Immunohistochemical expression of HER1, HER3, and HER4 in HER2-positive breast cancer patients treated with trastuzumab-containing neoadjuvant chemotherapy

Identification of genetic and immune signatures for the recurrence of HER2-positive breast cancer after trastuzumab-based treatment

PURPOSE

To determine the genetic and immune features associated with the recurrence of human epidermal growth factor receptor2-positive (HER2 +) breast cancer (BC) after trastuzumab-based treatment.

METHODS

A retrospective cohort study of 48 patients who received trastuzumab-based treatment was divided into recurrent and non-recurrent groups according to clinical follow-up. Baseline samples from all 48 patients were analyzed for genetic variation, HLA allele type, gene expression, and immune features, which were linked to HER2 + BC recurrence. Statistics included logistic regression models, Kaplan-Meier plots, and Univariate Cox proportional hazards models.

RESULTS

Compared with the non-recurrent group, the extracellular matrix-related pathway and 3 Hallmark gene sets were enriched in the recurrent group. The infiltration levels of immature B cells and activated B cells were significantly increased in the non-recurrent group, which correlated remarkably with improved overall survival (OS) in two other published gene expression datasets, including TCGA and METABRIC. In the TCGA cohort (n = 275), activated B cells (HR 0.23, 95%CI 0.13-0.43, p < 0.0001), and immature B cells (HR 0.26, 95%CI 0.12-0.59, p < 0.0001). In the METABRIC cohort (n = 236), activated B cells (HR 0.60, 95%CI 0.43-0.83, p = 0.002), and immature B cells (HR 0.65, 95%CI 0.47-0.91, p = 0.011). Cox regression suggested that immature B cells and activated B cells were protective factors for outcome OS.

CONCLUSIONS

Aberrant activation of multiple pathways and low baseline tumor-infiltrating B cells are related to HER2 + BC trastuzumab-based recurrence, which primarily affects the antitumor activity of trastuzumab.

Comparison of Antibodies for Immunohistochemistry-based Detection of HER3 in Breast Cancer

BACKGROUND

Growth factor receptor HER3 (ErbB3) lacks standardized immunohistochemistry (IHC)-based methods for formalin-fixed paraffin-embedded (FFPE) tissue samples. We compared 4 different anti-HER3 antibodies to explain the differences found in the staining results reported in the literature.

MATERIALS AND METHODS

Four commercial HER3 antibodies were tested on FFPE samples including mouse monoclonal antibody clones, DAK-H3-IC and RTJ1, rabbit monoclonal antibody clone SP71, and rabbit polyclonal antibody (SAB4500793). Membranous and cytoplasmic staining patterns were analyzed and scored as 0, 1+, or 2+ according to the intensity of the staining and completeness of membranous and cytoplasmic staining. A large collection of HER2-amplified breast cancers (n=177) was stained with the best performing HER3 antibody. The breast cancer cell line, MDA-453, and human prostate tissue were used as positive controls. IHC results were confirmed by analysis of flow cytometry performed on breast cancer cell lines. Staining results of FFPE samples were compared with samples fixed with an epitope-sensitive fixative (PAXgene).

RESULTS

Clear circumferential cell membrane staining was found only with the HER3 antibody clone DAK-H3-IC. Other antibodies (RTJ1, SP71, and polyclonal) yielded uncertain and nonreproducible staining results. In addition to cell membrane staining, DAK-H3-IC was also localized to the cytoplasm, but no nuclear staining was observed. In HER2-amplified breast cancers, 80% of samples were classified as 1+ or 2+ according to the HER3 staining on the cell membrane. The results from FFPE cell line samples were comparable to those obtained from unfixed cells in flow cytometry. IHC conducted on FFPE samples and on PAXgene-fixed samples showed equivalent results.

CONCLUSIONS

We conclude that IHC with the monoclonal antibody, DAK-H3-IC, on FFPE samples is a reliable staining method for use in translational research. Assessment of membranous HER3 expression may be clinically relevant in selecting patients who may most benefit from pertuzumab or other novel anti-HER3 therapies.

Evaluation of the prognostic value of all four HER family receptors in patients with metastatic breast cancer treated with trastuzumab: A Hellenic Cooperative Oncology Group (HeCOG) study

In the current study, we performed a complete analysis, with four different methods, of all four HER family receptors, in a series of patients with metastatic breast cancer treated with trastuzumab-based regimens and evaluated their prognostic value. Formalin-fixed paraffin-embedded tumor tissue samples were collected from 227 patients, considered to be HER2-positive when assessed at the local laboratories. We evaluated gene amplification, copy number variations (CNVs), mRNA and protein expression of all four HER family members. In addition, our analysis included the evaluation of several other factors by immunohistochemistry (IHC), such as pHER2^Tyr1221/1222, pHER2^Tyr877 and PTEN. Central review of HER2 status by IHC and fluorescence in situ hybridization revealed that of the 227 patients, only 139 (61.2%) were truly HER2-positive. Regarding the 191 patients treated with trastuzumab as first-line therapy, median time to progression (TTP) was 15.3 and 10.4 months for HER2-positive and HER2-negative participants, respectively, whereas median survival was 50.4 and 38.1 months, respectively. In HER2-positive patients, high HER3 mRNA expression was of favorable prognostic significance for TTP and survival (HR = 0.43, 95% CI 0.21–0.88, Wald’s p = 0.022 and HR = 0.43, 95% CI 0.21–0.88, p = 0.021, respectively), while EGFR copy gain and EGFR protein expression were associated with higher risk for disease progression in HER2-negative patients (HR = 3.53, 95% CI 1.19–10.50, p = 0.023 and HR = 3.37, 95% CI 1.12–10.17, p = 0.031, respectively). Positive HER3 protein expression was a favorable factor for TTP in HER2-negative patients (HR = 0.43, 95% CI 0.22–0.84, p = 0.014). In the multivariate analysis, only EGFR copy gain retained its prognostic significance for TTP in the HER2-negative population (HR = 3.96, 95% CI 1.29–12.16, p = 0.016), while high HER3 mRNA expression retained its favorable prognostic significance for TTP in the HER2-positive subgroup (HR = 0.47, 95% CI 0.23–0.99, p = 0.048). The present study suggests that EGFR copy gain represents a negative prognostic factor for TTP in HER2-negative patients with metastatic breast cancer treated with trastuzumab. In addition, high HER3 mRNA expression appears to be of favorable prognostic significance for TTP in HER2-positive patients. Given the small number of patients included in the current analysis and the retrospective nature of the study, our findings should be validated in larger cohorts.

Clinicopathological and prognostic correlations of HER3 expression and its degradation regulators, NEDD4-1 and NRDP1, in primary breast cancer

Background

Human epidermal growth factor receptor HER3 (ErbB3), especially in association with its relative HER2 (ErbB2), is known as a key oncogene in breast tumour biology. Nonetheless, the prognostic relevance of HER3 remains controversial. NEDD4–1 and NRDP1 are signalling molecules closely related to the degradation of HER3 via ubiquitination. NEDD4–1 and NRDP1 have been reported to contribute to HER3-mediated signalling by regulating its localization and cell membrane retention. We studied correlations between HER3, NEDD4–1, and NRDP1 protein expression and their association with tumour histopathological characteristics and clinical outcomes.

Methods

The prevalence of immunohistochemically detectable expression profiles of HER3 (n = 177), NEDD4–1 (n = 145), and NRDP1 (n = 145) proteins was studied in primary breast carcinomas on archival formalin-fixed paraffin-embedded (FFPE) samples. Clinicopathological correlations were determined statistically using Pearson’s Chi-Square test. The Kaplan-Meier method, log-rank test (Mantel-Cox), and Cox regression analysis were utilized for survival analysis.

Results

HER3 protein was expressed in breast carcinomas without association with HER2 gene amplification status. Absence or low HER3 expression correlated with clinically aggressive features, such as triple-negative breast cancer (TNBC) phenotype, basal cell origin (cytokeratin 5/14 expression combined with ER negativity), large tumour size, and positive lymph node status. Low total HER3 expression was prognostic for shorter recurrence-free survival time in HER2-amplified breast cancer (p = 0.004, p = 0.020 in univariate and multivariate analyses, respectively). The majority (82.8%) of breast cancers demonstrated NEDD4–1 protein expression - while only a minor proportion (8.3%) of carcinomas expressed NRDP1. NEDD4–1 and NRDP1 expression were not associated with clinical outcomes in HER2-amplified breast cancer, irrespective of adjuvant trastuzumab therapy.

Conclusions

Low HER3 expression is suggested to be a valuable prognostic biomarker to predict recurrence in HER2-amplified breast cancer. Neither NEDD4–1 nor NRDP1 demonstrated relevance in prognostics or in the subclassification of HER2-amplified breast carcinomas.

Electronic supplementary material

The online version of this article (10.1186/s12885-018-4917-1) contains supplementary material, which is available to authorized users.

Mechanisms Underlying the Action and Synergism of Trastuzumab and Pertuzumab in Targeting HER2-Positive Breast Cancer

Human epidermal growth factor receptor (HER) 2 (HER2) is overexpressed in 20⁻30% of breast cancers. HER2 is a preferred target for treating HER2-positive breast cancer. Trastuzumab and pertuzumab are two HER2-targeted monoclonal antibodies approved by the Food and Drug Administration (FDA) to use as adjuvant therapy in combination with docetaxel to treat metastatic HER2-positive breast cancer. Adding the monoclonal antibodies to treatment regimen has changed the paradigm for treatment of HER2-positive breast cancer. Despite improving outcomes, the percentage of the patients who benefit from the treatment is still low. Continued research and development of novel agents and strategies of drug combinations is needed. A thorough understanding of the molecular mechanisms underlying the action and synergism of trastuzumab and pertuzumab is essential for moving forward to achieve high efficacy in treating HER2-positive breast cancer. This review examined and analyzed findings and hypotheses regarding the action and synergism of trastuzumab and pertuzumab and proposed a model of synergism based on available information.

De-escalation of treatment in HER2-positive breast cancer: Determinants of response and mechanisms of resistance

Overexpression and/or gene amplification of HER2, a crucial member of the HER family of four receptors, occur in about 15-20% of breast cancers and define an aggressive subtype of the disease. Activated HER homo and heterodimers govern a complex and redundant downstream signaling network that regulates cell survival and metastasis. Despite treatment with effective HER2-targeted therapies, many HER2-positive tumors fail to respond, or initially respond but eventually develop resistance. One of the upfront reasons for this treatment failure is failure to accurately select the tumors that are truly dependent on HER2 for survival and so would benefit the most from HER2-targeted therapy. In these truly HER2-addicted tumors (i.e. physiologically dependent), resistance could be the result of an incomplete inhibition of signaling at the HER receptor layer. In this regard, preclinical and clinical studies have documented the superiority of combination anti-HER2 therapy over single agent therapy to achieve a more comprehensive inhibition of the various HER receptor dimers. HER2 can be further activated or reactivated by mutations or other alterations in HER2 itself, or in other HER family members. Even when a complete and sustained HER inhibition is achieved, resistance to anti-HER therapy can arise by other somewhat dominant mechanisms, including preexisting or emerging alternative signaling pathways such as the estrogen receptor, deregulated downstream signaling components, especially of the PI3K pathway, and the tumor immune microenvironment. Most of the clinical trials that have investigated the efficacy of anti-HER2 therapies took place in the background of aggressive chemotherapy regimens, thus confounding the identification of key factors of resistance to the anti-HER2 treatments. Recent studies, however, have suggested that some HER2-amplified tumors may benefit from anti-HER2 therapy combined with only a single chemotherapy agent or in the absence of any chemotherapy. This de-escalation approach, a promising therapeutic strategy, is currently being explored in the clinic. In this review, we summarize the major molecular determinants that play a crucial role in influencing tumor response and resistance to HER2-targeted therapy, and discuss the growing need for patient stratification in order to facilitate the development of de-escalation strategies using HER2-targeted therapy alone with no chemotherapy.

Proteins Involved in HER2 Signalling Pathway, Their Relations and Influence on Metastasis-Free Survival in HER2-Positive Breast Cancer Patients Treated with Trastuzumab in Adjuvant Setting

Aim: Resistance to trastuzumab (which is a standard therapy for breast cancer patients with HER2 overexpression) is associated with higher risk of progression or cancer death, and might be related to activation of signalling cascades (PI3K/AKT/mTOR, Ras/Raf/MAPK) and decreased level of their inhibitors.

Material and methods: Formalin-fixed paraffin-embedded tumour specimens from 118 HER2-overexpressing breast cancer patients treated with radical local therapy and trastuzumab in adjuvant setting were used for the assessment of: (1) PIK3CA gene mutations (p.H1047R and p.E545K) by qPCR, and (2) expression of Ki-67, EGFR, MUC4, HER3 and PTEN by immunohistochemistry.

Results: Lower Ki-67LI was observed in EGFR-immunonegative and in PTEN-immunopositive tumours. MUC4-immunonegative tumours more frequently were PTEN- and HER3-immunonegative. Favourable metastasis-free survival was observed in patients with tumours characterized by Ki-67LI≤50% (p=0.027), HER3 immunonegativity or PTEN immunopositivity (vs. tumours with HER3 expression and lack of PTEN expression, p=0.043), additionally, the trend was observed for patients with pN0+pN1 pathological tumour stage (vs. pN2+pN3) (p=0.086). Cox model revealed that independent negative prognostic factors were: (i) Ki-67LI>50% (p=0.014, RR=4.6, 95% CI 1.4-15.4), (ii) HER3 immunopositivity together with PTEN immunonegativity (p=0.034, RR=3.7, 95% CI 1.1-12.5).

Conclusion: The results of our study suggest that combined analysis of HER3 and PTEN expression might bring information on trastuzumab sensitivity in the group of HER2-positive breast cancer patients treated with trastuzumab in adjuvant setting.

Predicting and Overcoming Chemotherapeutic Resistance in Breast Cancer

Our understanding of breast cancer and its therapeutic approach has improved greatly due to the advancement of molecular biology in recent years. Clinically, breast cancers are characterized into three basic types based on their immunohistochemical properties. They are triple-negative breast cancer, estrogen receptor (ER) and progesterone receptor (PR)-positive-HR positive breast cancer, and human epidermal growth factor receptor 2 (HER2)-positive breast cancer. Even though these subtypes have been characterized, assessment of a breast cancer's receptor status is still widely used to determine whether or not a targeted therapy could be applied. Moreover, drug resistance is common in all breast cancer types despite the different treatment modalities applied. The development of resistance to different therapeutics is not mutually exclusive. It seems that tumor could be resistant to multiple treatment strategies, such as being both chemoresistant and monoclonal antibody resistant. However, the underlying mechanisms are complicated and need further investigation. In this chapter, we aim to provide a brief review of the different types of breast cancer and their respective treatment strategies. We also review the possible mechanisms of potential drug resistance associated with each treatment type. We believe that a better understanding of the drug resistance mechanisms can lead to a more effective and efficient therapeutic success.

The Therapeutic Challenge of Targeting HER2 in Endometrial Cancer

Endometrial cancer is the most common gynecologic cancer in the United States, diagnosed in more than 50,000 women annually. While the majority of women present with low-grade tumors that are cured with surgery and adjuvant radiotherapy, a significant subset of women experience recurrence and do not survive their disease. A disproportionate number of the more than 8,000 annual deaths attributed to endometrial cancer are due to high-grade uterine cancers, highlighting the need for new therapies that target molecular alterations specific to this subset of tumors. Numerous correlative scientific investigations have demonstrated that the HER2 (ERBB2) gene is amplified in 17%-33% of carcinosarcoma, uterine serous carcinoma, and a subset of high-grade endometrioid endometrial tumors. In breast cancer, this potent signature has directed women to anti-HER2-targeted therapies such as trastuzumab and lapatinib. In contrast to breast cancer, therapy with trastuzumab alone revealed no responses in women with recurrent HER2 overexpressing endometrial cancer, suggesting that these tumors may possess acquired or innate trastuzumab resistance mechanisms. This review explores the literature surrounding HER2 expression in endometrial cancer, focusing on trastuzumab and other anti-HER2 therapy and resistance mechanisms characterized in breast cancer but germane to endometrial tumors. Understanding resistance pathways will suggest combination therapies that target both HER2 and key oncogenic escape pathways in endometrial cancer.

IMPLICATIONS FOR PRACTICE

This review summarizes the role of HER2 in endometrial cancer, with a focus on uterine serous carcinoma. The limitations to date of anti-HER2 therapy in this disease site are examined, and mechanisms of drug resistance are outlined based on the experience in breast cancer. Potential opportunities to overcome inherent resistance to anti-HER2 therapy in endometrial cancer are detailed, offering opportunities for further clinical study with the goal to improve outcomes in this challenging disease.

HER4 expression status correlates with improved outcome in both neoadjuvant and adjuvant Trastuzumab treated invasive breast carcinoma

Prognostic and predictive markers utilized in invasive breast carcinoma are limited and include ER, PR, Ki67, and ERBB2 (HER2). In the case of HER2, over-expression or amplification serves as eligibility for anti-HER2 based therapy, including trastuzumab (Herceptin®, Genentech). While clinical trials have shown trastuzumab improves overall survival and time to progression, an individual's response to anti-HER2 based therapy is highly variable. This suggests that, in a “uniform” HER2 positive population, additional markers could help in predicting patient outcome to therapy. Here we utilized a recently validated high-specificity HER4 antibody (E200) and generated a standard clinical HER4 scoring algorithm (HER4 H-Score) utilizing two breast carcinoma cohorts: 1) patients receiving neoadjuvant trastuzumab (n=47) and 2) patients receiving trastuzumab for metastatic disease (n=33). Our HER4 H-Score showed significant correlation with high sensitivity RT-qPCR performed on matched patients (p=<0.0001). In addition, patients with HER2/HER4 co-over-expression status showed a significant delay in development of metastasis after neo-adjuvant trastuzumab therapy (p= 0.04) and showed a significant improvement in progression free survival after adjuvant trastuzumab therapy (p=0.03). These findings suggest HER4 IHC, used in conjunction with a standard HER2 testing algorithm, could aid in predicting clinical outcome and help identify patients likely to show improved response to trastuzumab therapy.

TNK2 gene amplification is a novel predictor of a poor prognosis in patients with gastric cancer

BACKGROUNDS AND OBJECTIVES

We previously examined the amplification status of 10 kinase genes (PIK3CA, EPHB3, TNK2, PTK7, EGFR, MET, ERBB2, HCK, SRC, and AURKA) in gastric cancer (GC). This study aimed to determine the prognostic significance of these gene amplifications in GC.

METHODS

A survival analysis was performed for GC patients. Since TNK2 amplification was identified as a prognostic marker in the analysis, we also examined the functional effect of TNK2 overexpression on gastric cells.

RESULTS

A Kaplan-Meier analysis showed that the prognosis of patients with GC exhibiting TNK2 or AURKA amplification was significantly poorer than the prognosis of patients with GC without TNK2 or AURKA amplification. A further multivariate analysis revealed that TNK2 amplification was an independent predictor of a poor survival outcome among patients with GC (hazard ratio, 3.668; 95% confidence interval, 1.513-7.968; P = 0.0056). TNK2-overexpressing GC cells showed an increase in cell migration and non-anchored cell growth. Finally, microarray and pathway analyses revealed the aberrant regulation of some cancer-related pathways in TNK2-overexpressing GC cells.

CONCLUSIONS

These results suggested that TNK2 amplification is an independent predictor of a poor prognosis in patients with GC and leads to an increase in the malignant potential of GC cells.

Immunohistochemical analysis of the monoclonal antibody 4B5 in breast tissue expressing human epidermal growth factor receptor 4 (HER4)

AIMS

A recent study examining the specificity of human epidermal growth factor receptor (HER) 2 pharmacodiagnostic antibodies demonstrated that CB11 and 4B5 stain both HER2-transfected and HER4-transfected cell lines. However, there has been no evidence showing that 4B5 has affinity for HER4 in clinically obtained tissues, and, if so, whether this has any impact on the assessment of HER2. We therefore sought to determine the expression of membrane-bound HER4 in clinical breast carcinomas, and evaluate its impact on the clinical utility of 4B5 in determining HER2 status.

METHODS AND RESULTS

Breast carcinomas were assessed by immunohistochemistry (IHC) for membrane-bound HER4 using anti-HER4 clone E200. HER2 expression in these cases was then assessed using anti-HER2 clone 4B5, and a reference clone, SP3. In all 117 membrane HER4-positive cases (out of 241), 4B5 scored equal to or less than the reference anti-HER2 clone SP3. Eighteen cases were positive for membrane-bound HER4 by E200 and negative by 4B5, including a membrane HER4 level 3+ case.

CONCLUSIONS

No cross-reactivity of 4B5 with membrane-bound HER4 was identified in the clinical IHC analysis of formalin-fixed paraffin-embedded breast carcinoma cases as evidenced by the HER4 antibody clone E200.

Quantum dot-based quantitative immunofluorescence detection and spectrum analysis of epidermal growth factor receptor in breast cancer tissue arrays

BACKGROUND

The epidermal growth factor receptor (EGFR) is a promising therapeutic target in cancer, but its clinical value in breast cancer remains controversial. Our previous studies have found that quantitative analysis of biomarkers with quantum dot-based nanotechnology had better detection performance than conventional immunohistochemistry. The present study was undertaken to investigate the prognostic value of EGFR in breast cancer using quantum dot-based quantitative spectral analysis.

METHODS

EGFR expression in 65 breast cancer specimens was detected by immunohistochemistry and quantum dot-immunohistochemistry, and comparisons were made between the two methods. EGFR expression in tissue microarrays of 240 breast cancer patients was then detected by quantum dot-immunohistochemistry and spectral analysis. The prognostic value of EGFR immunofluorescence area (EGFR area) for five-year recurrence-free survival was investigated.

RESULTS

The same antigen localization, high correlation of staining rates (r = 0.914), and high agreement of measurement (κ = 0.848) of EGFR expression in breast cancer were found by quantum dot-immunohistochemistry and immunohistochemistry. The EGFR area showed significant differences by tumor grade, lymph node status, HER2 status, and hormone receptor status (all P < 0.05). Patients in the large EGFR area (≥ 30.51) group had a significantly higher five-year recurrence rate (47.2% versus 27.4%, P = 0.002) and worse five-year recurrence-free survival (log-rank test, P = 0.0015) than those in the small EGFR area (<30.51) group. In the subgroups, EGFR area was an independent prognosticator in the HER2-positive and lymph node-positive subgroups.

CONCLUSION

Quantum dot-based quantitative detection demonstrates the prognostic value of EGFR area in the HER2-positive and lymph node-positive subgroups of invasive breast cancer.

Primary trastuzumab resistance: new tricks for an old drug

Trastuzumab is the first Food and Drug Administration (FDA)-approved therapeutic targeting a HER-family receptor tyrosine kinase (HER2/ErbB2/neu). Although trastuzumab is effective in the treatment of HER2-positive breast cancer, a substantial proportion of patients will not respond to trastuzumab-based regimens (primary resistance), and those who do respond will often lose clinical benefits (i.e., secondary resistance). Although multiple mechanisms underlying the development of secondary trastuzumab resistance have been identified, few studies have specifically examined the basis of primary trastuzumab resistance. Here, we review these studies, which together demonstrate that trastuzumab induces phenotypic changes in tumor cells, even when they are not growth inhibited by trastuzumab, including changes in gene expression. These changes have important clinical implications, including the sensitization of malignant cells to other therapeutic drugs. In light of these observations, we propose that the conventional definition of resistance as it pertains to trastuzumab and, perhaps, to other targeted therapeutics, may require revision. The results of these studies will be useful in informing the direction of future basic and clinical research focused on overcoming primary trastuzumab resistance.