Discordance of Oncotype DX scores in synchronous bilateral and unilateral multifocal breast cancers

PURPOSE

Oncotype DX, a 21-gene expression profiling test, has become standard of care in the management of estrogen receptor (ER)-positive breast cancer. In multifocal tumors, it is unclear whether testing of the different foci is necessary. We evaluated the concordance of Oncotype DX recurrence scores (RS) between 2 tumor foci in synchronous bilateral or unilateral multifocal tumors and characterized pathological predictors of discordance.

METHODS

We reviewed 713 ER+, HER2- primary invasive breast cancer patients with Oncotype RS and identified 17 bilateral synchronous patients (34 tumors) and 13 unilateral multifocal patients (26 tumors) with available Oncotype RS on all foci. Discordance in Oncotype RS between synchronous tumors was recorded and associations with clinicopathologic features including tumor size, histology, Nottingham histologic grade, progesterone receptor staining, and Ki67 index were analyzed.

RESULTS

Bilateral synchronous tumors were present in older patients (median age 59 years) and had larger tumor (median size 17 mm) and more discordant histology (10/17, 59%) as compared to unilateral multifocal tumors (median age 49 years, p < 0.01; median tumor size 12 mm, p = 0.01; discordant histology 2/13, 15%, p = 0.03). Oncotype RS were discordant in 47% (8/17) of bilateral and 54% (7/13) of unilateral multifocal tumors. Concordant Oncotype RS was associated with similar histologic grade and Ki67 index in 78% (7/9) of bilateral and 100% (6/6) of multifocal tumors. In contrast, only 25% (2/8) of bilateral (p = 0.06) and 14% (1/7) of unilateral multifocal (p < 0.01) cases with discordant Oncotype RS had concordant histology grades and Ki67 levels. In synchronous tumors with discordant Oncotype RS and Ki67 index, all (4/4) foci with higher RS had higher Ki67 index.

CONCLUSION

Discordance of Oncotype RS is common in both bilateral and unilateral multifocal breast cancer and is likely associated with discordant histologic grade or Ki67.

Intragenic EGFR::EGFR.E1E8 Fusion (EGFRvIII) in 4331 Solid Tumors

Epidermal growth factor receptor variant III (EGFRvIII, the deletion of exons 2-7) is a recurrent intragenic EGFR::EGFR.E1E8 fusion that occurs in high-grade gliomas. The presence of EGFRvIII in other solid tumors has not been well characterized. We retrospectively reviewed advanced malignant solid tumor cases tested by a custom hybrid capture 610-gene next-generation sequencing platform from 2021 to 2022. EGFRvIII was identified in 17 of 4331 (0.4%) cases, including 16 of 238 (7%) brain tumors and 1/301 (0.3%) breast tumors. EGFRvIII-positive brain tumors were all glioblastoma IDH-wildtype, most with concurrent TERT promoter mutation (14 of 16), EGFR amplification (13 of 16), and EGFR mutation (8 of 16). The only EGFRvIII-positive breast lesion was a sarcomatoid neoplasm in a young female patient. A separate breast case tested outside our institution with reported EGFRvIII was noted in a young female patient with a malignant phyllodes tumor with stromal overgrowth. Microscopically, both EGFRvIII-positive breast tumors showed high-grade sarcomatoid morphology with brisk mitotic activity. In summary, EGFRvIII is rare, occurring primarily in glioblastoma and rarely in breast sarcomatoid neoplasm, with no instances identified in other tumor types in our series. This select group of patients may benefit from chemotherapy and/or targeted anti-EGFR therapy.

Clinical outcome and therapeutic impact on neuroendocrine neoplasms of the breast: a national cancer database study

PURPOSE

Neuroendocrine neoplasms (NENs) of the breast are rare and not well-studied. NEN are subcategorized as well-differentiated neuroendocrine tumor (NET) and poorly differentiated neuroendocrine carcinoma (NEC). The objectives of the current study were to review the clinicopathologic features of NENs, therapeutic efficacy of current systemic therapy and clinical outcomes of NEN of the breast.

METHODS

Between 2004 and 2015, 420 NET, 205 NEC, 146 Adenocarcinoma with NE differentiation (ACNED) and 1,479,520 of invasive carcinoma, not otherwise specified (IC-NOS) of the breast were identified in the National Caner Database. Overall survival was compared among groups using Kaplan-Meier method and Log-rank test. Multivariate analyses were performed to identify prognostic factors.

RESULTS

After adjusting for other prognostic factors, both NET and NEC of the breast showed significantly worse OS than IC-NOS (HR (95% CI) = 1.41 (1.17, 1.72), p = 0.005 and HR (95% CI) = 2.11 (1.67, 2.67), p < 0.001, respectively). Both NET and NEC benefited from endocrine therapy if the tumors were hormonal receptor positive (median OS for treated with vs without: 125 vs 57 months in NET, not reached vs 29 months in NEC). NEC also benefited from chemotherapy (median OS for treated with vs without: 42 vs 34 months), but not NET.

CONCLUSION

NEN is a unique pathologic and clinical entity, which has worse clinical outcome compared to IC-NOS of the breast. Current therapeutics used in the treatment of IC-NOS improve, but do not fully mitigate, the poorer prognosis of NEN patients. More effective therapy for patients with this unique tumor type are needed.

Chimeric RNAs reveal putative neoantigen peptides for developing tumor vaccines for breast cancer

Introduction

We present here a strategy to identify immunogenic neoantigen candidates from unique amino acid sequences at the junctions of fusion proteins which can serve as targets in the development of tumor vaccines for the treatment of breastcancer.

Method

We mined the sequence reads of breast tumor tissue that are usually discarded as discordant paired-end reads and discovered cancer specific fusion transcripts using tissue from cancer free controls as reference. Binding affinity predictions of novel peptide sequences crossing the fusion junction were analyzed by the MHC Class I binding predictor, MHCnuggets. CD8+ T cell responses against the 15 peptides were assessed through in vitro Enzyme Linked Immunospot (ELISpot).

Results

We uncovered 20 novel fusion transcripts from 75 breast tumors of 3 subtypes: TNBC, HER2+, and HR+. Of these, the NSFP1-LRRC37A2 fusion transcript was selected for further study. The 3833 bp chimeric RNA predicted by the consensus fusion junction sequence is consistent with a read-through transcription of the 5'-gene NSFP1-Pseudo gene NSFP1 (NSFtruncation at exon 12/13) followed by trans-splicing to connect withLRRC37A2 located immediately 3' through exon 1/2. A total of 15 different 8-mer neoantigen peptides discovered from the NSFP1 and LRRC37A2 truncations were predicted to bind to a total of 35 unique MHC class I alleles with a binding affinity of IC50<500nM.); 1 of which elicited a robust immune response.

Conclusion

Our data provides a framework to identify immunogenic neoantigen candidates from fusion transcripts and suggests a potential vaccine strategy to target the immunogenic neopeptides in patients with tumors carrying the NSFP1-LRRC37A2 fusion.

Abstract 6521: Subtype-specific molecular signatures of field cancerization in patients with sporadic breast cancer

Background: We have previously shown the presence of molecular field cancerization in patients with sporadic breast cancer. Given the heterogeneity of breast cancer, we hypothesized that such field cancerization is likely to be subtype-specific.

Methods: RNA exome sequencing was performed on 360 samples obtained from 75 breast cancer patients undergoing mastectomy; 25 cases were selected from each subtype: hormone receptor (HR) positive, Her2 positive, triple negative (TN) breast cancer. Four sites were sampled from each patient: primary tumor (A), adjacent normal parenchyma within 2cm of the tumor (B), 2 separate, histologically normal sites at least 2cm away from the tumor (C &D) or, if available, tissue from the unaffected contralateral breast (E). Normal breast tissue (N) from cancer-free controls was obtained from reduction mammoplasty. Tumor-associated genes (TAGs) were identified by comparison of primary tumor to tissue from cancer free controls. We estimated tumor content that was shared across samples B-E by applying deconvolutional analysis to the tumor associated genes, to calculate indices that ranged from 0, indicating normal, to 1, indicating tumor. Molecular field-associated genes and pathways were identified by Spearman’s correlation coefficient analysis between the differential genes/pathways and ISTC.

Results: Across all subtypes, the proportion of tumor content present in the histologically normal breast tissue samples (samples B, C, D, E) obtained from cancer patients ranged from 80% in tissue adjacent to the tumor to approximately 50% in tissue obtained from the contralateral breast. We found over 600 deregulated genes to constitute the molecular field across all of the 3 major subtypes tested (Her2+, HR, and TNBC), of which approximately 20% were shared in the molecular field of all 3 subtypes of breast cancer. Among the 664 genes noted to be part of the molecular field in TNBC, 23.8% were unique to this subtype. In contrast, only 13% of the genes that constituted the field cancerization in the Her2 and HR+ subtypes were subtype-specific. PIP3-AKT, TCR signaling, and DNA synthesis were among the top pathways specifically activated in the molecular field of the Her2+ subtype of breast cancer. The molecular field of HR+ breast cancer was uniquely characterized by upregulation in the mitotic cell cycle, G1- S transition, and RB pathway. The field of cancerization in the TNBC subtype showed an upregulation in MEK-MAPK, mTOR, and JNK-JUN-TAK1 pathways.

Conclusions: Our study suggests the presence of a breast cancer molecular field effect that extends beyond the adjacent normal breast tissue and includes the entire mammary gland. A substantial proportion of this field cancerization is subtype specific with uniquely deregulated pathways within each subtype. These findings provide new opportunities for developing subtype-specific chemoprevention strategies.

Citation Format: Anjana Bhardwaj, Zhenlin Ju, Constance Albarracin, Celestine Trinidad, Preethi Gunaratne, Jing Wang, Randa El-Zein, Isabelle Bedrosian. Subtype-specific molecular signatures of field cancerization in patients with sporadic breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 6521.

Targeting Replicative Stress and DNA Repair by Combining PARP and Wee1 Kinase Inhibitors Is Synergistic in Triple Negative Breast Cancers with Cyclin E or BRCA1 Alteration

Simple Summary

Triple-negative breast cancer (TNBC) is a subtype of invasive breast cancer with an aggressive phenotype that has decreased survival compared with other types of breast cancers, due in part to the lack of biomarker driven targeted therapies. Here, we show that breast cancer patients whose tumors show high levels of cyclin E expression have a higher prevalence of BRCA1/2 alterations and have the worst clinical outcomes. In vitro and in vivo studies revealed that combination therapies with poly (ADP-ribose) polymerase (PARP) and Wee1 kinase inhibitors in TNBC cells with either BRCA1 mutations or high levels of cyclin E results in synergistic cell death due to induction of replicative stress and downregulation of DNA repair. These studies suggest that by preselecting patients whose tumors have high cyclin E levels or harbor mutations in BRCA1, only those cases with the highest replicative stress properties will be subjected to combination treatment and likely result in synergistic activity of the two agents.

Abstract

The identification of biomarker-driven targeted therapies for patients with triple negative breast cancer (TNBC) remains a major clinical challenge, due to a lack of specific targets. Here, we show that cyclin E, a major regulator of G1 to S transition, is deregulated in TNBC and is associated with mutations in DNA repair genes (e.g., BRCA1/2). Breast cancers with high levels of cyclin E not only have a higher prevalence of BRCA1/2 mutations, but also are associated with the worst outcomes. Using several in vitro and in vivo model systems, we show that TNBCs that harbor either mutations in BRCA1/2 or overexpression of cyclin E are very sensitive to the growth inhibitory effects of AZD-1775 (Wee 1 kinase inhibitor) when used in combination with MK-4837 (PARP inhibitor). Combination treatment of TNBC cell lines with these two agents results in synergistic cell killing due to induction of replicative stress, downregulation of DNA repair and cytokinesis failure that results in increased apoptosis. These findings highlight the potential clinical application of using cyclin E and BRCA mutations as biomarkers to select only those patients with the highest replicative stress properties that may benefit from combination treatment with Wee 1 kinase and PARP inhibitors.

TRPS1: a highly sensitive and specific marker for breast carcinoma, especially for triple-negative breast cancer

Currently there is no highly specific and sensitive marker to identify breast cancer-the most common malignancy in women. Breast cancer can be categorized as estrogen receptor (ER)/progesterone receptor (PR)-positive luminal, human epidermal growth factor receptor 2 (HER2)-positive, or triple-negative breast cancer (TNBC) types based on the expression of ER, PR, and HER2. Although GATA3 is the most widely used tumor marker at present to determine the breast origin, which has been shown to be an excellent marker for ER-positive and low-grade breast cancer, but it does not work well for TNBC with sensitivity as low as <20% in metaplastic breast carcinoma. In the current study, through TCGA data mining we identified trichorhinophalangeal syndrome type 1 (TRPS1) as a specific gene for breast carcinoma across 31 solid tumor types. Moreover, high mRNA level of TRPS1 was found in all four subtypes of breast carcinoma including ER/PR-positive luminal A and B types, HER2-positive type, and basal-type/TNBC. We then analyzed TRPS1 expression in 479 cases of various types of breast cancer using immunochemistry staining, and found that TRPS1 and GATA3 had comparable positive expression in ER-positive (98% vs. 95%) and HER2-positive (87% vs. 88%) breast carcinomas. However, TRPS1 which was highly expressed in TNBC, was significantly higher than GATA3 expression in metaplastic (86% vs. 21%) and nonmetaplastic (86% vs. 51%) TNBC. In addition, TRPS1 expression was evaluated in 1234 cases of solid tumor from different organs. In contrast to the high expression of GATA3 in urothelial carcinoma, TRPS1 showed no or little expression in urothelial carcinomas or in other tumor types including lung adenocarcinoma, pancreatic adenocarcinoma, colon and gastric adenocarcinoma, renal cell carcinoma, melanoma, and ovarian carcinoma. These findings suggest that TRPS1 is a highly sensitive and specific marker for breast carcinoma and can be used as a great diagnostic tool, especially for TNBC.

Validation of prognostic significance of the proposed uniform classification framework in neuroendocrine neoplasms of the breast

PURPOSE

A uniform classification framework for neuroendocrine neoplasms (NENs) in all the organ systems has been recently proposed by an International Agency for Research on Cancer (IARC) and World Health Organization (WHO) expert panel. Based on the new classification system, the NENs of the breast are divided into well-differentiated neuroendocrine tumors (NETs) and poorly differentiated neuroendocrine carcinomas (NECs). This study is aimed to analysis the prognostic differences between NENs and invasive ductal carcinomas of no special type (IDCs-NST).

METHODS

The surveillance, epidemiology, and end results (SEER) database released on November 2018 was used for this study. Between 2003 and 2016, 361 NENs (NET = 239, NEC = 122) of the breast and 491,908 of IDCs-NST were identified. Survival analysis was performed for disease-specific survival (DSS) and overall survival (OS).

RESULTS

The 5-year DSS of NET, NEC, and IDC-NST was 63.39%, 46.00%, and 89.17%, respectively. And the 5-year OS of NET, NEC, and IDC-NST was 55.66%, 38.87%, and 83.17%, respectively. Within the same clinical stage or grade, NETs and NECs of the breast had worse DSS and OS than corresponding stage or grade IDCs-NST (all P < 0.050). In univariate and multivariate survival analysis, NENs of the breast had significantly worse DSS and OS than IDCs-NST (P < 0.001).

CONCLUSION

The universal classification framework for NEN allowed us to further refine the breast carcinoma with neuroendocrine differentiation as a unique pathologic and clinical entity, which has worse clinical outcome compared to IDC-NST.

Abstract 20: Fluvastatin inhibits the development of breast cancer in SV40C3Tag mouse model of triple negative breast cancer

Introduction: Primary prevention of breast cancer that is effective at preventing both HR- and HR+ tumors, remains an important clinical need and repurposing of existing low toxicity drugs represents a low cost, efficient strategy for meeting this goal. Cholesterol pathway activation is associated with poor prognosis across all subtypes of breast cancer patients. Relevant to breast cancer prevention, the breast epithelium in women with atypical hyperplasia, a known high risk state, is known to have increase in cholesterol levels and an increase in oxidative products of cholesterol. Additionally, cholesterol pathway genes such as HMG Co A reductase (HMGCR) are deregulated in transformed cells and drive the initiation and progression of breast cancer. These observations suggest a role for the cholesterol pathway early in tumorigenesis, thus making it an attractive target for prevention.

Methods: Using SV40C3 tag mice, a transgenic mouse model of TNBC, we targeted the cholesterol pathway by fluvastatin. Fluvastatin is a cholesterol lowering drug that blocks the cholesterol pathway activation through inhibition of HMGCR, a rate limiting enzyme of the pathway. Ten mice each were treated with fluvastatin (10mg/kg body weight/ day) alone, in combination with aspirin, AMPK activator, or vehicle control for 16 weeks starting at the age of about 6 weeks. Starting at the age of 10 weeks, mice were regularly examined for the presence of mammary tumors and any palpable mass of 0.3mm or bigger was considered as a lesion. At the end of 16 weeks of treatment, all mice were euthanized and mammary glands were excised, weighed and divided in 2 parts- one was fixed in formalin for any histochemical analyses and the other half was snap frozen for RNA extractions.

Results: Fluvastatin treatment for 16 weeks reduced the tumor incidence and average tumor burden by 50%. Additionally, in animals that developed tumors, fluvastatin delayed the onset of palpable tumors by 2.5 weeks and inhibited tumor size, as indicated by a 4- fold lesser tumor weight in the fluvastatin treated group relative to vehicle control group. To our surprise, the combo group (fluvastatin and aspirin) did not inhibit tumor incidence or size. We found the growth inhibitory effects of fluvastatin to be mediated by increased programmed cell death.

Conclusions: In line with NCI's emphasis to repurpose low toxicity drugs for prevention of cancer, our pre-clinical data supports efforts to test the efficacy of fluvastatin for prevention of TNBC in clinical trials.

Citation Format: Anjana Bhardwaj, Matthew D. Embury, Raniv D. Rojo, Constance Albarracin, Isabelle Bedrosian. Fluvastatin inhibits the development of breast cancer in SV40C3Tag mouse model of triple negative breast cancer [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 20.

Abstract P6-08-06: Characteristics of ductal carcinoma in situ (DCIS) in patients who underwent multigene panel testing for hereditary breast cancer

Background: Multigene panel testing (MPG) for hereditary breast cancer has recently increased significantly. While clinical and pathological characteristics for invasive breast cancer in patients with non BRCA germline mutations is emerging, there is very limited data in patients with ductal carcinoma in situ (DCIS). This study evaluates the clinical and pathological characteristics of patients with DCIS who underwent MPG testing for hereditary breast cancer.

Methods: Patients with DCIS who underwent MPG testing between 2014-2019 were identified from our prospectively maintained and IRB-approved research registry study and included in this analysis. Clinical and tumor characteristics were analyzed using descriptive statistics. Variables included in the analysis included: Age at diagnosis, family history of breast and ovarian cancer, tumor characteristics including ER/PR and nuclear grade and genetic testing results.

Results: In this prospective cohort, 324 patients with DCIS underwent multigene panel testing. Age of diagnosis was 50.5 years (range: 18-86), a family history of breast and/or ovarian cancer was positive in 283 (87.3%) patients. Genetic testing results were as follows: Pathogenic or likely pathogenic mutations were found in 28 (8.6%) patients: BRCA1 2 (7.1%), BRCA2 6 (21.4%), PALB2 6 (21.4%), CHEK2 5 (17.9%), ATM 3 (10.7%), APC 2 (7.1%), BARD1 1 (3.6%), BRIP1 1 (3.6%), MSH2 1 (3.6%), MUTYH 1 (3.6%). The variant of uncertain significance rate was 16% (52): 7 (13.5%) in BRCA1 or 2 and 45 (86.5%) in other genes. 244 (75.3%) of patients had negative results.

Conclusion: Our data demonstrates that, in addition to BRCA 1 and 2 genes, patients with DCIS have other hereditary genes involved. In fact, 71.4% of the germline mutations were in non-BRCA genes. Regardless of gene status, most patients had ER positive disease, this can have implications for chemopreventive therapy. Furthermore, patients with germline mutations have a higher percentage of nuclear grade III DCIS than gene negative patients. Larger studies are needed to evaluate the clinical implications of these findings. Genetic testing with a larger panel, other than BRCA1 and BRCA2 genes only, should be considered for patients with DCIS.

NegativeBRCA1+BRCA2+PALB2+CHEK2+ATM+Variablesn%n%n%n%n%n%ERpositive17471.32100.0583.3350.0480.03100.0negative187.400.000.0116.7120.000.0unknown5120.900.0116.7233.300.000.0PRpositive15262.3150.0583.3350.0480.03100.0negative3815.6150.000.0116.7120.000.0unknown5422.100.0116.7233.300.000.0NGI187.4150.000.000.0240.000.0II10041.000.0116.7350.0240.0133.3III8534.8150.0466.7233.300.0266.7unknown4116.800.0116.7116.7120.000.0Totals244100.02100.06100.06100.05100.03100.0

Citation Format: Loredana Militello, Angelica M Gutierrez Barrera, Henry Kuerer, Constance Albarracin, Banu K Arun. Characteristics of ductal carcinoma in situ (DCIS) in patients who underwent multigene panel testing for hereditary breast cancer [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P6-08-06.

Abstract P6-08-26: Clinical characteristics of breast cancer patients with ATM mutations

Background: Pathogenic ATM gene mutations are associated with increased risk of developing several cancers such as lymphoid, gastric, breast, central nervous system, skin, and other cancers. The relative risk of breast cancer is 2.3, with a higher risk seen for women under the age of 50 years. Only few and small studies have reported on the characteristics of breast cancers in women with ATM mutations. Here, we aimed to describe the clinical and pathological characteristics of a single institution largest cohort, to the best of our knowledge, of breast cancer patients with ATM mutations.

Methods: Patients with breast cancer who presented to the University of Texas MD Anderson Cancer Center Clinical Cancer Genetics clinics and underwent genetic testing for hereditary breast cancer and were found to have an ATM mutation were included. A retrospective review of a prospectively maintained research database was performed for ATM mutation status as well as patient clinical and pathological characteristics. IRB approval was granted for this analysis.

Results: Between 2012 and 2019, a total of 4093 breast cancer patients underwent genetic testing for hereditary breast cancer that included ATM gene testing. The median age of diagnosis of breast cancer was 49.3 (17-89), and median age at genetic testing was 52.1 (18-86). 72% of patients had stage 0-III and 3.2% stage 4 disease. Among patients with ATM pathogenic mutations, 37.7% (10) versus 21.7% (843) of ATM negative patients had a history of multiple primaries of any cancers. The table below shows characteristics of ATM pathogenic mutation carriers versus ATM negative patients.

Conclusion: This is a single institution cohort of breast cancer patients with ATM mutations that show distinct clinical characteristics, such as multiple primary cancers. These findings could have therapeutic implications and should be confirmed in larger cohorts.

Pathogenic Mutation of ATM ATM NegativesVariablesn%n%ERPositive4075.5221757.1Negative11.976019.6Unknown1222.690423.3PRPositive3667.9188448.5Negative59.4107027.6Pos/Neg00.010.03Unknown1222.692623.9Her2Positive1018.958611.3Negative2241.5206257.0Unknown2139.6123314.2Stage059.43178.2I1324.597825.2II1120.8106527.4III713.243611.2IV47.51243.2Unknown1324.596124.8Nuclear GradeI23.82596.7II1935.8111228.7III1120.8115629.8Unknown2139.6135434.9Triple Negative?Yes00.053913.9No3769.8222757.4Unknown1630.2111528.7

Citation Format: Loredana Militello, Angelica M Gutierrez Barrera, Constance Albarracin, Isabelle Bedrosian, Banu K Arun. Clinical characteristics of breast cancer patients with ATM mutations [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P6-08-26.

EF2-kinase targeted cobalt-ferrite siRNA-nanotherapy suppresses BRCA1-mutated breast cancer

Aim: To investigate the role of EF2K in BRCA1-mutated breast cancer. Materials & methods: We developed silica coated cobalt-ferrite (CoFe) nanoparticles for in vivo delivery of small interfering RNAs (siRNAs) into BRCA1-mutated breast cancer. Results: Expression of EF2K is highly upregulated in the majority (78.5%) of BRCA1-mutated patients and significantly associated with poor patient survival and metastasis. Silencing of EF2K reduced cell proliferation, migration and invasion of the cancer cells. In vivo therapeutic targeting of EF2K by CoFe-siRNA-nanoparticles leads to sustained EF2K gene knockdown and suppressed tumor growth in orthotopic xenograft models of BRCA1-mutated breast cancer. Conclusion: EF2K is a potential novel molecular target in BRCA1-mutated tumors and CoFe-based siRNA nanotherapy may be used as a novel approach to target EF2K.

Abstract P6-12-02: isomiR-140-3p-regulated mevalonic acid pathway as a potiental target for prevention of triple negative breast cancer

Background: Prevention of triple negative breast cancer (TNBC) is hampered by lack of knowledge about the drivers of tumorigenesis. Methods: In order to identify molecular markers and their downstream networks that can potentially be targeted for TNBC prevention, we analyzed small RNA and RNA sequencing of a cell line model that represents early stages of TNBC development. We identified direct gene targets of an isomiRNA and using cell based and in vivo model systems we demonstrate the utility of targeting downstream pathways for prevention of TNBC. Results: These analyses showed that 5'isomiRNA of miR-140-3p (miR-140-3p-1) were deregulated in the normal-to- preneoplastic transition. We also identified novel direct gene targets of miR140-3p-1, HMG-CoA reductase (HMGCR) and HMG-CoA synthase 1(HMGCS1), key enzymes in the cholesterol biosynthesis pathway, and found that these too are deregulated in the normal to preneoplastic transition, resulting in activation of the cholesterol synthesis pathway. Upregulation in the cholesterol pathway creates a metabolic vulnerability that can be targeted with the statin class of inhibitors. Consistent with this hypothesis, we found direct targeting of miR-140-3p-1 and its downstream pathway by fluvastatin inhibits growth of these preneoplastic MCF10.AT1 cells. However, although, fluvastatin inhibited the growth of MCF10.AT1-derived xenografts, histological progression remained unchanged. The cholesterol pathway is highly regulated, and HMGCR enzymatic activity inhibition is known to trigger a feedback response leading to restoration of the pathway. Indeed, we found fluvastatin treatment induced HMGCR transcript levels in the explanted xenografts, with higher transcript induction directly correlated with the degree of histological progression of lesions, indicating an adaptive resistance mechanism that circumvents statin targeting of HMGCR. Therefore, we hypothesized that dual targeting of HMGCR and the feedback loops are necessary to overcome this adaptive resistance. To test this hypothesis, we generated MCF10AT1 cells resistant to fluvastatin. We then treated these resistance AT1 cells with an activator of AMP-activated protein kinase (AMPK), a brake in the cholesterol feedback pathway. AMPK activation by aspirin effectively abrogated the statin-induced upregulation of HMGCR and sensitized these resistant cells to fluvastatin. Conclusions: Our preclinical data suggests that the statin treatment induced homeostatic upregulation of the cholesterol pathway is a barrier to effective chemoprevention with statins. However, our results also suggest that this adaptive resistance mechanism can be abrogated by combined treatment with statin and AMPK activators such as aspirin. Clinical studies of this combined regimen should be considered in high risk patients.

Citation Format: Bhardwaj A, Singh H, Trinidad CM, Albarracin C, Hunt KK, Bedrosian I. isomiR-140-3p-regulated mevalonic acid pathway as a potiental target for prevention of triple negative breast cancer [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P6-12-02.

Comparative Effectiveness of an mTOR-Based Systemic Therapy Regimen in Advanced, Metaplastic and Nonmetaplastic Triple-Negative Breast Cancer

BACKGROUND

Triple-negative breast cancer (TNBC) is a heterogeneous disease with subtypes having different "targetable" molecular aberrations. Metaplastic breast cancers (MpBCs) are typically TNBCs and commonly have alterations in the PI3K/Akt/mTOR pathway. We previously reported efficacy for an mTOR-based chemotherapy regimen in MpBC. To determine if tumor subtype influences prognosis, we compared treatment outcomes of patients with MpBC with those of patients with nonmetaplastic TNBC receiving an mTOR-based systemic therapy regimen.

PATIENTS AND METHODS

Patients with advanced MpBC and nonmetaplastic TNBC were treated at our institution from April 16, 2009, through November 4, 2014, using mTOR inhibition (temsirolimus or everolimus) with liposomal doxorubicin and bevacizumab (DAT/DAE). Median progression-free survival (PFS) and overall survival (OS) were estimated by the Kaplan-Meier method. Cox regression analyses were used to evaluate associations between tumor histology and outcomes. Multivariable models were adjusted for all covariates.

RESULTS

Fourteen patients with nonmetaplastic TNBC and 59 patients with advanced MpBC were treated with DAT/DAE. MpBC patients were older (p = .002) and less likely to have a history of bevacizumab use (p = .023). Median PFS for the nonmetaplastic TNBC and MpBC patients was 2.5 months and 4.8 months, respectively. This difference in PFS was statistically significant on univariable (p = .006) but not multivariable analysis (p = .087). Median OS for the nonmetaplastic TNBC and MpBC patients was 3.7 months and 10.0 months, respectively (p = .0003). MpBC remained significantly associated with improved OS on multivariable analysis (p < .0001).

CONCLUSION

In our study, DAT/DAE appeared to be more effective in MpBC compared with nonmetaplastic TNBC. These data support patient selection for targeted therapy in TNBC.

IMPLICATIONS FOR PRACTICE

Metaplastic breast cancers (MpBCs) represent <1% of all breast cancers, demonstrate mesenchymal differentiation, and are typically resistant to chemotherapy. Patients with advanced MpBC treated with an mTOR-based systemic therapy regimen had better long-term outcomes compared with patients with nonmetaplastic triple-negative breast cancer treated with the same regimen, suggesting that metaplastic histology may predict benefit from agents targeting the PI3K/Akt/mTOR pathway.

Abstract 2192: Single-molecule single-cell DNA sequencing identifies ongoing copy number evolution in BRCA breast cancers

BRCA2 germline mutation carriers have a lifetime risk of 72% for developing invasive breast cancer. Although BRCA2 has been implicated in double-stranded break repair, the role of this mutation in genome evolution and maintaining genome instability during the expansion of the primary tumor mass is not well understood. To investigate these questions, we developed a novel method for single-cell, single-molecule (SCSM) sequencing. SCSM uses a Tn5 transposase to directly fragment and ligate adapters for PCR amplification, thereby omitting the whole-genome-amplification (WGA) step, which introduces technical noise into single-cell sequencing datasets. This approach provides single-molecule data by positional barcoding, reducing WGA artifacts that are typically associated with amplification bias. We further utilize a dual-barcoding approach and acoustic liquid transfer technology to increase throughput (N=384) and reduce cost to $1 per cell using nanoliter volumes. We applied SMSC to sequence copy number profiles from ~1000 single cells from two patients with BRCA2-positive breast tumors. In both cases we identified several major clonal subpopulations that shared a set of truncal CNAs, suggesting that they evolved from a single normal epithelial cell in the breast, not multiple initiating cells. We also identified many small subclonal CNAs that further diversified the major clones, which suggests that copy number evolution was ongoing during the expansion of the primary tumor mass. These data demonstrate the technical feasibility of SMSC sequencing, and further show that minor copy number evolution is ongoing in BRCA-positive breast cancer patients.

Citation Format: Haowei Du, Alexander Davis, Ruli Gao, Medina Colic, Emi Sei, Min Hu, Angelica Gutierrez Barrera, Anna Casasent, Constance Albarracin, Banu Arun, Nicholas E. Navin. Single-molecule single-cell DNA sequencing identifies ongoing copy number evolution in BRCA breast cancers [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 2192.

DCIS Margins and Breast Conservation: MD Anderson Cancer Center Multidisciplinary Practice Guidelines and Outcomes

Recent published guidelines suggest that adequate margins for DCIS should be ≥ 2 mm after breast conserving surgery followed by radiotherapy (RT). Many groups now use this guideline as an absolute indication for additional surgery. This article describes detailed multidisciplinary practices including extensive preoperative/intraoperative pathologic/histologic image-guided assessment of margins, offering some patients with small low/intermediate grade DCIS no RT, the use/magnitude of radiation boost tailoring to margin width, and endocrine therapy for ER-positive DCIS. Use of these protocols over the past 20-years has resulted in 10-year local recurrence rates below 5% for patients with negative margins < 2 mm who received RT. Patients with margins < 2 mm who do not receive RT experience significantly higher local failure rates. Thus, there is not an absolute need to achieve wider negative surgical margins when < 2 mm for patients treated with RT and this should be determined by the multidisciplinary team. Utilization of these multidisciplinary treatment protocols and techniques may not be exportable and extrapolated to all hospitals, breast programs and systems as they can be complex and resource intensive.

Factors impacting the accuracy of intra-operative evaluation of sentinel lymph nodes in breast cancer

Sentinel lymph node dissection (SLND) is a standard axillary staging technique in breast cancer and intraoperative sentinel lymph node (SLN) assessment is important for decision-making regarding additional treatment and reconstruction. This study was undertaken to investigate clinicopathologic factors impacting the accuracy of intraoperative SLN evaluation. Records of patients with clinically node-negative, invasive breast cancer who underwent SLND with frozen section intraoperative pathologic evaluation from 2004 to 2007 were reviewed. Intraoperative SLN assessment results were compared to final pathology. Patients with positive SLNs that were initially reported as negative during intraoperative assessment were considered false negative (FN) events. Primary tumor histology, grade, receptor status, size, lymphovascular invasion (LVI), multifocality, neoadjuvant chemotherapy or hormonal therapy, number of SLNs retrieved, and SLN metastasis size were evaluated. The study included 681 patients, of whom 262 (38%) received neoadjuvant therapy. There were 183 (27%) patients who had a positive SLN on final pathology, of whom 60 (33%) had FN events. On univariate analysis, lobular histology, favorable histology, absence of LVI and micrometastasis were associated with a higher FN rate. On multivariate analysis, favorable and lobular histology and micrometastasis were independent predictors of FN events whereas LVI and receipt of neoadjuvant therapy were not statistically significant predictors. The accuracy of intraoperative SLN evaluation for breast cancer is affected by primary tumor histology and size of the SLN metastasis. There was no significant association between neoadjuvant therapy and the FN rate by intraoperative assessment. This information may be helpful in counseling patients about their risk for a FN intraoperative SLN assessment and for planning for immediate breast reconstruction in patients undergoing mastectomy.

Targeting the PI3K/AKT/mTOR Pathway for the Treatment of Mesenchymal Triple-Negative Breast Cancer: Evidence From a Phase 1 Trial of mTOR Inhibition in Combination With Liposomal Doxorubicin and Bevacizumab

Importance

Triple-negative breast cancer (TNBC) classified by transcriptional profiling as the mesenchymal subtype frequently harbors aberrations in the phosphoinositide 3-kinase (PI3K) pathway, raising the possibility of targeting this pathway to enhance chemotherapy response. Up to 30% of mesenchymal TNBC can be classified histologically as metaplastic breast cancer, a chemorefractory group of tumors with a mixture of epithelial and mesenchymal components identifiable by light microscopy. While assays to identify mesenchymal TNBC are under development, metaplastic breast cancer serves as a clinically identifiable surrogate to evaluate potential regimens for mesenchymal TNBC.

Objective

To assess safety and efficacy of mammalian target of rapamycin (mTOR) inhibition in combination with liposomal doxorubicin and bevacizumab in patients with advanced metaplastic TNBC.

Design, Setting, and Participants

Phase 1 study with dose escalation and dose expansion at the University of Texas MD Anderson Cancer Center of patients with advanced metaplastic TNBC. Patients were enrolled from April 16, 2009, to November 4, 2014, and followed for outcomes with a cutoff date of November 1, 2015, for data analysis.

Interventions

Liposomal doxorubicin, bevacizumab, and the mTOR inhibitors temsirolimus or everolimus using 21-day cycles.

Main Outcomes and Measures

Safety and response. When available, archived tissue was evaluated for aberrations in the PI3K pathway.

Results

Fifty-two women with metaplastic TNBC (median age, 58 years; range, 37-79 years) were treated with liposomal doxorubicin, bevacizumab, and temsirolimus (DAT) (N = 39) or liposomal doxorubicin, bevacizumab, and everolimus (DAE) (N = 13). The objective response rate was 21% (complete response = 4 [8%]; partial response = 7 [13%]) and 10 (19%) patients had stable disease for at least 6 months, for a clinical benefit rate of 40%. Tissue was available for testing in 43 patients, and 32 (74%) had a PI3K pathway aberration. Presence of PI3K pathway aberration was associated with a significant improvement in objective response rate (31% vs 0%; P = .04) but not clinical benefit rate (44% vs 45%; P > .99).

Conclusions and Relevance

Using metaplastic TNBC as a surrogate for mesenchymal TNBC, DAT and DAE had notable activity in mesenchymal TNBC. Objective response was limited to patients with PI3K pathway aberration. A randomized trial should be performed to test DAT and DAE for metaplastic TNBC, as well as nonmetaplastic, mesenchymal TNBC, especially when PI3K pathway aberrations are identified.

Genome-wide copy number aberrations and HER2 and FGFR1 alterations in primary breast cancer by molecular inversion probe microarray

Breast cancer remains the second leading cause of cancer-related death in women despite stratification based on standard hormonal receptor (HR) and HER2 testing. Additional prognostic markers are needed to improve breast cancer treatment. Chromothripsis, a catastrophic genome rearrangement, has been described recently in various cancer genomes and affects cancer progression and prognosis. However, little is known about chromothripsis in breast cancer. To identify novel prognostic biomarkers in breast cancer, we used molecular inversion probe (MIP) microarray to explore genome-wide copy number aberrations (CNA) and breast cancer-related gene alterations in DNA extracted from formalin-fixed paraffin-embedded tissue. We examined 42 primary breast cancers with known HR and HER2 status assessed via immunohistochemistry and FISH and analyzed MIP microarray results for correlation with standard tests and survival outcomes. Global genome-wide CNA ranged from 0.2% to 65.7%. Chromothripsis-like patterns were observed in 23/38 (61%) cases and were more prevalent in cases with ≥10% CNA (20/26, 77%) than in cases with <10% CNA (3/12, 25%; p<0.01). Most frequently involved chromosomal segment was 17q12-q21, the HER2 locus. Chromothripsis-like patterns involving 17q12 were observed in 8/19 (42%) of HER2-amplified tumors but not in any of the tumors without HER2 amplification (0/19; p<0.01). HER2 amplification detected by MIP microarray was 95% concordant with conventional testing (39/41). Interestingly, 21% of patients (9/42) had fibroblast growth factor receptor 1 (FGFR1)amplification and had a 460% higher risk for mortality than those without FGFR1 amplification (p<0.01). In summary, MIP microarray provided a robust assessment of genomic CNA of breast cancer.

Long-Term Safety of Observation in Selected Women Following Core Biopsy Diagnosis of Atypical Ductal Hyperplasia

PURPOSE

Atypical ductal hyperplasia (ADH) found on core biopsy is associated with an upgrade to carcinoma in 10-30 % of women, thus surgical excision remains the standard of care. This study compares the incidence of breast cancer in women with ADH who were observed with those who underwent surgical excision of the ADH site.

METHODS

Our departmental, prospectively maintained registry was reviewed to identify patients with ADH diagnosed by core biopsy. Surgically treated patients were excluded if upstaged to carcinoma following excision for ADH diagnosis. Breast cancer events were classified as index site (site of ADH biopsy), ipsilateral breast unrelated to index site, or contralateral breast.

RESULTS

Overall, 175 women met the study criteria; 125 were observed and 50 underwent excision. With a median follow-up of 3 years, 14 breast cancer events were noted in 13 patients. In the surgery group, six women developed breast cancer (12 %), including one bilateral, compared with seven cancers (5.6 %) in the observed group (p = 0.14). Index site events and ipsilateral cancers were the same in both groups [2 vs. 0.8 % (p = 0.49) and 4 versus 4.8 % (p = 1.00), respectively]. All contralateral cancers occurred in the surgical group (8 vs. 0 %; p < 0.01). A prior history of breast cancer was the only variable associated with subsequent breast cancer events (hazard ratio 12.53, 95 % confidence interval 3.30-47.57).

CONCLUSION

Observation is appropriate in selected women with ADH on core biopsy. Index site failures are rare and are superseded by cancer risk elsewhere in the breast.

Abstract 2273: Targeting the PI3K/AKT/mTOR pathway for the treatment of metaplastic breast cancer: Does location of PIK3CA mutation or histology affect response

Background: Metaplastic breast cancers (MpBCs) are a chemo-refractory group of tumors that contain a component of squamous and/or mesenchymal differentiation identifiable by light microscopy. MpBCs contain a high frequency of aberrations in the PI3K/AKT/mTOR pathway, making this pathway a potential target for therapy.

Methods: Patients with advanced MpBC (N = 52) were treated with liposomal doxorubicin (D), bevacizumab (A) and the mTOR inhibitors temsirolimus (T) or everolimus (E). D and A were administered IV on day 1 with T (IV on days 1, 8 and 15) or E (continuous daily oral administration) using 21 day cycles. All tumors were evaluated to assess histology of metaplasia (spindle, mixed spindle vs non-spindle cell). Response was assessed every 6 weeks using RECIST. When available, archived tissue was evaluated for aberrations in the PI3K pathway using standard assays.

Results: Fifty-two MpBC patients were treated with DAT (N = 39) or DAE (N = 13). Median age was 58 (range 37-79); median number of prior regimens for metastatic disease was 1 (range 0-5). The objective response rate (ORR) was 21% [complete response (CR) = 4 (8%); partial response (PR) = 7 (13%)] and 10 (19%) pts had stable disease (SD)≥6 months for a clinical benefit rate (CBR) of 40%. Tissue was available in 43 pts and 32 (74%) had a PI3K pathway activating aberrations. PI3K pathway aberration was associated with a significant improvement in ORR (31 vs 0%; P = 0.04) but not CBR (44 vs 45%; P = 1.00) or progression-free survival (median 5 vs 3 months; P = 0.35). The most frequent PI3K pathway aberration was mutation in PIK3CA, occurring in 19 patients. Outcomes were similar if mutations of PIK3CA were located in the helical or kinase domain (ORR 25% vs 27%; P = 1.00 and CBR 38% vs 47%; P = 1.00, respectively). Spindle cell was the most frequent metaplastic histology seen, occurring in 18 tumors and mixed with other metaplastic histologies including squamous, chondroid and osseous in 14 additional tumors, while 20 tumors had non-spindle cell morphologies. The incidence of PI3K pathway aberration was similar across histologies (61% in spindle vs 67% in mixed spindle vs 60% in non-spindle cell). Tumors with mixed histology had lower ORR, CBR and PFS, but this was not statistically significant, likely due to small numbers in each cohort: ORR 22% in spindle vs 7% in mixed spindle vs 30% in non-spindle cell, P = 0.27; CBR 50% in spindle vs 21% in mixed spindle vs 40% in non-spindle cell, P = 0.25; and PFS median 4 months in spindle vs 2 months in mixed spindle vs 5 months in non-spindle cell, P = 0.68.

Conclusions: Response to mTOR inhibition is enhanced in MpBCs with PI3K pathway aberrations. However, specific aberrations in PIK3CA do not lead to differential response to mTOR inhibition. PI3K pathway aberrations and response to mTOR inhibition are seen across all histologies of MpBC, and the response is not enhanced in particular histologies.

Citation Format: Reva K. Basho, Michael Gilcrease, Rashmi K. Murthy, Thorunn Helgason, Daniel J. Booser, Daniel D. Karp, Funda Meric-Bernstam, Kenneth R. Hess, Shelley M. Herbrich, Vicente Valero, Constance Albarracin, Jennifer Litton, Mariana Chavez-MacGregor, Nuhad K. Ibrahim, James L. Murray, Kimberly B. Koenig, David Hong, Vivek Subbiah, Razelle Kurzrock, Filip Janku, Stacy Moulder. Targeting the PI3K/AKT/mTOR pathway for the treatment of metaplastic breast cancer: Does location of PIK3CA mutation or histology affect response. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 2273.

Abstract P3-14-02: Targeting the PI3K/AKT/mTOR pathway for the treatment of mesenchymal triple-negative breast cancer (TNBC): Evidence of efficacy and proof of concept from a phase I trial with dose expansion of mTOR inhibition in combination with liposomal doxorubicin and bevacizumab

Background: Approximately 30% of TNBCs are characterized by microarray as claudin-low, mesenchymal or mesenchymal stem cell-like and, unlike basal TNBCs, these tumors frequently harbor aberrations in the PI3K/AKT/mTOR axis, raising the possibility of targeting this axis to enhance chemotherapy response. Assays to clinically identify mesenchymal TNBCs are under development, but published results confirm that up to 30% are metaplastic breast cancers (MpBCs), a chemo-refractory group of tumors that contain a mixture of epithelial and mesenchymal components, making them identifiable by microscopy. As such, MpBCs serve as surrogates of response for potential regimens to treat mesenchymal TNBC.

Methods: Patients (pts) with advanced TNBC (N=64) were treated with liposomal doxorubicin (D), bevacizumab (A) and the mTOR inhibitors temsirolimus (T) or everolimus (E). D and A were administered IV on day 1 with T (IV on days 1, 8 and 15) or E (continuous daily oral administration) using 21 day cycles. Response was assessed every 6 weeks using RECIST. When available, archived tissue was evaluated for aberrations in the PI3K pathway using standard assays.

Results: Fifty-two MpBC pts were treated with DAT (N=39) or DAE (N=13). Median age was 58 (range 37-79); median # of prior regimens for metastatic disease was 1 (range 0-5). The objective response rate (ORR) was 21% [complete response (CR)=4 (8%); partial response (PR)=7 (13%)] and 10 (19%) pts had stable disease (SD)≥6 months for a clinical benefit rate (CBR) of 40%. Tissue was available for testing in 43 pts and 32 (74%) had a PI3K pathway activating aberration (Table 1).

Response According to PI3K Pathway AberrationPI3K Pathway AberrationN (%)CRPRSD≥6monthsCBRORRAny PI3K Pathway Aberration*32 (74)46444%31%PIK3CA Mutation19 (59)23447%26%p.H1047R12 (38)21350%25%p.E545K6 (19)02150%33%p.G1007R1 (3)010100%100%p.E545A1 (3)0000%0%p.H1047Y1 (3)0000%0%p.K111E1 (3)0000%0%p.E542K1 (3)0000%0%PIK3CA Amplification1 (3)010100%100%PTEN Mutation5 (16)0000%0%PTEN Loss5 (16)02040%40%AKT1 p.E17K Mutation2 (6)0000%0%AKT2 Amplification1 (3)100100%100%PIK3R1 Mutation2 (6)01050%50%NF2 Mutation1 (3)100100%100%No PI3K Pathway Aberration11 (26)00545%0%*Some tumors had &gt;1 aberration detected

PI3K pathway activation was associated with a significant improvement in ORR (31 vs 0%; P=0.043) but not CBR (44 vs 45%; P=1.000) or progression-free survival (median 5.1 vs 2.9 months; P=0.352). A pt with 5 year+ durable CR (on maintenance everolimus) had a mutation in NF2. To emphasize the importance of pt selection, it is notable that 12 pts with non-metaplastic TNBC were also treated with DAT, and only 1 pt had a response (CR/PR=1; SD≥6 months=0), for a CBR that was significantly worse than pts with MpBC (8 vs 40%; P=0.045).

Conclusions: Using MpBC as a surrogate of response, DAT/DAE has significantly better activity in mesenchymal compared to non-selected TNBC. Response is enhanced in pts with PI3K pathway activation. DAT/DAE should be tested in non-metaplastic, mesenchymal TNBC once a diagnostic assay is available.

Citation Format: Basho RK, Gilcrease M, Murthy RK, Helgason T, Booser DJ, Karp DD, Meric-Bernstam F, Wheler JJ, Valero V, Albarracin C, Litton J, Chavez-MacGregor M, Ibrahim NK, Murray JL, Koenig KB, Hong D, Subbiah V, Kurzrock R, Janku F, Moulder S. Targeting the PI3K/AKT/mTOR pathway for the treatment of mesenchymal triple-negative breast cancer (TNBC): Evidence of efficacy and proof of concept from a phase I trial with dose expansion of mTOR inhibition in combination with liposomal doxorubicin and bevacizumab. [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 P3-14-02.

Rare Malignant Tumors of the Breast

While the more common forms of breast cancer are well understood and recognized, there are many important rare malignancies that are less appreciated. Many of these cancers have imaging findings that, when understood, help to formulate a more educated differential diagnosis. In this article, the clinical features, imaging, and pathologic findings of rare breast malignancies will be discussed.

Elafin is downregulated during breast and ovarian tumorigenesis but its residual expression predicts recurrence

INTRODUCTION

Elafin is an endogenous serine protease inhibitor. The majority of breast cancer cell lines lack elafin expression compared to human mammary epithelial cells. In this study, we hypothesized that elafin is downregulated during breast and ovarian tumorigenesis.

METHODS

We examined elafin expression by immunohistochemistry (IHC) in specimens of normal breast tissue (n = 24), ductal carcinoma in situ (DCIS) (n = 54), and invasive breast cancer (n = 793). IHC analysis of elafin expression was also performed in normal fallopian tube tissue (n = 20), ovarian cystadenomas (n = 9), borderline ovarian tumors (n = 21), and invasive ovarian carcinomas (n = 216). To understand the significance of elafin in luminal breast cancer cell lines, wild-type or M25G elafin (lacking the protease inhibitory function) were exogenously expressed in MCF-7 and T47D cells.

RESULTS

Elafin expression was downregulated in 24% of DCIS and 83% of invasive breast tumors when compared to elafin expression in the normal mammary epithelium. However, the presence of elafin-positive cells in invasive breast tumors, even at low frequency, correlated with poor recurrence-free survival (RFS), reduced overall survival (OS), and clinicopathological markers of aggressive tumor behavior. Elafin-positive cells were an especially strong and independent prognostic marker of reduced RFS in IHC-defined luminal A-like tumors. Elafin was also downregulated in 33% of ovarian cystadenomas, 43% of borderline ovarian tumors, and 86% of invasive ovarian carcinomas when compared to elafin expression in the normal fallopian tube. In ovarian tumors, elafin-positive cells were correlated with reduced RFS, OS and disease-specific survival (DSS) only in stage I/II patients and not in stage III/IV patients. Notably, exogenous expression of elafin or elafin M25G in the luminal breast cancer cell lines MCF-7 and T47D significantly decreased cell proliferation in a protease inhibitory domain-independent manner.

CONCLUSIONS

Elafin predicts poor outcome in breast and ovarian cancer patients and delineates a subset of endocrine receptor-positive breast cancer patients susceptible to recurrence who could benefit from more aggressive intervention. Our in vitro results suggest that elafin arrests luminal breast cancer cells, perhaps suggesting a role in tumor dormancy.

Reproducibility of residual cancer burden for prognostic assessment of breast cancer after neoadjuvant chemotherapy

The residual cancer burden index was developed as a method to quantify residual disease ranging from pathological complete response to extensive residual disease. The aim of this study was to evaluate the inter-Pathologist reproducibility in the residual cancer burden index score and category, and in their long-term prognostic utility. Pathology slides and pathology reports of 100 cases from patients treated in a randomized neoadjuvant trial were reviewed independently by five pathologists. The size of tumor bed, average percent overall tumor cellularity, average percent of the in situ cancer within the tumor bed, size of largest axillary metastasis, and number of involved nodes were assessed separately by each pathologist and residual cancer burden categories were assigned to each case following calculation of the numerical residual cancer burden index score. Inter-Pathologist agreement in the assessment of the continuous residual cancer burden score and its components and agreement in the residual cancer burden category assignments were analyzed. The overall concordance correlation coefficient for the agreement in residual cancer burden score among pathologists was 0.931 (95% confidence interval (CI) 0.908-0.949). Overall accuracy of the residual cancer burden score determination was 0.989. The kappa coefficient for overall agreement in the residual cancer burden category assignments was 0.583 (95% CI 0.539-0.626). The metastatic component of the residual cancer burden index showed stronger concordance between pathologists (overall concordance correlation coefficient=0.980; 95% CI 0.954-0.992), than the primary component (overall concordance correlation coefficient=0.795; 95% CI 0.716-0.853). At a median follow-up of 12 years residual cancer burden determined by each of the pathologists had the same prognostic accuracy for distant recurrence-free and survival (overall concordance correlation coefficient=0.995; 95% CI 0.989-0.998). Residual cancer burden assessment is highly reproducible, with reproducible long-term prognostic significance.

Abstract P1-15-03: Long term outcomes in patients with phyllodes tumor of the breast: The UT MD Anderson experience

Purpose: Phyllodes tumor is a relatively rare disease of the breast, and the risk factors for local versus distant failure are unclear. The goal of this study was to identify factors influencing local, distant, and cause-specific survival outcomes in patients with phyllodes tumors, and to assess the impact of local radiotherapy (RT).

Methods: We retrospectively reviewed the records of 387 patients recorded in the MD Anderson tumor registry as having "cystosarcoma phyllodes" or "phyllodes". After excluding patients with recurrent disease at presentation to the institution, concurrent invasive ductal carcinoma, absence of confirmation of phyllodes tumor, or inadequate follow up after surgery, 229 patients diagnosed from 1964-2011 were evaluable. The median tumor size was 4 cm (range, 0.7-28 cm); histology was benign in 29%, indeterminate in 7%, and malignant in 41% (23% unknown). Stromal overgrowth was present in 18% (n=40). Local therapy consisted of breast-conserving surgery (n=184) or mastectomy (n=43); 15% (n=34) also received local RT. Chemotherapy was administered in 9% (n=21). We used Kaplan-Meier analyses and Cox proportional hazards models to estimate the associations between patient/tumor characteristics and treatment on local control (LC), distant metastasis-free survival (DMFS), and cause specific survival (CSS).

Results: At a median follow-up of 76 months (range, 1-485 months), the actuarial 5-yr LC for the entire cohort was 75%; 5-yr DMFS was 78%; and 5-yr CSS was 86%. Factors influencing LC included receipt of RT (5-yr LC 97% versus 72%, p=.005) and age over 50 (85% versus 72%, p=.044). Neither malignant histology nor stromal overgrowth increased the risk of local failure. Factors influencing DMFS included malignant histology (5-yr DMFS 65% versus 91%, p=.001) and stromal overgrowth (50% versus 84%, p&lt;.001). Factors influencing CSS included malignant histology (5-yr CSS 77% versus 100%, p=.002) and stromal overgrowth (58% versus 92%, p&lt;.001). Patients with stromal overgrowth or malignant histology were much more likely to receive RT (p&lt;.001 for both factors). RT improved 5-yr LC for both breast conserved and mastectomy patients, but did not improve DMFS or CSS. In multivariable models, the following associations were noted (HR=hazard ratio; CI= 95% confidence interval): LC – RT (HR 0.13, CI .03-.55); DMFS – malignant histology (HR 2.99, CI 1.41-6.34); CSS – malignant histology (HR 4.18, CI 1.43-12.24).

Conclusions: Adjuvant RT after surgery improves local control in phyllodes tumor; however, it does not improve DMFS or CSS. Stromal overgrowth and malignant histology are associated with worse DMFS and CSS, but do not impact local control. Therefore malignant histology and stromal overgrowth should not be deciding factors in the use of local RT, as escalated local therapy in patients with these tumor characteristics does not improve DMFS or CSS. Other strategies should be considered for patients with phyllodes tumor who are at high risk of distant failure, including systemic therapy.

Citation Format: Bobbi A Porche, Pamela K Allen, Simona Shaitelman, B Ashleigh Guadagnolo, Wendy A Woodward, Constance Albarracin, Abenaa M Brewster, Kelly K Hunt, Welela Tereffe. Long term outcomes in patients with phyllodes tumor of the breast: The UT MD Anderson experience [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 P1-15-03.

Inhibition of the phosphoinositide 3-kinase pathway for the treatment of patients with metastatic metaplastic breast cancer

BACKGROUND

Mesenchymal/metaplastic breast cancers (MpBCs) are often triple-negative (TNBC), and chemo-refractory, and can harbor phosphoinositide 3-kinase (PI3kinase) alterations; thus, therapy with mTor inhibitors may demonstrate activity.

PATIENTS AND METHODS

Patients with mesenchymal/MpBC treated with temsirolimus-based regimens were evaluated. Mutational analyses [polymerase chain reaction (PCR)-based DNA sequencing method, mass spectrometric detection (Sequenom MassARRAY), or next-generation sequencing] as well as loss of phosphatase and tensin homolog (PTEN) (immunohistochemistry) were performed (archived tissue when available).

RESULTS

Twenty-three patients (one of whom was on two separate trials) were treated using temsirolimus-containing regimens: temsirolimus alone (n = 1 patient) or combined with the following: liposomal doxorubicin and bevacizumab (DAT, n = 18); liposomal doxorubicin (DT, n = 1); paclitaxel and bevacizumab (TAT, n = 2); paclitaxel (TT, n = 1); carboplatin and bevacizumab (CAT, n = 1). Response rate [complete response (CR) + partial response (PR)] was 25% across all regimens; 32% in the anthracycline-based regimens [DAT and DT (CR = 2, PR = 4; N = 19)]. An additional two patients achieved stable disease (SD) ≥6 months [total SD ≥6 months/CR/PR = 8 (33%)]. Molecular aberrations in the PI3K pathway were common: PIK3CA mutation = 6/15 (40%), PTEN mutation = 3/11 (27%), and PTEN loss = 2/11 (18%). A point mutation in the NF2 gene (K159fs*16; NF2 alterations can activate mTor) was found in one patient who attained CR (3+ years). Of the eight patients who achieved SD ≥6 months/CR/PR, all 4 patients with available tissue had a molecular aberration that activate the PIK3CA/Akt/mTOR axis: PIK3CA mutation = 2; PTEN loss = 1; NF2 aberration = 1.

CONCLUSIONS

DAT has activity in MpBCs including complete CRs. Molecular aberrations that can activate the PI3 K/Akt/mTOR axis are common in MpBC.

Predictors that influence contralateral prophylactic mastectomy election among women with ductal carcinoma in situ who were evaluated for BRCA genetic testing

BACKGROUND

Patients with ductal carcinoma in situ (DCIS) are at increased risk for developing contralateral breast cancer (CBC). Consequently, more women with DCIS are electing to undergo contralateral prophylactic mastectomy (CPM). We evaluated factors associated with CPM in patients with DCIS who underwent genetic counseling for BRCA testing.

METHODS

This retrospective study involved 165 women with DCIS referred for genetic counseling between 2003 and 2011. Patient characteristics were age, marital and educational status, tumor markers, nuclear grade, family history of breast cancer (BC) and ovarian cancer (OC), race, Ashkenazi Jewish ancestry, and BRCA results. Univariate and multivariate logistic regression analyses were used to determine predictive factors associated with CPM election.

RESULTS

Of 165 patients, 44 (27 %) underwent CPM. Patients <45 years of age were more likely to elect CPM (p = 0.0098). A BRCA+ mutation was found in 17 patients (10.3 %), and BRCA+ women were more likely to elect CPM than BRCA or untested women (p = 0.0001). Patients who had a family history of OC (57.7 %) were more likely to choose CPM than those with no family history (p = 0.0004). Younger age, BRCA+, and an OC family history remained significant in the multivariate model (p < 0.008).

CONCLUSION

The CPM rate among patients with DCIS who undergo genetic counseling is high. Factors associated with increased likelihood of CPM among this group were age, BRCA+, and a family history of OC. Further studies are needed to evaluate patients' perceptions of CBC risk and their role in the likelihood of CPM choice.

Multi-institutional comparison of whole slide digital imaging and optical microscopy for interpretation of hematoxylin-eosin-stained breast tissue sections

CONTEXT

Whole slide imaging (WSI) is now used for educational purposes, for consultation, and for archiving and quantitation of immunostains. However, it is not routinely used for the primary diagnosis of hematoxylin-eosin-stained tissue sections.

OBJECTIVE

To compare WSI using the Aperio digital pathology system (Aperio Technologies, Inc, Vista, California) with optical microscopy (OM) for the interpretation of hematoxylin-eosin-stained tissue sections of breast lesions.

DESIGN

The study was conducted at 3 clinical sites; 3 breast pathologists interpreted 150 hematoxylin-eosin-stained slides at each site, 3 times each by WSI and 3 times each by OM. For WSI, slides were scanned using an Aperio ScanScope and interpreted on a computer monitor using Aperio ImageScope software and Aperio Spectrum data management software. Pathologic interpretations were recorded using the College of American Pathologists breast checklist. WSI diagnoses were compared with OM diagnoses for accuracy, precision (interpathologist variation), and reproducibility (intrapathologist variation). Results were considered accurate only if the interpretation matched exactly between WSI and OM. The proportion of accurate results reported by each pathologist was expressed as a percentage for the comparison of the 2 platforms.

RESULTS

The accuracy of WSI for classifying lesions as not carcinoma or as noninvasive (ductal or lobular) or invasive (ductal, lobular, or other) carcinoma was 90.5%. The accuracy of OM was 92.1%. The precision and reproducibility of WSI and OM were determined on the basis of pairwise comparisons (3 comparisons for each slide, resulting in 36 possible comparisons). The overall precision of WSI was 90.5% in comparison with 92.1% for OM; reproducibility of WSI was 91.6% in comparison with 94.5% for OM, respectively.

CONCLUSIONS

In this study, we demonstrated that WSI and OM have similar accuracy, precision, and reproducibility for interpreting hematoxylin-eosin-stained breast tissue sections. Further clinical studies using routine surgical pathology specimens would be useful to confirm these findings and facilitate the incorporation of WSI into diagnostic practice.

Abstract P5-20-09: Tumor mutational analysis and therapy outcomes for patients (pts) with metastatic/unresectable locally advanced myoepithelial/metaplastic breast cancer treated with PI3K targeted therapy

Background: Metaplastic breast cancers are considered a chemorefractory subset of triple negative breast cancers. Molecular profiling has demonstrated that metaplastic tumors are enriched for epithelial-to-mesenchymal transition (EMT), frequently express myoepithelial differentiation, make up a component of the ‘claudin-low’ subtype, and harbor relatively high rates of mutations/activation of the PI3kinase pathway (Hennessy, Cancer Research, 2009; Prat, Breast Cancer Res, 2010).

Methods: Data from pts with myoepithelial/metaplastic breast cancer treated within the Center for Targeted Therapy using regimens with known inhibitors of the PI3K pathway were evaluated to determine response to therapy. Mutational analyses were performed in archived tumor samples when available.

Results: 23 pts have been treated using 6 different therapy regimens and one pt was treated on two separate clinical trials for a total of 24 analyzable outcomes. Patients were treated with liposomal doxorubicin, bevacizumab and the mTOR inhibitor, temsirolimus (DAT, n=17); liposomal doxorubicin and temsirolimus (DT, n=1); paclitaxel, bevacizumab and temsirolimus (TAT, n=3); paclitaxel and temsirolimus (TT, n=1), paclitaxel in combination with an experimental PI3K inhibitor (TEx, n=1), or temsirolimus alone (tem, n=1). Response was measured every two cycles using RECIST criteria. Most pts had received prior chemotherapy, median of 2 prior regimens (range 0–7). Three patients were not evaluated for response, one who died of pneumonia during cycle 2 (DAT) and two who have not yet completed 2 cycles of therapy (DAT, TEx). Response rate (CR+PR) was 35% (CR = 2, PR=4, SD≥6 months=2, SD&lt;6 months=2, PD/death=7) with the anthracycline based regimens, DAT and DT; whereas, stable disease was the best response seen thus far with the paclitaxel based regimens or temsirolimus alone: TAT (SD&lt;6months=2, PD=1), TT (SD&lt;6months=1), tem (SD&lt;6months=1). 8 of 9 tumors tested (89%) were found to have mutations that would lead to activation of the PI3K pathway: PIK3CA=5 (62%), PTEN=2 (25%) and NF2=1(13%). The two patients with CR from DAT had mutations in NF2 and PIK3CA, respectively. Both patients remain in CR (2+ years and 1+ year respectively) after discontinuing protocol therapy, and both continue maintenance everolimus.

Conclusion: Activating mutations in the PI3K pathway are common in metaplastic breast cancers, a tumor subtype that shares molecular features with claudin-low and mesenchymal/mesenchymal-stem cell like triple negative breast cancers. DAT has demonstrated activity in myoepithelial/metaplastic breast cancer including two durable CRs to therapy. This regimen should be explored in larger, randomized trials to test superiority to chemotherapy alone.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P5-20-09.

Molecular evidence in support of the neoplastic and precursor nature of microglandular adenosis

AIMS

  Microglandular adenosis (MGA) is a proliferative breast lesion, which has been proposed to be a potential precursor of triple-negative breast cancers. The aims of this study were to determine whether MGAs harbour genetic alterations and if any such genetic aberrations found in MGAs are similar to those found in matched invasive carcinomas.

METHODS AND RESULTS

  Twelve cases of MGA and/or atypical MGA (AMGA), 10 of which were associated with invasive carcinoma, were evaluated. Immunohistochemical profiling revealed that all invasive carcinomas were of triple-negative phenotype and expressed S100, cytokeratins 8/18 and 'basal' markers. The morphologically distinct components of each case (MGA, AMGA and/or invasive carcinoma) were microdissected and subjected to microarray comparative genomic hybridization. Apart from three typical MGAs, all samples harboured genetic alterations. The percentage of the genome affected by copy number aberrations in MGA/AMGA ranged from 0.5 to 61.9%, indicating varying levels of genetic instability. In three cases, MGA/AMGA displayed copy number aberrations similar to those found in matched invasive components, providing strong circumstantial evidence that MGA may constitute the substrate for the invasive carcinoma development.

CONCLUSIONS

  Our results support the contention that MGA can be a clonal lesion and non-obligate precursor of triple-negative breast cancer.

Response to neoadjuvant systemic therapy for breast cancer in BRCA mutation carriers and noncarriers: a single-institution experience

PURPOSE

To compare the pathologic complete response (pCR) rate and relapse-free survival (RFS) and overall survival (OS) after neoadjuvant systemic chemotherapy (NST) in patients with breast cancer with and without deleterious BRCA1 and BRCA2 mutations.

PATIENTS AND METHODS

A total of 317 women who underwent BRCA genetic testing and were treated with NST for breast cancer between 1997 and 2009 were included in the study. The Kaplan-Meier product-limit method was used to estimate RFS and OS rates. Logistic regression models were fit to determine the associations between BRCA status, pCR, and survival.

RESULTS

Fifty-seven (18%) and 23 (7%) patients had BRCA1 and BRCA2 mutations, respectively. Twenty-six (46%) of 57 BRCA1 carriers achieved a pCR, compared with three (13%) of 23 BRCA2 carriers and 53 (22%) of 237 BRCA noncarriers (P < .001). In the multivariate logistic model, BRCA1 status (odds ratio [OR] = 3.16; 95% CI, 1.55 to 6.42; P = .002), estrogen receptor (ER) negativity (OR = 1.96; 95% CI:1.05 to 3.65; P = .03) and concurrent trastuzumab use (OR = 4.18; 95% CI, 2.04 to 8.57; P < .001) remained as independent significant predictors for a pCR. At a median follow-up of 3.2 years, 69 patients (22%) experienced a disease recurrence or death. No significant differences were noted in survival outcomes with respect to BRCA status and type of NST received. However, among BRCA1 carriers, patients who achieved a pCR had better 5-year RFS (P = .001) and OS (P = .01) rates than patients who did not.

CONCLUSION

BRCA1 status and ER negativity are independently associated with higher pCR rates in patients with breast cancer. Overall prognosis of breast cancer in BRCA carriers is similar to sporadic breast cancers.

Distinct function of androgen receptor coactivator ARA70α and ARA70β in mammary gland development, and in breast cancer

Steroid receptor coactivators are important in regulating the function of the receptors in endocrine organ development and in cancers, including breast. Androgen receptor (AR) coactivator ARA70, was first identified as a gene fused to the ret oncogene and later characterized as an AR coactivator. We previously reported that the full length ARA70α functions as a tumor suppressor gene and that ARA70β functions as an oncogene in prostate cancer. Here we show that both ARA70α and ARA70β function as AR and estrogen receptor (ER) coactivators in breast cancer cells. However, ARA70α and ARA70β serve different functions in mammary gland development and breast cancer tumorigenesis. We observed hypoplastic development of mammary glands in MMTV driven ARA70α transgenic mice and overgrowth of mammary glands in ARA70β transgenic mice at virgin and pregnant stages. We determined that ARA70α inhibited cell proliferation, and that ARA70β promotes proliferation in MCF7 breast cancer cells. These effects were observed in hormone-free media, or in media with androgen or estrogen, though to varying degrees. Additionally, we observed that ARA70β strongly enhanced the invasive ability of MCF7 breast cancer cells in in vitro Matrigel assays. Significantly, decreased ARA70α expression is associated with increased tendency of breast cancer metastasis. In summary, ARA70α and ARA70β have distinct effects in mammary gland development and in the progression of breast cancer.

The stimulation of HSD17B7 expression by estradiol provides a powerful feed-forward mechanism for estradiol biosynthesis in breast cancer cells

Our laboratory has previously cloned and purified an ovarian protein found to be a novel 17β-hydroxysteroid dehydrogenase type 7 enzyme (HSD17B7) (formerly prolactin receptor-associated protein) that converts the weak estrogen, estrone, to the highly potent estradiol. The regulation of this enzyme has not yet been explored. In this report, we show high expression of HSD17B7 in human ductal carcinoma and breast cancer cell lines and present evidence for a strong up-regulation of this enzyme by estradiol at the level of mRNA, protein expression, and promoter activity in MCF-7 cells. The effect of estradiol is mediated by estrogen receptor (ER)α, whereas ERβ prevents this stimulation. ER antagonists, ICI 182,780 and 4-hydroxytamoxifen, prevent estradiol-induced stimulation of the endogenously expressed HSD17B7, suggesting that these inhibitors not only block estradiol action but also its production. We have identified a -185-bp region of the hsd17b7 promoter that is highly conserved among rat, mouse, and human and confers regulation by estradiol in MCF-7 cells. This region is devoid of a classical estradiol-response element but contains a nuclear factor 1 (NF1) site that is essential for estradiol action. We found that estradiol stimulates the recruitment and DNA binding of NF1 to this region of the hsd17b7 promoter. Furthermore, knockdown of NF1 family members, NF1B, NF1A, and NF1X, completely prevents induction of this gene by estradiol. In summary, our findings demonstrate that estradiol stimulates HSD17B7 transcriptional activity in breast cancer cells through a novel mechanism requiring NF1 and strongly suggest a positive feedback mechanism to increase local estradiol synthesis causing growth of estrogen-dependent breast cancers.

Abstract P6-10-04: Outcome of Triple Negative Breast Cancer in Patients with or without Deleterious BRCA Mutations

Background: Triple-negative breast cancer (TNBC) affects 10-17% of all breast cancers and is associated with a poor prognosis. The biology of TNBC is poorly understood; however, it has been shown that up to 60% of BRCA1 mutation carriers develop TNBC. The aim of this study was to determine if there were differences in the progression-free survival (PFS) and overall survival (OS) rates of BRCA mutation-associated TNBC and Non-BRCA mutation-associated TNBC.

Methods: Patients with TNBC who were referred between 1997 and 2010 for genetic counseling were included in the analysis. Data was collected from a prospectively maintained IRB-approved research database. All patients with one primary breast cancer and negative expression of ER, PR, and Her2 were included in this study. A Kaplan-Meier survival analysis was performed to determine survival outcomes. Results: Out of 98 TNBC patients, 48 (48 %) were BRCA negative, and 47 (49%) were found to have a deleterious BRCA mutation (42 BRCA1 and 5 BRCA 2); 3 (3%) patients had a variant of uncertain significance in BRCA2 and were removed from study. The median age of diagnosis for BRCA positive TNBC was 42 years (range, 21-71) and for BRCA negative TNBC was 40.5 years (range, 21-64). There were no significant differences between age at diagnosis, nuclear grade, stage (I-III), or tumor histology of BRCA positive and BRCA negative TNBCs. The PFS for BRCA positive patients was 230.7 (range, 2-271) months and for BRCA negative was 203.1 (range, 2-258) months (p = 0.19). The overall survival (OS) for BRCA positive patients was 263.4 (range, 2-292) months and for BRCA negative 236.2 (2-279) months (p = 0.39). Conclusion: Outcome of triple-negative breast cancer is not different in BRCA mutation carriers versus non carriers. Further studies need to evaluate whether different therapies will change the outcome in these subgroups of TNBC.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P6-10-04.

Recombinant human erythropoietin antagonizes trastuzumab treatment of breast cancer cells via Jak2-mediated Src activation and PTEN inactivation

We found that the receptor for erythropoietin (EpoR) is coexpressed with human epidermal growth factor receptor-2 (HER2) in a significant percentage of human breast tumor specimens and breast cancer cell lines. Exposure of HER2 and EpoR dual-positive breast cancer cells to recombinant human erythropoietin (rHuEPO) activated cell signaling. Concurrent treatment of the cells with rHuEPO and trastuzumab reduced the cells' response to trastuzumab both in vitro and in vivo. We identified Jak2-mediated activation of Src and inactivation of PTEN as underlying mechanisms through which rHuEPO antagonizes trastuzumab-induced therapeutic effects. Furthermore, we found that compared with administration of trastuzumab alone, concurrent administration of rHuEPO and trastuzumab correlated with shorter progression-free and overall survival in patients with HER2-positive metastatic breast cancer.

Prognostic factors of survival in the trastuzumab era among women with breast cancer and brain metastases who receive whole brain radiotherapy: a single-institution review

BACKGROUND

The objective of this study was to review the outcome of women with breast cancer with known receptor status who were treated with whole brain radiotherapy for brain metastases and to determine factors that impact survival.

METHODS

A total of 223 women with breast cancer and brain metastases, who received whole brain radiotherapy, were identified. All women with HER-2-positive disease had received trastuzumab. Kaplan-Meier product limit method was used to determine overall survival (OS) estimates. Cox proportional hazards models were then fitted to explore the association of OS with various patient and tumor characteristics.

RESULTS

Median age at brain metastases diagnosis was 50 years. Sixty-seven (30.2%) patients had hormone receptor-positive/HER-2-negative disease, 101 (45.50%) had HER-2-positive disease, and 54 (24.3%) had triple receptor-negative disease. Median OS from brain metastases was 6 months, with 1-year survival of 30% (95% confidence interval [CI], 23%-36%). Women with hormone receptor-positive/HER-2-negative, HER-2-positive, and triple-negative tumors had median survivals of 5, 9, and 5 months, respectively (P = .0069). In the multivariate model, women with HER-2-positive disease had a significantly decreased risk of death compared with women with hormone receptor-positive/HER-2-negative disease (hazard ratio, 0.63; 95%CI, 0.42-0.94; P = .02). The risk of death among women with triple-negative disease compared with hormone receptor-positive/HER-2-negative disease was not significantly different (P = .54). Lower recursive partitioning analysis class and > or = 30-gray brain radiation dose were also significantly associated with a decreased risk of death.

CONCLUSIONS

Breast tumor subtype has a significant prognostic role among women with breast cancer and brain metastases. In addition, in the trastuzumab era factors such as recursive partitioning analysis and adequate radiation dose continue to be important prognostic factors.

Prognostic impact of discordance between triple-receptor measurements in primary and recurrent breast cancer

BACKGROUND

We evaluated discordance in expression measurements for estrogen receptor (ER), progesterone receptor (PR), and HER2 between primary and recurrent tumors in patients with recurrent breast cancer and its effect on prognosis.

METHODS

A total of 789 patients with recurrent breast cancer were studied. ER, PR, and HER2 status were determined by immunohistochemistry (IHC) and/or FISH. Repeat markers for ER, PR, and HER2 were available in 28.9%, 27.6%, and 70.0%, respectively. Primary and recurrent tumors were classified as triple receptor-negative breast cancer (TNBC) or receptor-positive breast cancer (RPBC, i.e. expressing at least one receptor). Discordance was correlated with clinical/pathological parameters.

RESULTS

Discordance for ER, PR, and HER2 was 18.4%, 40.3%, and 13.6%, respectively. Patients with concordant RPBC had significantly better post-recurrence survival (PRS) than discordant cases; patients with discordant receptor status had similarly unfavorable survival as patients with concordant TNBC. IHC scores for ER and PR showed weak concordance between primary and recurrent tumors. Concordance of HER2-FISH scores was higher.

CONCLUSIONS

Concordance of quantitative hormone receptor measurements between primary and recurrent tumors is modest consistent with suboptimal reproducibility of measurement methods, particularly for IHC. Discordant cases have poor survival probably due to inappropriate use of targeted therapies. However, biological change in clinical phenotype cannot be completely excluded.

Survival among women with triple receptor-negative breast cancer and brain metastases

BACKGROUND

The purpose of this study was to determine the incidence of and survival following brain metastases among women with triple receptor-negative breast cancer.

PATIENTS AND METHODS

In all, 679 patients with nonmetastatic triple receptor-negative breast cancer diagnosed from 1980 to 2006 were identified. Cumulative incidence of brain metastases was computed. Cox proportional hazards models were fitted to explore factors that predict for development of brain metastases. Survival was computed using the Kaplan-Meier product limit method.

RESULTS

Median follow-up was 26.9 months. In all, 42 (6.2%) patients developed brain metastases with a cumulative incidence at 2 and 5 years of 5.6% [95% confidence interval (CI) 3.8% to 7.9%] and 9.6% (95% CI 6.8% to 13%), respectively. A total of 24 (3.5%) patients developed brain metastases as the first site of recurrence with cumulative incidence at 2 and 5 years of 2.0% (95% CI 2.6% to 6.0%) and 4.9% (95% CI 3.2% to 7.0%), respectively. In the multivariable model, no specific factor was observed to be significantly associated with time to brain metastases. Median survival for all patients who developed brain metastases and those who developed brain metastases as the first site of recurrence was 2.9 months (95% CI 2.0-7.6 months) and 5.8 months (95% CI 1.7-11.0 months), respectively.

CONCLUSION

In this single-institutional study, patients with nonmetastatic triple receptor-negative breast tumors have a high early incidence of brain metastases associated with poor survival and maybe an ideal cohort to target brain metastases preventive strategies.

Triple receptor-negative breast cancer: the effect of race on response to primary systemic treatment and survival outcomes

PURPOSE

The goal of this study was to describe the effect of race on pathologic complete response (pCR) rates and survival outcomes in women with triple receptor-negative (TN) breast cancers.

PATIENTS AND METHODS

Four hundred seventy-one patients with TN breast cancer diagnosed between 1996 and 2005 and treated with primary systemic chemotherapy were included. pCR was defined as no residual invasive cancer in the breast and axillary lymph nodes. Overall survival (OS) and recurrence-free survival (RFS) were estimated using the Kaplan-Meier product-limit method and compared between groups using the log-rank test. Cox proportional hazards models were fitted for each survival outcome to determine the relationship of patient and tumor variables with outcome.

RESULTS

Median follow-up time was 24.5 months. One hundred patients (21.2%) were black, and 371 patients (78.8%) were white/other race. Seventeen percent of black patients (n = 17) and 25.1% of white/other patients (n = 93) achieved a pCR (P = .091). Three-year RFS rates were 68% (95% CI, 56% to 76%) and 62% (95% CI, 57% to 67%) for black and white/other patients, respectively, with no significant difference observed between the two groups (P = .302). Three-year OS was similar for the two racial groups. After controlling for patient and tumor characteristics, race was not significantly associated with RFS (hazard ratio [HR] = 1.08; 95% CI, 0.69 to 1.68; P = .747) or OS (HR = 1.08; 95% CI, 0.69 to 1.68; P = .735) when white/other patients were compared with black patients.

CONCLUSION

Race does not significantly affect pCR rates or survival outcomes in women with TN breast cancer treated in a single institution under the same treatment conditions.

Loss of trimethylation at lysine 27 of histone H3 is a predictor of poor outcome in breast, ovarian, and pancreatic cancers

Methylation of lysine 27 on histone H3 (H3K27) by the EZH2 complex is an epigenetic mark that mediates gene silencing. EZH2 is overexpressed in many cancers and correlates with poor prognosis in both breast and prostate cancers. However, the status of H3K27 methylation and its clinical implication in cancer patients have not been reported. We thus examined trimethylation of H3K27 (H3K27me3) by immunohistochemistry and its association with clinical variables and prognosis in breast, ovarian, and pancreatic cancers. We found that H3K27me3 expression was significantly lower in breast, ovarian and pancreatic cancers than in normal tissues (62% in breast cancer vs. 88% in normal breast tissue, P = 0.001; 38.4% in ovarian cancer vs. 83.3% in normal ovarian tissue, P < 0.05; and 26% in pancreatic cancer vs. 89% in normal pancreatic tissue, P < 0.001). H3K27me3 expression showed significant prognostic impact in breast, ovarian and pancreatic cancers in univariate survival analyses. In all three cancer types, patients with low expression of H3K27me3 had significantly shorter overall survival time when compared with those with high H3K27me3 expression. In a multivariate model, H3K27me3 expression was an independent prognostic value for overall survival in all three cancer types. These results suggest that H3K27me3 expression is a prognostic indicator for clinical outcome in patients with breast, ovarian, and pancreatic cancers.

Development of new cancers in patients with DCIS: the M.D. Anderson experience

BACKGROUND

The purpose of this study was to describe clinical characteristics and outcome of mammographically and clinically detected new cancers in patients with previously diagnosed ductal carcinoma in situ (DCIS).

METHOD

Our database was searched to identify patients with a primary diagnosis of DCIS. Those with prior evidence of invasive carcinoma were excluded from the analysis. Cumulative incidence of new cancers was estimated according to the method of Gray. Survival times were estimated using the Kaplan Meier product limit method.

RESULTS

A total of 799 patients diagnosed and treated for DCIS were included in the analysis. Median age at diagnosis was 54 years (range 22-88 years) and median tumor size was 1.4 cm (range 0.2-15 cm). After a median follow-up of 2.9 years, 45 patients (5.6%) had a second event: 14 (31%) with in-situ and 31 (69%) with invasive disease. Median disease-free interval was 3.5 years (range 0.5-20.8 years). The majority of second events (63%) occurred in the opposite breast (P = 0.048) and the cumulative incidence at 5 years was 6.6%. Overall survival at 5 years was 97.4%; that for the second event was 76.1%. For mammography and self-palpation, respectively, the 5-year survival by method of detection of the second event was 63.2% and 100% (P = 0.08 with a 33% power to detect a difference).

CONCLUSION

Second events following DCIS occurs primarily in the opposite breast and have a negative impact on survival.

Profile of Ets gene expression in human breast carcinoma

BACKGROUND

Ets genes encode a family of transcription factors that play key roles in cell proliferation, differentiation and apoptosis. Fusions of Ets genes with other targets have been described in Ewing's sarcoma, chronic myelomonocytic leukemia and more recently prostate carcinoma. Ets expression in breast carcinoma has not been comprehensively studied, and is the focus of this study.

METHODS

RT-Q-PCR was used to determine the expression of Ets genes in a panel of ten common breast cancer cell lines, two immortalized normal breast epithelial cell lines, and one primary culture of human mammary epithelial cells. Ets with altered expression in cancer cell lines were verified in primary breast tumors.

RESULTS

Transcripts of 21 of the 27 Ets genes were detected in either normal or cancer cells. Of the 21 detectable genes, 14 were expressed at a similar level in both normal and breast cancer cell lines. Four genes, Ehf, Elf3, Elf5 and Pdef, were expressed at higher levels in breast cancer cells than normal epithelials. Surprisingly, the expression of Elk3, Etsl and Flil was repressed in breast cancer cells. The protein status of Ehf, Elf3, Pdef, Elk3, Etsl and Flil, strongly correlated with the transcript data, suggesting that Ets expression is regulated primarily at the transcriptional level. Similarly, Elf3, Pdef and Tel2 were overexpressed, while Elk3, Etsl and Flil were under-expressed in primary breast tumor specimens in comparison with normal mammary tissues.

CONCLUSIONS

Our study identified a subset of Ets genes with altered expression in breast carcinoma, implicating their roles in mammary tumorigenesis. While the Ets over-expression pattern is useful to uncover recurrent genetic alterations involving Ets genes, the repressed expression of several Ets genes suggests that some Ets proteins may play suppressor roles during breast cancer progression. Our results warrant detailed studies of individual Ets activity during mammary gland neoplasia.