Targeting the Ezrin Adaptor Protein Sensitizes Metastatic Breast Cancer Cells to Chemotherapy and Reduces Neoadjuvant Therapy-induced Metastasis

The main cause of cancer-associated deaths is the spread of cancer cells to distant organs. Despite its success in the primary tumor setting, modern chemotherapeutic strategies are rendered ineffective at treating metastatic disease, largely due to the development of resistance. The adaptor protein ezrin has been shown to promote cancer metastasis in multiple preclinical models and is associated with poor prognosis in several cancer types, including breast cancer. Ezrin promotes pro-survival signaling, particularly in disseminated cancer cells, to facilitate metastatic outgrowth. However, the role of ezrin in breast cancer chemoresistance is not fully known. In this study, we show that upregulating or downregulating ezrin expression modifies the sensitivity of breast cancer cells to doxorubicin and docetaxel treatment in vitro and is associated with changes in PI3K/Akt and NFκB pathway activation. In addition, we tested the effects of systemic treatment with a small-molecule ezrin inhibitor, NSC668394, on lung metastatic burden in vivo as a monotherapy, or in combination with anthracycline- or taxane-based chemotherapy treatment. We show that anti-ezrin treatment alone reduces metastatic burden and markedly sensitizes metastases to doxorubicin or docetaxel in neoadjuvant as well as neoadjuvant plus adjuvant treatment models. Taken together, our findings demonstrate the impact of anti-ezrin treatment in modulating response to chemotherapy in breast cancer cells as well as the efficacy of anti-ezrin treatment in combination with chemotherapy at reducing metastatic burden.

Significance

This work provides preclinical evidence for combining anti-ezrin treatment with chemotherapy as a novel strategy for effectively targeting metastasis, particularly in a neoadjuvant treatment setting.

Neurocognitive outcomes following fetal exposure to chemotherapy for gestational breast cancer: A Canadian multi-center cohort study

Background

Limited knowledge exists on outcomes of children exposed prenatally to chemotherapy for breast cancer (BC). The purpose of this study was to compare long-term neurocognitive, behavioral, developmental, growth, and health outcomes of children exposed in-utero to chemotherapy for BC.

Methods

This is a multi-center matched cross-sectional cohort study involving seven cancer centers across the region of Southern Ontario (Canada), and the Hospital for Sick Children (Toronto, Ontario). Using standardized psychological and behavioral tests, we compared cognitive and behavioral outcomes in children exposed to chemotherapy during pregnancy for BC to age-matched pairs exposed to known non-teratogens.

Results

We recruited 17 parent-child pairs and their matched controls. There were more preterm deliveries in the chemotherapy-exposed group compared to controls (p < 0.05). Full Scale IQ of children in the chemotherapy group was significantly confounded by maternal IQ and prematurity. Exposed children born at term were not different in cognitive outcomes. Children from both groups were similar in their developmental milestones, pediatric anthropometric measurements and health problems. There were no cases of autoimmune cytopenia.

Conclusions

This is the first Canadian prospective comparative study designed to assess pediatric cognition following prenatal exposure to chemotherapy for BC. Chemotherapy was not found to be neurotoxic in this cohort and did not affect pediatric health. The decision to plan a preterm birth for initiating or continuing chemotherapy treatment must be taken into consideration in context of pediatric implications. While these results may assist in such decision making, replication with a larger sample is needed for more conclusive findings.

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Limited knowledge exists on outcomes of children exposed prenatally to chemotherapy for breast cancer (BC).

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We compared cognitive and behavioral outcomes in children exposed to chemotherapy during pregnancy for BC to controls.

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FSIQ of children in the chemotherapy group was significantly confounded by prematurity.

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Chemotherapy was not found to be neurotoxic and did not affect pediatric health.

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Pediatric implications of planned preterm birth for further treatment should be considered.

An epigenetic increase in mitochondrial fission by MiD49 and MiD51 regulates the cell cycle in cancer: Diagnostic and therapeutic implications

Excessive proliferation and apoptosis-resistance are hallmarks of cancer. Increased dynamin-related protein 1 (Drp1)-mediated mitochondrial fission is one of the mediators of this phenotype. Mitochondrial fission that accompanies the nuclear division is called mitotic fission and occurs when activated Drp1 binds partner proteins on the outer mitochondrial membrane. We examine the role of Drp1-binding partners, mitochondrial dynamics protein of 49 and 51 kDa (MiD49 and MiD51), as drivers of cell proliferation and apoptosis-resistance in non-small cell lung cancer (NSCLC) and invasive breast carcinoma (IBC). We also evaluate whether inhibiting MiDs can be therapeutically exploited to regress cancer. We show that MiD levels are pathologically elevated in NSCLC and IBC by an epigenetic mechanism (decreased microRNA-34a-3p expression). MiDs silencing causes cell cycle arrest through (a) increased expression of cell cycle inhibitors, p27^Kip1 and p21^Waf1 , (b) inhibition of Drp1, and (c) inhibition of the Akt-mTOR-p70S6K pathway. Silencing MiDs leads to mitochondrial fusion, cell cycle arrest, increased apoptosis, and tumor regression in a xenotransplant NSCLC model. There are positive correlations between MiD expression and tumor size and grade in breast cancer patients and inverse correlations with survival in NSCLC patients. The microRNA-34a-3p-MiDs axis is important to cancer pathogenesis and constitutes a new therapeutic target.

Intravital imaging reveals systemic ezrin inhibition impedes cancer cell migration and lymph node metastasis in breast cancer

Background

Limited understanding of the cancer biology of metastatic sites is a major factor contributing to poor outcomes in cancer patients. The regional lymph nodes are the most common site of metastasis in most solid cancers and their involvement is a strong predictor of relapse in breast cancer (BC). We have previously shown that ezrin, a cytoskeletal–membrane linker protein, is associated with lymphovascular invasion and promotes metastatic progression in BC. However, the efficacy of pharmacological inhibition of ezrin in blocking cancer cell migration and metastasis remains unexplored in BC.

Methods

We quantified ezrin expression in a BC tissue microarray (n = 347) to assess its correlation with risk of relapse. Next, we developed a quantitative intravital microscopy (qIVM) approach, using a syngeneic lymphatic reporter mouse tumor model, to investigate the effect of systemic ezrin inhibition on cancer cell migration and metastasis.

Results

We show that ezrin is expressed at significantly higher levels in lymph node metastases compared to matched primary tumors, and that a high tumor ezrin level is associated with increased risk of relapse in BC patients with regional disease. Using qIVM, we observe a subset of cancer cells that retain their invasive and migratory phenotype at the tumor-draining lymph node. We further show that systemic inhibition of ezrin, using a small molecule compound (NSC668394), impedes the migration of cancer cells in vivo. Furthermore, systemic ezrin inhibition leads to reductions in metastatic burden at the distal axillary lymph node and lungs.

Conclusions

Our findings demonstrate that the tumor ezrin level act as an independent biomarker in predicting relapse and provide a rationale for therapeutic targeting of ezrin to reduce the metastatic capacity of cancer cells in high-risk BC patients with elevated ezrin expression.

Electronic supplementary material

The online version of this article (10.1186/s13058-018-1079-7) contains supplementary material, which is available to authorized users.

Abstract 4187: Targeting the cytoskeleton protein ezrin sensitizes metastatic breast cancer cells to anthracycline based chemotherapy

The main cause of cancer-associated deaths is the spread of cancer cells to distant organ sites. Despite recent advances in treating primary tumors, modern chemotherapeutic strategies are relatively ineffective at treating metastasis, with clinical trials showing minimal improvements in overall survival for patients with metastatic disease. This is in large part due to chemotherapy resistance which remains a major clinical challenge limiting therapeutic responses for metastatic cancer patients. The cytoskeleton crosslinker protein ezrin has been shown to promote cancer metastasis in multiple preclinical models and is associated with poor prognosis in several cancer types, including breast cancer (BC). Ezrin also promotes pro-survival signaling, particularly in disseminated cancer cells, to facilitate metastatic outgrowth. However, whether ezrin plays a role in chemoresistance in BC is not yet known. In this study, we sought to determine whether ezrin can predict response to chemotherapy in BC patients and whether pharmacologic inhibition of ezrin alters the sensitivity of metastatic BC cells to anthracycline-based chemotherapy in preclinical models of metastasis. Ezrin protein expression was assessed in a BC patient cohort by tissue microarray immunohistochemistry (IHC) using the automated quantitative platform HaloTM. Among patients treated with systemic chemotherapy across all prognostic groups, high ezrin levels were associated with reduced disease-free, distant metastasis-free, as well as overall survival, compared to patients with lower ezrin levels. Next, we sought to determine whether targeting ezrin using a small molecule inhibitor (NSC668394) could enhance the efficacy of systemic doxorubicin treatment in vivo. Using an experimental lung metastasis model, we showed that the addition of NSC668394 sensitized metastatic BC cells to doxorubicin treatment, compared to either agent alone. We also tested the efficacy of these agents in targeting microscopic metastasis using neoadjuvant and adjuvant treatment models. Our results show that in both treatment modalities, NSC668394 or doxorubicin treatment alone was not able to reduce metastasis, however the addition of the ezrin inhibitor markedly sensitized metastases to doxorubicin and reduced overall lung metastatic burden. Taken together, our data suggest that ezrin may be a novel predictive marker of treatment response in BC patients and provide rationale for potential targeting of ezrin in patients with metastatic disease as an adjunct to chemotherapy. (Supported by OMPRN, CRS and BCAK).

Citation Format: Victoria Hoskin, Abdi Ghaffari, Xiaolong Yang, Yolanda Madarnas, Sandip SenGupta, Sonal Varma, Peter A. Greer, Bruce E. Elliott. Targeting the cytoskeleton protein ezrin sensitizes metastatic breast cancer cells to anthracycline based chemotherapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4187.

Novel prognostic and predictive microRNA targets for triple-negative breast cancer

Triple-negative breast cancers (TNBCs) account for ∼25% of all invasive carcinomas and represent a large subset of aggressive, high-grade tumors. Despite current research focused on understanding the genetic landscape of TNBCs, reliable prognostic and predictive biomarkers remain limited. Although dysregulated microRNAs (miRNAs) have emerged as key players in many cancer types, the role of miRNAs in TNBC disease progression is unclear. We performed miRNA profiling of 51 TNBCs by next-generation sequencing to reveal differentially expressed miRNAs. A total of 228 miRNAs were identified. Three miRNAs (miR-224-5p, miR-375, and miR-205-5p) separated the tumors based on basal status. Six miRNAs (high let-7d-3p, miR-203b-5p, and miR-324-5p; low miR-30a-3p, miR-30a-5p, and miR-199a-5p) were significantly associated with decreased overall survival (OS) and 5 miRNAs (high let-7d-3p; low miR-30a-3p, miR-30a-5p, miR-30c-5p, and miR-128-3p) with decreased relapse-free survival (RFS). On multivariate analysis, high expression of let-7d-3p and low expression of miR-30a were independent predictors of decreased OS and RFS. High expression of miR-95-3p was significantly associated with decreased OS and RFS in patients treated with anthracycline-based chemotherapy. Five miRNAs (let-7d-3p, miR-30a-3p, miR-30c-5p, miR-128-3p, and miR-95-3p) were validated by quantitative RT-PCR. Our findings unveil novel prognostic and predictive miRNA targets for TNBC, including a miRNA signature that predicts patient response to anthracycline-based chemotherapy. This may improve clinical management and/or lead to the development of novel therapies.-Turashvili, G., Lightbody, E. D., Tyryshkin, K., SenGupta, S. K., Elliott, B. E., Madarnas, Y., Ghaffari, A., Day, A., Nicol, C. J. B. Novel prognostic and predictive microRNA targets for triple-negative breast cancer.

Abstract P5-01-01: Real-time imaging of lymph node metastasis in response to systemic ezrin inhibitor treatment in breast cancer

Lymph node (LN) metastasis is a key driver of recurrence and survival in breast cancer (BC) patients. However, the mechanisms of metastatic dissemination of tumour cells from LNs to distant sites and their predictors of response to systemic therapy remain poorly understood, mainly due to a lack of non-invasive in vivo imaging models. We have recently described ezrin, a pro-metastatic crosslinker protein, as a regulator of tumour lymphangiogenesis and metastasis in BC (Breast Cancer Res. 2014; 16(5): 438). Furthermore, we demonstrated significant association of high ezrin expression with lymphovascular invasion in a cohort (n=63) of premenopausal patients with invasive BC (p =0.024). These findings prompted us to examine the role of ezrin in migration and invasion of metastatic tumour cells in LNs and their response to ezrin-targeted therapy. Using a locally accrued LN positive patient cohort (n=94), we demonstrated a significant association between high ezrin levels and reduced recurrence-free survival (univariate Log-rank test, p=0.033), suggesting that ezrin is a potential predictor of relapse in LN positive BC. To address the mechanistic role of ezrin in LN metastasis, we developed a novel intravital imaging model using a lymphatic reporter transgenic mouse (B6-prox1-mOrange2-pA-BAC) to examine the response of tumour-draining LN to anti-ezrin systemic therapy in real time. Next, we tested the effects of a small molecule ezrin inhibitor (NSC668394) in vitro and observed significant suppression of ezrin activation (p-T567) and cancer cell invasive phenotype. Intravital imaging of inguinal LN metastases, derived from subcutaneously implanted breast adenocarcinoma E0771-LMV (lung metastatic variant) cells, demonstrated significant reduction in mobility and invasiveness (Mann Whitney, p&lt;0.0001) of metastatic cells following systemic treatment with NSC668394 (0.5 mg/kg at 24h and 8h prior to imaging). Interestingly, LN metastases engagement by host T cell (CD3+) was notably increased, whereas T cell mobility was not affected by ezrin inhibition. Our findings present a novel non-invasive imaging model to study the LN metastasis response to anti-cancer therapy in real time, and provide new insight into the role of ezrin as a potential anti-metastatic target in BC.

(Supported by CRS, CIHR, CBCF, BCAK, Queen's SRC).

Citation Format: Ghaffari A, Hoskin V, Mullins G, Greer P, Kiefer F, Madarnas Y, SenGupta S, Elliott B. Real-time imaging of lymph node metastasis in response to systemic ezrin inhibitor treatment in breast cancer. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P5-01-01.

Locoregional therapy of locally advanced breast cancer: a clinical practice guideline

QUESTIONS

In female patients with locally advanced breast cancer (labc) and good response to neoadjuvant chemotherapy (nact), including endocrine therapy, what is the role of breast-conserving surgery (bcs) compared with mastectomy?In female patients with labc, is radiotherapy (rt) indicated for those who have undergone mastectomy?does locoregional rt, compared with breast or chest wall rt alone, result in a higher survival rate and lower recurrence rates?is rt indicated for those achieving a pathologic complete response (pcr) to nact?In female patients with labc who receive nact, is the most appropriate axillary staging procedure sentinel lymph node biopsy (slnb) or axillary dissection? Is slnb indicated before nact rather than at the time of surgery?How should female patients with labc that does not respond to initial nact be treated?

METHODS

This guideline was developed by Cancer Care Ontario's Program in Evidence-Based Care (pebc) and the Breast Cancer Disease Site Group (dsg). A systematic review was prepared based on literature searches conducted using the medline and embase databases for the period 1996 to December 11, 2013. Guidelines were located from that search and from the Web sites of major guideline organizations. The working group drafted recommendations based on the systemic review. The systematic review and recommendations were then circulated to the Breast Cancer dsg and the pebc Report Approval Panel for internal review; the revised document underwent external review. The full three-part evidence series can be found on the Cancer Care Ontario Web site.

RECOMMENDATIONS

For most patients with labc, modified radical mastectomy should be considered the standard of care. For some patients with noninflammatory labc, bcs can be considered on a case-by-case basis when the surgeon deems that the disease can be fully resected and the patient expresses a strong preference for breast preservation.For patients with labc, rt after mastectomy is recommended.It is recommended that, after bcs or mastectomy, patients with labc receive locoregional rt encompassing the breast or chest wall and local node-bearing areas.It is recommended that postoperative rt remain the standard of care for patients with labc who achieve pcr to nact.It is recommended that axillary dissection remain the standard of care for axillary staging in labc, with the judicious use of slnb in patients who are advised of the limitations of the current data.Although slnb either before or after nact is technically feasible, the data are insufficient to make any recommendation about the optimal timing of slnb with respect to nact. Limited data suggest higher sentinel lymph node identification rates and lower false negative identification rates when slnb is conducted before nact; however, those data must be balanced against the requirement for two operations if slnb is not performed at the time of resection of the main tumour.It is recommended that patients receiving neoadjuvant anthracycline-taxane-based therapy (or other sequential regimens) whose tumours do not respond to the initial agent or agents, or who experience disease progression, be expedited to the next agent or agents of the regimen.For patients who, in the opinion of the treating physician, fail to respond or progress on first-line nact, several therapeutic options can be considered, including second-line chemotherapy, hormonal therapy (if appropriate), rt, or immediate surgery (if technically feasible). Treatment should be individualized through discussion at a multidisciplinary case conference, considering tumour characteristics, patient factors and preferences, and risk of adverse effects.It is recommended that prospective randomized clinical trials be designed for patients with labc who fail to respond to nact so that more definitive treatment recommendations can be developed.

A novel role for ezrin in breast cancer angio/lymphangiogenesis

INTRODUCTION

Recent evidence suggests that tumour lymphangiogenesis promotes lymph node metastasis, a major prognostic factor for survival of breast cancer patients. However, signaling mechanisms involved in tumour-induced lymphangiogenesis remain poorly understood. The expression of ezrin, a membrane cytoskeletal crosslinker and Src substrate, correlates with poor outcome in a diversity of cancers including breast. Furthermore, ezrin is essential in experimental invasion and metastasis models of breast cancer. Ezrin acts cooperatively with Src in the regulation of the Src-induced malignant phenotype and metastasis. However, it remains unclear if ezrin plays a role in Src-induced tumour angio/lymphangiogenesis.

METHODS

The effects of ezrin knockdown and mutation on angio/lymphangiogenic potential of human MDA-MB-231 and mouse AC2M2 mammary carcinoma cell lines were examined in the presence of constitutively active or wild-type (WT) Src. In vitro assays using primary human lymphatic endothelial cells (hLEC), an ex vivo aortic ring assay, and in vivo tumour engraftment were utilized to assess angio/lymphangiogenic activity of cancer cells.

RESULTS

Ezrin-deficient cells expressing activated Src displayed significant reduction in endothelial cell branching in the aortic ring assay in addition to reduced hLEC migration, tube formation, and permeability compared to the controls. Intravital imaging and microvessel density (MVD) analysis of tumour xenografts revealed significant reductions in tumour-induced angio/lymphangiogenesis in ezrin-deficient cells when compared to the WT or activated Src-expressing cells. Moreover, syngeneic tumours derived from ezrin-deficient or Y477F ezrin-expressing (non-phosphorylatable by Src) AC2M2 cells further confirmed the xenograft results. Immunoblotting analysis provided a link between ezrin expression and a key angio/lymphangiogenesis signaling pathway by revealing that ezrin regulates Stat3 activation, VEGF-A/-C and IL-6 expression in breast cancer cell lines. Furthermore, high expression of ezrin in human breast tumours significantly correlated with elevated Src expression and the presence of lymphovascular invasion.

CONCLUSIONS

The results describe a novel function for ezrin in the regulation of tumour-induced angio/lymphangiogenesis promoted by Src in breast cancer. The combination of Src/ezrin might prove to be a beneficial prognostic/predictive biomarker for early-stage metastatic breast cancer.

Information needs of post-menopausal women with hormone receptor positive early-stage breast cancer considering adjuvant endocrine therapy

OBJECTIVE

To identify questions that post-menopausal women with receptor-positive early-stage breast cancer want answered before their adjuvant-endocrine-therapy decision is made.

METHODS

We surveyed patients eligible for adjuvant-endocrine therapy in the previous 3-18 months. Participants rated the importance of getting each of 95 questions answered before the decision is made (options: essential/desired/not important or no opinion/avoid). For each question rated "essential"/"desired", the participant also identified the purpose(s) for the answer: to help her understand, decide, plan, or other reason(s).

RESULTS

The response rate was 55% (188/343). Participants rated a mean of 57 (range: 1-95) questions "essential", 80 (range: 1-95) "essential" or "desired", and 2 (range: 0-27) "avoid". Every question was "essential" to ≥31% of participants, and "essential"/"desired" to ≥63%. All but eleven questions were rated as "avoid" by ≥1 participant. The most frequent purposes for "essential" questions were to: understand their situations (mean 45, range: 0-95), decide (mean 18, range: 0-94), and plan (mean 13, range: 0-95).

CONCLUSION

Many patients want a lot of information before this decision is made but there is wide variation within the group in both the number and in which questions they want answered.

PRACTICE IMPLICATIONS

Patient education in this setting needs to be tailored to the needs of the individual patient.

Real-world experience with adjuvant fec-d chemotherapy in four Ontario regional cancer centres

BACKGROUND

The efficacy of adjuvant chemotherapy with fec-d (5-fluorouracil-epirubicin-cyclophosphamide followed by docetaxel) is superior to that with fec-100 alone in women with early-stage breast cancer. As the use of fec-d increased in clinical practice, health care providers anecdotally noted higher-than-expected toxicity rates and frequent early treatment discontinuations because of toxicity. In the present study, we compared the rates of serious adverse events in patients who received adjuvant fec-d chemotherapy in routine clinical practice with the rates reported in the pacs-01 trial.

METHODS

We retrospectively reviewed all patients prescribed adjuvant fec-d for early-stage breast cancer at 4 regional cancer centres in Ontario. Information was collected from electronic and paper charts by a physician investigator from each centre. Data were analyzed using chi-square tests, independent samples t-tests, one-way analysis of variance, and univariate regression.

RESULTS

The 671 electronic and paper patient records reviewed showed a median patient age of 52.2 years, 229 patients (34.1%) with N0 disease, 508 patients (75.7%) with estrogen or progesterone receptor-positive disease (or both), and 113 patients (26%) with her2/neu-overexpressing breast cancer. Febrile neutropenia occurred in 152 patients (22.7%), most frequently at cycle 4, coincident with the initiation of docetaxel [78/152 (51.3%)]. Primary prophylaxis with hematopoietic growth factor support was used in 235 patients (35%), and the rate of febrile neutropenia was significantly lower in those who received prophylaxis than in those who did not [15/235 (6.4%) vs. 137/436 (31.4%); p < 0.001; risk ratio: 0.20].

CONCLUSIONS

In routine clinical practice, treatment with fec-d is associated with a higher-than-expected rate of febrile neutropenia, in light of which, primary prophylaxis with growth factor should be considered, per international guidelines. Adoption based on clinical trial reports of new therapies into mainstream practice must be done carefully and with scrutiny.

Immunohistochemical Assessment of Expression of Centromere Protein-A (CENPA) in Human Invasive Breast Cancer

Abnormal cell division leading to the gain or loss of entire chromosomes and consequent genetic instability is a hallmark of cancer. Centromere protein –A (CENPA) is a centromere-specific histone-H3-like variant gene involved in regulating chromosome segregation during cell division. CENPA is one of the genes included in some of the commercially available RNA based prognostic assays for breast cancer (BCa)—the 70 gene signature MammaPrint^® and the five gene Molecular Grade Index (MGI^SM). Our aim was to assess the immunohistochemical (IHC) expression of CENPA in normal and malignant breast tissue. Clinically annotated triplicate core tissue microarrays of 63 invasive BCa and 20 normal breast samples were stained with a monoclonal antibody against CENPA and scored for percentage of visibly stained nuclei. Survival analyses with Kaplan–Meier (KM) estimate and Cox proportional hazards regression models were applied to assess the associations between CENPA expression and disease free survival (DFS). Average percentage of nuclei visibly stained with CENPA antibody was significantly higher (p = 0.02) in BCa than normal tissue. The 3-year DFS in tumors over-expressing CENPA (>50% stained nuclei) was 79% compared to 85% in low expression tumors (<50% stained nuclei). On multivariate analysis, IHC expression of CENPA showed weak association with DFS (HR > 60.07; p = 0.06) within our small cohort. To the best of our knowledge, this is the first published report evaluating the implications of increased IHC expression of CENPA in paraffin embedded breast tissue samples. Our finding that increased CENPA expression may be associated with shorter DFS in BCa supports its exploration as a potential prognostic biomarker.

Patient adherence to aromatase inhibitor treatment in the adjuvant setting

Improvements in adjuvant systemic therapy and detection of early disease have resulted in a decline of breast cancer death rates across all patient age groups in Canada. Non-adherence to adjuvant hormonal therapy in the setting of early breast cancer may significantly affect patient outcome. Factors associated with medication adherence are complex and may be patient-related, therapy-related, and health care provider-related. To date, there is a gap in the literature concerning a comprehensive understanding of factors related to medication adherence with anti-estrogen therapy in the adjuvant setting. The literature suggests that strategies for improving adherence should focus on education of patients, assessment of the ability of patients to understand their disease and related recurrence factors, and facilitation of adherence by patients by providing adequate support and strategies for good self-management. However, more research is needed to better understand how health care providers can support women with breast cancer on oral therapy in the adjuvant setting.

Models of care for early-stage breast cancer in Canada

There is growing evidence that follow-up for patients with early breast cancer (ebc) can be effectively carried out by the primary health care provider if a plan is in place. Here, we present data from a recent survey conducted in Ontario indicating that a shared-care model could work if communication between all health professionals involved in the care of ebc patients were to be improved. Patients and primary care providers benefit when the specialist provides written information about what their roles are and what to expect. Primary care providers need to have easy access to the specialist to discuss areas of concern. Patients also need to share responsibility for their care, ensuring that they attend follow-up visits on a regular basis and that they discuss areas of concern with their primary health care provider. A shared-care model has the potential to provide the best care for the least cost to the health system.

An updated review on the efficacy of adjuvant endocrine therapies in hormone receptor-positive early breast cancer

The third-generation aromatase inhibitors (AIS) are largely replacing tamoxifen in the adjuvant treatment of early-stage breast cancer in postmenopausal women with hormone receptor–positive tumours. To date, multiple trials have been conducted comparing tamoxifen treatment with an AI, and all have demonstrated improved disease-free survival with AI treatment. Trials have included direct 5-year comparisons between tamoxifen and an AI, switching to an AI within 5 years after initial tamoxifen treatment, or extending treatment with an AI after 5 years of completed tamoxifen treatment. Some of these trials have been completed; others are ongoing; and head-to-head trial comparisons of individual AIS are also in progress. The present article summarizes the data obtained from various clinical trials of hormonal therapy for early breast cancer. It also reviews recent data so as to shed light on the current status of these therapies. The focus is on the efficacy of treatment with an AI. Toxicity is discussed in the second article in this supplement.

Abstract 3207: Automated quantitative analysis of p53, cyclin D1 and pErk expression in breast carcinoma does not differ from expert pathologist scoring and correlates well with clinico-pathological characteristics

Prognosis and risk assessment of breast cancer patients are currently driven by TNM stage, ER/PR/HER2 expression, tumor grade and lymphovascular invasion (LVI). However there is critical need for improved biomarker assessment platforms to better predict systemic treatment response. One roadblock is the lack of semi-quantitative methods to reliably measure expression, activity and localization of biomarkers in formalin-fixed tumor specimens. The present study assesses reliability of automated IHC scoring compared to manual scoring of routine and non-routine biomarkers (HER2, cyclin D1, p53 and phospho(p)-ERK) on a human breast cancer tissue microarray according to REMARK guidelines, and correlates these markers with clinical-pathological data.

Using a triplicate core TMA of formalin-fixed paraffin embedded tissues, we investigated 63 primary invasive breast cancers, for which ER/PR/HER2 status, LVI, grade and recurrence status were recorded. IHC was performed on the TMA for the above biomarkers (pH 6 citrate buffer conditions). Histologic (H) scores (% positive tumor area × staining intensity 0-3) were determined manually by two independent evaluators with resolution of discordant cases by a senior pathologist. Excellent replicability was observed between H scores for each marker compared on replicate slides, as determined by Spearman correlations (0.79-0.82). Each TMA slide was then scanned into the Ariol Imaging System, algorithms were trained for each marker, and H scores were calculated. Pearson correlation coefficients (with data left as continuous) and Kappa statistics (with dichotomized data) were used for inter-method comparisons. Associations between biomarker positivity and clinical data were assessed by Fisher's exact test.

Excellent concordance between manual and automated Ariol scores was observed for all four markers based on Kappa statistics (0.667-0.813) and Pearson correlation coefficients (0.790-0.885). Distinct proportions of tumor cases showed any positive staining for membranous HER2 (19/63), nuclear p53 (16/56), cyclin D1 (26/57) and pERK (32/59). A statistically significant association of pERK positivity with absence of LVI (p=0.0025) and lymph node negativity (p=0.0006) was observed. In contrast, pERK positivity was associated with high-grade tumors (p=0.0040), consistent with a role of pERK in poorly differentiated high-grade primary tumors. p53 over-expression, characteristic of dysfunctional p53 in breast cancer, was also associated with high tumor grade (p=0.0074). Thus automated quantitation of immunostaining yields objective results that do not differ from pathologists’ scoring, and provide meaningful associations with clinico-pathological data. (Supported by CIHR, PSI, and Queen's Dept. Pathol. & Mol. Med.)

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 3207. doi:10.1158/1538-7445.AM2011-3207

Abstract P2-06-11: Ramifications of HER2/ER/PR Guidelines from ASCO/CAP for Translational Cancer Research Using a Cohort from a Tertiary Care Centre in Ontario

Background: A transdisciplinary team from basic science, pathology, clinical and biostatistics was assembled to establish a framework with which to take novel laboratory biomarkers and targets to clinical validation. Human epidermal growth factor receptor (HER2), estrogen (ER) and progesterone (PR) receptor are of important prognostic and predictive value and drivers of systemic therapy for breast cancer (BC). As a first step, the current ASCO/CAP guidelines were used to re-assign centrally reviewed tumour specimens and compare to the clinically assigned scores for ER/PR and HER2.

Methods: With REB approval, a cohort of 62 cases of non-metastatic invasive BC with banked tumour specimens was assembled between 2005 and 2007. Clinico-pathological information for each case was retrospectively obtained from the medical file and entered into an anonymized database. Full section slides were originally stained by routine immunohistochemistry (IHC). Categorical clinical scores for ER/PR (negative-neg/weak/positive-pos) were compared to the continuous scores assigned in a blinded fashion using ASCO/CAP criteria (% pos/H-score). Categorical clinical scores obtained with duplicate IHC antibody staining of full sections for HER2 (neg/equivocal-eq/pos) were compared to those obtained from IHC assessments of triplicate 6mm cores in a tissue microarray (TMA) that were assigned to be neg/eq/pos using ASCO/CAP criteria. A senior breast pathologist adjudicated discordant specimens. Exact Fisher tests were used to compare the two sets of categorical assessments.

Results: Mean age was 43.5 years, (range 29-49). The majority of the cohort (59.7%) had N0 disease and received adjuvant chemotherapy (74.2%); 72.6% of the cohort was alive at the time of this analysis. Score means and ranges of ER/PR are displayed below. Two of 16 clinically ER neg cases (12.5%) were rescored as pos and 0/43 clinically ER pos cases were rescored as neg, P&lt;0.0001. Two of 13 clinically PR neg cases (15.4%) were rescored as pos and 4/46 clinically PR pos cases (8.7%) were rescored as neg, (P&lt;0.0001). HER2 status was reassessed for 51 cases, 41 of which (80%) had concordant scores (P&lt;0.0001). Thirty-nine (76%) cases were classified as HER2 neg on TMA, 7 of which (18%) were eq on routine IHC and neg by fluorescence in situ hybridization. In routine IHC, 15.7% of tumours were eq. Four TMA cases were eq (7.8%%); with routine IHC, one of these was neg, one eq, and two were pos. Eight patients were HER2 pos in both assessments.

ER/PR scores

Conclusions: Systemic therapy recommendations could be impacted in a small but substantive number of cases by the methodology used for biomarker assessment and scoring, particularly near threshold values. This study illustrates that the scoring criteria used may be an important contributor to variability in correlative biomarker studies. Consideration should be given to routine systematic reassessment with continuous scoring for biomarker data proposed for use in correlative science studies.

A Population Based Patterns of Care Study for Male Breast Cancer in Ontario

Background: Tamoxifen has been the standard endocrine treatment for both early breast cancer (EBC) and metastatic breast cancer (MBC) in women for over 30 years(y). Over the last decade the third generation aromatase inhibitors (AIs) have proven effective in the treatment of MBC and are incorporated into adjuvant therapy for EBC. Due to the rarity of male breast cancer there are no trials to guide therapy and treatment decisions in men are made by extrapolation from the existing published data for women. We set out to conduct a population based cohort study in the most populous Canadian province to describe contemporary patterns of Tamoxifen and AI use for male breast cancer from 1992-2007.Methods: In the province of Ontario cancer reporting is mandatory and date of diagnosis (Dx) and death are collected by the Ontario Cancer Registry (OCR), but stage information is not uniformly available. The government of Ontario subsidizes drugs for individuals &gt;65y through the Ontario Drug Benefits (ODB) program and maintains electronic prescription records for all eligible citizens. Linkage of these administrative databases allowed us to assemble a cohort of male breast cancer cases in order to describe patterns of endocrine therapy and outcomes.Results: Through OCR we identified 845 cases of invasive male breast cancer (ICD9 175) with a date of Dx between 03Jan1992 and 27Dec2007. Mean age at the time of Dx was 66.9 ±12.6y, median age was 68y, range 16-97y respectively. A total of 490 men were ≥66y at Dx. Using ODB prescription records between 01Jan1992 and 31Dec2008 we looked for a first prescription for any of the following drugs: Tamoxifen(T), Anastrozole(A), Letrozole(L), or Exemestane(E). As stage information is not uniformly available in OCR, prescription &lt;12 months from Dx was used as a surrogate for therapy with adjuvant intent (EBC group) and those with a first prescription for T or an AI &gt;12 months from Dx were classified as MBC. Using these criteria, 172 cases received no prescription for endocrine therapy (35.0% stage unknown), 297 cases were EBC (271 prescribed T (55.3%) and 26 prescribed an AI (5.3%) &lt; 1 y of Dx and 21 (4.3%) were MBC being prescribed either T or an AI &gt; 1 y post Dx. Prescription of endocrine therapy increased over time: 60% (92-99) vs. 68% in (00-08) At a median follow up of 46.3 months overall survival(OS) is 64.96% for the entire group, 53.27% for stage unknown, 72.17% for EBC and 60.53% for MBC and has not changed significantly over time; 66.33% for 92-99 and 64% for 00-08 for the group as a whole.Conclusions: In this provincial cohort of male breast cancer spanning a 15 y period we observed that: 1) most men are prescribed some form of adjuvant endocrine therapy and in keeping with the paucity of data for AIs in male breast cancer, Tamoxifen was the most commonly prescribed agent; 2) use of endocrine therapy increased over time; 3) overall survival has not changed significantly over time. This study is limited by its use of administrative data, retrospective nature, and by the surrogate assignation of stage. That said, it does represent the largest cohort of male breast cancer and describes trends in modern endocrine therapy.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 2108.

Patterns of care and outcomes of locally advanced breast cancer at the Cancer Centre of Southeastern Ontario

e11614

Background: Preoperative chemotherapy (PCT) is the standard of care for locally advanced breast cancer (LABC). As part of a multicentre provincial initiative we undertook a review of practice patterns and outcomes for women with LABC at our institution. Methods: We reviewed electronic and paper records for M0 pts receiving PCT for LABC between 1995–2007 at our institution, collecting demographic, disease and treatment-related, and outcome variables. Results: Sixty pts with LABC who received PCT were included in this review. Median age was 54y (31–80), 38% premenopausal. Median BMI was 28kg/m2, 78% were overweight or obese. Stage distribution: 10% IIB, 11% IIIA, 77% IIIB and 2% IIIC, of which 45% had inflammatory breast cancer (IBC). At biopsy 90% were invasive ductal carcinoma, 36% were ER and PR(-) and 25% were her2(+). Median time from surgical consultation to PCT was 22d (6–126). PCT was anthracycline-based alone in 85% of pts, 8% received a taxane, 3% also received preop endocrine therapy (ET), no pts received trastuzumab (T) preop. Pts received a median of 6 (3–8) cycles of PCT. Local therapy: mastectomy (M) in 82% of pts and partial M in 11%. Axillary surgery was done in only 92% of pts (axillary node dissection 90%, sentinel node biopsy 1pt) and 7% had no definitive breast or axillary surgery due to local progression (3) or refusal (1). All pts received radiotherapy. Postop systemic therapy: CT in 5% of pts, ET in 65% and T in 10% of pts. Clinical complete response (CR) rate was 28%. At definitive surgery 10% of pts had no residual disease in breast or axilla and 3 pts had only DCIS present, for a pathologic (p)CR rate of 15% using MDACC criteria. Median follow-up was 24mo (1–238). Median 5y DFS was not reached for the entire population and those with a pCR vs. 26mo for pts with IBC; corresponding 5y DFS rates were 58%, 78%, and 41% respectively. Median 5y OS was for the entire population was 52mo vs. 48mo for pts with a pCR and 47mo in the IBC group; corresponding 5y OS rates were 62%, 78% and 44% respectively. Conclusions: Management of LABC in our cohort is fairly uniform and consistent with current guidelines. Local outcomes of LABC managed with PCT are in keeping with the published literature and arguably better since almost half of our cohort is represented by IBC which carries a worse prognosis.

No significant financial relationships to disclose.

Cardiac toxicity and adjuvant trastuzumab for breast cancer – the Cancer Centre of Southeastern Ontario experience

Abstract #3158

Background: In May 2005 several large randomized trials reported a significant improvement in DFS following the addition of trastuzumab (T) to adjuvant chemotherapy (CT) in early stage breast cancer (BC) such that in the summer of 2005 adjuvant T became standard of care for patients (pts) whose tumors over-expressed her2. Cardiotoxicity had been reported as the main toxicity suffered by pts exposed to T. As the generalizability of clinical trial results to the 'real world' is under increasing scrutiny from the oncology community, we undertook this study to identify and follow the population of interest and to characterize cardiac toxicity related to adjuvant T as practice changed.&#x2028; Methods: We conducted a retrospective review of electronic and paper records of all pts prescribed adjuvant T for early stage BC at the Cancer Centre of Southeastern Ontario from June 2005 through January 2007; collecting demographic, disease-related, and treatment-related variables, along with serial left ventricular ejection fraction (LVEF) measurements for each pt.&#x2028; Results: 54 pts prescribed adjuvant T were identified in this time period, nearly half of which were still on T at the time of this analysis. Mean age was 54.4 ± 9.5 years, 38.9% had N0 disease, and 40.7% had left sided tumors, with 42.6% being ER+ and 50% being PR+. Most pts received anthracycline based CT (53.7%) and 39% received an anthracycline/taxane combination. T was concurrently with CT in 14.8% of pts, concurrently with radiotherapy in 33.3% and sequentially in the remainder. T was initiated at a mean of 91.2 days from completion of chemotherapy (range 19-365). Our local protocol mandated LVEF assessments at baseline pre CT, upon completion of CT and/or prior to initiation of T for all pts, and while on T all pts underwent LVEF assessments at 12, 24, 36, 48 and 52 weeks, and in response to any symptoms suggesting cardiac dysfunction. Mean LVEF pre CT and post CT was 64% and 62% respectively. We saw no change in LVEF post CT and pre T. We noted a significant decline in LVEF after 12 weeks on T, from 60.5 ± 6.2% to 56.5 ± 9.5% respectively (p = 0.003), with LVEF values remaining stable thereafter. However, at the time of this analysis only approximately half the pts had completed the full year of therapy. Twelve pts (22.2%) interrupted their T therapy due to a drop in LVEF of &gt;10%, only one pt experienced symptomatic cardiotoxicity requiring treatment. Of these twelve, only two pts restarted T at a later date. Follow-up of those patients still on trastuzumab is ongoing.&#x2028; Discussion: Adjuvant trastuzumab in general clinical practice is associated with significant decreases in LVEF that are associated with premature discontinuation of therapy. A better understanding of factors associated with LVEF decline and the trends in LVEF over time may allow for targeted interventions for pts at risk.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 3158.

Breast cancer in pregnancy: a literature review

PURPOSE

Breast cancer in pregnancy is a clinically challenging situation for patients and their physicians. A review of the literature was performed to help identify optimal treatment strategies.

METHODS

A Medline search between 1966 to the present using the keywords "breast", "carcinoma", and "pregnancy" revealed numerous hits, from which English-language articles including epidemiologic studies, case series, and general summaries were reviewed.

RESULTS

There is a paucity of prospective studies regarding diagnosis and treatment of breast cancer in pregnancy due to its rarity. However a general review of the literature database reveals that women diagnosed with breast cancer during pregnancy have similar disease characteristics to age-matched controls. Surgery remains the mainstay of treatment of breast cancer during pregnancy, and in some circumstances breast-conserving surgery is an acceptable option. Adjuvant treatment can proceed with some modifications that minimize harm to the fetus, namely limiting radiation exposure and timing chemotherapy properly. Post-partum decisions regarding lactation and future fertility should be addressed on a per-patient basis.

CONCLUSION

Breast cancer in pregnancy is an uncommon phenomenon but one which poses dilemmas for patients and their physicians. A multi-disciplinary approach is recommended for optimal clinical-decision making.

Fasting insulin and outcome in early-stage breast cancer: results of a prospective cohort study

PURPOSE

Insulin, a member of a family of growth factors that includes insulin-like growth factor (IGF)-I and IGF-II, exerts mitogenic effects on normal and malignant breast epithelial cells, acting via insulin and IGF-I receptors. Because of this and because of its recognized association with obesity, an adverse prognostic factor in breast cancer, we examined the prognostic associations of insulin in early-stage breast cancer.

PATIENTS AND METHODS

A cohort of 512 women without known diabetes, who had early-stage (T1 to T3, N0 to N1, and M0) breast cancer, was assembled and observed prospectively. Information on traditional prognostic factors and body size was collected, and fasting blood was obtained.

RESULTS

Fasting insulin was associated with distant recurrence and death; the hazard ratios and 95% confidence intervals (CI) for those in the highest (> 51.9 pmol/L) versus the lowest (< 27.0 pmol/L) insulin quartile were 2.0 (95% CI, 1.2 to 3.3) and 3.1 (95% CI, 1.7 to 5.7), respectively. There was some evidence to suggest that the association of insulin with breast cancer outcomes may be nonlinear. Insulin was correlated with body mass index (Spearman r = 0.59, P <.001), which, in turn, was associated with distant recurrence and death (P <.001). In multivariate analyses that included fasting insulin and available tumor- and treatment-related variables, adjusted hazard ratios for the upper versus lower insulin quartile were 2.1 (95% CI, 1.2 to 3.6) and 3.3 (95% CI, 1.5 to 7.0) for distant recurrence and death, respectively.

CONCLUSION

Fasting insulin level is associated with outcome in women with early breast cancer. High levels of fasting insulin identify women with poor outcomes in whom more effective treatment strategies should be explored.

Are medical oncologists biased in their treatment of the large woman with breast cancer?

PURPOSE

Obesity and breast cancer are common conditions that often coexist. Concerns of relative overdosing of chemotherapy in the large cancer patient have led clinicians to apply empiric dose reductions, 'cap' the body surface area (BSA) at 2 m2, or use ideal rather than actual body weight to calculate BSA. There are no data supporting or refuting these practices and their prevalence is unknown. We sought to determine the distribution of body size and prevalence of obesity in the breast cancer population of our cancer centre, and to determine clinician chemotherapy dosing practices in the era of modern adjuvant chemotherapy.

PATIENTS AND METHODS

Women with invasive breast cancer receiving systemic therapy at our institution between 1980 and 1998 were identified and their recorded height and weight were used to calculate BSA and body mass index (BMI). We reviewed the first cycle adjuvant chemotherapy dosing practices from 1990-1998. The ideal dose of chemotherapy was calculated based on calculated BSA, and then contrasted with the actual dose received at cycle one. Discrepancies were recorded and categorized, using the largest single drug reduction if more than one drug was reduced.

RESULTS

Mean BMI in the systemic therapy population was 26.4 +/- 5.3 kg/m2, 54% were overweight, 2% severely obese and 18% moderately so. Their mean BSA was 1.7 +/- 0.2 m2 and only 5% had a BSA > or = 2 m2. In the adjuvant chemotherapy subgroup, most patients received > or = 85% of their ideal dose. The mean dose reduction was 5.3 +/- 11.3% versus 9.9 +/- 11.3% in the BSA < 2 and > or = 2 m2 groups, respectively (p = 0.02), and 4.3 +/- 8.2% versus 6.7 +/- 13.1% in the BMI < 25 and > or = 25 kg/m2 groups, respectively (p = 0.008). While only 24% of chemotherapy dose reductions of > or = 15% were in the BSA > or = 2 m2 group, 76% were in the BMI > or = 25 kg/m2 group.

CONCLUSIONS

Obesity is prevalent in this breast cancer population. BSA is not a sensitive index of large body size. We consistently detected more frequent empiric dose reductions at cycle one of adjuvant chemotherapy, with reductions of greater magnitude in the largest women (BSA > or = 2 m2) and those who were overweight (BMI > or = 25 kg/m2).

Irinotecan-associated pulmonary toxicity

We present the circumstances surrounding a 57-year-old Caucasian man with advanced colorectal cancer who developed relapsing interstitial lung disease following a single exposure to irinotecan (CPT-11). Progressive pulmonary insufficiency and death were reported in the initial Japanese studies, despite institution of empiric steroid therapy for a syndrome similar to that which our patient experienced. As a result, patients with compromised pulmonary function were generally excluded from US clinical trials. Notwithstanding this, cough and dyspnea were reported in approximately 20% of patients in the US studies. As the clinical indications for the use of this agent expand, we describe irinotecan-associated interstitial pneumonitis as a serious potential adverse effect. Patients with pre-existing pulmonary disease may be at higher risk for this complication and clinicians should be alert to this possibility.