Anti-HER2 neoadjuvant and adjuvant therapies in HER2 positive breast cancer

HER2-targeted PET/CT imaging provides potential biomarkers for differentiating HER2-zero, -low, and -positive breast cancer

PURPOSE

Human epidermal growth factor receptor 2 (HER2)-targeted antibody-drug conjugates (ADCs) in breast cancer is progressing rapidly, asking for precise categorization of HER2 expression. Our aim was to explore the HER2-affibody uptake characteristics in breast cancer and to find potential biomarkers for differentiating HER2 status, in comparison with 18F-FDG PET/CT.

METHODS

In this prospective study conducted from May 2024 to Jan 2025, participants with newly diagnosed breast cancer underwent both 68Ga-HER2-affibody and 18F-FDG PET/CT examinations. The relationship between PET parameters (such as maximum standardized uptake value (SUVmax), mean standardized uptake value (SUVmean), tumor-to-background SUV ratio (TBR)) and HER2 expression statuses (HER2-zero, -low and -positive) was analyzed.

RESULTS

A total of 57 female participants (58 primary lesions) with newly diagnosed breast cancer were included. In the paired comparison of 68Ga-HER2-affibody and 18F-FDG PET/CT, HER2-TBR was higher than FDG-TBR in the HER2-low and HER2-positive group, respectively (P < 0.001). HER2-SUVmax and HER2-SUVmean exhibited differences across most comparisons, especially HER2-zero vs. -low (P < 0.05). HER2-SUVmean emerged as an independent predictor (P = 0.01; OR: 2.8) for differentiating HER2-low/positive and -zero, yielding an AUC of 0.91. Under detailed HER2 immunohistochemistry, HER2-SUVmax, -SUVmean and -TBR demonstrated intergroup differences (P < 0.05).

CONCLUSION

HER2-targeted PET/CT imaging demonstrated distinct advantages over 18F-FDG PET/CT imaging in characterizing the HER2 status of primary lesions. Parameters based on HER2-affibody differed significantly among different HER2 statuses, and might be potential imaging indicators for screening patients with HER2-low/positive who could benefit from HER2-targeted ADCs.

CLINICALTRIALS

GOV IDENTIFIER

NCT06289517 (2024-03-04).

Not All HER2-Positive Breast Cancers Are the Same: Intratumoral Heterogeneity, Low-Level HER2 Amplification, and Their Impact on Neoadjuvant Therapy Response

Human epidermal growth factor receptor 2 (HER2)-positive breast cancers are frequently treated with neoadjuvant anti-HER2 and chemotherapy (NACT). However, treatment response varies, with a subset of tumors showing high residual cancer burden (RCB). This study investigates the relationship between HER2 immunohistochemical (IHC) intratumoral heterogeneity (ITH), low-level HER2 amplification, and tumor response to NACT. A total of 205 post-NACT HER2-positive breast carcinomas with available RCB results were classified into the following 5 HER2 groups: (1) IHC 3+ (HER2 IHC positive, no fluorescence in situ hybridization performed), (2) Group 1-High (fluorescence in situ hybridization HER2 copies > 8 or HER2/CEP17 ratio > 4), (3) Group 1-Intermediate (HER2 copies > 6-8 or HER2/CEP17 ratio > 3-4), (4) Group 1-Low (HER2 copies 4-6 and HER2/CEP17 ratio 2-3), and (5) Group 3 (HER2 copies ≥ 6 and HER2/CEP17 ratio < 2). Low-level HER2 amplification, collectively designated as HER2 copies 4 to 8 or HER2/CEP17 ratio < 4, was associated with reduced response to HER2-targeted therapy and higher RCB post-NACT. HER2 IHC ITH, defined as the presence of at least 3 distinct staining intensities, with at least 10% of tumor cells exhibiting weak or no staining, was significantly more prevalent in low-level HER2 amplification groups (Group 1-Intermediate: 93.3%, Group 1-Low: 87.5%, and Group 3: 80.0%) compared with high-level amplification groups (IHC 3+: 24.7% and Group 1-High: 28.6%) (P < .001). Both low-level HER2 amplification and HER2 IHC ITH, regardless of hormone receptor status, were independently associated with poor treatment response, and tumors demonstrating both features had the highest likelihood of low therapeutic efficiency. These findings suggest that both low-level HER2 amplification and HER2 IHC ITH contribute to poor NACT response and may warrant alternative therapeutic strategies. Further prospective studies are needed to refine the clinical significance of low-level HER2 amplification and IHC ITH, particularly in the context of novel HER2-targeted therapies such as antibody-drug conjugates.

Trastuzumab-induced optic neuritis: "blindness" side effect

INTRODUCTION

Trastuzumab improved the prognosis of patients with human epidermal growth factor receptor 2 (HER2)+ breast cancer (BC). Here, we present a patient who developed acute vision loss due to optic atrophy in both eyes after trastuzumab.

CASE REPORT

A 60-year-old female patient was diagnosed with locally advanced HER2+ BC in January 2021. After four cycles of neoadjuvant anthracycline-based chemotherapy followed by four cycles of docetaxel, trastuzumab, and pertuzumab combined treatment, the patient underwent a right modified radical mastectomy. Three days after the end of the second cycle of adjuvant trastuzumab, she presented with acute vision loss. The patient's visual acuity was 90% in the right eye and 60% in the left eye. The left eye had optic nerve edema and spindle hemorrhages. First, on suspicion of optic neuritis, the patient was given a 1 gram/day pulse steroid for three days. However, optic neuritis was not considered during the follow-up. Metastasis was considered at the exit of the left optic nerve. Trastuzumab was started by making a mutual decision with the patient. Six days after the sixth dose of adjuvant trastuzumab, she presented with almost complete vision loss.

MANAGEMENT AND OUTCOME

The patient was diagnosed with optic neuritis, and a pulse steroid was administered. Trastuzumab was permanently discontinued. However, the patient's visual acuity in both eyes remained at 5-10%.

DISCUSSION

Vision loss due to optic neuritis is a devastating side effect. Understanding that trastuzumab-induced optic neuritis may develop will help clinicians detect side effects early and manage them more effectively.

Clinicopathological Factors Predicting Pathological Complete Response to Neoadjuvant Anti-HER2 Therapy in HER2-Positive Breast Cancer

INTRODUCTION

Human epidermal growth factor receptor 2 (HER2)-targeted therapies have shown effectiveness against HER2-positive breast cancer. This makes neoadjuvant chemotherapy (NAC) a valuable option for treating both early and advanced stages of the disease. The tumor's response to HER2-targeted NAC provides crucial prognostic information. Additionally, it allows for tailoring adjuvant treatment strategies for HER2+ breast cancer based on pathological responses. This study aimed to investigate the clinicopathological factors that influence tumor response.

METHODS

We retrospectively analyzed 122 patients diagnosed with HER2+ breast cancer. These patients received NAC and HER2-directed therapy between January 2018 and December 2022 at the Pusan National University Yangsan Hospital. Following surgery, tumor response was evaluated, categorizing patients into two groups: pathological complete response (pCR) and non-pCR groups. We analyzed data on various factors, including age, NAC regimen, type of breast and axillary surgery, clinical stage (cTNM), historical grade, and preoperative levels of carcinoembryonic antigen, cancer antigen 15-3 (CA 15-3), estrogen receptor (ER), progesterone receptor (PR), HER2, p53, and KI-67.

RESULTS

Out of the 122 patients, 75 achieved pCR, while 47 did not. Most clinicopathological factors showed no significant difference between the pCR and non-pCR groups. However, several factors were associated with a higher pCR rate: normal preoperative CA 15-3 levels (odds ratio [OR]: 3.74, confidence interval [CI]: 1.19-11.72, p = 0.02), preoperative ER positivity (OR: 2.65, CI: 1.25-5.59, p = 0.01), PR negativity (OR: 3.92, CI: 1.82-8.45, p < 0.05), and strong preoperative HER2 immunohistochemistry (IHC) 3+ staining. Multivariate analysis confirmed that PR negativity (OR: 2.8, CI: 1.23-6.42, p = 0.01) and strong preoperative HER2 IHC 3+ staining (OR: 0.18, CI: 0.03-0.84, p = 0.04) were independent predictors of a higher pCR rate.

CONCLUSIONS

A pCR after NAC impacts patient prognosis and influences the choice of adjuvant treatment for HER2+ breast cancer. Clinicopathological factors can help predict responses to HER2-targeted NAC. In our study, pre-ER/PR negativity, high pre-HER2 levels, and normal CA 15-3 levels were found to be potential predictors of pCR. These findings may contribute to developing more effective treatment strategies for HER2+ breast cancer.

Evolving Management of Breast Cancer in the Era of Predictive Biomarkers and Precision Medicine

Breast cancer is the most common cancer among women in the world as well as in the United States. Molecular and histological differentiation have helped clinicians optimize treatments with various therapeutics, including hormonal therapy, chemotherapy, immunotherapy, and radiation therapy. Recently, immunotherapy has become the standard of care in locally advanced triple-negative breast cancer and an option across molecular subtypes for tumors with a high tumor mutation burden. Despite the advancements in personalized medicine directing the management of localized and advanced breast cancers, the emergence of resistance to these therapies is the leading cause of death among breast cancer patients. Therefore, there is a critical need to identify and validate predictive biomarkers to direct treatment selection, identify potential responders, and detect emerging resistance to standard therapies. Areas of active scientific and clinical research include novel personalized and predictive biomarkers incorporating tumor microenvironment, tumor immune profiling, molecular characterization, and histopathological differentiation to predict response and the potential emergence of resistance.

Metastatic site patterns by intrinsic subtype and HER2DX in early HER2-positive breast cancer

BACKGROUND

Even with contemporary treatment strategies, more than 10% of HER2-positive early stage breast cancer patients may experience distant metastasis as first event during follow-up. Tools for predicting unique patterns of metastatic spread are needed to plan personalized surveillance. We evaluated how molecular heterogeneity affects the pattern of distant relapse in HER2-positive breast cancer.

METHODS

A total of 677 HER2-positive stage I-III breast cancer patients from ShortHER trial, Cher-LOB trial, and 2 institutional cohorts were included. PAM50 molecular subtypes and research-based HER2DX scores were evaluated. The cumulative incidence of distant relapse as the first event (any site and site specific) was evaluated using competing risk analysis. Median follow-up was 8.4 years. Tests of statistical significance are 2-sided.

RESULTS

Stage III and high HER2DX risk score identified patients at the highest risk of distant relapse as first event (10-year incidence 24.5% and 19.7%, respectively). Intrinsic molecular subtypes were associated with specific patterns of metastatic spread: compared with other subtypes, HER2-enriched tumors were more prone to develop brain metastases (10-year incidence 3.8% vs 0.6%, P = .005), basal-like tumors were associated with an increased risk of lung metastases (10-year incidence 11.1% vs 2.6%, P = .001), and luminal tumors developed more frequently bone-only metastases (10-year incidence 5.1% vs 2.0%, P = .042). When added to stage or HER2DX risk score in competing risk regression models, intrinsic subtype maintained an independent association with site-specific metastases.

CONCLUSIONS

The integration of intrinsic molecular subtypes with stage or HER2DX risk score predicts site-specific metastatic risk in HER2-positive breast cancer, with potential implications for personalized surveillance and clinical trials aimed at preventing site-specific recurrence.

Antitumor activities against breast cancers by an afucosylated anti-HER2 monoclonal antibody H2 Mab-77-mG2a -f

Breast cancer patients with high levels of human epidermal growth factor receptor 2 (HER2) expression have worse clinical outcomes. Anti-HER2 monoclonal antibody (mAb) is the most important therapeutic modality for HER2-positive breast cancer. We previously immunized mice with the ectodomain of HER2 to create the anti-HER2 mAb, H2 Mab-77 (mouse IgG1 , kappa). This was then altered to produce H2 Mab-77-mG2a -f, an afucosylated mouse IgG2a . In the present work, we examined the reactivity of H2 Mab-77-mG2a -f and antitumor effects against breast cancers in vitro and in vivo. BT-474, an endogenously HER2-expressing breast cancer cell line, was identified by H2 Mab-77-mG2a -f with a strong binding affinity (a dissociation constant [KD ]: 5.0 × 10-9  M). H2 Mab-77-mG2a -f could stain HER2 of breast cancer tissues in immunohistochemistry and detect HER2 protein in Western blot analysis. Furthermore, H2 Mab-77-mG2a -f demonstrated strong antibody-dependent cellular cytotoxicity (ADCC) and complement-dependent cytotoxicity (CDC) for BT-474 cells. MDA-MB-468, a HER2-negative breast cancer cell line, was unaffected by H2 Mab-77-mG2a -f. Additionally, in the BT-474-bearing tumor xenograft model, H2 Mab-77-mG2a -f substantially suppressed tumor development when compared with the control mouse IgG2a mAb. In contrast, the HER2-negative MDA-MB-468-bearing tumor xenograft model showed no response to H2 Mab-77-mG2a -f. These findings point to the possibility of H2 Mab-77-mG2a -f as a treatment regimen by showing that it has antitumor effects on HER2-positive breast tumors.

HER2 Intratumoral Heterogeneity in Breast Cancer, an Evolving Concept

Amplification and/or overexpression of human epidermal growth factor receptor 2 (HER2) in breast cancer is associated with an adverse prognosis. The introduction of anti-HER2 targeted therapy has dramatically improved the clinical outcomes of patients with HER2-positive breast cancer. Unfortunately, a significant number of patients eventually relapse and develop distant metastasis. HER2 intratumoral heterogeneity (ITH) has been reported to be associated with poor prognosis in patients with anti-HER2 targeted therapies and was proposed to be a potential mechanism for anti-HER2 resistance. In this review, we described the current definition, common types of HER2 ITH in breast cancer, the challenge in interpretation of HER2 status in cases showing ITH and the clinical applications of anti-HER2 agents in breast cancer showing heterogeneous HER2 expression. Digital image analysis has emerged as an objective and reproducible scoring method and its role in the assessment of HER2 status with ITH remains to be demonstrated.

Clinical and biological heterogeneities in triple-negative breast cancer reveals a non-negligible role of HER2-low

Background

HER2-low could be found in some patients with triple-negative breast cancer (TNBC). However, its potential impacts on clinical features and tumor biological characteristics in TNBC remain unclear.

Methods

We enrolled 251 consecutive TNBC patients retrospectively, including 157 HER2-low (HER2low) and 94 HER2-negtive (HER2neg) patients to investigate the clinical and prognostic features. Then, we performed single-cell RNA sequencing (scRNA-seq) with another seven TNBC samples (HER2negvs. HER2low, 4 vs. 3) prospectively to further explore the differences of tumor biological properties between the two TNBC phenotypes. The underlying molecular distinctions were also explored and then verified in the additional TNBC samples.

Results

Compared with HER2neg TNBC, HER2low TNBC patients exhibited malignant clinical features with larger tumor size (P = 0.04), more lymph nodes involvement (P = 0.02), higher histological grade of lesions (P < 0.001), higher Ki67 status (P < 0.01), and a worse prognosis (P < 0.001; HR [CI 95%] = 3.44 [2.10–5.62]). Cox proportional hazards analysis showed that neoadjuvant systemic therapy, lymph nodes involvement and Ki67 levels were prognostic factors in HER2low TNBC but not in HER2neg TNBC patients. ScRNA-seq revealed that HER2low TNBC which showed more metabolically active and aggressive hallmarks, while HER2neg TNBC exhibited signatures more involved in immune activities with higher expressions of immunoglobulin-related genes (IGHG1, IGHG4, IGKC, IGLC2); this was further confirmed by immunofluorescence in clinical TNBC samples. Furthermore, HER2low and HER2neg TNBC exhibited distinct tumor evolutionary characteristics. Moreover, HER2neg TNBC revealed a potentially more active immune microenvironment than HER2low TNBC, as evidenced by positively active regulation of macrophage polarization, abundant CD8+ effector T cells, enriched diversity of T-cell receptors and higher levels of immunotherapy-targeted markers, which contributed to achieve immunotherapeutic response.

Conclusions

This study suggests that HER2low TNBC patients harbor more malignant clinical behavior and aggressive tumor biological properties than the HER2neg phenotype. The heterogeneity of HER2 may be a non-negligible factor in the clinical management of TNBC patients. Our data provide new insights into the development of a more refined classification and tailored therapeutic strategies for TNBC patients.

Prognostic impact of extracranial disease control in HER2+ breast cancer-related brain metastases

BACKGROUND

Brain metastases (BM) are common among HER2+ breast cancer (BC) and prognostic stratification is crucial for optimal management. BC-GPA score and subsequent refinements (modified-GPA, updated-GPA) recapitulate prognostic factors. Since none of these indexes includes extracranial disease control, we evaluated its prognostic value in HER2+ BCBM.

METHODS

Patients diagnosed with HER2+ BCBM at Istituto Oncologico Veneto-Padova (2002-2021) and Montpellier Cancer Institute (2001-2015) were included as exploratory and validation cohorts, respectively. Extracranial disease control at BM diagnosis (no disease/stable disease/response vs. progressive disease) was evaluated.

RESULTS

In the exploratory cohort of 113 patients (median OS 12.2 months), extracranial control (n = 65, 57.5%) was significantly associated with better OS at univariate (median OS 17.7 vs. 8.7 months, p = 0.005) and multivariate analysis after adjustment for BC-GPA (HR 0.61, 95% CI 0.39-0.94), modified-GPA (HR 0.64, 95% CI 0.42-0.98) and updated-GPA (HR 0.63, 95% CI 0.41-0.98). The prognostic impact of extracranial disease control (n = 66, 56.4%) was then confirmed in the validation cohort (n = 117) at univariate (median OS 20.2 vs. 9.1 months, p < 0.001) and multivariate analysis adjusting for BC-GPA (HR 0.41, 95% CI 0.27-0.61), modified-GPA (HR 0.44, 95% CI 0.29-0.67) and updated-GPA (HR 0.42, 95% CI 0.28-0.63).

CONCLUSIONS

Extracranial disease control provides independent prognostic information in HER2+ BCBM beyond commonly used prognostic scores.

The role of HER2 alterations in clinicopathological and molecular characteristics of breast cancer and HER2-targeted therapies: a comprehensive review

Breast cancer (BC) is the most common malignancy in women and one of the leading causes of cancer mortality, despite significant treatment advancements over the last decades. Human epidermal growth factor receptor-2 (HER2) is a member of the ERBB family of receptor tyrosine kinases which have long been known to mediate cancer cell growth and invasion through constitutive activation of oncogenic downstream signaling, such as PI3K/Akt/mTOR and MAPK. Overexpression/amplification of HER2 in various tumors, especially BC, offers the possible therapeutic potential for target therapies. HER2-targeted therapies, either with a combination of chemotherapy or through multi-anti-HER2 therapies without chemotherapy, have significantly improved the prognosis of HER2-positive tumors. In recent years, novel anti-HER2 agents and combination therapies have garnered much attention, especially for heavily treated advanced or metastatic BCs. HER2-positive BC is biologically a heterogeneous group depending on HER2 activation mechanisms, hormone receptor status, genome variations, tumor heterogeneity, and treatment resistance, which affect the treatment benefit and patients' outcomes. This review will discuss HER2 alternations (gene amplification or receptor overexpression) in BC, their correlation with clinicopathological characteristics and molecular characteristics, and HER2-based therapies in tumors with HER2 overexpression/amplification.

Cell Proliferation Receptor-Enhanced 3D High-Throughput Screening Model for Optimized Drug Efficacy Evaluation in Breast Cancer Cells

A higher correlation of epidermal growth factor receptor (EGFR)-targeting drugs has been reported with the use of the cell proliferation receptor-enhanced three-dimensional high-throughput screening model (CPRE 3D-HTS model) compared with two-dimensional (2D) cell-based HTS. A greater expression of differential human EGFR 2 (HER2) protein between HER2-positive and HER2-negative cell lines was observed in breast cancer (BC) cell lines cultured using the CPRE 3D-HTS model compared with 2D-cultured cells. When using 2D-cultured cells, properties such as the expression of the cell proliferation receptor are lost as the cells attach to the bottom of the well plate. In an effort to solve this problem, the CPRE 3D-HTS model expressing high cell proliferation receptors was optimized by the selection of alginate as the extracellular matrix. Results from the use of the CPRE 3D-HTS model showed higher drug resistance with increased expression of drug resistance-related proteins. Of particular interest, a higher correlation of HER2-targeted drugs was observed with the use of the CPRE 3D-HTS model. In order to validate this higher correlation of target drugs observed in the CPRE 3D-HTS model, the results of Western blot analysis and high content imaging analysis were analyzed, which confirmed that 3D-cultured BC cell lines showed a greater difference in the expression of HER2-positive and HER2-negative BC cell lines than 2D-cultured cells. Thus, the use of CPRE 3D-HTS using a 384-pillar plate resulted in increased accuracy when screening HER2-targeted drugs in BC, and it is a very useful platform for analyzing the efficacy of targeted drugs by enhancing the expression of HER2.

Combined analysis of receptor expression reflects inter-and intra-tumor heterogeneity in HR+/HER2+ breast cancer

BACKGROUND

Hormone receptor-positive and human epidermal growth factor receptor 2-positive (HR+/HER2+ breast cancer comprise approximately 5-10% of all invasive breast cancers. However, the lack of knowledge regarding the complexity of tumor heterogeneity in HR+/HER2+ disease remains a barrier to more accurate therapies. This study aimed to describe the tumor heterogeneity of HR+/HER2+ breast cancer and to establish a novel indicator to identify the HER2-enriched subtype in patients with HR+/HER2+ breast cancer.

METHODS

First of all, a comprehensive analysis was performed on HR+/HER2+ breast cancer samples from the TCGA (n = 141) and METABRIC (n = 104) databases. We determined the distribution of PAM50 intrinsic subtypes within the two cohorts and compared the somatic mutational profile and RNA expression features between HER2-enriched and non-HER2-enriched subtypes. From this, we constructed a novel marker termed rH/E, which was calculated as ERBB2 expression quantity/(ESR1 expression quantity + 1). Secondly, we performed multiplex immunofluorescence (mIF) to evaluate HER2 and estrogen receptor (ER) expression simultaneously in the third cohort, enrolling 43 cases of early HR+/HER2+ breast cancer from Cancer Hospital, Chinese Academy of Medical Sciences (CAMS). When using mIF, rH/E was adjusted to prH/E, which was calculated as HER2-positive cells%/(ER-positive cells + 1)%.

RESULTS

All four main intrinsic subtypes were identified in HR+/HER2+ breast cancer, of which the luminal B subtype was the most common, followed by the HER2-enriched and luminal A subtypes. Significantly increased TP53 and ERBB3 and decreased PIK3CA somatic mutation frequency were observed in the HER2-enriched subtype compared with the non-HER2-enriched subtype. In addition, the HER2-enriched subtype was characterized by significantly higher ERBB2 and lower ESR1 expression. We then constructed a marker termed rH/E to reflect the relative expression of ERBB2 to ESR1 in each patient. rH/E discriminates the HER2-enriched subtype from the better than the expression of ERBB2 or ESR1 alone. In the CAMS cohort, we observed four subtypes of tumor cells: ER+/HER2-, ER+/HER2+, ER-/HER2+, and ER-/HER2-. Tumor cell diversity was common, with 86% of patients having all four subtypes of tumor cells. Moreover, prH/E showed a significant prognostic association in the CAMS cohort.

CONCLUSIONS

This study furthers our understanding of the complexity of tumor heterogeneity in HR+/HER2+ breast cancer, and suggests that the combined analysis of ERBB2 and ESR1 expression may contribute to identifying patients with specific subtypes in this population.

Survival after neoadjuvant therapy with trastuzumab-lapatinib and chemotherapy in patients with HER2-positive early breast cancer: a meta-analysis of randomized trials

BACKGROUND

Studies testing the addition of lapatinib to neoadjuvant trastuzumab + chemotherapy reported an increase in pathologic complete response (pCR), with, nevertheless, discordant results in terms of survival, mainly due to suboptimal power. We here leverage the meta-analytic approach to resolve these inconsistencies.

METHODS

We conducted a meta-analysis of randomized phase II/III studies testing lapatinib + trastuzumab in combination with neoadjuvant chemotherapy for human epidermal growth factor receptor (HER2)-positive early breast cancer (BC). Recurrence-free survival (RFS) and overall survival (OS) were adopted as survival endpoints. Pooled hazard ratios (HR) were obtained for the effect of lapatinib + trastuzumab versus trastuzumab, pCR versus no-pCR in the whole study populations and pCR versus no-pCR according to hormone receptor status.

RESULTS

Four phase II/III randomized trials were included in the meta-analysis (CALGB 40601, Cher-LOB, NSABP-B41, NeoALTTO) for an overall population of 1410 patients receiving neoadjuvant chemotherapy in association with either trastuzumab, lapatinib or their combination. RFS was significantly improved with dual HER2 blockade as compared to trastuzumab [HR 0.62, 95% confidence interval (CI) 0.46-0.85]. Dual blockade also led to significantly improved OS (HR 0.65, 95% CI 0.43-0.98). For all treatments combined, patients achieving pCR had better RFS and OS than those with residual disease (HR 0.45, 95% CI 0.34-0.60, and HR 0.32, 95% CI 0.22-0.48, for RFS and OS, respectively). In patients with hormone receptor-negative tumors, pCR was associated with 65% and 73% relative reduction of risk of relapse and death, respectively. Patients with hormone receptor-positive tumors also experienced improved RFS if they achieved pCR; however, the benefit was smaller than that in hormone receptor-negative disease.

CONCLUSION

Findings from this meta-analysis further validate the role of pCR as a strong predictor of outcome in patients with HER2-positive BC, especially in hormone receptor-negative disease. Moreover, we provide robust evidence that dual blockade with lapatinib + trastuzumab in combination with neoadjuvant chemotherapy prolongs OS, suggesting that the role of lapatinib could be reconsidered in the early setting.

Trastuzumab-lapatinib as neoadjuvant therapy for HER2-positive early breast cancer: Survival analyses of the CHER-Lob trial

AIM

The Cher-LOB randomised phase II study showed that the combination of lapatinib-trastuzumab plus chemotherapy increases pathologic complete response (pCR) rate compared with chemotherapy plus either trastuzumab or lapatinib. Here, we report the post hoc survival analysis as per treatment arm, pCR and biomarkers.

METHODS

The Cher-LOB study randomised 121 patients with human epidermal growth factor receptor 2-positive, stage II-IIIA breast cancer. A specific protocol to collect recurrence-free survival (RFS) and overall survival (OS) data was designed. Tumour-infiltrating lymphocytes (TILs) and PAM50-intrinsic subtyping were evaluated at baseline.

RESULTS

At 9-year median follow-up, a trend towards RFS improvement with lapatinib-trastuzumab over trastuzumab was observed (hazard ratio [HR] 0.44, 95% confidence interval [CI] 0.18-1.05). Combining treatment arms, pCR was significantly associated with both RFS (HR 0.12, 95% CI 0.03-0.49) and OS (HR 0.12, 95% CI 0.03-0.49). TILs were significantly associated with RFS (HR = 0.978 for each 1% increment). Luminal-A subtype was a significant and independent predictor of improved RFS as compared with other PAM50-based intrinsic subtypes at the multivariate analysis including the most relevant clinicopathologic variables (HR 0.29, 95% CI 0.09-0.94, p = 0.040).

CONCLUSIONS

Cher-LOB trial survival analysis confirmed the prognostic role of pCR and TILs and showed a signal for a better outcome with lapatinib-trastuzumab over trastuzumab.

TRIAL REGISTRATION

NCT00429299.

Neoadjuvant approach as a platform for treatment personalization: focus on HER2-positive and triple-negative breast cancer

The neoadjuvant setting provides unquestionable clinical benefits for high-risk breast cancer (BC) patients, mainly in terms of expansion of locoregional treatment options and prognostic stratification. Additionally, it is also emerging as a strategical tool in the research field. In the present review, by focusing on HER2-positive and triple-negative subtypes, we examined the role of the neoadjuvant setting as a research platform to facilitate and rationalize the placement of escalation strategies, promote the adoption of biomarker-driven approaches for the investigation of de-escalated treatments, and foster the conduction of comprehensive translational analyses, thus ultimately aiming at pursuing treatment personalization. The solid prognostic role of pathologic complete response after neoadjuvant therapy, and its use as a surrogate endpoint to accelerate the drug approval process were discussed. In this context, available data on escalated treatment strategies capable of enhancing pathologic complete response (pCR) rate or improving prognosis of patients with residual disease (RD) after neoadjuvant treatment, were comprehensively reviewed. We also summarized evidence regarding the possibility of obtaining pCR with de-escalated strategies, with particular emphasis on the role of biomarker-driven approaches for patient selection. Pitfalls of the dichotomy of pCR/RD were also deepened, and data on alternative/complementary biomarkers with a possible clinical relevance in this regard were reviewed.

Emerging strategies for treating metastasis

The systemic spread of tumor cells is the ultimate cause of the majority of deaths from cancer, yet few successful therapeutic strategies have emerged to specifically target metastasis. Here we discuss recent advances in our understanding of tumor-intrinsic pathways driving metastatic colonization and therapeutic resistance, as well as immune activating strategies to target metastatic disease. We focus on therapeutically exploitable mechanisms, promising strategies in preclinical and clinical development, and emerging areas with potential to become innovative treatments.

Biomarkers for HER2-positive metastatic breast cancer: Beyond hormone receptors

The overexpression of human epidermal growth factor receptor-2 (HER2) results in a biologically and clinically aggressive breast cancer (BC) subtype. Since the introduction of anti-HER2 targeted agents, survival rates of patients with HER2-positive metastatic BC have dramatically improved. Currently, although the treatment decision process in metastatic BC is primarily based on HER2 and hormone-receptor (HR) status, a rapidly growing body of data suggests that several other sources of biological heterogeneity may characterize HER2-positive metastatic BC. Moreover, pivotal clinical trials of new anti-HER2 antibody-drug conjugates showed encouraging results in HER2-low metastatic BC, thus leading to the possibility, in the near future, to expand the pool of patients suitable for HER2-targeted treatments. The present review summarizes and puts in perspective available evidence on biomarkers that hold the greatest promise to become potentially useful tools for optimizing HER2-positive metastatic BC patients' prognostic stratification and treatment in the next future. These biomarkers include HER2 levels and heterogeneity, HER3, intrinsic molecular subtypes by PAM50 analysis, DNA mutations, and immune-related factors. Molecular discordance between primary and metastatic tumors is also discussed.

Droplet Microfluidic and Magnetic Particles Platform for Cancer Typing

Analyses of nucleic acids are routinely performed in hospital laboratories to detect gene alterations for cancer diagnosis and treatment decision. Among the different possible investigations, mRNA analysis provides information on abnormal levels of genes expression. Standard laboratory methods are still not adapted to the isolation and quantitation of low mRNA amounts and new techniques needs to be developed in particular for rare subsets analysis. By reducing the volume involved, time process, and the contamination risks, droplet microfluidics provide numerous advantages to perform analysis down to the single cell level.We report on a droplet microfluidic platform based on the manipulation of magnetic particles that allows the clinical analysis of tumor tissues. In particular, it allows the extraction of mRNA from the total-RNA sample, Reverse Transcription, and cDNA amplification, all in droplets.

ErbB2 activation upregulates glutaminase 1 expression which promotes breast cancer cell proliferation

Active glutamine utilization is critical for tumor cell proliferation. Glutaminolysis represents the first and rate-limiting step of glutamine utilization and is catalyzed by glutaminase (GLS). Activation of ErbB2 is one of the major causes of breast cancers, the second most common cause of death for women in many countries. However, it remains unclear whether ErbB2 signaling affects glutaminase expression in breast cancer cells. In this study, we show that MCF10A-NeuT cell line has higher GLS1 expression at both mRNA and protein levels than its parental line MCF10A, and knockdown of ErbB2 decreases GLS1 expression in MCF10A-NeuT cells. We further show that in these cells, ErbB2-mediated upregulation of GLS1 is not correlated to c-Myc expression. Moreover, activation of neither PI3K-Akt nor MAPK pathway is sufficient to upregulate GLS1 expression. Interestingly, inhibition of NF-κB blocks ErbB2-stimulated GLS1 expression, whereas stimulation of NF-κB is sufficient to enhance GLS1 levels in MCF10A cells, suggesting a PI3K-Akt-independent activation of NF-κB upregulates GLS1 in ErbB2-positive breast cancer cells. Finally, knockdown or inhibition of GLS1 significantly decreased the proliferation of breast cancer cells with high GLS1 levels. Taken together, our data indicate that ErbB2 activation promotes GLS1 expression via a PI3K-Akt-independent NF-κB pathway in breast cancer cells, identifying another oncogenic signaling pathway which stimulates GLS1 expression, and thus promoting glutamine utilization in cancer cells. These findings, if validated by in vivo model, may facilitate the identification of novel biochemical targets for cancer prevention and therapy.

Microenvironment, oncoantigens, and antitumor vaccination: lessons learned from BALB-neuT mice

The tyrosine kinase human epidermal growth factor receptor 2 (HER2) gene is amplified in approximately 20% of human breast cancers and is associated with an aggressive clinical course and the early development of metastasis. Its crucial role in tumor growth and progression makes HER2 a prototypic oncoantigen, the targeting of which may be critical for the development of effective anticancer therapies. The setup of anti-HER2 targeting strategies has revolutionized the clinical outcome of HER2⁺ breast cancer. However, their initial success has been overshadowed by the onset of pharmacological resistance that renders them ineffective. Since the tumor microenvironment (TME) plays a crucial role in drug resistance, the design of more effective anticancer therapies should depend on the targeting of both cancer cells and their TME as a whole. In this review, starting from the successful know-how obtained with a HER2⁺ mouse model of mammary carcinogenesis, the BALB-neuT mice, we discuss the role of TME in mammary tumor development. Indeed, a deeper knowledge of antigens critical for cancer outbreak and progression and of the mechanisms that regulate the interplay between cancer and stromal cell populations could advise promising ways for the development of the best anticancer strategy.

Assessing reproducibility of diffusion-weighted magnetic resonance imaging studies in a murine model of HER2+ breast cancer

BACKGROUND AND PURPOSE

The use of diffusion-weighted magnetic resonance imaging (DW-MRI) as a surrogate biomarker of response in preclinical studies is increasing. However, before a biomarker can be reliably employed to assess treatment response, the reproducibility of the technique must be established. There is a paucity of literature that quantifies the reproducibility of DW-MRI in preclinical studies; thus, the purpose of this study was to investigate DW-MRI reproducibility in a murine model of HER2+ breast cancer.

MATERIALS AND METHODS

Test-Retest DW-MRI scans separated by approximately six hours were acquired from eleven athymic female mice with HER2+ xenografts using a pulsed gradient spin echo diffusion-weighted sequence with three b values [150, 500, and 800s/mm(2)]. Reproducibility was assessed for the mean apparent diffusion coefficient (ADC) from tumor and muscle tissue regions.

RESULTS

The threshold to reflect a change in tumor physiology in a cohort of mice is defined by the 95% confidence interval (CI), which was±0.0972×10(-3)mm(2)/s (±11.8%) for mean tumor ADC. The repeatability coefficient defines this threshold for an individual mouse, which was±0.273×10(-3)mm(2)/s. The 95% CI and repeatability coefficient for mean ADC of muscle tissue were±0.0949×10(-3)mm(2)/s (±8.30%) and±0.266×10(-3)mm(2)/s, respectively.

CONCLUSIONS

Mean ADC of tumors is reproducible and appropriate for detecting treatment-induced changes on both an individual and mouse cohort basis.

Ophthalmic complications of targeted cancer therapy and recently recognized ophthalmic complications of traditional chemotherapy

As our understanding of cancer pathophysiology has increased, so have the number of targeted therapeutic agents available. By targeting specific molecules involved in tumorigenesis, targeted therapeutic agents offer the potential for significant efficacy against tumor cells while minimizing the adverse effects. We highlight the recently recognized ophthalmic complications of targeted cancer therapy, as well as recently recognized complications of traditional chemotherapeutic agents.

Reproducibility of static and dynamic (18)F-FDG, (18)F-FLT, and (18)F-FMISO MicroPET studies in a murine model of HER2+ breast cancer

PURPOSE

The objective of this study is to determine the reproducibility of static 2-deoxy-2-[(18)F]fluoro-D-glucose ((18)F-FDG), 3'-deoxy-3'-[(18)F]fluorothymidine ((18)F-FLT), and [(18)F]-fluoromisonidazole ((18)F-FMISO) microPET measurements, as well as kinetic parameters returned from analyses of dynamic (18)F-FLT and (18)F-FMISO data.

PROCEDURES

HER2+ xenografts were established in nude mice. Dynamic data were acquired for 60 min, followed by a repeat injection and second scan 6 h later. Reproducibility was assessed for the percent-injected dose per gram (%ID/g) for each radiotracer, and with kinetic parameters (K (1) -k (4) , K ( i )) for (18)F-FLT and (18)F-FMISO.

RESULTS

The value needed to reflect a change in tumor physiology is given by the 95 % confidence interval (CI), which is ±14, ±5, and ±6 % for (18)F-FDG (n = 12), (18)F-FLT (n = 11), and (18)F-FMISO (n = 11) %ID/g, respectively. V ( d ) (=K (1) /k (2)), k (3), and K (FLT) are the most reproducible (18)F-FLT (n = 9) kinetic parameters, with 95 % CIs of ±18, ±10, and ±18 %, respectively. V ( d ) and K (FMISO) are the most reproducible (18)F-FMISO kinetic parameters (n = 7) with 95 % CIs of ±16 and ±14 %, respectively.

CONCLUSIONS

Percent-injected dose per gram measurements are reproducible and appropriate for detecting treatment-induced changes. Kinetic parameters have larger threshold values, but are potentially sufficiently reproducible to detect treatment response.

The in vitro influences of epidermal growth factor and heregulin-β1 on the efficacy of trastuzumab used in Her-2 positive breast adenocarcinoma

Background

Human epidermal growth factor receptor-2 (Her-2) is over expressed in approximately 25-30% of all primary breast tumors resulting in a distinctive breast cancer subtype associated with a poor prognosis and a decrease in overall survival. Trastuzumab (Herceptin®), an anti-Her-2 monoclonal antibody, has dramatically altered the prognosis of Her-2 positive breast cancer. Trastuzumab is, however, associated with primary and acquired resistance.

Aim and methods

To investigate the in-vitro effects of trastuzumab on cell viability (tetrazolium conversion assay), cell cycling (propidium iodide staining), apoptosis (executioner caspases and annexin-V) and relative surface Her-2 receptor expression (anti-Her-2 affibody molecule) in Her-2-positive (SK-Br-3) and oestrogen receptor positive (MCF-7) breast adenocarcinoma cells and to determine potential augmentation of these effects by two endogenous ligands, epidermal growth factor (EGF) and heregulin-β1 (HRG- β1).

Results

Cell viability was decreased in SK-Br-3 cells by exposure to trastuzumab. This was associated with G1 accumulation and decreased relative surface Her-2 receptor density, supporting the cytostatic nature of trastuzumab in vitro. SK-Br-3 cells exposed to EGF and heregulin-β1 produced differential cell responses alone and in combination with trastuzumab, in some instances augmenting cell viability and cell cycling. Relative surface Her-2 receptor density was reduced substantially by trastuzumab, EGF and heregulin-β1. These reductions were amplified when ligands were used in combination with trastuzumab.

Conclusion

Cell type specific interactions of endogenous ligands appear to be dependent on absolute Her-receptor expression and cross activation of signaling pathways. This supports the notion that receptor density of Her-family members and multiplicity of growth ligands are of mutual importance in breast cancer cell proliferation and therefore also in resistance associated with trastuzumab.

New insights into the role of the immune microenvironment in breast carcinoma

Recently, immune edition has been recognized as a new hallmark of cancer. In this respect, some clinical trials in breast cancer have reported imppressive outcomes related to laboratory immune findings, especially in the neoadjuvant and metastatic setting. Infiltration by tumor infiltrating lymphocytes (TIL) and their subtypes, tumor-associated macrophages (TAM) and myeloid-derived suppressive cells (MDSC) seem bona fide prognostic and even predictive biomarkers, that will eventually be incorporated into diagnostic and therapeutic algorithms of breast cancer. In addition, the complex interaction of costimulatory and coinhibitory molecules on the immune synapse and the different signals that they may exert represent another exciting field to explore. In this review we try to summarize and elucidate these new concepts and knowledge from a translational perspective focusing on breast cancer, paying special attention to those aspects that might have more significance in clinical practice and could be useful to design successful therapeutic strategies in the future.

Biospecimens and biorepositories for the community pathologist

Pathologists have long served as custodians of human biospecimens collected for diagnostic purposes. Rapid advancements in diagnostic technologies require that pathologists change their practices to optimize patient care. The proper handling of biospecimens creates opportunities for pathologists to improve their diagnoses while assessing prognosis and treatment. In addition, the growing need for high-quality biorepositories represents an opportunity for community pathologists to strengthen their role within the health care team, ensuring that clinical care is not compromised while facilitating research. This article provides a resource to community pathologists learning how to create high-quality biorepositories and participating in emerging opportunities in the biorepository field. While a variety of topics are covered to provide breadth of information, the intent is to facilitate a level of understanding that permits community pathologists to make more informed choices in identifying how best their skills and practice may be augmented to address developments in this field.

[Cell signalling and cancer: characterisation of therapeutic targets]

Cellular communication is required for the life of pluricellular organisms. The informations exchanged between cells belong to six major types of order to be executed, opposite each other: proliferate or differentiate; remain attached or migrate; survive or die. The cancer cell is genetically unstable, able to explore all the functions encoded by the genome and to consider every proliferative or migratory advantage for selecting it and transmit it to its descent. All the signalling pathways involved in proliferation or differentiation, in adhesion and migration, in survival and death may be altered by oncogenic alterations. These alterations are precisely those which can be targeted for therapy: from this observation was forged the concept of targeted therapy. We present here some examples of therapeutic targeting at the level of a major proliferation pathway by showing how it was possible to identify and characterise relevant targets, invent original new therapeutic tools and decipher the mechanisms of resistance which occur and hinder the success of targeted therapies. This example is the proliferation signalling pathway which starts from the activation of tyrosine kinase receptors by cognate growth factors and ends by the activation of transcription factors which trigger the transcription of the genes required for DNA replication, after undergoing through numerous intermediate molecules constituting the MAP kinase pathway: RAS, RAF, MEK and ERK.

ER and HER2 expression are positively correlated in HER2 non-overexpressing breast cancer

INTRODUCTION

Estrogen receptor-α (ER) and human epidermal growth factor receptor 2 (HER2) positivity are inversely correlated by standard criteria. However, we investigated the quantitative relation between ER and HER2 expression at both RNA and protein levels in HER2+ve and HER2-ve breast carcinomas.

METHODS

ER and HER2 levels were assessed with immunohistochemistry (IHC) and (for HER2) fluorescent in situ hybridization (FISH) and by quantitative reverse transcription-polymerase chain reaction (q-RT-PCR) in formalin-fixed primary breast cancers from 448 patients in the National Cancer Research Institute (NCRI) Adjuvant Breast Cancer Trial (ABC) tamoxifen-only arm. Relations at the RNA level were assessed in 1,139 TransATAC tumors.

RESULTS

ER and HER2 RNA levels were negatively correlated as expected in HER2+ve (IHC 3+ and/or FISH-amplified) tumors (r = -0.45; P = 0.0028). However, in HER2-ve tumors (ER+ve and ER-ve combined), a significant positive correlation was found (r = 0.43; P < 0.0001), HER2 RNA levels being 1.74-fold higher in ER+ve versus ER-ve tumors. This correlation was maintained in the ER+veHER2-ve subgroup (r = 0.24; P = 0.0023) and confirmed in this subgroup in 1,139 TransATAC tumours (r = 0.25; P < 0.0001). The positive relation extended to IHC-detected ER in ABC: mean ± 95% confidence interval (CI) H-scores were 90 ± 19 and 134 ± 19 for 0 and 1+ HER2 IHC categories, respectively (P = 0.0013). A trend toward lower relapse-free survival (RFS) was observed in patients with the lowest levels of ER and HER2 RNA levels within the ER+veHER2-ve subgroup both for ABC and TransATAC cohorts.

CONCLUSIONS

ER and HER2 expression is positively correlated in HER2-ve tumors. The distinction between HER2+ve and HER2-ve is greater in ER-ve than in ER+ve tumors. These findings are important to consider in clinical trials of anti-HER2 and anti-endocrine therapy in HER2-ve disease.

TRIAL REGISTRATION

Clinical trial identifier: ISRCTN31514446.

Potential role of HER2-overexpressing exosomes in countering trastuzumab-based therapy

Exosomes are endosome-derived nanovesicles actively released into the extracellular environment and biological fluids, both under physiological and pathological conditions, by different cell types. We characterized exosomes constitutively secreted by HER2-overexpressing breast carcinoma cell lines and analyzed in vitro and in vivo their potential role in interfering with the therapeutic activity of the humanized antibody Trastuzumab and the dual tyrosine kinase inhibitor (TKI) Lapatinib anti-HER2 biodrugs. We show that exosomes released by the HER2-overexpressing tumor cell lines SKBR3 and BT474 express a full-length HER2 molecule that is also activated, although to a lesser extent than in the originating cells. Release of these exosomes was significantly modulated by the growth factors EGF and heregulin, two of the known HER2 receptor-activating ligands and naturally present in the surrounding tumor microenvironment. Exosomes secreted either in HER2-positive tumor cell-conditioned supernatants or in breast cancer patients' serum bound to Trastuzumab. Functional assays revealed that both xenogeneic and autologous HER2-positive nanovesicles, but not HER2-negative ones, inhibited Trastuzumab activity on SKBR3 cell proliferation. By contrast, Lapatinib activity on SKBR3 cell proliferation was unaffected by the presence of autologous exosomes. Together, these findings point to the role of HER2-positive exosomes in modulating sensitivity to Trastuzumab, and, consequently, to HER2-driven tumor aggressiveness.

89Zr-Radiolabeled Trastuzumab Imaging in Orthotopic and Metastatic Breast Tumors

The human epidermal growth factor receptor 2 (HER2/neu) is overexpressed in 20-30% of breast cancers and is associated with tumor growth, angiogenesis, and development of distant metastases. Trastuzumab, an anti-HER2 monoclonal antibody, is used for the treatment of HER2 positive breast cancer and clinical efficacy of this agent is dependent on HER2 expression. Targeted PET imaging of HER2 with radiolabeled trastuzumab may be used to determine HER2 expression levels and guide therapy selection. The purpose of the current study was to evaluate a facile 89Zr-trastuzumab preparation method that can be efficiently applied for clinical grade production. Also, relative HER2 expression levels in orthotopic and metastatic breast cancer models were assessed by PET imaging using the 89Zr-trastuzumab produced by this simpler method.

The After Breast Cancer Pooling Project: rationale, methodology, and breast cancer survivor characteristics

The After Breast Cancer Pooling Project was established to examine the role of physical activity, adiposity, dietary factors, supplement use, and quality of life (QOL) in breast cancer prognosis. This paper presents pooled and harmonized data on post-diagnosis lifestyle factors, clinical prognostic factors, and breast cancer outcomes from four prospective cohorts of breast cancer survivors (three US-based and one from Shanghai, China) for 18,314 invasive breast cancer cases diagnosed between 1976 and 2006. Most participants were diagnosed with stage I-II breast cancer (84.7%). About 60% of breast tumors were estrogen receptor (ER)+/progesterone receptor (PR)+; 21% were ER-/PR-. Among 8,118 participants with information on HER-2 tumor status, 74.8% were HER-2- and 18.5% were HER-2+. At 1-2 years post-diagnosis (on average), 17.9% of participants were obese (BMI ≥ 30 kg/m2), 32.6% were overweight (BMI 25-29 kg/m2), and 59.9% met the 2008 Physical Activity Guidelines for Americans (≥ 2.5 h per week of moderate activity). During follow-up (mean = 8.4 years), 3,736 deaths (2,614 from breast cancer) and 3,564 recurrences have been documented. After accounting for differences in year of diagnosis and timing of post-diagnosis enrollment, five-year overall survival estimates were similar across cohorts. This pooling project of 18,000 breast cancer survivors enables the evaluation of associations of post-diagnosis lifestyle factors, QOL, and breast cancer outcomes with an adequate sample size for investigation of heterogeneity by hormone receptor status and other clinical predictors. The project sets the stage for international collaborations for the investigation of modifiable predictors for breast cancer outcomes.

Responsiveness of adjacent ductal carcinoma in situ and changes in HER2 status after neoadjuvant chemotherapy/trastuzumab treatment in early breast cancer--results from the GeparQuattro study (GBG 40)

Adjacent ductal carcinoma in situ (DCIS) is found in approximately 45% of invasive ductal carcinomas (IDC) of the breast. Pure DCIS overexpresses HER2 in approximately 45%. There is uncertainty whether adjacent DCIS impacts on the response to neoadjuvant chemotherapy and trastuzumab as well as whether HER2 expression in IDC component or adjacent DCIS changes throughout treatment. Core biopsies and surgical tissue from participants of the GeparQuattro study with HER2-positive IDC were centrally examined for the area of invasive ductal component and adjacent DCIS before and after receiving neoadjuvant anthracycline-taxane-trastuzumab containing chemotherapy. HER2 overexpression in IDC and adjacent DCIS was quantified separately by immunohistochemistry using the Ventana automated staining system. Pathological complete response (pCR) was defined as no residual invasive or non-invasive tumor tissue. Fifty-nine (37.3%) of 158 IDCs presented with adjacent DCIS at diagnosis. These tumors showed lower regression grades than pure IDC (P = 0.033). The presence of adjacent DCIS was an independent negative predictor of pCR [odds ratio 0.42 (95% CI 0.2-0.9), P = 0.027]. Adjacent DCIS area decreased from pre-treatment to surgery (r = 0.205) with 30 (50.8%) IDCs with adjacent DCIS showing complete eradication of adjacent DCIS. HER2 status of adjacent DCIS was highly correlated with HER2 status of IDC component before (r = 0.892) and after treatment (r = 0.676). Degree of HER2 overexpression of the IDC component decreased in 16 (33.3%) out of 49 patients without a pCR. These 16 IDCs showed lower RGs compared to the 33 IDCs with unchanged HER2 expression (P = 0.055). HER2-positive IDCs with adjacent DCIS is less responsive to neoadjuvant chemotherapy and trastuzumab compared to pure IDC. However, complete eradication of adjacent DCIS is frequently observed. HER2-overexpression of the invasive ductal component decreases in a subset of tumors, which showed less tumor regression.

Minichromosome Maintenance Protein 7 is a potential therapeutic target in human cancer and a novel prognostic marker of non-small cell lung cancer

BACKGROUND

The research emphasis in anti-cancer drug discovery has always been to search for a drug with the greatest antitumor potential but fewest side effects. This can only be achieved if the drug used is against a specific target located in the tumor cells. In this study, we evaluated Minichromosome Maintenance Protein 7 (MCM7) as a novel therapeutic target in cancer.

RESULTS

Immunohistochemical analysis showed that MCM7 was positively stained in 196 of 331 non-small cell lung cancer (NSCLC), 21 of 29 bladder tumor and 25 of 70 liver tumor cases whereas no significant staining was observed in various normal tissues. We also found an elevated expression of MCM7 to be associated with poor prognosis for patients with NSCLC (P = 0.0055). qRT-PCR revealed a higher expression of MCM7 in clinical bladder cancer tissues than in corresponding non-neoplastic tissues (P < 0.0001), and we confirmed that a wide range of cancers also overexpressed MCM7 by cDNA microarray analysis. Suppression of MCM7 using specific siRNAs inhibited incorporation of BrdU in lung and bladder cancer cells overexpressing MCM7, and suppressed the growth of those cells more efficiently than that of normal cell strains expressing lower levels of MCM7.

CONCLUSIONS

Since MCM7 expression was generally low in a number of normal tissues we examined, MCM7 has the characteristics of an ideal candidate for molecular targeted cancer therapy in various tumors and also as a good prognostic biomarker for NSCLC patients.