Shaveta Vinayak

Phase II Study of Gemcitabine, Carboplatin, and Iniparib As Neoadjuvant Therapy for Triple-Negative and BRCA1/2 Mutation–Associated Breast Cancer With Assessment of a Tumor-Based Measure of Genomic Instability: PrECOG 0105

PURPOSE This study was designed to assess efficacy, safety, and predictors of response to iniparib in combination with gemcitabine and carboplatin in early-stage triple-negative and BRCA1/2 mutation-associated breast cancer. PATIENTS AND METHODS This single-arm phase II study enrolled patients with stage I to IIIA (T ≥ 1 cm) estrogen receptor-negative (≤ 5%), progesterone receptor-negative (≤ 5%), and human epidermal growth factor receptor 2-negative or BRCA1/2 mutation-associated breast cancer. Neoadjuvant gemcitabine (1,000 mg/m(2) intravenously [IV] on days 1 and 8), carboplatin (area under curve of 2 IV on days 1 and 8), and iniparib (5.6 mg/kg IV on days 1, 4, 8, and 11) were administered every 21 days for four cycles, until the protocol was amended to six cycles. The primary end point was pathologic complete response (no invasive carcinoma in breast or axilla). All patients underwent comprehensive BRCA1/2 genotyping, and homologous recombination deficiency was assessed by loss of heterozygosity (HRD-LOH) in pretreatment core breast biopsies. RESULTS Among 80 patients, median age was 48 years; 19 patients (24%) had germline BRCA1 or BRCA2 mutations; clinical stage was I (13%), IIA (36%), IIB (36%), and IIIA (15%). Overall pathologic complete response rate in the intent-to-treat population (n = 80) was 36% (90% CI, 27 to 46). Mean HRD-LOH scores were higher in responders compared with nonresponders (P = .02) and remained significant when BRCA1/2 germline mutations carriers were excluded (P = .021). CONCLUSION Preoperative combination of gemcitabine, carboplatin, and iniparib is active in the treatment of early-stage triple-negative and BRCA1/2 mutation-associated breast cancer. The HRD-LOH assay was able to identify patients with sporadic triple-negative breast cancer lacking a BRCA1/2 mutation, but with an elevated HRD-LOH score, who achieved a favorable pathologic response. Confirmatory controlled trials are warranted.

18F-FDG PET/CT for Monitoring of Treatment Response in Breast Cancer

Changes in tumor metabolic activity have been shown to be an early indicator of treatment effectiveness for breast cancer, mainly in the neoadjuvant setting. The histopathologic response at the completion of chemotherapy has been used as the reference standard for assessment of the accuracy of 18F-FDG PET in predicting a response during systemic treatment. Although a pathologic complete response (pCR) remains an important positive prognostic factor for an individual patient, a recent metaanalysis could validate pCR as a surrogate marker for patient outcomes only in aggressive breast cancer subtypes. For establishment of the clinical application of metabolic treatment response studies, larger series of specific breast cancer subtypes—including hormone receptor–positive, human epidermal growth factor receptor 2–positive, and triple-negative breast cancers—are necessary. In addition, thresholds for relative changes in 18F-FDG uptake to distinguish between responding and nonresponding tumors need to be validated for different systemic treatment approaches, with progression-free survival and overall survival as references. A PET-based treatment stratification is applicable clinically only if valid alternative therapies are available. Of note, patients who do not achieve a pCR might still benefit from neoadjuvant therapy enabling breast-conserving surgery. In the metastatic setting, residual tumor metabolic activity after the initiation of systemic therapy is an indicator of active disease, whereas a complete resolution of metabolic activity is predictive of a successful treatment response.

Tumor BRCA1 Reversion Mutation Arising During Neoadjuvant Platinum-Based Chemotherapy in Triple-Negative Breast Cancer Is Associated with Therapy Resistance

Purpose: In germline BRCA1 or BRCA2 (BRCA1/2) mutation carriers, restoration of tumor BRCA1/2 function by a secondary mutation is recognized as a mechanism of resistance to platinum and PARP inhibitors, primarily in ovarian cancer. We evaluated this mechanism of resistance in newly diagnosed patients with BRCA1/2-mutant breast cancer with poor response to neoadjuvant platinum-based therapy. Experimental Design: PrECOG 0105 was a phase II neoadjuvant study of gemcitabine, carboplatin, and iniparib in patients with stage I–IIIA triple-negative or BRCA1/2 mutation–associated breast cancer (n = 80). All patients underwent comprehensive BRCA1/2 genotyping. For mutation carriers with moderate or extensive residual disease after neoadjuvant therapy, BRCA1/2 status was resequenced in the residual surgical breast tumor tissue. Results: Nineteen patients had a deleterious germline BRCA1/2 mutation, and four had moderate residual disease at surgery. BRCA1/2 sequencing of residual tissue was performed on three patients. These patients had BRCA1 1479delAG, 3374insGA, and W1712X mutations, respectively, with LOH at these loci in the pretreatment tumors. In the first case, a new BRCA1 mutation was detected in the residual disease. This resulted in a 14–amino acid deletion and restoration of the BRCA1 reading frame. A local relapse biopsy 4 months later revealed the identical reversion mutation, and the patient subsequently died from metastatic breast cancer. Conclusions: We report a BRCA1 reversion mutation in a patient newly diagnosed with triple-negative breast cancer that developed over 18 weeks of platinum-based neoadjuvant therapy. This was associated with poor therapy response, early relapse, and death. Clin Cancer Res; 23(13); 3365–70. ©2017 AACR.

Neoadjuvant therapy for early-stage breast cancer: the clinical utility of pertuzumab

Approximately 20% of breast cancer patients harbor tumors that overexpress human epidermal growth factor receptor 2 (HER2; also known as ErbB2), a receptor tyrosine kinase that belongs to the epidermal growth factor receptor family of receptor tyrosine kinases. HER2 amplification and hyperactivation drive the growth and survival of breast cancers through the aberrant activation of proto-oncogenic signaling systems, particularly the Ras/MAP kinase and PI3K/AKT pathways. Although HER2-positive (HER2+) breast cancer was originally considered to be a highly aggressive form of the disease, the clinical landscape of HER2+ breast cancers has literally been transformed by the approval of anti-HER2 agents for adjuvant and neoadjuvant settings. Indeed, pertuzumab is a novel monoclonal antibody that functions as an anti-HER2 agent by targeting the extracellular dimerization domain of the HER2 receptor; it is also the first drug to receive an accelerated approval by the US Food and Drug Administration for use in neoadjuvant settings in early-stage HER2+ breast cancer. Here, we review the molecular and cellular factors that contribute to the pathophysiology of HER2 in breast cancer, as well as summarize the landmark preclinical and clinical findings underlying the approval and use of pertuzumab in the neoadjuvant setting. Finally, the molecular mechanisms operant in mediating resistance to anti-HER2 agents, and perhaps to pertuzumab as well, will be discussed, as will the anticipated clinical impact and future directions of pertuzumab in breast cancer patients.

Interferon-beta represses cancer stem cell properties in triple-negative breast cancer

Significance Current cancer therapies fail to repress tumor recurrence and metastasis in triple-negative breast cancer (TNBC) because they fail to target cells that possess epithelial–mesenchymal (E-M) plasticity and acquire cancer stem cell (CSC) properties. Identifying and engaging signaling pathways that regulate E-M/CSC plasticity within TNBC therefore remains an unmet critical clinical need. Recent evidence demonstrates that presence of E-M/CSC plasticity in TNBC correlates with a repressed interferon/STAT gene signature. Our data demonstrate that exogenous IFN-β targets and represses E-M/CSC plasticity by reengaging type I IFN signaling in CSC. Our findings have clinical relevance, as IFN-β signaling correlates with improved patient survival and repressed CSC in TNBC. Thus, our work suggests a therapeutic use for IFN-β in the repression of E-M/CSC–driven tumor recurrence and metastasis in TNBC. Triple-negative breast cancer (TNBC), the deadliest form of this disease, lacks a targeted therapy. TNBC tumors that fail to respond to chemotherapy are characterized by a repressed IFN/signal transducer and activator of transcription (IFN/STAT) gene signature and are often enriched for cancer stem cells (CSCs). We have found that human mammary epithelial cells that undergo an epithelial-to-mesenchymal transition (EMT) following transformation acquire CSC properties. These mesenchymal/CSCs have a significantly repressed IFN/STAT gene expression signature and an enhanced ability to migrate and form tumor spheres. Treatment with IFN-beta (IFN-β) led to a less aggressive epithelial/non–CSC-like state, with repressed expression of mesenchymal proteins (VIMENTIN, SLUG), reduced migration and tumor sphere formation, and reexpression of CD24 (a surface marker for non-CSCs), concomitant with an epithelium-like morphology. The CSC-like properties were correlated with high levels of unphosphorylated IFN-stimulated gene factor 3 (U-ISGF3), which was previously linked to resistance to DNA damage. Inhibiting the expression of IRF9 (the DNA-binding component of U-ISGF3) reduced the migration of mesenchymal/CSCs. Here we report a positive translational role for IFN-β, as gene expression profiling of patient-derived TNBC tumors demonstrates that an IFN-β metagene signature correlates with improved patient survival, an immune response linked with tumor-infiltrating lymphocytes (TILs), and a repressed CSC metagene signature. Taken together, our findings indicate that repressed IFN signaling in TNBCs with CSC-like properties is due to high levels of U-ISGF3 and that treatment with IFN-β reduces CSC properties, suggesting a therapeutic strategy to treat drug-resistant, highly aggressive TNBC tumors.

Role of Platinum in Early-Stage Triple-Negative Breast Cancer

Opinion statementTriple-negative breast cancer (TNBC) is both a clinically and genomically heterogeneous disease, with distinct molecular subtypes; however, most epidemiologic and clinical studies to date have defined it under a “one disease” umbrella. This is an important point, since one therapeutic approach for all TNBCs is unlikely to be successful given the underlying biological diversity. In this review, we explore the role of platinums in the treatment of TNBC, as well as the potential for biomarkers to predict patient response to these agents. The results of neoadjuvant TNBC trials, with addition of platinum to anthracycline/taxane-based chemotherapies, have been very encouraging given increases in pathologic complete response (pCR) rates. However, we do not have any evidence yet that these agents would lead to improvement in disease-free and overall survival. Moreover, addition of platinums increases toxicity and can compromise current standard chemotherapy doses, which further impedes their use in all TNBC patients. Therefore, the addition of platinums to standard chemotherapy should be used with caution and in discussion with patients after a careful assessment of risks and benefits. Clinical trials addressing the role of platinums in TNBC further remain of significant value.

Abstract P3-04-07: Androgen receptor expression in triple negative breast cancer

Background: Patients with androgen receptor (AR) positive triple-negative breast cancer (TNBC) may derive a significant benefit from anti-androgen therapy. While AR positivity is often defined by protein expression by immunohistochemistry (IHC), the benefit of anti-androgen therapy in patients who have the Luminal Androgen Receptor (LAR) molecular subtype as defined by genomic profiling is unclear. Our aim was to study the clinical, pathologic and molecular profiles of AR+ tumors by IHC in a diverse set of TNBC. Methods: Tissue microarrays from two separate, well-annotated institutional cohorts (Case Western Reserve University, Yale University) of early-stage TNBC were evaluated for AR expression by IHC (clone SP107, Ventana Benchmark Ultra). AR positivity was defined as greater than or equal to 10% staining in tumor nuclei. AR expression was correlated with clinical and pathologic features such as age, race, grade, and stage within and between the two cohorts. Gene expression was analyzed with the DASL assay (Illumina) on RNA extracted from formalin-fixed paraffin-embedded material using the Ambion RecoverAll kit (Applied Biosystems AM1975). Pietenpol TNBC molecular subtypes were calculated using the online TNBC type tool. Co-expression of AR with other hormone-related proteins including gross cystic disease fluid protein-15 (GCDFP-15, clone EP1582Y, Ventana Benchmark Ultra) and GATA transcription factor 3 (GATA3, clone L50-823, Bondmax Leica) were also assessed. Results: Overall, 22% of cases (n=192) were AR+ by IHC. There was no association between AR expression and age, race, grade or stage within or between the two cohorts. Gene expression data was available on 88 tumors with AR staining results and demonstrated that AR positivity by IHC was not exclusive for the TNBC LAR molecular subtype. Three of five (3/5) tumors that were classified and LAR were in fact AR+ by IHC. Tumors that were AR+ by IHC were also identified in the basal-like 2 (BL2), mesenchymal stem-like (MSL), immunomodulatory (IM), and unstable molecular TNBC categories with low frequency. Notably, of cases that were rejected as ER+ by gene expression profiling despite being clinically TNBC, three of five (3/5) were in fact AR+ by IHC. Examination of other hormone-related proteins in a subset of these patients revealed that AR expression was significantly associated with GCDFP-15 expression (p=0.0007) and was borderline significant for GATA3 expression (p=0.068). Conclusions: AR protein expression levels by IHC were similar in two separate institutional archival cohorts of TNBC and did not correlate with age, race, grade or stage. Comparison of AR IHC data with genomic data suggests that the AR+ phenotype is not unique to LAR subtype of TNBC by gene expression profiling. AR protein expression may be seen in clinically TNBC patients who have a more luminal subtype as evidenced by co-expression of GCDFP-15 and GATA3. Our results suggest that AR staining by IHC may be necessary to capture all patients who may benefit from anti-androgen therapy. Citation Format: Hannah Gilmore, Vinay Varadan, Nicole Williams, Cheryl L Thompson, Stephanie Kim, Peter Hsu, Kristy Miskimen, Aditi Palkar, Shaveta Vinayak, Robert Lindner, Lyndsay Harris. Androgen receptor expression in triple negative breast cancer [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P3-04-07.

Abstract P5-04-03: Deconvoluting immune cell populations using ‘in silico flow cytometry’ with CIBERSORT: Association with neoadjuvant therapy response and genomic instability in TNBC

Background: Increased tumor infiltrating lymphocytes (TILs) are prognostic and predictive of therapy response in TNBC. CIBERSORT, a highly novel ‘in silico flow cytometry’ gene expression-based method, can assess the overall immune content and relative levels of distinct leukocyte subsets in tumors. Methods: We applied CIBERSORT to PrECOG 0105, a neoadjuvant trial of carboplatin, gemcitabine and iniparib for patients with clinical stage I-IIIA TN or BRCA1/2 mutation-associated BC. HE R 0.70, p Conclusions: Neoadjuvant platinum-based therapy response significantly associates with both iTILs and CIBERSORT immune score. A measure of global genomic instability (HRD score) significantly associates with immune score alone. Enumeration of 23 leukocyte subsets in therapy-naive TNBC by CIBERSORT revealed three distinct cell types that significantly predict pCR, two of which also associate with genomic instability. These results suggest an intimate interplay between genomic instability and immune infiltration, potentially shaping adaptive anti-tumor humoral immune responses, and thereby affecting neoadjuvant response in TNBC. Citation Format: Shaveta Vinayak, Aaron Newman, Sylvia Adams, Anosheh Afghahi, Kristin C Jensen, Sunil S Badve, James M Ford, Ash A Alizadeh, Melinda L Telli. Deconvoluting immune cell populations using ‘in silico flow cytometry’ with CIBERSORT: Association with neoadjuvant therapy response and genomic instability in TNBC [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P5-04-03.

Abstract P6-16-03: Intrinsic subtypes and MRI patterns in brain metastasis associated with breast cancer

Background: Breast cancer is the 2nd most common cancer to metastasize to the brain. The development of brain metastasis (BM) is associated with a lower median survival compared with other locations of metastasis and carries with it high morbidity and reduced quality of life. There are limited treatment options and virtually no approved targeted therapies for this disease. We have previously reported specific pathways enriched in BM compared to primary tumors and now further this study to examine pathways by intrinsic subtype and location of and number of BM. Methods: Archival FFPE material was obtained from BM using pathology records; clinical data, including MRI images, was retrieved from medical records and institutional tumor registry under an IRB protocol. Tumor DNA/RNA was extracted from 2 mm cores macrodissected from the FFPE tissue blocks using the Qiagen AllPrep DNA/RNA FFPE kit. Gene expression profiling was performed using Affymetrix Human Transcriptome Array 2.0 microarray on BM samples for which sufficient RNA was available. Gene-level expression quantification was derived after RMA normalization using the Affymetrix Transcriptome Analysis Console. PAM50 subtypes were assigned by clustering samples using median-subtracted PAM50 gene expression levels. Differential gene expression was estimated using the non-parametric Mann-Whitney test, followed by assessment of false discovery rate using the Banjamini-Hochberg FDR methodology. Pathway enrichment analysis was performed using the NCI Pathway Interaction Database. Results: Gene expression profiling showed the following intrinsic subtype distribution among all BM: luminal A 32% (19/59), luminal B 31% (18/59), HER2 enriched 7% (4/59), and basal subtype 31% (18/59). At time of development of BM 64% (38/59) of patients presented with a single lesion compared to 36% (21/59) of patients who presented with multiple lesions (p=0.12). Thirty-nine percent (7/18) of patients with basal subtypes were observed to present with multiple BM compared to 61% (11/18) non-basal subtypes (p=0.25). In addition, 12% (13/59) of BM were found to be exclusively dural-based lesions. They appeared more frequently in the luminal subtypes [11/13 vs 2/13; p=0.06]. A total of 314 genes were differentially expressed (Wilcox pval Conclusion: Identifying pathways that are differentially expressed between intrinsic subtypes may help us develop new targeted therapies to provide more treatment options for breast cancer patients with brain metastasis. Citation Format: Nicole Williams, Vinay Varadan, Aditi Vadodkar, Kristy Miskimen, Stephanie Kim, Shaveta Vinayak, Paula Silverman, Jill Barnholtz-Sloan, Andrew Sloan, Cheryl Thompson, Lisa Rogers, Hannah Gilmore, Lyndsay Harris. Intrinsic subtypes and MRI patterns in brain metastasis associated with breast cancer [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P6-16-03.

A breast multi-disciplinary genomic tumor board is feasible and can provide timely and impactful recommendations

University Hospitals Seidman Cancer Center, Cleveland, OH, USA Department of Nutrition, Case Western Reserve University, Cleveland, OH, USA Case Comprehensive Cancer Center, Case Western Reserve University, Cleveland, OH, USA Department of Pharmacology, Case Western Reserve University, Cleveland, OH, USA Department of Genetics and Genome Sciences, Case Western Reserve University, Cleveland, OH, USA National Cancer Institute, Bethesda, MD, USA