Abstract P1-06-03: Epithelial to mesenchymal transition (EMT) regulates the spontaneous generation of GD2+ breast cancer stem-like cells through NFκB activation

Breast cancer recurrence may be a consequence of persistent breast cancer stem-like cells (BCSCs) that survive chemo- or hormonal therapy. Therefore, targeting BCSCs could complement standard chemotherapy. We discovered that the ganglioside GD2 is expressed on and defines BCSCs (Battula et al., JCI, 2012), as consequence of activation of the enzyme GD3 synthase (GD3S). Inhibition of GD3S expression inhibited breast cancer metastasis to lung. We also observed that GD2- breast cancer cells spontaneously generate GD2+ cells in vitro. As induction of EMT generates a stem cell–like phenotype, we hypothesized that EMT regulates the generation of GD2+ breast cancer cells. To test this hypothesis, MDA-MB-231and SUM159 cells were cultured in vitro and the percentage of GD2+ cells was measured over time. Interestingly, the percentage and absolute number of GD2+ cells increased in a time-dependent manner, suggesting the spontaneous generation of GD2+ cells. Concomitantly, mesenchymal-related markers including vimentin, N-cadherin, and twist increased 3 to 6 - fold. To further investigate whether this process is operational in vivo, GFP+ MDA-MB-231 cells were transplanted into mammary fat pads of NOD/SCID mice. Each week, a group of mice was sacrificed, tumors were extracted and the number of GFP+GD2+ cells was determined by flow cytometry. In line with our in vitro results, we observed significant increases in GD2+ BCSCs with increasing tumor volume from 15.1%±4.6% to 37%±8.7% over a 6 week period, suggesting that breast cancer cells spontaneously undergo EMT during tumor progression and generate GD2+ BCSCs.

To identify possible targets to inhibit EMT in breast cancer cells, proteomic analysis using Kinexus® antibody arrays revealed activation of NFκB and focal adhesion kinase (FAK) signaling in GD2+ breast cancer cells. The activation of NFκB (phospho p65) in GD2+ cells was validated by CyTOF mass cytometry using metal tagged antibodies. These data suggest that inhibition of NFκB signaling may inhibit GD2+ BCSC growth. Indeed, the IKK inhibitor BMS345541 reduced GD2+ cells by >95% and inhibited GD3S expression (determined by qRT-PCR) in a dose- and time-dependent fashion. In contrast, treatment with doxorubicin increased the percentage of GD2+ cells, from 13.5±2.5% to 21±2.6% in MDA-MB-231 cells, suggesting that GD2+ cells are resistant to doxorubicin. In addition, treatment with BMS345541 inhibited the ability of breast cancer cells to form mammospheres by >90% in vitro. In-vivo tumorigenesis assay demonstrated that BMS345541 induced a significant decrease (p <0.01) in tumor volume, and increased survival of tumor bearing mice: median survival was 78 days for BMS345541-treated mice vs. 58 days for controls (p<0.002).

Conclusion: GD2+ BCSCs are spontaneously produced during tumor progression by EMT and NFκB and FAK mediated signaling might regulate this process. Inhibition of NFκB and FAK signaling pathways may inhibit the spread of BCSCs and reduce breast cancer metastases.

Citation Format: Battula VL, Sun J, Nguyen K, Hortobagyi G, Andreeff M. Epithelial to mesenchymal transition (EMT) regulates the spontaneous generation of GD2+ breast cancer stem-like cells through NFκB activation. [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 P1-06-03.

Incidence and time course of everolimus-related adverse events in postmenopausal women with hormone receptor-positive advanced breast cancer: insights from BOLERO-2

BACKGROUND

In the BOLERO-2 trial, everolimus (EVE), an inhibitor of mammalian target of rapamycin, demonstrated significant clinical benefit with an acceptable safety profile when administered with exemestane (EXE) in postmenopausal women with hormone receptor-positive (HR(+)) advanced breast cancer. We report on the incidence, time course, severity, and resolution of treatment-emergent adverse events (AEs) as well as incidence of dose modifications during the extended follow-up of this study.

PATIENTS AND METHODS

Patients were randomized (2:1) to receive EVE 10 mg/day or placebo (PBO), with open-label EXE 25 mg/day (n = 724). The primary end point was progression-free survival. Secondary end points included overall survival, objective response rate, and safety. Safety evaluations included recording of AEs, laboratory values, dose interruptions/adjustments, and study drug discontinuations.

RESULTS

The safety population comprised 720 patients (EVE + EXE, 482; PBO + EXE, 238). The median follow-up was 18 months. Class-effect toxicities, including stomatitis, pneumonitis, and hyperglycemia, were generally of mild or moderate severity and occurred relatively early after treatment initiation (except pneumonitis); incidence tapered off thereafter. EVE dose reduction and interruption (360 and 705 events, respectively) required for AE management were independent of patient age. The median duration of dose interruption was 7 days. Discontinuation of both study drugs because of AEs was higher with EVE + EXE (9%) versus PBO + EXE (3%).

CONCLUSIONS

Most EVE-associated AEs occur soon after initiation of therapy, are typically of mild or moderate severity, and are generally manageable with dose reduction and interruption. Discontinuation due to toxicity was uncommon. Understanding the time course of class-effect AEs will help inform preventive and monitoring strategies as well as patient education.

TRIAL REGISTRATION NUMBER

NCT00863655.

Abstract P2-16-17: Characterization of response to everolimus (EVE) in BOLERO-2: A phase 3 trial of EVE plus exemestane (EXE) in postmenopausal women with HR+, HER2- advanced breast cancer

Introduction: The BOLERO-2 trial demonstrated that combining the oral mammalian target of rapamycin (mTOR) inhibitor, EVE, with the steroidal aromatase inhibitor, EXE, more than doubled median progression-free survival (PFS) compared with placebo (PBO) plus EXE in postmenopausal women with hormone-receptor-positive (HR+), human epidermal growth factor receptor-2-negative (HER2−) breast cancer (BC) who relapsed or progressed following a nonsteroidal aromatase inhibitor (NSAI). Patients also achieved responses per Response Evaluation Criteria in Solid Tumors (RECIST) during treatment with EVE+EXE.

Methods: The phase 3, double-blind, BOLERO-2 trial randomized postmenopausal women with HR+ BC progressing or recurring after NSAIs in a 2:1 manner to EVE 10 mg once daily plus EXE 25 mg once daily (EVE+EXE; n = 485) or placebo (PBO) plus EXE (PBO+EXE; n = 239). The primary endpoint was PFS by local assessment. Overall response rate (ORR; complete + partial response per investigator assessment based on RECIST 1.0) and duration of overall response were secondary endpoints. In addition, best percentage change from baseline in sum of longest diameters of target lesions was assessed.

Results: At the time of final PFS analyses at 18 months’ median follow-up, ORR was significantly higher in the EVE+EXE arm compared with the PBO+EXE arm (12.6% vs 1.7%, respectively, by local assessment; P<.0001). Among patients with measurable disease at baseline, 71% in the EVE+EXE arm had a decrease in the sum of longest diameters of target lesions compared with baseline vs 30% in the PBO+EXE arm. Median duration of overall response was 10.5 months (95% confidence interval [CI]: 8.2, 21.9 months) for EVE+EXE and 6.9 months (95% CI: 4.2, 6.9 months) for PBO+EXE. Of note, only 4 patients in the PBO+EXE arm had an objective response to treatment.

Conclusions: In addition to PFS, the combination of EVE plus EXE significantly improved ORR vs PBO+EXE in patients with HR+, HER2− advanced BC progressing during or after NSAI therapy. Furthermore, greater than two-thirds of patients treated with EVE+EXE experienced tumor shrinkage during treatment. These results further support the rationale for combining EVE with EXE to improve clinical outcomes in HR+, HER2− advanced BC progressing after NSAI therapy.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P2-16-17.

Ganglioside GD2 identifies breast cancer stem cells and promotes tumorigenesis

Cancer stem cells (CSCs) are a small subpopulation of cancer cells that have increased resistance to conventional therapies and are capable of establishing metastasis. However, only a few biomarkers of CSCs have been identified. Here, we report that ganglioside GD2 (a glycosphingolipid) identifies a small fraction of cells in human breast cancer cell lines and patient samples that are capable of forming mammospheres and initiating tumors with as few as 10 GD2+ cells. In addition, the majority of GD2+ cells are also CD44hiCD24lo, the previously established CSC-associated cell surface phenotype. Gene expression analysis revealed that GD3 synthase (GD3S) is highly expressed in GD2+ as well as in CD44hiCD24lo cells and that interference with GD3S expression, either by shRNA or using a pharmacological inhibitor, reduced the CSC population and CSC-associated properties. GD3S knockdown completely abrogated tumor formation in vivo. Also, induction of epithelial-mesenchymal transition (EMT) in transformed human mammary epithelial cells (HMLER cells) dramatically increased GD2 as well as GD3S expression in these cells, suggesting a role of EMT in the origin of GD2+ breast CSCs. In summary, we identified GD2 as a new CSC-specific cell surface marker and GD3S as a potential therapeutic target for CSCs, with the possibility of improving survival and cure rates in patients with breast cancer.

Abstract 682: Increased stearoyl-CoA desaturase 1 expression is associated with shorter survival in breast cancer patients

Stearoyl-CoA desaturase 1 (SCD1) is an essential regulator of fatty acid synthesis that affects cell membrane composition and may play a role in cancer cell metabolism. We have previously shown that SCD1 expression is increased by mTOR signaling and that SCD1 increases breast cancer cell growth in vitro. The purpose of this study was to determine protein levels of SCD1 in breast cancer and to determine whether there is an association between SCD1 levels and survival. Fine needle aspirates were collected from the primary breast cancers of 253 patients with Stage I-III breast cancer and protein lysates were prepared. SCD1 expression was analyzed using reverse phase proteomic array. Patient demographic and clinical characteristics including age, ethnicity, menopausal status, clinical stage, tumor grade, and tumor subtype were reviewed. Samples were divided into high or low SCD1 levels based on a cut-off determined from martingale residual plots and regression tree analysis. SCD1 levels were significantly higher in older patients and lower in triple negative (estrogen, progesterone, and HER2 negative) cancers, After adjusting for tumor subtype, tumor grade, age, and clinical stage, patients who had high SCD1 levels had significantly shorter relapse-free survival (RFS) (p=0.013) and overall survival (OS) (p=0.038). SCD1 level varies by breast cancer subtype and predicts significantly shorter RFS and OS. Future studies are needed to define the role of SCD1 in breast cancer and evaluate its potential as a therapeutic target.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 682. doi:1538-7445.AM2012-682

Abstract CT-03: Aberrations in translational regulation are associated with poor prognosis in hormone receptor-positive breast cancer

Purpose: Translation initiation is activated in cancer through increase in eukaryotic initiation factor 4E (eIF4E), eIF4G, phosphorylated eIF4E-binding protein (p4E-BP1) and ribosomal protein S6 (pS6), and decreased programmed cell death protein 4 (pdcd4), a translational inhibitor. Further, translation elongation is deregulated though alterations in eukaryotic elongation factor 2 (eEF2) and eEF2 kinase (eEF2K). We sought to determine the association of these translational aberrations with clinical-pathologic factors and survival outcomes in hormone receptor-positive breast cancer. Methods: Primary tumors were collected from 190 patients with stage I-III hormone receptor-positive breast cancer. Expression of eIF4E, eIF4G, 4E-BP1, p4E-BP1 T37/46, p4E-BP1 S65, p4E-BP1 T70, S6, pS6 S235/236, pS6 S240/244, pdcd4, eEF2 and eEF2K was assessed by reverse phase protein arrays.: Univariable and multivariable analyses for recurrence-free survival (RFS) and overall survival (OS) were performed. Results: High eEF2, S6, pS6 S240/244, p4E-BP1 T70, and low pdcd4 were significantly associated with node-positivity. Median follow-up for alive patients was 96 months. High p4E-BP1 T36/47, p4E-BP1 S65, p4E-BP1 T70 and 4E-BP1 were associated with worse RFS. High p4E-BP1 T70 and pS6 S235/236, and low pdcd4, were associated with worse OS. In multivariable analysis, in addition to positive nodes, p4E-BP1 S65 remained a significant predictor of RFS (HR=1.62, 95%CI=1.13-2.31; P=0.008). In addition to age, pS6 S235/236 (HR=1.73, 95%CI=1.03-2.90, P=0.039), eEF2K (HR=2.19, 95%CI=1.35-3.56, P=0.002) and pdcd4 (HR=0.42, 95%CI=0.25-0.70, P=0.001) were associated with OS. Conclusions: Increased pS6, p4E-BP1, eEF2K and decreased pdcd4 are associated with poor prognosis in hormone receptor-positive breast cancer; suggesting their role as prognostic markers and therapeutic targets.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr CT-03. doi:1538-7445.AM2012-CT-03

Abstract LB-379: Combating trastuzumab resistance by targeting Src, a common node downstream of multiple resistance pathways

Objective of the study: Trastuzumab is a highly successful example of rationally designed ERBB2-targeted therapy. However, about half of patients with ERBB2-overexpressing breast cancer do not respond to trastuzumab-based therapies due to various resistance mechanisms. Clinically applicable regimens for overcoming trastuzumab resistance of different mechanisms are not yet available. The objective of the study is to find a common key node of multiple trastuzumab resistance mechanisms and design a clinical applicable strategy to target this common node to more effectively overcome trastuzumab resistance. Methodology: First, we evaluated Src activity in multiple acquired and de novo trastuzumab-resistant cell lines models. Cells with modulated Src activity were examined for trastuzumab resistance in vitro and in an orthotopic xenograft model. Moreover, tumors from patients receiving trastuzumab therapy were also analyzed retrospectively for clinical correlation of Src activity with trastuzumab response. Src activated trastuzumab-resistant cells were further treated with Src inhibitor (saracatinib), trastuzumab, or a combination of both in vitro and in vivo. Results: We demonstrate that the non-receptor tyrosine kinase Src serves as a critical modulator of trastuzumab response and a common node downstream of multiple trastuzumab resistance pathways. Src is activated in both acquired and de novo trastuzumab-resistant cells. Increased Src activation conferred significant trastuzumab resistance (P = 0.011) in breast cancer cells and correlated with trastuzumab resistance in patients. Targeting the common node Src in combination with trastuzumab universally sensitized multiple lines of trastuzumab-resistant cells to trastuzumab and eliminated trastuzumab-resistant tumors in vivo. Targeting Src, a critical convergence point of divergent trastuzumab resistance mechanisms, represents a highly effective and clinically convenient strategy to overcome trastuzumab resistance.

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 LB-379. doi:10.1158/1538-7445.AM2011-LB-379

Multidisciplinary meeting on male breast cancer: summary and research recommendations

Male breast cancer is a rare disease, accounting for less than 1% of all breast cancer diagnoses worldwide. Most data on male breast cancer comes from small single-institution studies, and because of the paucity of data, the optimal treatment for male breast cancer is not known. This article summarizes a multidisciplinary international meeting on male breast cancer, sponsored by the National Institutes of Health Office of Rare Diseases and the National Cancer Institute Divisions of Cancer Epidemiology and Genetics and Cancer Treatment and Diagnosis. The meeting included representatives from the fields of epidemiology, genetics, pathology and molecular biology, health services research, and clinical oncology and the advocacy community, with a comprehensive review of the data. Presentations focused on highlighting differences and similarities between breast cancer in males and females. To enhance our understanding of male breast cancer, international consortia are necessary. Therefore, the Breast International Group and North American Breast Cancer Group have joined efforts to develop an International Male Breast Cancer Program and to pool epidemiologic data, clinical information, and tumor specimens. This international collaboration will also facilitate the future planning of clinical trials that can address essential questions in the treatment of male breast cancer.

Quantitative immunohistochemical analysis and prognostic significance of TRPS-1, a new GATA transcription factor family member, in breast cancer

The trichorhinophalangeal syndrome 1 (TRPS-1) gene is a novel GATA transcription factor family member. Previously, using a gene expression profiling and immunohistochemistry (IHC) screen, we identified TRPS-1 as a highly prevalent gene in breast cancer (BC), expressed in >90% of estrogen receptor alpha (ERα)(+) and ERα(-) BC subtypes. TRPS-1 was also shown to be expressed in prostate cancer where it was shown to play a proapoptotic function during androgen withdrawal possibly through regulating antioxidant metabolism. The role of TRPS-1 and its prognostic significance in hormone-dependent and hormone-independent BC however is not known. In this study, we developed a new quantitative IHC (qIHC) method to further study TRPS-1 as a marker and possible prognostic indicator in BC. By using this method, a quantitative parameter for TRPS-1 expression called a quick score (QS) was derived from the measured labeling index and mean optical density after IHC and applied to a set of 152 stage II/III BC patients from 1993 to 2006 who did not receive preoperative chemotherapy. Associations between QS and tumor characteristics were evaluated using the Kruskal-Wallis test. A wide range of TRPS-1 QS was found among the sample set with higher TRPS-1 QS significantly associated with tumor ERα (p = 0.023 for QS and p = 0.028 for Allred score), progesterone receptor (p = 0.009), and GATA-3 (p < 0.0001). TRPS-1 QS was also positively associated with HER2 status (p = 0.026). Further analysis of different ductal structures in ten BC cases revealed that TRPS-1 expression was expressed at low levels in the remaining normal ducts and in areas of usual ductal hyperplasia but showed marked increase in expression in ductal carcinoma in situ and invasive carcinoma lesions in the tissue. An analysis of TRPS-1 expression in association with overall survival in the 152 stage II/III sample set also revealed that TRPS-1 QS (≥4.0) was significantly associated with improved survival (p = 0.0165). Patients with TRPS-1 QS <4 had a hazard ratio of 2 (p = 0.019) after univariate Cox proportional hazards analysis. In summary, this new qIHC approach was found to reveal critical differences in TRPS-1 expression in primary BC samples and found that it is a promising prognostic marker that should be further evaluated as a possible tumor suppressor gene facilitating improved survival in different subtypes of BC.

Different Biological Processes Are Associated with Prognosis and Chemotherapy Sensitivity in the Different Molecular Subtypes of Breast Cancer

Background: Breast cancer includes multiple different molecular subtypes. We hypothesized that different biological processes and molecular markers may be associated with prognosis and chemotherapy sensitivity in the different subtypes.Methods: We performed gene set analysis in ER-positive/HER-2-normal (ER+) and ER-negative/HER-2-normal (ER-) cancers separately to identify gene sets that are associated with prognosis and chemotherapy sensitivity. We tested 5295 different, functionally annotated gene sets (GS) that collectively represent almost all known biological and metabolic pathways in human cells. Significance was estimated with permutation test. Three separate cohorts on untreated HER2-normal patients (n=234, n=175, n=170) and 3 cohorts of patients with neoadjuvant therapy (n=198, n=85, n=61) were included in this analysis. We performed analysis of each data set separately and also as pooled data.Results: When data sets were analyzed individually, 753 to 938 GS were associated with prognosis (P≤0.05) in ER+ cancers including 186 common to all, and 408 to 579 GS were associated with prognosis in ER- cancers including 1 common to all and 141 common to at least two data sets. Within each data set, the number of overlapping GS between the ER+ and ER- prognostic lists ranged from 33 to 112. In the neoadjuvant data sets, 555 to 674 GS were associated with response in ER+ cancers (195 common to at least two, 4 common to all) and 543 to 730 in ER- cancers (268 common to two, 22 common to all). When the predictive GS for ER+ cancers were compared to those for ER- cancers, there were only 10 GS in common. A meta analyses of the combined prognostic data sets yielded 384 GS with p≤0.0001 in ER+ cancers and 47 in ER- cancers, respectively, with 12 GS common to both. A meta analyses of the combined neoadjuvant data sets yielded 92 GS associated with pCR in ER+ cancers and 110 GS in the ER- cancers. Only 2 GS were common to both. Functional analysis indicated that DNA replication, mitotic spindle checkpoint and plasma cell function were the most common prognostic pathways in ER+ cancer. T cell differentiation, glycolipid metabolism and immune functions were the most commonly prognostic pathways in ER- cancer with a notable absence of proliferation related gene sets. DNA replication, spindle and microtubule activity and cell cycle regulation were associated with chemotherapy response in ER+ cancers; oxidative stress, blood vessel formation in ER- cancers.Conclusion: These data indicate that prognosis and chemotherapy response are associated with different gene sets in ER+ and ER- cancers.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 6124.

Addition of Granulocyte-Macrophage Colony-Stimulating Factor (GM-CSF) to Trastuzumab Stabilizes Disease in Patients with Trastuzumab-Resistant, HER2+ Metastatic Breast Cancer

Introduction: Trastuzumab with or without chemotherapy is the standard of care for patients with HER2+ metastatic breast cancer. The proposed mechanism of trastuzumab-induced regression of HER2+ tumors includes inhibition of tumor cell proliferation, potentiation of chemotherapy, and facilitation of immune function through antibody-dependent cell-mediated cytotoxicity. GM-CSF (Leukine) is a cytokine that mediates antibody-dependent cell-mediated cytotoxicity. We studied the feasibility and efficacy of adding GM-CSF to trastuzumab in patients with trastuzumab-resistant, HER2+ metastatic breast cancer.Patients and Methods: Patients with measurable, HER2+ metastatic breast cancer that progressed after treatment with trastuzumab with or without chemotherapy were continued on trastuzumab alone at 2 mg/kg intravenous weekly. GM-CSF (250 μg/m2 subcutaneous daily) was added until the absolute neutrophil count (ANC) was greater than 10,000/mm3, then given every other day while the ANC was maintained below 10,000/mm3. Disease was restaged every 8 weeks. Treatment with trastuzumab and GM-CSF was continued until disease progression or intolerable toxicity.Results: Of 18 eligible patients with progressive HER2+ metastatic breast cancer, 17 (median age 48 yr, range 27–75 yr) were evaluable. Nine had hormone receptor–positive disease. The median number of metastatic sites was 2 (range 1–3); the most common site was the liver (n=10). The median number of prior regimens (trastuzumab with or without chemotherapy) for metastatic disease was 2 (range 1–5). One patient developed rapidly progressive disease 2 weeks after the start of study therapy and died soon after. The other 16 patients continued treatment until disease progression. No disease response was observed, but 5 patients (29%) had stable disease with a median duration of 15.8 weeks (range 10–53.9 weeks). Thirteen patients had grade 1 toxic effects; 6 patients, grade 2; and 2 patients, grade 3 (fatigue and muscle aches). The most common toxic effect was rash at the injection site, followed by skin rash, fatigue, and muscle aches. No grade 4 or irreversible toxic effect was seen.Conclusion: The addition of GM-CSF to trastuzumab alone in patients with trastuzumab-resistant, HER2+ metastatic breast cancer stabilizes the disease for a median duration of 15.8 weeks without causing any significant toxic effects in 29% of heavily pretreated patients. Its administration is simple, safe, and feasible. This regimen, trastuzumab and GM-CSF, needs further evaluation in combination with chemotherapy or other biological agents.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 5103.

Variants in the BRCA1/Fanconi-Anemia Repair Pathway and Taxane-Induced Neuropathy in SWOG S0221

Background: Taxane-induced peripheral neuropathy is a dose-limiting side effect that leads to suboptimal cancer treatment and diminished quality of life. The mode of taxane neurotoxicity is unclear, but may be through stabilization of microtubules and induction of spindle checkpoint, leading to cell cycle arrest at G2/M. Fanconi Anemia (FA) genes, including FANCD2, and FANCA, appear to be involved in G2/M phase checkpoint maintenance as well as spindle checkpoint in response to internal and external signals, such as taxane treatment. Thus, we hypothesized that variants in FA genes could impact severity of taxane-induced neuropathies.Methods: Using DNA extracted from blood collected from 893 breast cancer patients participating in a trial evaluating metronomic dosing of cyclophosphamide, doxorubicin and paclitaxel (S0221), we genotyped for single nucleotide polymorphisms (SNPs) that represent all of the variability across FANCA (44 SNPs) and FANCD2 (24 SNPs) in all race/ethnicity groups, as well as a panel of ancestry informative markers to control for potential population stratification, using Illumina GoldenGate platform. SNPs with minor allele frequency (MAF) less than 0.10 and those out of Hardy Weinberg Equilibrium (HWE) proportions (p&lt;0.001) were removed from analyses. Ordinal regression was used to test for allelic and haplotypic association with grade 3 or 4 toxicities relative to 0, 1, and 2 toxicities, adjusting for age, genetic admixture index and treatment arm. To adjust for multiple testing, permutation analyses were performed on both single SNP and haplotype models.Results: Eighteen SNPs in FANCD2 and 38 SNPs in FANCA passed MAF and HWE proportion requirements. For FANCD2, 4 SNPs spanning 67.5 Kb (rs7648104, rs2272125 [coding SNP], rs6786638 and rs644215), were significantly associated with taxane-induced neuropathy (p&lt;0.001) after controlling for multiple testing, with each SNP resulting in approximately a twofold increase in odds of severe taxane-induced neuropathy. Haplotype estimation showed that all 18 SNPs comprise a single haplotype. Two major (&gt;1% frequency) haplotypes were found. The frequencies of the risk haplotype in cases (patients with grade 3 or 4 neuropathy) and controls (patients with ≤ grade 2 neuropathy) were 0.25 and 0.15, respectively. Ordinal regression analyses were highly significant (p&lt;0.0005); patients with at least one copy of the risk haplotype had more than a twofold increased risk of grade 3 or 4 taxane-induced neuropathy (OR=2.2, 95% CI 1.44, 3.44). For FANCA, no SNPs or haplotypes were significantly associated with grade 3 or 4 neurotoxicity, either prior to or after correction for multiple testing.Conclusions: These results indicate that the Fanconi-Anemia pathway may be important for neurological sensitivity to taxanes, and that genotypic markers might be able to be used to identify patients at increased risk for severe taxane-induced neuropathy. Further studies will elucidate potential associations with survival outcomes.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 2001.

Synergistic Effect of Lapatinib and the Class 1 HDAC Inhibitor SNDX-275 in Breast Cancer

Background: Inflammatory breast cancer (IBC) is a rare but aggressive form of primary breast cancer with high metastasis rates and poor survival outcomes in patients. Currently, no specific targeted therapy is available to improve patient outcomes, although agents (i.e. trastuzumab and lapatinib) targeting the human epidermal growth factor 2 (HER2) have shown promise in clinical trials. Histone deactylases (HDACs) represent another family of proteins for which inhibitors have been clinically validated and shown to inhibit proliferation of breast cancer cells in vitro and in vivo. In these studies we determined the single agent activity of the class 1 selective HDAC inhibitor entinostat (SNDX-275) in IBC cell models and whether SNDX-275 was synergistic with the HER2 targeted agent lapatinib.Methods: SNDX-275 activity was evaluated in SUM190, SUM149 and KPL-4 IBC cell lines using standard proliferation assays and compared to the non-IBC cell lines MDA-MB-231, SKBr3 and MCF-7. Apoptotic activity and cell cycle analysis were analyzed. SNDX-275 combination with lapatinib was initially determined in vivo in a HER2+ breast cancer model and subsequently in the SUM190, SUM149, KPL-4 IBC cells. For xenograft studies, athymic nude mice bearing human breast (BT474) tumor xenografts were treated with SNDX-275 at 15 or 30 mg/kg/day and lapatinib at 30 mg/kg/ 2xday or 75 mg/kg/ 2xday.Results: Significant anti-proliferative activity of SNDX-275 was observed in IBC (IC50, 250–500 nM) when compared with the non-IBC breast cancer cell lines MDA-MB-231, SKBr3, and MCF-7 (IC50 2–5 mM). Cell cycle analysis showed the onset of apoptosis in IBC cell lines (10%-17%); in the non-IBC cell lines, very little apoptosis occurred (0.8%–3.1%), although G1 stage arrest was seen in the non-IBC cell lines MDA-231 and MCF-7. The SNDX-275–induced apoptosis in IBC cell lines was dependent on caspase 9 rather than Caspase 8 cleavage indicating that the intrinsic apoptotic pathway is activated. The experiments with lapatinib demonstrated a significant benefit of the SNDX-275/lapatinib combination in both the BT474 xenograft study as well as the IBC cell lines tested. In the animal group that was treated with 15 mg/kg SNDX-275 plus 75 mg/kg lapatinib, synergistic effects were observed with tumor regression that was continued at least for 4 weeks after treatment was stopped. Similarly, synergistic anti-proliferative activity was found in almost all (4 of the 5) cell lines tested (SUM190, SUM149, KPL-4, and BT474). Investigation into the mechanism of SNDX-275–mediated apoptosis and the combined effects of lapatinib and SNDX-275 in IBC are under way. Our data demonstrate that HDACi as single agents and particularly in combination with HER2 targeted agents represent a promising new approach for clinical development in IBC breast cancer and patients with HER2-overexpressing breast cancer.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 3135.

Clinical Outcomes in Two Different Cohorts of Patients with Inflammatory Breast Cancer (IBC) Treated at the MD Anderson Cancer Center: The Experience of the Morgan Welch IBC Research Program and Clinic

BACKGROUND: Inflammatory Breast Cancer (IBC) is a rare but aggressive manifestation of primary breast cancer. Survival in patients with IBC is significantly lower than for non-IBC breast cancer patients. Appropriate diagnostic and treatment strategies provided by a specialized multidisciplinary team could impact the overall prognosis of the disease. We recently established an IBC research program and clinic including investigators from various disciplines solely dedicated to this disease. We sought to compare the characteristics and clinical outcomes of newly diagnosed IBC patients evaluated and treated using novel diagnostic and therapeutic approaches with an historical cohort of IBC patients treated at our institution.METHODS: We included 240 IBC patients treated at MD Anderson Cancer Center between January 1970 and August 2000. In this analysis we compared characteristics, 1 year progression free survival (PFS) and 1 year survival between the historic cohort and 47 patients diagnosed with IBC and seen at our IBC clinic between August 2007 and September 2008. The new patients are part of a prospective IBC registry. All of them had staging and monitoring with breast MRI and FDG-PET/CT. When indicated, they were treated with targeted therapies (e.g. trastuzumab and tipifarnib), that were not available for the patients in the old cohort. Descriptive statistics were used. Kaplan Meier product-limit method was used to calculate survival outcomes, groups were compare by log-rank test.RESULTS: Median age was similar in both cohorts (53 vs 51). In the new cohort 40% of the patients had evidence of distant metastasis at presentation. The most common sites were contralateral lymph nodes (26%), pleura (16%), bone (16%) and liver (11%). In the old cohort only 17% presented with stage IV. 38.7% of the new patients had Her2-neu amplified and 34%, triple receptor negative IBC. There was no difference in 1-year survival between the two groups (92.4% vs. 93.8%, p=0.637). For patients with stage III disease, the 1-year survival was 95% for both groups. The 1 year-PFS was 86.4% in the new cohort compared to 77.9% (p=0.43) in the old cohort. With a median follow up of 13 months, 51%of the patients in the new cohort are disease free and 87% are still alive.CONCLUSIONS: IBC is an aggressive but rare disease with poor prognosis. We have established a specialized IBC research program and clinic that introduces novel concepts and strategies in laboratory, imaging diagnostics and targeted therapies. This approach may accelerate our understanding of the biology, develop new therapeutic strategies and finally improve the outcome of IBC. Early results of this multidisciplinary approach show a modest, but not significant difference in outcome. We hope that with additional patients and longer follow-up a significant improvement in outcomes will become apparent.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 5119.

The Molecular Anatomy of Breast Cancer Stroma; Independent Prognostic Role in ER-Positive and ER-Negative Cancers

BackgroundIn this paper we examine the various molecular components of a breast cancer stromal gene signature and correlate these with clinical phenotype and outcome including prognosis and response to preoperative chemotherapy.MethodsWe compared Affymetrix HGU133A-based gene expression profiles of 37 matching core needle biopsies (CNB) and fine-needle aspirations (FNA) from the same cancers. Genes over-expressed in CNB relative to the FNA were defined as the “stromal signature”. Gene expression data from 56 breast cancer cell lines, two separate neoadjuvant data sets (n=233, n=103), 3 independent cohorts of node negative, untreated patients (n=286, n=198, n=200) and 259 estrogen receptor-positive (ER+) tamoxifen-treated patients were used to assess the prognostic and predictive values of these genes in ER+ and ER- cancers separately. Univariate and multivariate Cox analyses were performed. Metagenes were defined as average expression of co-clustered genes.Results293 probe sets (206 genes) were significantly over-expressed in the CNBs (false discovery rate ≤ 0.001, fold-change ≥ 3). These genes overlapped with previously reported stromal signatures and fell into several co-expression clusters including a B-cell/Plasma Cell (B-cell), Dendritic cell, extracellular matrix (ECM), and TGFb-receptor metagenes. Interestingly, ER+ and ER- cancers showed a significantly different stroma-gene expression pattern, and many stromal genes were also differentially expressed between ER+ and ER- breast cancer cell lines. The ECM and TGFb metagenes had modest and variable prognostic value across different datasets in both ER groups. The Dendritic and B cell metagenes were highly co-expressed, but the B-cell metagene had more robust and consistent prognostic value. The B-cell metagene was statistically significant prognostic in univariate and multivariate analysis in ER+/High proliferative and ER- tumors, but it was not prognostic in ER+/Low proliferative tumors. In the 3 different node negative, untreated patient cohorts, the ER+/High proliferative cancers in the lowest B-cell metagene tertile had 10-year distant metastasis free survival (DMFS) of 0.18 (0.07-0.46), 0.22 (0.06-0.75), and 0.44 (0.21-0.92) compared to 0.71 (0.54-0.94), 0.89 (0.71-1.00) and 0.89 (0.71-1.00) in the highest tertile. Among the ER- cancers, the lowest B cell metagene group had 10-year DMFS of 0.57 (0.44-0.75), 0.63 (0.48-0.83), and 0.44 (0.25-0.76) compared to 0.93 (0.81-1.00), 0.83 (0.64-1.00) and 0.83 (0.58-1.00) in the highest B-cell metagene group in each prognostic dataset, respectively. The B-cell metagene was also prognostic in univariate (HR 0.83 (0.71-0.98) p=0.03) and multivariate (HR 0.80 (0.68-0.94) p=0.007) analysis in the Tamoxifen-treated cohort. None of the above stromal metagenes showed reproducible association with response to chemotherapy.ConclusionsThe B-cell/Plasma cell metagene component of the “stroma-related genes” is a robust and reproducible prognostic marker in ER+/High proliferative and also in ER- cancers. Other stromal genes are variably expressed in ER+ and ER- tumors and many are also expressed by neoplastic cells in culture and by primary tumors and carry less reproducible prognostic value.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 105.

Thomboembolic Events in Patients with Breast Cancer: A Population Based Study

BACKGROUND: Thromboembolic events (TEEs) are common in patients with cancer. Metastatic disease, treatment and comorbidities have been associated with increased risk. In this population-based study we sought to evaluate the risk factors and the prevalence of different TEEs in patients with breast cancer.METHODS: Retrospective cohort study using the SEER-Medicare linked database. Patients with breast cancer (stage I-IV) diagnosed from 1992-2002, who were 66 and older, and had full coverage of Medicare A and B were identified. ICD-9, HCPCS codes were used to identify different TEEs that occurred within one year of the breast cancer diagnosis. We identified pulmonary embolism (PE), deep venous thrombosis (DVT)/thrombophlebitis, other TEEs, as well as the use of chemotherapy, radiotherapy, surgery and comorbidities. Analyses were conducted using descriptive statistics and logistic regression.RESULTS: 71,864 patients were included. Age groups were distributed as follows: 66-70 (24.1%), 71-75 (26.4%), 76-80 (23.2%), &gt;80 (26.3%). At diagnosis 52.4% of patients had stage I, 35.2% stage II, 6.6% stage III and 5.8% stage IV. 66.8% of the patients had ER-positive breast cancer. Within one year of diagnosis, 2652 (3.7%) of patients developed a TEE, including 800 patients with at least two events. 3565 total number of events were observed. A total of 596 (0.85%) PEs, 1252 (1.74%) DVT/thrombophlebitis, and 1717 (3.39%) other TEEs were identified. In the univariate analysis race, marital status, education and poverty level, geographical location, stage, tumor grade, estrogen receptor status, comorbidities, as well as surgical modality, radiation therapy and chemotherapy use, were associated with the development of any TEE.After adjusting for potential confounders, the development of any TEE was associated with ER-positive tumors (OR 1.20, 95% CI 1.07-1.34), stage II vs. I (OR 1.22, 95% CI 1.11-1.35), stage III vs. I (OR 1.63, 95% CI 1.40-1.90), stage IV vs. I (OR 2.16, 95% CI 1.82-2.57), chemotherapy (OR 2.02, 95% CI 1.82-2.23), radiotherapy (OR 1.39, 95% CI 1.27-1.52), comorbidity score (OR 1.19, 95% CI 1.08-1.32 and OR 1.74, 95% CI 1.54-1.96 for score 1 and 2 respectively), and type of surgery (OR 1.25, 95% CI 1,13-1.38 for mastectomy vs. breast conservation surgery and OR 1.23, 95% CI 1.02-1.49 for no surgery vs. breast conservation surgery). Borderline association was seen with age (using 66-70 as a reference value, the ORs for the 71-75, 76-80 and &gt;80 year old categories were: 1.14, 95%CI 1.02-1.28; 1.17, 95% CI 1.04-1.32; and 1.15, 95% CI 1.01-1.29 respectively). Relatively similar estimates were seen for the analysis of PE, DVT/thrombophlebitis and other TEEs.CONCLUSION: 3.7% of patients in this cohort developed a TEE within one year from breast cancer diagnosis. Age, stage, type of treatment, comorbidities and receptor status were associated with the development of TEEs. To the best of our knowledge this is the largest cohort of patients older than 66years old, in which the patterns and risk factors associated with TEEs are analyzed. Whether these observations apply to patients younger than age 65, remains to be established.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 2053.

Evaluation of the Predictive Performance and Regimen Specificity of a 30-Gene Predictor of Pathologic Complete Response in a Prospective Randomized Neoadjuvant Clinical Trial for Stage I-III Breast Cancer

Purpose: To prospectively evaluate in a randomized trial if a previously reported multigene predictor of pathologic complete response (pCR) to preoperative weekly paclitaxel and fluorouracil-doxorubicin-cyclophosphamide (T/FAC) chemotherapy can accurately predict pCR to neoadjuvant T/FAC chemotherapy, and if it also predicts pCR to FAC only chemotherapy. Furthermore, it is unknown if the T/FAC regimen is superior to 6 courses of FAC; therefore we compare the pCR rates for patients who receive T/FAC versus FACx6 preoperative chemotherapy.Materials and Methods: Patients with stage I-III breast cancer (n=273) were randomly assigned to receive either 12 courses of weekly paclitaxel followed by 4 courses of FAC (T/FAC, n=138), or 6 courses of FAC (FACx6, n=135) neoadjuvant chemotherapy. All patients underwent a pretreatment FNA biopsy of the tumor for gene expression profiling on oligonucleotide microarrays, and treatment response prediction (pCR versus residual disease, RD) was performed using the multigene predictor. Predicted and observed pathologic responses were compared independently in the two treatment arms.Results: The pCR rate was 19% with T/FAC and 9% with FACx6 (p&lt;0.05). In the T/FAC arm, the positive predictive value (PPV) of the genomic predictor was 38% (95%CI:21-56%), the negative predictive value (NPV) 88% (CI:77-95%), sensitivity 63% (CI:38-84%), specificity 72% (CI:60-82%), and the AUC 0.711. In the FAC only treatment arm, the PPV was 9% (CI:1-29%), the NPV 92% (CI:83-97%), sensitivity 29% (CI:4-71%), specificity 75% (CI:64-84%), and the AUC 0.584. This suggests that the genomic predictor is regimen-specific. In a multivariate analysis including age, tumor size, nodal status, histologic grade, HER2 and estrogen receptor (ER) status and the genomic predictor, only ER status was a significant predictor of pCR.Discussion: Pathologic complete response rate was significantly higher in the T/FAC arm compared to the FACx6 arm indicating a higher efficacy of the paclitaxel containing arm. Patients who were predicted to achieve pCR to T/FAC had a significantly higher pCR rate (38%) than unselected patients (19%) or patients predicted to have RD (12%) when treated with this regimen. These results confirm that the multigene predictor can identify patients with greater than average sensitivity to T/FAC chemotherapy.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 101.

Brain Metastases in Women with Inflammatory Breast Cancer (IBC): Incidence, Treatment and Outcome

Background: Brain metastases are an uncommon metastatic recurrence site in breast cancer with a median incidence of approximately 6% in unselected populations. Inflammatory breast cancer (IBC) is an aggressive disease associated with dismal outcome. The purpose of this study was to determine the incidence of and survival following brain metastases among women with IBC.Material and Methods: Two hundred and six women with newly diagnosed stage III or IV IBC diagnosed between the period of between 2003 and 2008 were identified in a prospectively maintained IBC database at the MD Anderson Cancer Center. Cumulative incidence of brain metastases was computed. Cox proportional hazards models were fitted to explore factors that predict for the development of brain metastases. Survival was computed using the Kaplan-Meier product limit method.Results: Median follow-up was 20 months. Eighty three (40.3%) women had de-novo stage IV disease and 123 (59.7%) had stage III disease at diagnosis. Thirty-three (16%) patients developed brain metastases with a cumulative incidence at 1 and 3 years of 2.7% and 22% respectively. Eleven (5.3%) patients developed brain metastases as the first site of recurrence with cumulative incidence at 1 and 3 years of 1.6% and 6.7% respectively. In the multivariable model, no specific factor was observed to be significantly associated with time to brain metastases, including HER-2 status. Median overall survival for the whole cohort was not reached. 3-year overall survival for the whole cohort was 78% (95% CI 69%-86%). Median survival following a diagnosis of brain metastases for all women who developed brain metastases or those who developed brain metastases as the first site of recurrence was 6 months.Conclusion: In this single-institutional study, women with IBC demonstrated a high early incidence of brain metastases associated with poor survival. As such IBC may be an ideal cohort to target screening procedures for brain metastases and/or enrollment of these women in clinical trials evaluating additional adjuvant preventive strategies.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 2102.