and 25 cases. Variance threshold, SelectKBest, and LASSO logistic regression model were employed for feature selection. The ML classifiers were K-nearest-neighbor algorithm (KNN), support vector machine (SVM), XGBoost, RF, LR, and DT, and the performance of classifiers was evaluated by ROC analysis.

Results

The SVM classifier had the highest score in portal venous phase. The results were as follows: The AUC value of the poor prognosis group in validation set was 0.865, the sensitivity was 0.77, and the specificity was 0.83. The AUC value of the good prognosis group in validation set was 0.865, the sensitivity was 0.83, and the specificity was 0.77. In arterial phase, the XGBoost classifier had the highest score. The AUC value of the poor prognosis group in validation set was 0.601, the sensitivity was 0.69, and the specificity was 0.38. The AUC value of the good prognosis group in validation set was 0.601, the sensitivity was 0.38, and the specificity was 0.69. The LR classifier had the highest score in delayed phase. The AUC value of poor prognosis group in validation set was 0.628, the sensitivity was 0.62, and the specificity was 0.67. The AUC value of the good prognosis group in validation set was 0.628, the sensitivity was 0.67, and the specificity was 0.62.

Conclusion

Radiomics analysis represents a promising tool in predicating the efficacy of anti-HER2 therapy for patients with liver metastases from breast cancer. The ROI in portal venous phase is most suitable for predicting the efficacy of anti-HER2 therapy, and the SVM algorithm model has the best efficiency.

PharmacoDB 2.0: improving scalability and transparency of in vitro pharmacogenomics analysis

Cancer pharmacogenomics studies provide valuable insights into disease progression and associations between genomic features and drug response. PharmacoDB integrates multiple cancer pharmacogenomics datasets profiling approved and investigational drugs across cell lines from diverse tissue types. The web-application enables users to efficiently navigate across datasets, view and compare drug dose-response data for a specific drug-cell line pair. In the new version of PharmacoDB (version 2.0, https://pharmacodb.ca/), we present (i) new datasets such as NCI-60, the Profiling Relative Inhibition Simultaneously in Mixtures (PRISM) dataset, as well as updated data from the Genomics of Drug Sensitivity in Cancer (GDSC) and the Genentech Cell Line Screening Initiative (gCSI); (ii) implementation of FAIR data pipelines using ORCESTRA and PharmacoDI; (iii) enhancements to drug-response analysis such as tissue distribution of dose-response metrics and biomarker analysis; and (iv) improved connectivity to drug and cell line databases in the community. The web interface has been rewritten using a modern technology stack to ensure scalability and standardization to accommodate growing pharmacogenomics datasets. PharmacoDB 2.0 is a valuable tool for mining pharmacogenomics datasets, comparing and assessing drug-response phenotypes of cancer models.

Clinical and Pathologic Features Associated With Invasive Breast Carcinoma with 2018 American Society of Clinical Oncology/College of American Pathologists In Situ Hybridization Group 2 Results (Human Epidermal Growth Factor Receptor 2 [HER2]/Chromosome 17 Centromere [CEP17] Ratio ≥2.0 and Average HER2 Copy Number <4.0)

CONTEXT.—

The American Society of Clinical Oncology/College of American Pathologists updated the human epidermal growth factor receptor 2 (HER2) breast carcinoma testing guideline in 2018 to address issues from uncommon HER2 fluorescence in situ hybridization (FISH) results. Based on the 2013 American Society of Clinical Oncology/College of American Pathologists guideline, cases wherein the HER2/chromosome 17 centromere (CEP17) ratio of 2.0 or more with an average HER2 copy number of less than 4.0 were considered in situ hybridization (ISH) positive. Under the 2018 guideline, such cases are classified as ISH Group 2 and are no longer considered eligible for anti-HER2 therapy when the corresponding HER2 immunohistochemistry result is 0, 1+, or 2+.

OBJECTIVE.—

To assess the clinical, pathologic, and treatment aspects of patients with ISH Group 2 results.

DESIGN.—

We retrospectively reviewed HER2 FISH results at our center between January 2012 and December 2014 and identified and characterized cases with ISH Group 2 results.

RESULTS.—

Thirty-nine cases with ISH Group 2 results from 39 patients were reviewed. Twenty of 39 (51%) patients received anti-HER2 therapy. Patients treated with HER2-targeted therapy were less likely to have hormone receptor-positive tumors, compared with patients without anti-HER2 treatment, though not significantly (P = .30). The only significant difference between the 2 patient groups was receipt of cytotoxic chemotherapy treatment (P < .001). Overall, clinical outcome was similar between the 2 groups (P > .99).

CONCLUSIONS.—

This retrospective study with median follow-up of at least 6 years shows patients with ISH Group 2 tumors had similar clinical outcomes, irrespective of HER2-targeted therapy. Further analysis in the prospective setting would provide valuable data that would potentially inform clinical decision making.

MiR-221 confers lapatinib resistance by negatively regulating p27kip1 in HER2-positive breast cancer

Development of acquired resistance to lapatinib, a dual epidermal growth factor receptor (EGFR)/human epidermal growth factor receptor 2 (HER2) tyrosine kinase inhibitor, severely limits the duration of clinical response in advanced HER2‐driven breast cancer patients. Although the compensatory activation of the PI3K/Akt survival signal has been proposed to cause acquired lapatinib resistance, comprehensive molecular mechanisms remain required to develop more efficient strategies to circumvent this therapeutic difficulty. In this study, we found that suppression of HER2 by lapatinib still led to Akt inactivation and elevation of FOX3a protein levels, but failed to induce the expression of their downstream pro‐apoptotic effector p27^kip1, a cyclin‐dependent kinase inhibitor. Elevation of miR‐221 was found to contribute to the development of acquired lapatinib resistance by targeting p27^kip1 expression. Furthermore, upregulation of miR‐221 was mediated by the lapatinib‐induced Src family tyrosine kinase and subsequent NF‐κB activation. The reversal of miR‐221 upregulation and p27^kip1 downregulation by a Src inhibitor, dasatinib, can overcome lapatinib resistance. Our study not only identified miRNA‐221 as a pivotal factor conferring the acquired resistance of HER2‐positive breast cancer cells to lapatinib through negatively regulating p27^kip1 expression, but also suggested Src inhibition as a potential strategy to overcome lapatinib resistance.

Targeting HER2 genomic alterations in non-small cell lung cancer

Oncogenic mutations and amplifications in the erythroblastic oncogene B (ERBB2), or human epidermal growth factor receptor 2 (HER2), have emerged as distinct oncogenic drivers and drug targets in non-small cell lung cancer (NSCLC). Each genomic alteration occurs in 2-4% of NSCLC by next generation sequencing and is associated with constitutive HER2 activation. The most common HER2 mutations in NSCLC are exon 20 mutation A775_G776insYVMA mutation in the kinase domain and S310F mutation in the extracellular domain. Unlike in breast and gastric cancer, HER2 protein overexpression in NSCLC is not validated to be a biomarker predictive of clinical response to HER2-targeted agents. High HER2 protein overexpression by immunohistochemistry (3+) only occurs in 2-4% of NSCLC. Until now HER2-targeted agents (such as afatinib and ado-trastuzumab emtansine) only demonstrate modest clinical activity in patients with HER2-mutant NSCLC. Retrospective studies show concern for inferior clinical benefit of immune checkpoint inhibitors in HER2-mutated NSCLC. Therefore, platinum-based chemotherapy with or without an anti-angiogenesis inhibitor remains the first line standard treatment for this patient population. In May 2020 trastuzumab deruxtecan (T-DXd) received the U.S. Food and Drug Administration breakthrough therapy designation for HER2-mutant metastatic NSCLC, and was added as an option for HER2-mutant NSCLC to the NCCN guidelines V1.2021. A global phase III study of pyrotinib compared to docetaxel as a second line therapy for advanced NSCLC harboring HER2 exon 20 mutations was just opened for enrollment in September 2020. In this review, we highlight the current knowledge and perspectives on targeting-HER2 genomic alterations in NSCLC.

The emerging role of radionuclide molecular imaging of HER2 expression in breast cancer

Targeting of human epidermal growth factor type 2 (HER2) using monoclonal antibodies, antibody-drug conjugates and tyrosine kinase inhibitors extends survival of patients with HER2-expressing metastatic breast cancer. High expression of HER2 is a predictive biomarker for such specific treatment. Accurate determination of HER2 expression level is necessary for stratification of patients to targeted therapy. Non-invasive in vivo radionuclide molecular imaging of HER2 has a potential of repetitive measurements, addressing issues of heterogeneous expression and conversion of HER2 status during disease progression or in response to therapy. Imaging probes based of several classes of targeting proteins are currently in preclinical and early clinical development. Both preclinical and clinical data suggest that the most promising are imaging agents based on small proteins, such as single domain antibodies or engineered scaffold proteins. These agents permit a very specific high-contrast imaging at the day of injection.

Overview of New Treatments with Immunotherapy for Breast Cancer and a Proposal of a Combination Therapy

According to data from the U.S. National Cancer Institute, cancer is one of the leading causes of death worldwide with approximately 14 million new cases and 8.2 million cancer-related deaths in 2018. More than 60% of the new annual cases in the world occur in Africa, Asia, Central America, and South America, with 70% of cancer deaths in these regions. Breast cancer is the most common cancer in women, with 266,120 new cases in American women and an estimated 40,920 deaths for 2018. Approximately one in six women diagnosed with breast cancer will die in the coming years. Recently, novel therapeutic strategies have been implemented in the fight against breast cancer, including molecules able to block signaling pathways, an inhibitor of poly [ADP-ribose] polymerase (PARP), growth receptor blocker antibodies, or those that reactivate the immune system by inhibiting the activities of inhibitory receptors like cytotoxic T-lymphocyte antigen 4 (CTLA-4) and programmed death protein 1 (PD-1). However, novel targets include reactivating the Th1 immune response, changing tumor microenvironment, and co-activation of other components of the immune response such as natural killer cells and CD8+ T cells among others. In this article, we review advances in the treatment of breast cancer focused essentially on immunomodulatory drugs in targeted cancer therapy. Based on this knowledge, we formulate a proposal for the implementation of combined therapy using an extracorporeal immune response reactivation model and cytokines plus modulating antibodies for co-activation of the Th1- and natural killer cell (NK)-dependent immune response, either in situ or through autologous cell therapy. The implementation of "combination immunotherapy" is new hope in breast cancer treatment. Therefore, we consider the coordinated activation of each cell of the immune response that would probably produce better outcomes. Although more research is required, the results recently achieved by combination therapy suggest that for most, if not all, cancer patients, this tailored therapy may become a realistic approach in the near future.

Towards integration of 64Cu-DOTA-trastuzumab PET-CT and MRI with mathematical modeling to predict response to neoadjuvant therapy in HER2 + breast cancer

While targeted therapies exist for human epidermal growth factor receptor 2 positive (HER2 +) breast cancer, HER2 + patients do not always respond to therapy. We present the results of utilizing a biophysical mathematical model to predict tumor response for two HER2 + breast cancer patients treated with the same therapeutic regimen but who achieved different treatment outcomes. Quantitative data from magnetic resonance imaging (MRI) and 64Cu-DOTA-trastuzumab positron emission tomography (PET) are used to estimate tumor density, perfusion, and distribution of HER2-targeted antibodies for each individual patient. MRI and PET data are collected prior to therapy, and follow-up MRI scans are acquired at a midpoint in therapy. Given these data types, we align the data sets to a common image space to enable model calibration. Once the model is parameterized with these data, we forecast treatment response with and without HER2-targeted therapy. By incorporating targeted therapy into the model, the resulting predictions are able to distinguish between the two different patient responses, increasing the difference in tumor volume change between the two patients by > 40%. This work provides a proof-of-concept strategy for processing and integrating PET and MRI modalities into a predictive, clinical-mathematical framework to provide patient-specific predictions of HER2 + treatment response.

Next-generation assessment of human epidermal growth factor receptor 2 gene (ERBB2) amplification status in invasive breast carcinoma: a focus on Group 4 by use of the 2018 American Society of Clinical Oncology/College of American Pathologists HER2 testing guideline

AIMS

The American Society of Clinical Oncology/College of American Pathologists (ASCO/CAP) updated the testing guideline in 2018 to address issues arising from uncommon human epidermal growth factor receptor 2 (HER2) fluorescence in-situ hybridisation (FISH) results according to the 2013 guideline. Next-generation sequencing (NGS) may be used to better classify patients. The aim of this study was to assess the ERBB2 amplification status of invasive breast carcinoma with equivocal HER2 immunohistochemistry (IHC) results by using NGS, focusing on Group 4 (HER2/CEP17 ratio of <2.0; average HER2 signals/cell of ≥4.0 and <6.0).

METHODS AND RESULTS

We retrospectively reviewed HER2 FISH and NGS data of HER2 IHC-equivocal breast carcinomas at our centre between January 2009 and September 2019, wherein all three assays were performed on the same tissue block, and compared HER2 FISH results, according to the 2018 ASCO/CAP guideline, and the ERBB2 amplification status determined with NGS. A total of 52 HER2 FISH and NGS results from 51 patients with HER2 IHC-equivocal breast carcinomas were reviewed. The cohort included eight cases classified as 2018 ASCO/CAP in-situ hybridisation Group 1, three classified as Group 2, three classified as Group 3, 14 classified as Group 4, and 24 classified as Group 5. Thirteen of 14 (92.9%) Group 4 (HER2-negative) cases were classified as ERBB2-non-amplified by the use of NGS; the discordant case was later classified as Group 1 with alternative sample FISH testing. NGS revealed no significant difference in somatic mutations or copy number alterations between Groups 4 and 5.

CONCLUSIONS

Our NGS findings support the reclassification of HER2 FISH-equivocal cases as HER2-negative under the 2018 ASCO/CAP guideline.

New HER2-negative breast cancer subtype responsive to anti-HER2 therapy identified

Purpose

HER2 signaling functional activity may be important to measure in addition to HER2 protein quantification when identifying patients eligible for HER2 therapies. A HER2 Signaling Function (CELx HSF) Test for HER2-negative patients uses patient’s live tumor cells on a biosensor to identify patients with abnormally high HER2-related signaling (HSFs+) likely to respond to anti-HER2 therapies.

Methods

The CELx HSF test was employed to: (1) characterize the sensitivity and specificity of the test to detect abnormal levels of HER2 signaling; (2) evaluate the inhibitory effectiveness of five different anti-HER2 therapies; (3) assess the correlation between CELx HSF test detection of abnormal HER2 signaling and response to HER2 therapy using xenograft models; and (4) confirm the prevalence of abnormal HER2 signaling amongst HER2-negative breast cancer patients (HER2−/HSFs+).

Results

HER2−/HSFs+ breast cancer patient samples were identified and showed sensitivity to five approved anti-HER2 therapies. Xenograft studies using both HER2+ and HER2− cell lines confirmed that CELx HER2 signaling status better predicts HER2 inhibitor efficacy than HER2 receptor status. In a study of 114 HER2-negative breast tumor patient samples, 27 (23.7%; 95% CI = 17–32%) had abnormal HER2 signaling (HSFs+). A ROC curve constructed with this dataset projects the CELx HSF Test would have greater than 90% sensitivity and specificity to detect the HER2−/HSFs+ patient population.

Conclusions

The CELx HSF test is a well-characterized functional biomarker assay capable of identifying dynamic HER2-driven signaling dysfunction in tumor cells from HER2-negative breast cancer patients. This test has demonstrated efficacy of various HER2 targeted therapies in live tumor cells from the HSFs+ population and correlated the test result to HER2 drug response in mouse xenograft studies. The proportion of HER2-negative breast cancer patients found to have abnormal HER2 signaling in a 114 patient sample study, 20–25%, is significant. A clinical trial to evaluate the efficacy of anti-HER2 therapies in this patient population is warranted.

Electronic supplementary material

The online version of this article (10.1007/s00432-020-03144-7) contains supplementary material, which is available to authorized users.

Assessment of ERBB2/HER2 Status in HER2-Equivocal Breast Cancers by FISH and 2013/2014 ASCO-CAP Guidelines

Importance

The 2013/2014 American Society of Clinical Oncology and College of American Pathologists (ASCO-CAP) guidelines for HER2 testing by fluorescence in situ hybridization (FISH) designated an "equivocal" category (average HER2 copies per tumor cell ≥4-6 with HER2/CEP17 ratio <2.0) to be resolved as negative or positive by assessments with alternative control probes. Approximately 4% to 12% of all invasive breast cancers are characterized as HER2-equivocal based on FISH.

Objective

To evaluate the following hypotheses: (1) genetic loci used as alternative controls are heterozygously deleted in a substantial proportion of breast cancers; (2) use of these loci for assessment of HER2 by FISH leads to false-positive assessments; and (3) these HER2 false-positive breast cancer patients have outcomes that do not differ from clinical outcomes for patients with HER2-negative breast cancer.

Design, Setting, and Participants

We retrospectively assessed the use of chromosome 17 p-arm and q-arm alternative control genomic sites (TP53, D17S122, SMS, RARA, TOP2A), as recommended by the 2013/2014 ASCO-CAP guidelines for HER2 testing, in patients whose data were available through Molecular Taxonomy of Breast Cancer International Consortium (METABRIC) and whose tissues were available through the Breast Cancer International Research Group clinical trials. We used data from an international cohort database of invasive breast cancers (1980 participants) and international clinical trial of adjuvant chemotherapy in invasive, node-positive breast cancer patients.

Main Outcomes and Measures

The primary objectives were to (1) assess frequency of heterozygous deletions in chromosome 17 genomic sites used as FISH internal controls for evaluation of HER2 status among HER2-equivocal cancers; (2) characterize impact of using deleted sites for determination of HER2-to-internal-control-gene ratios; (3) assess HER2 protein expression in each subgroup; and (4) compare clinical outcomes for each subgroup.

Results

Of the 1980 patients in METABRIC,1915 patients were fully evaluated. In addition, 100 HER2-equivocal breast cancers by FISH and 100 comparator FISH-negative breast cancers from the BCIRG-005 trial were analyzed. Heterozygous deletions, particularly in specific p-arm sites, were common in both HER2-amplified and HER2-not-amplified breast cancers. Use of alternative control probes from these regions to assess HER2 by FISH in HER2-equivocal as well as HER2-not-amplified breast cancers resulted in high rates of false-positive ratios (HER2-to-alternative control ratio ≥2.0) owing to heterozygous deletions of control p-arm genomic sites used in ratio denominators. Misclassification of HER2 status was observed not only in breast cancers with ASCO-CAP equivocal status but also in breast cancers with an average of fewer than 4.0 HER2 copies per tumor cell when using alternative control probes.

Conclusions and Relevance

The indiscriminate use of alternative control probes to calculate HER2 FISH ratios in HER2-equivocal breast cancers may lead to false-positive interpretations of HER2 status resulting from unrecognized heterozygous deletions in 1 or more of these alternative control genomic sites and incorrect HER2 ratio determinations.

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

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.

A Roundtable Discussion of the Breast Cancer Therapy Expert Group (BCTEG): Clinical Developments and Practice Guidance on Human Epidermal Growth Factor Receptor 2 (HER2)-positive Breast Cancer

Expression of human epidermal growth factor receptor 2 (HER2) in breast cancer defines a subset of patients (∼15%-20%) who are candidates for anti-HER2 therapies, most notably, trastuzumab, pertuzumab, antibody drug conjugates (eg, T-DM1), and tyrosine kinase inhibitor (TKI) drugs (eg, lapatinib and neratinib), all of which have dramatically changed the prognosis for this aggressive subtype of breast cancer. A roundtable meeting of the Breast Cancer Therapy Expert Group (BCTEG) was convened in March 2018 in an effort to discuss and clarify, from the perspective of the practicing community oncologist, recent developments in the diagnosis and treatment of HER2-positive (HER2⁺) breast cancer. Members of the group selected 4 key topics for discussion prior to the meeting, including diagnosis of HER2⁺ disease, and its treatment in the neoadjuvant, adjuvant, and metastatic settings. Approved testing methods, such as immunohistochemistry and fluorescence in situ hybridization, are used to demonstrate overexpression and/or amplification of HER2 in breast tumors, and established clinical guidelines are used to appropriately define treatment plans for patients with HER2⁺ disease. The panel acknowledges a range of treatment options now available for treatment of HER2⁺ breast cancer in the neoadjuvant, adjuvant, and advanced/metastatic settings, although it is noted that many controversies remain, including the optimal sequence of therapies, the most appropriate treatment(s) for subsets of patients with HER2⁺ disease (eg, hormone receptor-negative or -positive/HER2⁺), and uncertainties surrounding the diagnosis and definition of HER2⁺ disease. The current report summarizes the discussion of the BCTEG panel on this topic.

Molecular alterations and poziotinib efficacy, a pan-HER inhibitor, in human epidermal growth factor receptor 2 (HER2)-positive breast cancers: Combined exploratory biomarker analysis from a phase II clinical trial of poziotinib for refractory HER2-positive breast cancer patients

We aimed to investigate the impact of genetic alterations on the efficacy of poziotinib in a phase II clinical trial of patients with heavily treated HER2-positive metastatic breast cancer (BC). We performed targeted ultra-deep sequencing with a customized cancer gene panel and RNA expression assay using BC specimens. Of 106 patients, biomarker data were available for 85. Copy number (CN) amplifications of HER2 were observed in 72 patients (85%), and CN >8 in 50 (59%). Single nucleotide variants (SNVs) of HER2 were found in 16 patients (19%). Genetic alterations of PIK3CA pathway were found in 40 patients (47%). Median progression free survival (PFS) of the biomarker analysis group was 3.61 months. In terms of PFS, HER2 with CN >8 prolonged (hazard ratio (HR) 0.61, 95% CI: 0.38, 0.97, p = 0.037) and alteration of PIK3CA pathway shortened the duration of survival (HR 2.25, 95% CI: 1.39, 3.63, p = 0.001). SNVs of HER2 increased survival duration, but the effect was not significant (HR: 0.58, 95% CI: 0.31, 1.08, p = 0.085). In addition, SNVs in the ERBB3 cytoplasmic domain decreased poziotinib response (HR: 4.58, 95% CI: 2.02, 10.37, p < 0.001). In multigene analysis, BC with HER2 CN >8 and intact PIK3CA pathway had significantly longer PFS compared to others (HR: 0.37, 95% CI: 0.21, 0.66, p = 0.001), while SNVs in the ERBB3 cytoplasmic domain predicted poor prognosis (HR: 4.28, 95% CI: 1.71, 10.71, p < 0.001). In conclusion, HER2 CN amplification, PIK3CA pathway alteration, and ERBB3 cytoplasmic mutation showed predictive roles on clinical outcomes of HER2-positive MBC treated with poziotinib.

Phosphoproteomic analysis reveals PAK2 as a therapeutic target for lapatinib resistance in HER2-positive breast cancer cells

The human epidermal growth factor receptor 2 (HER2)-positive breast cancer with overexpression of HER2 accounts for approximately 25% of breast cancers and is more aggressive than other types of breast cancer. Lapatinib has been widely used as a HER2-targeted therapy, however, a number of patients develop lapatinib resistance and still suffer from poor prognosis. Therefore, it is essential to identify novel therapeutic targets that could overcome lapatinib resistance. In this study, we carried out phosphoproteomic analysis of lapatinib sensitive and resistant cell lines (SKBR3 and SKBR3-LR) using stable isotope labeling with amino acids in cell culture (SILAC). We identified 3808 phosphopeptides from 1807 proteins and then analyzed signaling pathways, Gene Ontology, and protein-protein interaction networks. Finally, we identified PAK2 as a therapeutic target from the network analysis and validated that PAK2 knockdown and PAK inhibitor treatment resensitize the lapatinib resistant cells to lapatinib. This results suggest that PAK2 is a potent therapeutic target to overcome acquired lapatinib resistance in HER2-positive breast cancer cells.

Targeted Therapies Against Growth Factor Signaling in Breast Cancer

Breast cancer is the most prevalent female malignancy throughout the world. Conventional treatment strategies for breast cancer consist of chemotherapy, radiation, surgery, chemoradiation, hormone therapy, and targeted therapies. Among them, targeted therapies show advantages to reduce cost and toxicity for being possible for individualized treatments based on the intrinsic subtypes of breast cancer. With deeper understanding of key signaling pathways concerning tumor growth and survival, growth factor-controlled signaling pathways are frequently dysregulated in the development and progression of breast cancer. Thus, targeted therapies against growth factor-mediated signaling pathways have been shown to have promising efficacy in both preclinical animal models and human clinical trials. In this chapter, we will briefly introduce inhibitors and monoclonal antibodies that target the main growth factor-modulated scenarios including epidermal growth factor receptor (EGFR), transforming growth factor beta (TGF-β), insulin-like growth factor 1 receptor (IGF1R), and fibroblast growth factor receptor (FGFR) signaling pathways in breast cancer therapy.

PATRI, a Genomics Data Integration Tool for Biomarker Discovery

The availability of genomic datasets in association with clinical, phenotypic, and drug sensitivity information represents an invaluable source for potential therapeutic applications, supporting the identification of new drug sensitivity biomarkers and pharmacological targets. Drug discovery and precision oncology can largely benefit from the integration of treatment molecular discriminants obtained from cell line models and clinical tumor samples; however this task demands comprehensive analysis approaches for the discovery of underlying data connections. Here we introduce PATRI (Platform for the Analysis of TRanslational Integrated data), a standalone tool accessible through a user-friendly graphical interface, conceived for the identification of treatment sensitivity biomarkers from user-provided genomics data, associated with information on sample characteristics. PATRI streamlines a translational analysis workflow: first, baseline genomics signatures are statistically identified, differentiating treatment sensitive from resistant preclinical models; then, these signatures are used for the prediction of treatment sensitivity in clinical samples, via random forest categorization of clinical genomics datasets and statistical evaluation of the relative phenotypic features. The same workflow can also be applied across distinct clinical datasets. The ease of use of the PATRI tool is illustrated with validation analysis examples, performed with sensitivity data for drug treatments with known molecular discriminants.

Lapatinib

The human epidermal growth factor receptor (HER) family of receptor tyrosine kinases plays an important role in the biology of many cancers. In breast and gastrointestinal cancer, and at lower rates also in additional tumor types, HER2 and its homo- or heterodimerization with HER1 or HER3 are essential for cancer cell growth and survival. Breast cancer patients overexpressing HER2 have a more aggressive course of their disease. The poor prognosis associated with HER2 overexpression can be substantially improved by adding HER2-targeted therapy to standard of care using the monoclonal antibody trastuzumab. Lapatinib, an oral dual tyrosine kinase inhibitor, blocks HER1 and HER2 tyrosine kinase activity by binding to the ATP-binding site of the receptor's intracellular domain, resulting in inhibition of tumor cell growth. Lapatinib is generally well tolerated with diarrhea being the most common adverse effect. However, although being mainly of mild to moderate severity, interruption or discontinuation of treatment has been reported in a substantial proportion of patients in clinical trials. In 2007, lapatinib has been approved in combination with capecitabine in patients with advanced HER2-positive breast cancer upon progressive disease following standard therapy with anthracyclines, taxanes, and trastuzumab. In 2013, the approval was extended to a chemotherapy-free combination with trastuzumab for patients with metastatic HER2-positive, hormone receptor-negative breast cancer progressing on prior trastuzumab and chemotherapy. Since 2010, lapatinib is approved in combination with letrozole in the treatment of postmenopausal women with advanced HER2- and hormone receptor-positive breast cancer. In contrast, in first-line cytotoxic-based therapy of both early and advanced HER2-positive breast cancer, data from clinical trials did not provide evidence of additional benefit of lapatinib compared to trastuzumab. Moreover, over the past few years, novel HER2-targeted drugs, either alone or as a combined anti-HER2 approach, have been extensively evaluated, demonstrating a more favorable outcome. Also, neither in first- nor second-line treatment of advanced gastric cancer, lapatinib has been proven to be superior compared to trastuzumab as hitherto standard of care HER2 blockade. Therefore, lapatinib has become somewhat less important in patients with HER2-positive breast cancer during the past 10 years since its first introduction. Nevertheless, consideration of treatment with lapatinib appears to be reasonable in selected patients not only in the approved applications but also beyond, and further indications such as HER2-positive refractory metastatic colorectal cancer may arise in future. Also, lapatinib may have distinct advantages over antibodies in targeting truncated HER2 and crossing the blood-brain barrier. Finally, the favorable cardiac toxicity profile of lapatinib makes it an attractive alternative to trastuzumab-based regimens in patients at risk for cardiac events.

Predictive value of quantitative HER2, HER3 and p95HER2 levels in HER2-positive advanced breast cancer patients treated with lapatinib following progression on trastuzumab

Lapatinib is a HER1 and HER2 tyrosine kinase inhibitor (TKI) approved in second line treatment of advanced or metastatic breast cancer following progression on trastuzumab-containing therapy. Biomarkers for activity of lapatinib and other TKIs are lacking. Formalin-fixed, paraffin-embedded primary tumor samples were obtained from 189 HER2-positive patients treated with lapatinib plus capecitabine following progression on trastuzumab. The HERmark® Breast Cancer Assay was used to quantify HER2 protein expression. HER3 and p95HER2 protein expression was quantified using the VeraTag® technology. Overall survival (OS) was inversely correlated with HER2 (HR = 1.9/log; P = 0.009) for patients with tumors above the cut-off positivity level by the HERmark assay. OS was significantly shorter for those with above median HER2 levels (HR = 1.7; P = 0.015) and trended shorter for those below the cut-off level of positivity by the HERmark assay (HR = 1.7; P = 0.057) compared to cases with moderate HER2 overexpression. The relationship between HER2 protein expression and OS was best captured with a U-shaped parabolic function (P = 0.004), with the best prognosis at moderate levels of HER2 protein overexpression. In a multivariate model including HER2, increasing p95HER2 expression was associated with longer OS (HR = 0.35/log; P = 0.027). Continuous HER3 did not significantly correlate with OS. Patients with moderately overexpressed HER2 levels and high p95HER2 expression may have best outcomes while receiving lapatinib following progression on trastuzumab. Further study is warranted to explore the predictive utility of quantitative HER2 and p95HER2 in guiding HER2-directed therapies.

HER2 Gene Amplification Testing by Fluorescent In Situ Hybridization (FISH): Comparison of the ASCO-College of American Pathologists Guidelines With FISH Scores Used for Enrollment in Breast Cancer International Research Group Clinical Trials

Purpose

ASCO and the College of American Pathologists (ASCO-CAP) recently recommended further changes to the evaluation of human epidermal growth factor receptor 2 gene (HER2) amplification by fluorescent in situ hybridization (FISH). We retrospectively assessed the impact of these new guidelines by using annotated Breast Cancer International Research Group (BCIRG) -005, BCIRG-006, and BCIRG-007 clinical trials data for which we have detailed outcomes.

Patients and Methods

The HER2 FISH status of BCIRG-005/006/007 patients with breast cancers was re-evaluated according to current ASCO-CAP guidelines, which designates five different groups according to HER2 FISH ratio and average HER2 gene copy number per tumor cell: group 1 (in situ hybridization [ISH]–positive): HER2-to-chromosome 17 centromere ratio ≥ 2.0, average HER2 copies ≥ 4.0; group 2 (ISH-positive): ratio ≥ 2.0, copies < 4.0; group 3 (ISH-positive): ratio < 2.0, copies ≥ 6.0; group 4 (ISH-equivocal): ratio < 2.0, copies ≥ 4.0 and < 6.0; and group 5 (ISH-negative): ratio < 2.0, copies < 4.0. We assessed correlations with HER2 protein, clinical outcomes by disease-free survival (DFS) and overall survival (OS) and benefit from trastuzumab therapy (hazard ratio [HR]).

Results

Among 10,468 patients with breast cancers who were successfully screened for trial entry, 40.8% were in ASCO-CAP ISH group 1, 0.7% in group 2; 0.5% in group 3, 4.1% in group 4, and 53.9% in group 5. Distributions were similar in screened compared with accrued subpopulations. Among accrued patients, FISH group 1 breast cancers were strongly correlated with immunohistochemistry 3+ status (P < .0001), whereas groups 2, 3, 4, and 5 were not; however, groups 2, 4 and, 5 were strongly correlated with immunohistochemistry 0/1+ status (all P < .0001), whereas group 3 was not. Among patients accrued to BCIRG-005, group 4 was not associated with significantly worse DFS or OS compared with group 5. Among patients accrued to BCIRG-006, only group 1 showed a significant benefit from trastuzumab therapy (DFS HR, 0.71; 95% CI, 0.60 to 0.83; P < .0001; OS HR, 0.69; 95% CI, 0.55 to 0.85; P = .0006), whereas group 2 did not.

Conclusion

Our findings support the original categorizations of HER2 by FISH status in BCIRG/Translational Research in Oncology trials.

Successful Treatment of Advanced Primary Cutaneous Apocrine Carcinoma on the Scrotum with Systemic Chemotherapy and Radiotherapy Followed by Denosumab

Primary cutaneous apocrine carcinoma (PCAC) is a rare and highly aggressive cutaneous adnexal type of tumor that has a high metastasis rate and a poor prognosis. Although there are several case reports describing the successful treatment of PCAC with chemoradiotherapy or molecular targeting therapy, no standard therapy for the treatment of advanced PCAC has been established yet. Since receptor activator of nuclear factor kappa-B ligand (RANKL) is expressed in cancers of apocrine origin, leading to immunosuppression at the tumor site, we hypothesized that targeting RANKL with denosumab might be useful for the treatment of PCAC. In this report, we describe a case with advanced PCAC on the scrotum successfully treated with systemic chemotherapy using carboplatin and paclitaxel, and radiotherapy followed by denosumab.

Lapatinib resistance in HER2+ cancers: latest findings and new concepts on molecular mechanisms

In the era of new and mostly effective molecular targeted therapies, human epidermal growth factor receptor 2 positive (HER2+) cancers are still intractable diseases. Lapatinib, a dual epidermal growth factor receptor (EGFR) and HER2 tyrosine kinase inhibitor, has greatly improved breast cancer prognosis in recent years after the initial introduction of trastuzumab (Herceptin). However, clinical evidence indicates the existence of both primary unresponsiveness and secondary lapatinib resistance, which leads to the failure of this agent in HER2+ cancer patients. It remains a major clinical challenge to target the oncogenic pathways with drugs having low resistance. Multiple pathways are involved in the occurrence of lapatinib resistance, including the pathways of receptor tyrosine kinase, non-receptor tyrosine kinase, autophagy, apoptosis, microRNA, cancer stem cell, tumor metabolism, cell cycle, and heat shock protein. Moreover, understanding the relationship among these mechanisms may contribute to future tumor combination therapies. Therefore, it is of urgent necessity to elucidate the precise mechanisms of lapatinib resistance and improve the therapeutic use of this agent in clinic. The present review, in the hope of providing further scientific support for molecular targeted therapies in HER2+ cancers, discusses about the latest findings and new concepts on molecular mechanisms underlying lapatinib resistance.

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

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 <4.0 (group 2); 0.6% were "ISH-positive" with ratios <2.0 and average copies ≥6.0 (group 3); 4.6% were "ISH-equivocal" with ratios <2.0 and average copies ≥4.0 and <6.0 (group 4); and 76.7% were "ISH-negative" with ratios <2.0 and average copies <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.

Lapatinib in Combination With Capecitabine Plus Oxaliplatin in Human Epidermal Growth Factor Receptor 2–Positive Advanced or Metastatic Gastric, Esophageal, or Gastroesophageal Adenocarcinoma: TRIO-013/LOGiC—A Randomized Phase III Trial

Purpose

To evaluate the efficacy of adding lapatinib to capecitabine and oxaliplatin (CapeOx) in patients with previously untreated human epidermal growth factor receptor 2 (HER2) –amplified advanced gastroesophageal adenocarcinoma.

Patients and Methods

Patients with HER2-positive advanced gastroesophageal adenocarcinoma were randomly assigned at a one-to-one ratio to CapeOx plus lapatinib 1,250 mg or placebo daily. Primary end point was overall survival (OS) in patients with centrally confirmed HER2 amplification in the primary efficacy population.

Results

A total of 545 patients were randomly assigned, and 487 patients comprised the primary efficacy population. Median OS in the lapatinib and placebo arms was 12.2 (95% CI, 10.6 to 14.2) and 10.5 months (95% CI, 9.0 to 11.3), respectively, which was not significantly different (hazard ratio, 0.91; 95% CI, 0.73 to 1.12). Median progression-free survival in the lapatinib and placebo arms was 6.0 (95% CI, 5.6 to 7.0) and 5.4 months (95% CI, 4.4 to 5.7), respectively (hazard ratio, 0.82; 95% CI, 0.68 to 1.00; P = .0381). Response rate was significantly higher in the lapatinib arm: 53% (95% CI, 46.4 to 58.8) compared with 39% (95% CI, 32.9 to 45.3) in the placebo arm (P = .0031). Preplanned exploratory subgroup analyses showed OS in the lapatinib arm was prolonged in Asian and younger patients. No correlation was observed between HER2 immunohistochemistry status and survival. There were increased toxicities in the lapatinib arm, particularly diarrhea.

Conclusion

Addition of lapatinib to CapeOx did not increase OS in patients with HER2-amplified gastroesophageal adenocarcinoma. There were clear differences in the effect of lapatinib depending on region and age. Future studies could examine this correlation.

Epidermal Growth Factor Receptor, Excision-Repair Cross-Complementation Group 1 Protein, and Thymidylate Synthase Expression in Penile Cancer

OBJECTIVE

To describe the expression of tissue epidermal growth factor receptor (EGFR), excision-repair cross-complementation group 1 protein (ERCC1), and thymidylate synthase (TS) in patients with penile cancer and explore their association with stage and outcome.

METHODS

A total of 52 patients with penile squamous cell cancer who were treated at the University of Southern California from 1995 to 2010 were identified. Paraffin-embedded tissue underwent mRNA quantitation and immunohistochemistry for expression of EGFR, ERCC1, and TS. KRAS mutations were evaluated using polymerase chain reaction-based sequencing.

RESULTS

EGFR overexpression was common by mRNA (median, 5.09; range, 1.92-104.5) and immunohistochemistry. EGFR expression > 7 was associated with advanced stage and poor differentiation (P = .01 and .034 respectively) but not with survival in multivariate analysis. ERCC1 mRNA expression was a median of 0.65 (range, 0.21-1.87). TS expression was a median of 1.88 (range, 0.54-6.47). ERCC1 and TS expression were not associated with grade, stage, or survival. There were no KRAS mutations identified. A total of 17 men received chemotherapy; 8 (47%) had an objective response, including 1 with a pathologic complete response. There was a trend for lower expression of EGFR corresponding to a higher likelihood of response (response rate [RR]) to chemotherapy: 67% RR in EGFR mRNA < 7 versus 33% RR in EGFR > 7 (P = .31).

CONCLUSIONS

High expression of EGFR mRNA in squamous cell carcinoma of the penis is associated with advanced stage and poor differentiation, but not survival. In our small heterogeneous subset, molecular marker expression did not show a correlation with the likelihood of chemotherapy response. A prospective evaluation of the role of the EGFR pathway and its regulatory environment in penile cancer is warranted. Given the rarity of this cancer, collaborative prospective cohort evaluations and trials need to be encouraged.

Implications of the Updated 2013 American Society of Clinical Oncology/College of American Pathologists Guideline Recommendations on Human Epidermal Growth Factor Receptor 2 Gene Testing Using Immunohistochemistry and Fluorescence In Situ Hybridization for Breast Cancer

Context

Human epidermal growth factor receptor 2 (HER2/neu) amplification is used as a predictive marker for trastuzumab treatment in breast cancer. Both immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH) testing algorithms have been based on the 2007 American Society of Clinical Oncology/College of American Pathologists (ASCO/CAP) guidelines. In late 2013, the guidelines were updated with new scoring criteria.

Objective

—To assess the impact of the revised ASCO/CAP recommendations on both IHC and FISH results by using the dual-color HER2/neu and centromeric FISH probes.

Design

Retrospective analysis of 590 invasive carcinomas with concurrent IHC and dual-color HER2/neu and centromeric 17 (CEP17) FISH results, based on 2007 ASCO/CAP guidelines, was conducted from July 2011 to June 2013. With the revised guidelines, patients were recategorized and concordance rates between the 2 assays were recalculated.

Results

—Overall concordance rates for FISH and IHC decreased from 94.9% to 93.8% with reclassification. Negative FISH cases decreased from 79.1% to 69.3%. However, equivocal FISH cases were significantly increased from 0.7% to 9.5%, leading to more retesting. Both positive IHC and FISH cases were also noted to be increased, leading to more patients being eligible for trastuzumab treatment, especially those patients with concurrent HER2/neu and CEP17 polysomy. Approximately 1% of patients with initial FISH negative results were reclassified as having positive results when both the ratios and average copy number of HER2/neu were considered under the revised guidelines.

Conclusions

The revised 2013 ASCO/CAP guidelines can potentially lead to more patients being eligible for trastuzumab therapy but additional retesting is to be expected owing to an increased number of equivocal FISH cases.

The relationship between quantitative human epidermal growth factor receptor 2 gene expression by the 21-gene reverse transcriptase polymerase chain reaction assay and adjuvant trastuzumab benefit in Alliance N9831

Introduction

The N9831 trial demonstrated the efficacy of adjuvant trastuzumab for patients with human epidermal growth factor receptor 2 (HER2) locally positive tumors by protein or gene analysis. We used the 21-gene assay to examine the association of quantitative HER2 messenger RNA (mRNA) gene expression and benefit from trastuzumab.

Methods

N9831 tested the addition of trastuzumab to chemotherapy in stage I–III HER2-positive breast cancer. For two of the arms of the trial, doxorubicin and cyclophosphamide followed by paclitaxel (AC-T) and doxorubicin and cyclophosphamide followed by paclitaxel and trastuzumab concurrent chemotherapy-trastuzumab (AC-TH), recurrence score (RS) and HER2 mRNA expression were determined by the 21-gene assay (Oncotype DX®) (negative <10.7, equivocal 10.7 to <11.5, and positive ≥11.5 log₂ expression units). Cox regression was used to assess the association of HER2 expression with trastuzumab benefit in preventing distant recurrence.

Results

Median follow-up was 7.4 years. Of 1,940 total patients, 901 had consent and sufficient tissue. HER2 by reverse transcriptase polymerase chain reaction (RT-PCR) was negative in 130 (14 %), equivocal in 85 (9 %), and positive in 686 (76 %) patients. Concordance between HER2 assessments was 95 % for RT-PCR versus central immunohistochemistry (IHC) (>10 % positive cells = positive), 91 % for RT-PCR versus central fluorescence in situ hybridization (FISH) (≥2.0 = positive) and 94 % for central IHC versus central FISH. In the primary analysis, the association of HER2 expression by 21-gene assay with trastuzumab benefit was marginally nonsignificant (nonlinear p = 0.057). In hormone receptor-positive patients (local IHC) the association was significant (p = 0.002). The association was nonlinear with the greatest estimated benefit at lower and higher HER2 expression levels.

Conclusions

Concordance among HER2 assessments by central IHC, FISH, and RT-PCR were similar and high. Association of HER2 mRNA expression with trastuzumab benefit as measured by time to distant recurrence was nonsignificant. A consistent benefit of trastuzumab irrespective of mHER2 levels was observed in patients with either IHC-positive or FISH-positive tumors. Trend for benefit was observed also for the small groups of patients with negative results by any or all of the central assays.

Trial registration

Clinicaltrials.gov NCT00005970. Registered 5 July 2000.

Electronic supplementary material

The online version of this article (doi:10.1186/s13058-015-0643-7) contains supplementary material, which is available to authorized users.

HER2 testing and its predictive utility in anti-HER2 breast cancer therapy

Breast cancer treatment is dependent on accurate pathologic diagnosis. HER2 testing is now universally recommended as part of evaluation of invasive breast cancer. HER2 testing is available via various slide and non-slide based assays, and interpretation of results continues to evolve. Herein we review these testing modalities and their incorporation into the 2013 ASCO/CAP guidelines. Once accurate HER2 status has been established the proper treatment based on recent clinical trials can be instituted.

Review: Application of Nanoparticles in Urothelial Cancer of the Urinary Bladder

Bladder cancer is a common malignancy of the urinary tract, which generally develops in the epithelial lining of the urinary bladder. The specific course of treatment depends on the stage of bladder cancer; however, therapeutic strategies typically involve intravesical drug delivery to reduce toxicity and increase therapeutic effects. Recently, metallic, polymeric, lipid, and protein nanoparticles have been introduced to aid in the treatment of bladder cancer. Nanoparticles are also commonly used as pharmaceutical carriers to improve interactions between drugs and the urothelium. In this review, we classify the characteristics of bladder cancer and discuss the types of nanoparticles used in various treatment modalities. Finally we summarize the potential applications and benefits of various nanoparticles in intravesical therapy.

Targeting Insulin-Like Growth Factor Binding Protein-3 Signaling in Triple-Negative Breast Cancer

Insulin-like growth factor binding protein-3 (IGFBP-3) is a key regulatory molecule of the IGF axis and can function in a tissue-specific way as both a tumor suppressor and promoter. Triple-negative breast cancer (TNBC) has high tumor expression of IGFBP-3 associated with markers of poor prognosis and, although accounting for 15-20% of all breast cancers, is responsible for disproportionate rates of morbidity and mortality. Because they lack estrogen and progesterone receptors and overexpression of HER2, TNBC are resistant to treatments that target these molecules, making the development of new therapies an important goal. In addition to frequent high expression of IGFBP-3, these tumors also express EGFR highly, but targeting EGFR signaling alone in TNBC has been of little success. Identification of a functional growth-stimulatory interaction between EGFR and IGFBP-3 signaling prompted investigation into cotargeting these pathways as a novel therapy for TNBC. This involves inhibition of both EGFR kinase activity and a mediator of IGFBP-3's stimulatory bioactivity, sphingosine kinase-1 (SphK1), and has shown promise in a preclinical setting. Functional interaction between EGFR and IGFBP-3 may also promote chemoresistance in TNBC, and delineating the mechanisms involved may identify additional targets for development of therapies in cancers that express both IGFBP-3 and EGFR.

Lapatinib: an oral dual tyrosine kinase inhibitor for HER-2-positive breast cancer

Breast cancer is the most common form of cancer and the second leading cause of cancer deaths among women in the USA. A quarter of all newly diagnosed cases are characterized by overexpression of HER-2 which is associated with poor prognosis. In March 2007, lapatinib, an oral dual-tyrosine kinase inhibitor was approved in combination with capecitabine for metastatic HER-2-positive breast cancer that has progressed on prior trastuzumab therapy, and in combination with letrozole for postmenopausal women with HER-2 and hormone receptor-positive advanced breast cancer. In the future, lapatinib may play an important role in dual HER-2 blockade with trastuzumab and other targeted agents for women with HER-2-overexpressing breast cancer.

Quantification of HER family receptors in breast cancer

The clinical success of trastuzumab in breast cancer taught us that appropriate tumor evaluation is mandatory for the correct identification of patients eligible for targeted therapies. Although HER2 protein expression by immunohistochemistry (IHC) and gene amplification by fluorescence in situ hybridization (FISH) assays are routinely used to select patients to receive trastuzumab, both assays only partially predict response to the drug. In the case of epidermal growth factor receptor (EGFR), the link between the presence of the receptor or its amplification and response to anti-EGFR therapies could not be demonstrated. Even less is known for HER3 and HER4, mainly due to lack of robust and validated assays detecting these proteins. It is becoming evident that, besides FISH and IHC, we need better assays to quantify HER receptors and categorize the patients for individualized treatments. Here, we present the current available methodologies to measure HER family receptors and discuss the clinical implications of target quantification.

Gene protein detection platform--a comparison of a new human epidermal growth factor receptor 2 assay with conventional immunohistochemistry and fluorescence in situ hybridization platforms

Human epidermal growth factor receptor 2 (HER2) immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH) are widely used semiquantitative assays for selecting breast cancer patients for HER2 antibody therapy. However, both techniques have been shown to have disadvantages. Our aim was to test a recent automated technique of combined IHC and brightfield dual in situ hybridization-gene protein detection platform (GPDP)-in breast cancer HER2 protein, gene, and chromosome 17 centromere status evaluations, comparing the results in accordance to the American Society of Clinical Oncology/College of American Pathologists recommendations for HER2 testing in breast cancer from both 2007 and 2013. The GPDP technique performance was evaluated on 52 consecutive whole slide invasive breast cancer cases with HER2 IHC 2/3+ scoring results. Applying in turns the American Society of Clinical Oncology/College of American Pathologists recommendations for HER2 testing in breast cancer from 2007 and 2013 to both FISH and GPDP DISH assays, the HER2 gene amplification results showed 100% concordance among amplified/nonamplified cases, but there was a shift in 4 cases toward positive from equivocal results and toward equivocal from negative results. This might be related to the emphasis on the average HER2 copy number in the 2013 criteria. HER2 expression by IVD market IHC kit (Pathway®) has a strong correlation with GPDP HER2 protein, including a full concordance for all cases scored as 3+ and a reduction from 2+ to 1+ in 7 cases corresponding to nonamplified cases. Gene protein detection platform HER2 protein "solo" could have spared the need for 7 FISH studies. In addition, the platform offered advantages on interpretation reassurance including selecting areas for counting gene signals paralleled with protein IHC expression, on heterogeneity detection, interpretation time, technical time, and tissue expense.

HER2 assessment by silver in situ hybridization: where are we now?

HER2 testing in breast and gastric cancer is critical not only as a prognostic tool but also as a predictive marker for response to the humanized monoclonal antibody trastuzumab. Currently, HER2 status is assessed on histological and cytological specimens by conventional validated methods such as immunohistochemistry and FISH, while bright-field in situ hybridization techniques, such as silver in situ hybridization and chromogenic in situ hybridization, may offer performance benefits over FISH. The major points are first, technical issues, advantages and disadvantages relevant to each methods, and their clinical implications and second, the well-known genetic heterogeneity of HER2, and the occurrence of polysomy of chromosome 17. This review aims to summarize the growing body of literature on the accuracy of bright-field in situ techniques, notably silver in situ hybridization, in assessing HER2 status, and to discuss the role of such methods in pathology practice.

Comparison of the 2007 and 2013 ASCO/CAP evaluation systems for HER2 amplification in breast cancer

It has been proven that chromosome 17 centromere (CEP17) amplification causes misleading human epidermal growth factor receptor 2 (HER2) gene fluorescence in situ hybridization (FISH) results, precluding anti-HER2-based therapy in some patients with breast carcinoma. We used the 2013 American Society of Clinical Oncology/College of American Pathologists (ASCO/CAP) scoring criteria to evaluate HER2 amplification status in 175 cases of breast carcinoma with chromosome 17 polysomy. We used immunohistochemistry (IHC) to determine the HER2 amplification status, and 2-color FISH to detect CEP17, and reviewed the results of initial evaluation using the 2007 ASCO/CAP criteria. Of the 175 cases, 17, 95, and 63 were IHC 0/1+, 2+, and 3+, respectively. Evaluation of IHC HER2 status according to the 2013 ASCO/CAP criteria identified significantly more HER2-positive cases compared to cases evaluated using the 2007 criteria (p<0.05). When the FISH results were evaluated in parallel with the 2013 criteria, we found that 22 cases were not HER2-negative despite the presence of polysomy 17, which, according to the 2013 criteria, indicates HER2-positive status. Our findings indicate that in breast carcinoma, HER2 status in the presence of polysomy 17 may vary with the scoring criteria used. In turn, performing FISH and evaluating samples using the 2013 ASCO/CAP criteria means that more patients with breast cancer may be appropriate for targeted treatment with trastuzumab, potentially improving their outcome.

A pan-cancer proteomic perspective on The Cancer Genome Atlas

Protein levels and function are poorly predicted by genomic and transcriptomic analysis of patient tumours. Therefore, direct study of the functional proteome has the potential to provide a wealth of information that complements and extends genomic, epigenomic and transcriptomic analysis in The Cancer Genome Atlas (TCGA) projects. Here we use reverse-phase protein arrays to analyse 3,467 patient samples from 11 TCGA 'Pan-Cancer' diseases, using 181 high-quality antibodies that target 128 total proteins and 53 post-translationally modified proteins. The resultant proteomic data are integrated with genomic and transcriptomic analyses of the same samples to identify commonalities, differences, emergent pathways and network biology within and across tumour lineages. In addition, tissue-specific signals are reduced computationally to enhance biomarker and target discovery spanning multiple tumour lineages. This integrative analysis, with an emphasis on pathways and potentially actionable proteins, provides a framework for determining the prognostic, predictive and therapeutic relevance of the functional proteome.

Neuromedin U: a candidate biomarker and therapeutic target to predict and overcome resistance to HER-tyrosine kinase inhibitors

Intrinsic and acquired resistance to HER-targeting drugs occurs in a significant proportion of HER2-overexpressing breast cancers. Thus, there remains a need to identify predictive biomarkers that could improve patient selection and circumvent these types of drug resistance. Here, we report the identification of neuromedin U (NmU) as an extracellular biomarker in cells resistant to HER-targeted drugs. NmU overexpression occurred in cells with acquired or innate resistance to lapatinib, trastuzumab, neratinib, and afatinib, all of which displayed a similar trend upon short-term exposure, suggesting NmU induction may be an early response. An analysis of 3,489 cases of breast cancer showed NmU to be associated with poor patient outcome, particularly those with HER2-overexpressing tumors independent of established prognostic indicators. Ectopic overexpression of NmU in drug-sensitive cells conferred resistance to all HER-targeting drugs, whereas RNAi-mediated attenuation sensitized cells exhibiting acquired or innate drug resistance. Mechanistic investigations suggested that NmU acted through HSP27 as partner protein to stabilize HER2 protein levels. We also obtained evidence of functional NmU receptors on HER2-overexpressing cells, with the addition of exogenous NmU eliciting an elevation in HER2 and EGFR expression along with drug resistance. Finally, we found that NmU seemed to function in cell motility, invasion, and anoikis resistance. In vivo studies revealed that NmU attenuation impaired tumor growth and metastasis. Taken together, our results defined NmU as a candidate drug response biomarker for HER2-overexpressing cancers and as a candidate therapeutic target to limit metastatic progression and improve the efficacy of HER-targeted drugs.