Subset Of Breast Cancers Research Articles

Abstract 3998: Metronomic gemcitabine plus neratinib effectively inhibits the growth of human Her-2 positive breast cancer cells intracranially implanted into immunodeficient mice

Abstract Metastatic breast cancer is a major cause of death for women in the US, and breast cancers that metastasize to the brain have a particularly poor prognosis. To treat brain metastases of Her-2 positive breast cancers a number of Her-2 targeting drugs are now clinically available, including lapatinib, neratinib and tucatinib, among others. However, in part as a consequence of poor penetration of many drugs into the brain, combinations of standard chemotherapy plus targeted agent have only modest impact on progression free survival for such patients. We have developed preclinical models of human Her-2 positive breast cancer brain metastases to help address these issues. We selected human MDA-MD-361 and BT474 breast cancer cells lines by in vivo passaging in SCID mice, followed by molecular tagging of the derived variants (MDA361R and BT474R respectively), and then the stereotactic implantation of such cells into the brain of female SCID mice. Using luciferase-tagged BT474R we implanted 75,000 cells into the brains of the mice, and thereafter confirmed by luminescence the growth of the cells, which allowed for randomization of the mice to receive control saline (n=7), metronomic gemcitabine (100mg/kg/3days; i.p.; n=8), neratinib (40mg/kg/3 days; p.o.; n=7), or the combination of gemcitabine plus neratinib (n=8), which continued for 5 months largely in the absence of overt toxicity. The gemcitabine plus neratinib combination prolonged survival over the controls (150 days vs 65 days, p<0.5), although eventually all mice succumbed to disease. Tumors cells have been isolated from these therapy-administered mice for further characterization. Neratinib alone did not result in an increase in survival compared to controls, whereas metronomic gemcitabine improved survival but was inferior to the combination. We confirmed these findings using MDA361R tagged with human chorionic gonadotropin (hCG), which allows for the growth of cells to be monitored by assessment of hCG in the mouse urine, and these cells were implanted intracranially into female SCID mice. After urine hCG levels confirmed the presence of growing cells in the brain, the mice were randomized to the above 4 therapies (n=4/group), which showed an increase in survival of the combination compared to controls. These results point to intriguing effects of chemotherapy when used at continuous low (metronomic) doses, that in these studies involved gemcitabine administration every 3 days, and which in these models can be effectively combined with neratinib to suppress the growth of Her-2 positive breast cancer cells implanted into the mouse brain. These results highlight promising combination that could be used to suppress Her-2 positive breast cancer brain metastatic growth, and the developed models should facilitate the study of this subset of breast cancers. Citation Format: Serina Batson, Alejandro Sanchez, Hector M. Padilla, Diana L. Prospero, Brenda Lugo, Valeria V. Lopez, Daniella E. Estrada, Nydia De Avila, Saeedeh Darvishi, Arlene Levario, Shan Man, Ping Xu, Robert S. Kerbel, Guido Bocci, Giulio Francia. Metronomic gemcitabine plus neratinib effectively inhibits the growth of human Her-2 positive breast cancer cells intracranially implanted into immunodeficient mice. [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 3998.

Abstract 4164: Relieving immune suppressive pathways in breast cancer to improve outcomes

Abstract Triple negative breast cancer (TNBC)represents the most aggressive subset of breast cancer with limited treatment options leading to high mortality. While treatment of metastatic cancers with immune checkpoint inhibitors (ICIs) offers promise for many, early results from clinical trials evaluating ICIs in TNBC showed benefit for only a subset of patients. Preclinical data indicate that infiltrating macrophages foster tumor progression by limiting CD8+ T cell infiltration, activation and cytotoxicity in tumor microenvironments. We hypothesized that response to ICI therapy could be enhanced by sequentially combining a microtubule poison (paclitaxel; PTX) that enhances tumor immunogenicity, with a macrophage-depleting/reprograming agent, e.g. colony-stimulating factor 1 receptor blocking antibody (aCSF1R), in addition to an ICI targeting the PD-1/PD-L1 axis. Immune-competent mammary tumor-bearing MMTV-PyMT transgenic mice were randomized at day 80, and enrolled into experimental groups evaluating PTX, aCSF1R mAb, αPD-1 mAb, as monotherapy and in combinations. Cohorts were analyzed at distinct time points for primary and metastatic tumor burden, in addition to immunophenotyping (flow cytometry), transcriptional (RNA-Seq), epigenetic (sciATAC-Seq), and T cell receptor (TCR) changes correlating with outcomes. These studies revealed tumor regression and improved outcome for 60% of mice receiving PTX/aCSF1R/aPD-1, associated with localized CD8+ T effector and resident memory cell expansion, increased antigen-specific clonal expansion at the primary tumor site. To address epigenetic plasticity as a limiting factor for long-term T cell memory, a class 1 benzamide histone deacetylase (HDAC) inhibitor (e.g., entinostat) was sequentially added to PTX/aCSF1R/aPD-1 triple therapy resulting in primary tumor stasis in 100% of mice, and significantly enhanced overall survival. Improved outcome and tumor stasis were associated with an increased presence of long-lived central and stem-like memory CD8+ T cell infiltration, associated with increased intra-tumoral B memory cell and CD4+ T follicular helper cell infiltration. Improved outcomes were CD8+ T cell-dependent; depletion of CD19+/CD20+ B cells resulted in complete loss of granzyme B + CD8+ T cell infiltration into primary tumors, and rapid tumor expansion. These preclinical studies indicate that therapies targeting myeloid-mediated T cell suppression can be leveraged to improve anti-tumor T cell memory, and that durable long-term T cell memory can be instated upon addition of an epigenetic modulator. Citation Format: Amanda Poissonnier, Eivind Valen Egeland, Rossin Erbe, Wesley Horton, Ana Howells-Ferreira, Shamilene Sivagnanam, Nell Kirchberger, Dhaarini Murugan, Andrew Fields, Peter Ordentlich, Andrew C. Adey, Elana J. Fertig, Lisa M. Coussens. Relieving immune suppressive pathways in breast cancer to improve outcomes. [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 4164.

Analysis of the PARP1, ADP-Ribosylation, and TRIP12 Triad With Markers of Patient Outcome in Human Breast Cancer

PARP inhibitors (PARPi) are increasingly used in breast cancer therapy, including high-grade triple-negative breast cancer (TNBC) treatment. Varying treatment responses and PARPi resistance with relapse currently pose limitations to the efficacy of PARPi therapy. The pathobiological reasons why individual patients respond differently to PARPi are poorly understood. In this study, we analyzed expression of PARP1, the main target of PARPi, in normal breast tissue, breast cancer, and its precursor lesions using human breast cancer tissue microarrays covering a total of 824 patients, including more than 100 TNBC cases. In parallel, we analyzed nuclear adenosine diphosphate (ADP)-ribosylation as a marker of PARP1 activity and TRIP12, an antagonist of PARPi-induced PARP1 trapping. Although we found PARP1 expression to be generally increased in invasive breast cancer, PARP1 protein levels and nuclear ADP-ribosylation were lower in higher tumor grade and TNBC samples than non-TNBCs. Cancers with low levels of PARP1 and low levels of nuclear ADP-ribosylation were associated with significantly reduced overall survival. This effect was even more pronounced in cases with high levels of TRIP12. These results indicate that PARP1-dependent DNA repair capacity may be compromised in aggressive breast cancers, potentially fueling enhanced accumulation of mutations. Moreover, the results revealed a subset of breast cancers with low PARP1, low nuclear ADP-ribosylation, and high TRIP12 levels, which may compromise their response to PARPi, suggesting a combination of markers for PARP1 abundance, enzymatic activity, and trapping capabilities might aid patient stratification for PARPi therapy.

Detection of Increased Expression of Claudin-1 in Triple-Negative Breast Cancer: Analysis and Clinical-Pathological Correlation.

Background Triple-negative breast cancer (TNBC) is a highly aggressive disease that lacks therapeutic targets and prognostic biomarkers. Claudin-1 is a well-described tight junction protein with prognostic value in many human cancers. Aims The need for the discovery of biomarkers of TNBC disease was a major reason for this study. Claudin-1 is a tight junction protein that has shown promising results in the prognosis and management of cancer in general. In the breast, claudin-1 expression and significance have shown variable results, especially in TNBC patients. Our study assessed expression of claudin-1 in a group of TNBC patients, and correlated this expression with clinical-pathological parameters, and with the expression of β-catenin. Materials and methods Tissues from a group of 52 TNBC patients were retrieved from the archives of the community hospital. All related information including demographical, pathologicand clinical data were retrieved. Immunohistochemistry assays ofa rabbit polyclonal antibody anti-human claudin-1 were applied using theavidin-biotin peroxidase methodology. Results A statistically significant majority of TNBC cases positively expressed claudin-1 (81%, χ2=13.705; p<0.001).Most TNBC cases had grade 2 β-catenin expression (77.5%; p<0.001), and positive expression for claudin-1 correlated with that of β-catenin (χ2= 23.757; p<0.001). Claudin-1 and β-catenin expressions within tumour cells shared several features including absent or weakness of membranous expression, and redistribution of both proteins to the cytoplasm of tumour cells, and in some cases to the nuclei of these cells. Claudin-1 expression also correlates with adverse survival outcomes, where only four of 20 claudin-1-positive patients who received neo-adjuvant chemotherapy (NAC) achieved pathological complete response (pCR). Conclusions The above presents a complex role of claudin-1 in TNBC patients. In this study, claudin-1 expression was associated with poor prognostic features including invasion, metastases and adverse clinical outcomes. Claudin-1 expression in TNBC correlated with the expression of β-catenin, an important oncogene and a major contributor to the epithelial mesenchymal transition (EMT) phenomenon. Overall, the above results may serve as an impetus for further mechanistic studies to assess the exact role of claudin-1 in TNBC and its possible use in the management of this subset of breast cancer.

Lineage plasticity enables low-ER luminal tumors to evolve and gain basal-like traits

Stratifying breast cancer into specific molecular or histologic subtypes aids in therapeutic decision-making and predicting outcomes; however, these subtypes may not be as distinct as previously thought. Patients with luminal-like, estrogen receptor (ER)-expressing tumors have better prognosis than patients with more aggressive, triple-negative or basal-like tumors. There is, however, a subset of luminal-like tumors that express lower levels of ER, which exhibit more basal-like features. We have found that breast tumors expressing lower levels of ER, traditionally considered to be luminal-like, represent a distinct subset of breast cancer characterized by the emergence of basal-like features. Lineage tracing of low-ER tumors in the MMTV-PyMT mouse mammary tumor model revealed that basal marker-expressing cells arose from normal luminal epithelial cells, suggesting that luminal-to-basal plasticity is responsible for the evolution and emergence of basal-like characteristics. This plasticity allows tumor cells to gain a new lumino-basal phenotype, thus leading to intratumoral lumino-basal heterogeneity. Single-cell RNA sequencing revealed SOX10 as a potential driver for this plasticity, which is known among breast tumors to be almost exclusively expressed in triple-negative breast cancer (TNBC) and was also found to be highly expressed in low-ER tumors. These findings suggest that basal-like tumors may result from the evolutionary progression of luminal tumors with low ER expression.

Abstract P3-05-02: Trends in clinical treatment of early stage ER+PR- breast cancer in the National Cancer Database

Abstract Background Estrogen receptor positive (ER+) progesterone receptor negative (PR-) tumors are a distinct subset of breast cancers that are not well characterized. It is critical to better understand the biology of ER+PR- tumors and tailor therapy accordingly for this unique subgroup. The objective of this study is to compare the ER+PR- subgroup of breast cancer as compared to the double positive ER+PR+ group in a large, well-characterized database to determine if the tumors that are PR- are associated with higher rates of genomic testing and chemotherapy receipt. Methods We identified patients diagnosed with ER+Her2-, Stage 1-3 invasive breast cancer from 2010-2015 in the National Cancer Database. We excluded patients who received neoadjuvant therapy. Demographics and clinical characteristics for the ER+PR+ and ER+PR- groups were obtained. Differences between groups were assessed using the chi-square test. Multivariable logistic regression analysis was performed on both the node negative and node positive patients in order to identify factors independently associated with having a genomic test and receiving chemotherapy in the ER+PR+ and ER+PR- cohorts. Results Of the 363,945 eligible patients, 327,357 (89.9%) patients had ER+PR+ breast cancer and 36,588 (10.1%) had ER+PR- breast cancer. A trend towards larger tumor size in the ER+PR- population as compared to the ER+PR+ population was noted with 23.1% vs 17.3% of tumors 2-5cm and 2.2% vs 1.2% of tumors &amp;gt; 5cm, respectively. Higher grade was also seen in the ER+PR- group as compared to the ER+PR+ group with 27.1% versus 11.7% grade 3 tumors. In both the node negative and node positive populations, genomic testing was less likely to be sent on a PR- breast cancer than a PR+ breast cancer. When genomic testing was sent, there were more high risk Oncotype Recurrence scores (RS &amp;gt; 30) in the PR- group than the PR+ group. For node negative breast cancer high risk Oncotype recurrence scores were found in 32.4% of the ER+PR- population versus 5.6% in the ER+PR+ population. In the node positive cohort high risk Oncotype Recurrence scores were seen in 27.8% of the ER+PR- population as compared to 5.0% in the ER+PR+ population. Patients with discordant ER+PR- breast cancer were more likely to receive chemotherapy than their ER+PR+ counterparts in both the node negative cohort (32.2% vs 12.7%) and the node positive cohort (73.2% vs 64.5%). Conclusion There have been limited studies to date specifically focused on the ER+PR- subgroup. Patients with ER+PR- breast cancer have a higher grade, larger size, higher risk genomic testing, and are more likely to receive chemotherapy than their ER+PR+ counterparts. Discordance in hormone receptor status contributes to a more aggressive type of breast cancer that may impact clinical and treatment decisions. Citation Format: Poornima Saha, Angeline Yu, Priya Thakkar, Kristine Kuchta, Katharine Yao. Trends in clinical treatment of early stage ER+PR- breast cancer in the National Cancer Database [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P3-05-02.

Abstract P6-05-59: Clinical Characteristics and Prognosis of Postpartum Breast Cancer

Abstract Background: Postpartum breast cancer (PPBC) is a not well-established subset of breast cancer, and only few studies address its poorer prognosis. However, there are previous studies that PPBC is associated with worse outcome with higher rates of metastasis than in young women’s breast cancer (YWBC). The purpose of this study was to analyze the clinical characteristics and prognosis according to the onset period of PPBC, Materials and methods: 208,780 breast cancer patients from the online Korean Breast Cancer Society (KBCS) registry database between January 2000 and December 2014 were reviewed retrospectively. Premenopausal women aged 20 to 50 years who underwent breast cancer surgery were included. According to the diagnosis period of breast cancer, it was classified into groups diagnosed within 5 years (PPBC&amp;lt; 5) after delivery, between 5-10 years((5≤PPBC&amp;lt; 10), and after 10 years(PPBC≥10). Results: The patients in PPBC &amp;lt; 5 group showed a younger and more advanced stage compared to other groups, and the expression of estrogen receptor (ER) and progesterone receptor (PR) was lower and the HER2 positive rate was higher. PPBC&amp;lt; 5 group had worse survival rate compared to nulliparous and other group (5-year cumulative survival; PPBC&amp;lt; 5 group, 89% vs. nulliparous group, 97.3% vs. 5≤ PPBC&amp;lt; 10 group 93%). In multivariate analysis, PPBC&amp;lt; 5 group was associated with worse survival rate (Hazard ratio 1.55, 95% CI 1.148-2.094, p=0.004) after adjustment for age at diagnosis, breast cancer stage, ER and HER2 status, Ki-67 level, and chemotherapy. Conclusion: We demonstrated that patients with breast cancer diagnosed within first five years after delivery had aggressive characteristics and a worse survival rate. In order to improve the survival rate of PPBC, the cause should be identified and new therapeutic strategy should be established. Citation Format: Soo Youn Bae, Pill Sun Paik, Young Joo Lee, Young-Joon Kang. Clinical Characteristics and Prognosis of Postpartum Breast Cancer [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P6-05-59.

Abstract P2-23-15: Histologic, immunohistochemical and genomic comparison between classic Invasive lobular carcinomas and lobular-like invasive ductal carcinomas

Abstract Background: Invasive lobular carcinomas (ILCs) are the most frequent special histologic subtype of breast cancer, accounting for up to 15% of all breast cancer cases. ILCs are characterized by a distinctive discohesive growth pattern, with cells arranged in single cell infiltrative file and dispersed throughout the stroma, which stems from the loss of E-cadherin expression due to bi-allelic inactivation of the CDH1 gene. A subset of breast cancers display a similar single cell infiltrative growth pattern but, in contrast to classic ILC, display diffuse strong membranous E-cadherin reactivity and membranous p120 expression. We refer to such cases as “lobular-like invasive ductal carcinoma” (LLIDC), but it is unclear if this terminology is appropriate and if such cases show biallelic inactivation of CDH1, similarly to ILCs. Here, we sought to define whether LLIDCs would harbor bi-allelic alterations of CDH1 and to perform an exploratory, hypothesis generating analysis of the repertoire of somatic genetic alterations of LLIDCs and classic ILCs. Materials and methods: Representative H&amp;Es, as well as sections subjected to E-cadherin and p120 immunohistochemistry from seven classic ILCs and seven bona fide “lobular-like invasive ductal carcinomas” were retrieved and independently reviewed by two pathologists with experience and expertise in breast pathology. DNA samples were extracted from representative sections from tumor and normal breast tissue from each patient and subjected to an FDA-approved targeted sequencing assay comprising the coding regions and selected regulatory elements of 515 genes. Somatic single nucleotide variants (SNVs) were detected with MuTect, indels with Strelka, Varscan2, Scalpel and Lancet. All mutations were manually inspected using the Integrative Genomics Viewer (IGV). The cancer cell fraction (CCF) of each mutation was inferred, as well as clonal probability, using ABSOLUTE. Copy number alterations and loss of heterozygosity were determined using FACETS. Mutational signatures were inferred using SigMA based on all synonymous and nonsynonymous somatic mutations. Results: Based on the histopathologic evaluation, of the 14 cases analyzed, seven were classified as ILC, and the other seven were classified as LLIDC. Sequencing analysis revealed that the classic ILCs harbored 16q LOH and CDH1 mutations (7/7), of which five were frameshift indel and two were splice site mutations consistently coupled with loss-of-heterozygosity (LOH) of the wild-type allele. Conversely, five of the seven LLIDCs did not harbor CDH1 mutations or genomic rearrangements. CDH1 mutations were identified in 2 LLIDCs: one harbored a subclonal CDH1 in-frame indel mutation coupled with LOH. This case displayed membranous E-cadherin and p120 expression with areas of aberrant expression. The other CDH1-mutated LLIDC harbored a complex in-frame indel with subclonal LOH. This case displayed membranous E-cadherin and p120 expression. The comparative analysis of the repertoire of somatic genetic alterations and mutational signatures present in LLIDCs and classic ILCs did not reveal any significant differences. Conclusion: Despite the histologic similarities, LLIDCs differ from classic lobular carcinomas based on the lack of CDH1 bi-allelic inactivation and the patterns of expression of E-cadherin and p120 catenin. Further whole-genome sequencing analyses are warranted to define the molecular basis of the discohesive cancer cells of LLIDC display. Citation Format: Edaise M. da Silva, Thais Basili, Jing Yu, Juan Blanco-Heredia, Pier Selenica, Qiqi Ye, Arnaud da Cruz Paula, Higinio Dopeso, Antonio Marra, Steffi Oesterreich, Jorge Reis-Filho, Rohit Bhargava. Histologic, immunohistochemical and genomic comparison between classic Invasive lobular carcinomas and lobular-like invasive ductal carcinomas [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P2-23-15.

Abstract GS1-11: Sacituzumab Govitecan (SG) vs Treatment of Physician’s Choice (TPC): Efficacy by Trop-2 Expression in the TROPiCS-02 Study of Patients (Pts) With HR+/HER2– Metastatic Breast Cancer (mBC)

Abstract Background: HR+/HER2– mBC, the most common subset of breast cancer, is treated with sequential endocrine therapy + targeted agents followed by sequential single-agent chemotherapy (CT), with increasingly shorter benefit duration with each subsequent treatment. High Trop-2 expression is observed in breast cancer regardless of subtype. SG is a Trop-2-directed antibody-drug conjugate approved for pre-treated metastatic triple-negative breast cancer. In the phase 3 TROPiCS-02 study, SG showed both significant progression-free survival (PFS) benefit (HR, 0.66; P&amp;lt;0.001; median 5.5 vs 4.0 mo; JCO 2022) at the primary analysis and overall survival (OS) benefit (median 14.4 vs 11.2 mo; HR, 0.79; P=0.02; ESMO 2022) at the 2nd planned interim OS analysis vs TPC in pretreated HR+/HER2- mBC. Here we compare efficacy outcomes for SG and TPC by Trop-2 expression. Methods: Eligible pts had HR+/HER2- locally recurrent inoperable or mBC; received ≥1 prior taxane, endocrine therapy, a CDK4/6 inhibitor; and received 2-4 prior CT regimens for mBC. Pts were randomized 1:1 to receive SG (10 mg/kg IV on d 1 and 8, every 21 d) or TPC (eribulin, gemcitabine, capecitabine, or vinorelbine) until disease progression or unacceptable toxicity. The primary endpoint was PFS by independent review per RECIST v1.1; OS and objective response rate (ORR) were key secondary endpoints. ORR was assessed by blinded independent central review per RECIST v1.1. Membrane Trop-2 expression on archival tumor tissue was assessed by immunohistochemistry and expressed as a histochemical score (H-score; range, 0-300); efficacy outcomes were assessed in H-score &amp;lt;100 and ≥100 groups. The H-score &amp;lt;100 group was further divided into H-score ≤10 and &amp;gt;10- &amp;lt;100 subgroups to assess the activity of SG in pts with very low Trop-2 expression. Results: Data cut-off was January 3, 2022 for PFS (median follow-up, 10.2 mo) and July 1, 2022 for OS (median follow-up, 12.5 mo). In total, 543 pts were randomized to receive SG (n=272) vs TPC (n=271). Pts had a median of 3 prior CT regimens for mBC; 95% had visceral metastases. There were 238 (88%) vs 224 (83%) Trop-2-evaluable pts in the SG vs TPC groups, respectively; of these, 95% had tumors with Trop-2 H-score &amp;gt;0. Of Trop-2-evaluable pts, 192 (42%) and 270 (58%) had H-scores &amp;lt;100 and ≥100, respectively. Demographics and baseline characteristics were generally consistent across H-score groups. PFS and OS benefit was observed for SG vs TPC across both Trop-2 groups (Table). Median PFS was 5.3 vs 4.0 mo (HR, 0.77; 95% CI, 0.54-1.09) and 6.4 vs 4.1 mo (HR, 0.60; 95% CI, 0.44-0.81) in the H-score &amp;lt;100 and ≥100 groups; median OS was 14.6 vs 11.3 mo (HR, 0.75; 95% CI, 0.54-1.04) and 14.4 vs 11.2 mo (HR, 0.83; 95% CI, 0.62-1.11), respectively. Disease response was observed in the 34 pts with H-score ≤10 who received SG. In pts who received SG, those with H-score ≤10, &amp;gt;10- &amp;lt;100, and ≥100 had ORRs of 24%, 18%, and 23%, respectively. The safety profile for SG by Trop-2 H-score was consistent with previous reports. Conclusions: In this TROPiCS-02 post-hoc analysis, improved efficacy with SG vs TPC was observed regardless of Trop-2 expression, and there was no clear level of Trop-2 expression at which a better treatment effect for SG was observed. These results support SG as an effective novel treatment option for patients with pretreated, endocrine-resistant HR+/HER2- mBC, and reinforce that Trop-2 testing is not required for SG treatment. Table Citation Format: Hope Rugo, Aditya Bardia, Frederik Marmé, Javier Cortés, Peter Schmid, Delphine Loirat, Olivier Trédan, Eva Ciruelos, Florence Dalenc, Patricia Gómez Pardo, Komal Jhaveri, Monica Motwani, Oh Kyu Yoon, Hao Wang, Wendy Verret, Sara Tolaney. Sacituzumab Govitecan (SG) vs Treatment of Physician’s Choice (TPC): Efficacy by Trop-2 Expression in the TROPiCS-02 Study of Patients (Pts) With HR+/HER2– Metastatic Breast Cancer (mBC) [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr GS1-11.

Selected Articles from This Issue

Highlights| January 17 2023 Selected Articles from This Issue Author & Article Information Online Issn: 1557-3265 Print Issn: 1078-0432 ©2023 American Association for Cancer Research2023American Association for Cancer Research Clin Cancer Res (2023) 29 (2): 297. https://doi.org/10.1158/1078-0432.CCR-29-2-HI Related Content A commentary has been published: Human Metastatic Cholangiocarcinoma Patient-Derived Xenografts and Tumoroids for Preclinical Drug Evaluation A commentary has been published: Triple-Negative PAM50 Non-Basal Breast Cancer Subtype Predicts Benefit from Extended Adjuvant Capecitabine A commentary has been published: Intraperitoneal Monocytes plus IFNs as a Novel Cellular Immunotherapy for Ovarian Cancer: Mechanistic Characterization and Results from a Phase I Clinical Trial View more A commentary has been published: High-Sensitivity Mutation Analysis of Cell-Free DNA for Disease Monitoring in Endometrial Cancer View less Views Icon Views Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Cite Icon Cite Search Site Article Versions Icon Versions Version of Record January 17 2023 Citation Selected Articles from This Issue. Clin Cancer Res 15 January 2023; 29 (2): 297. https://doi.org/10.1158/1078-0432.CCR-29-2-HI Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest Search Advanced Search Overall survival for advanced ovarian cancer remains poor, particularly for women with platinum-resistant disease. Green and colleagues report the bench to bedside development of a novel cytokine stimulated autologous monocyte therapy for advanced, platinum-resistant or -refractory ovarian cancer. Activated monocytes killed tumor cells in mice via a TRAIL-dependent pathway. Treatment was well tolerated and produced partial responses by RECIST criteria. These findings characterize the mechanism of a novel cellular immunotherapy for ovarian cancer, which is well tolerated with evidence of clinical activity in a heavily pretreated patient population. This therapy may serve as the backbone for a combination immunotherapy regimen incorporating additional agents targeting T-regulatory cells and/or myeloid-derived suppressor cells (MDSCs). Identifying predictive biomarkers that define the subset of triple-negative breast cancer (TNBC) deriving the most benefit from adjuvant capecitabine is necessary in clinical practice. In this hypothesis-testing study, Asleh and colleagues examined the capacity of candidate RNA biomarkers to... You do not currently have access to this content.

PDJ amplicon in triple negative breast cancer

Amplification of chromosome 9p24.1 targeting PD-L1, PD-L2, and JAK2 (PDJ amplicon) is present in subsets of triple negative breast cancers (TNBCs) and is associated with poor clinical outcomes. However, the prevalence of PDJ+ TNBCs varies extensively across studies applying different methods for interrogating samples of interest. To rigorously assess the prevalence of PDJ amplicons in TNBC, its prognostic value and whether it is enriched by chemotherapy, we interrogated 360 TNBC samples including 74 surgical resections from patients treated in the neoadjuvant setting, and tissue microarrays (TMAs) with 31 cases from African American women and 255 resected non-metastatic cases, with a 3 color fluorescence in situ hybridization (FISH) assay targeting the 9p24.1 PDJ amplicon, 9q24.3, and 9q34.1. Samples with mean PDJ signal of > 4.5 copies, and ratios of PDJ/9q24 ≥ 2 and/or PDJ/9q34.1 ≥ 2 were called amplified (PDJ+). Correlative analyses included the association of tumor infiltrating lymphocytes (TILs) with PDJ amplicons in TNBCs. In addition, we investigated intratumor copy number of PDJ amplicons in PDJ+ and PDJ− TNBCs. Matched pre- and post-neoadjuvant treatment biopsies were available from patients (n = 6) to evaluate the effects of therapy on PDJ status. Our study provides a rigorous analysis of the prevalence, distribution, and clinical correlatives of the PDJ amplicon in TNBC.

EHD2 overexpression promotes tumorigenesis and metastasis in triple-negative breast cancer by regulating store-operated calcium entry.

With nearly all cancer deaths a result of metastasis, elucidating novel pro-metastatic cellular adaptations could provide new therapeutic targets. Here, we show that overexpression of the EPS15-Homology Domain-containing 2 (EHD2) protein in a large subset of breast cancers (BCs), especially the triple-negative (TNBC) and HER2+ subtypes, correlates with shorter patient survival. The mRNAs for EHD2 and Caveolin-1/2, structural components of caveolae, show co-overexpression across breast tumors, predicting shorter survival in basal-like BC. EHD2 shRNA knockdown and CRISPR-Cas9 knockout with mouse Ehd2 rescue, in TNBC cell line models demonstrate a major positive role of EHD2 in promoting tumorigenesis and metastasis. Mechanistically, we link these roles of EHD2 to store-operated calcium entry (SOCE), with EHD2-dependent stabilization of plasma membrane caveolae ensuring high cell surface expression of the SOCE-linked calcium channel Orai1. The novel EHD2-SOCE oncogenic axis represents a potential therapeutic target in EHD2- and CAV1/2-overexpressing BC.

Breast cancer sub-types display heterogeneity in gene amplification and mRNA expression of the anti-apoptotic members of BCL2 family

BackgroundProgress in therapies and improved outcomes in recent decades have followed a better understanding of breast cancers pathogenesis and their heterogeneity but new treatments are needed especially for metastatic disease which remains incurable. Inhibition of apoptosis is a hallmark characteristic of cancer and can be targeted for therapy. MethodsThe five anti-apoptotic members of the BCL2 family are at the core of apoptosis execution and are involved in apoptosis evasion of transformed cells. Genetic lesions as well as mRNA regulation of these members in breast cancer and its sub-types and implications for survival outcomes were investigated using data from various publicly available databases. ResultsGenes encoding for anti-apoptotic BCL2 proteins are rarely mutated in breast cancer and copy number alterations are observed only in MCL1 gene which is amplified in a minority of breast cancer ranging from 1.6% to 18.7% in breast cancers. Over-expression of BCL2, BCL-X and MCL1 is observed in luminal A cancers, while cases of luminal B and basal breast cancers display mRNA up-regulation of BCL-X and MCL1, respectively. Basal cancers possess also more frequently than other sub-sets MCL1 amplifications. Survival outcomes are not significantly different in cancers with higher expression of anti-apoptotic BCL2 mRNAs. ConclusionTherapeutic targeting of the apoptotic process in breast cancer sub-types will be improved by a detailed understanding of the core players in the process, including anti-apoptotic BCL2 family proteins. A sub-set of breast cancers harbor amplifications of MCL1 and dysregulations of expression of most family members that could affect the sensitivity to their inhibition by altering the cell’s apoptotic threshold.

Abstract 1290: Basal expression of nuclear transcription factor, NR4A1, is lower in triple negative breast cancer compared to other breast cancer subsets

Abstract 1290: Basal expression of nuclear transcription factor, NR4A1, is lower in triple negative breast cancer compared to other breast cancer subsets

Abstract C051: Unraveling the biology of TNBC in African American women through the WHITNEY study

Abstract Cancer disparities arise from structural racism in the United States, which affects overall standard of living due to unequal access to crucial resources. Barriers in access to clinical care among under-served populations in combination with a vast underrepresentation at a scientific research level further perpetuate inequalities in cancer treatment. Specifically, Black women in the US are approximately twice as likely as Caucasian women to die of Triple-Negative Breast Cancer (TNBC), a particularly aggressive breast cancer subset, lacking expression of estrogen receptors, progesterone receptors, and human epidermal growth factor receptor-2. Our previous work and that of others has shown racial differences in TNBC tumor biology, with preference of basal-like subtypes in African American (AA) women. Herein, we present the Women’s Health Initiative for Triple-Negative Breast Cancer Equity (WHITNEY) study, a first of its kind, coordinated effort between Massachusetts General Hospital, and Boston Medical Center, the largest safety-net hospital in New England. The WHITNEY study seeks to understand factors contributing to biological differences and outcome of TNBC diagnoses in AA women. Response to neoadjuvant chemotherapy (NACT) response is a strong predictor of TNBC outcomes and failure to achieve a pathological complete response (pCR) in the breast following NACT is associated with a high probability of metastatic relapse. As Black women with TNBC have lower pCR rates, WHITNEY has collected pre-treatment biopsies from AA and other TNBC patients undergoing NACT to understand actionable insights into the biological differences in TNBC. Our prior published work has suggested that intratumoral heterogeneity is greater in TNBCs among AA patients than others, and that epigenetic silencing of key tumor suppressors is selectively increased in these TNBCs. Core needle baseline biopsies were obtained from consented patients diagnosed with TNBC at either MGH or BMC. We utilized single-cell RNA sequencing, spatial transcriptomics, genomic and epigenetic profiling to characterize minor cell subpopulations that drive poor outcomes among African American TNBC patients. Here, we outline our preliminary tissue collection, processing and analysis methods used in the WHITNEY study to better understand the biology of TNBC in African American women. Citation Format: Malalage N. Peiris, Emma Kelly, Christina Ennis, Kiana Mahdaviani, Aylin Dedeoglu, Adrian Ilinski, Esther Rheinbay, Ruben Dries, Naomi Ko, Leif Ellisen. Unraveling the biology of TNBC in African American women through the WHITNEY study [abstract]. In: Proceedings of the 15th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2022 Sep 16-19; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2022;31(1 Suppl):Abstract nr C051.

Current Biological, Pathological and Clinical Landscape of HER2-Low Breast Cancer.

HER2-low breast cancer (BC) is a newly defined subset of HER2-negative BC that has HER2 immunohistochemical (IHC) score of 1+ or score of 2+/in situ hybridization (ISH) negative phenotype. Recent clinical trials have demonstrated significant clinical benefits of novel HER2 directing antibody-drug conjugates (ADCs) in treating this group of tumors. Trastuzumab-deruxtecan (T-Dxd), a HER2-directing ADC was recently approved by the U.S. Food and Drug Administration as the first targeted therapy to treat HER2-low BC. However, HER2-low BC is still not well characterized clinically and pathologically. This review aims to update the current biological, pathological and clinical landscape of HER2-low BC based on the English literature published in the past two years and to propose the future directions on clinical management, pathology practice, and translational research in this subset of BC. We hope it would help better understand the tumor biology of HER2-low BC and the current efforts for identifying and treating this newly recognized targetable group of BC.

On the Therapeutic Potential of ERK4 in Triple-Negative Breast Cancer.

ERK3 and ERK4 define a distinct and understudied subfamily of mitogen-activated protein kinases (MAPKs). Little is known about the physiological roles of these atypical MAPKs and their association with human diseases. Interestingly, accumulating evidence points towards a role for ERK3 and ERK4 signaling in the initiation and progression of various types of cancer. Notably, a recent study reported that ERK4 is expressed in a subset of triple-negative breast cancer (TNBC) cell lines and that this expression is critical for AKT activation and for sustaining TNBC cell proliferation in vitro and tumor growth in mice. The authors also showed that depletion of ERK4 sensitizes TNBC cells to phosphatidylinositol-3-kinase (PI3K) inhibitors. They concluded that ERK4 is a promising therapeutic target for TNBC and has potential for combination therapy with PI3K inhibitors. Here, we raise concerns about the cellular models and experimental approaches used in this study, which compromise the conclusions on the oncogenic role of ERK4 in TNBC.

178P Antibody engineering to evaluate binding, internalisation, and intracellular routing of recombinant immunotherapeutic fusion proteins

Recombinant immunotherapeutic fusion proteins (rIFPs) were designed to target triple-negative breast cancer (TNBC). This is a heterogeneous and aggressive subset of breast cancer accounting for 15-20% of all diagnosed breast cancer cases, with women of premenopausal age and African descent inordinately predisposed. Based on previous studies, we hypothesised that the ability to bind to two identical antigens through a bivalent antibody increases the total strength of the reaction and that increasing the affinity and valency of tumour-targeting antibodies results in improved tumour uptake.

PDLIM2 is highly expressed in Breast Cancer tumour-associated macrophages and is required for M2 macrophage polarization.

The PDZ-LIM domain-containing protein 2 (PDLIM2) regulates cell polarity and the protein stability of key transcription factors in epithelial and hemopoietic cells. We previously reported that PDLIM2 is more highly expressed in Triple Negative Breast Cancer (TNBC) than in other breast cancer types or normal breast tissue. In the course of the TNBC study, it was noted that PDLIM2 was highly expressed in the stroma of PDLIM2-expressing tumours. Here, we investigated the phenotype of these stromal cells and whether any infiltrating immune population was linked to PDLIM2 expression. We found that high PDLIM2 expression in breast tumours was associated with higher levels of infiltrating M2 macrophages, but was not associated with infiltrating T cell sub-populations. We then tested whether PDLIM2 contributes to macrophage differentiation or function by using cultures of bone marrow-derived macrophages from wildtype and Pdlim2 knockout mice. This demonstrated that PDLIM2 is required for naïve macrophage migration and for the full adoption of IL-4-induced M2 polarization, including expression of M2 phenotypic markers, cell adhesion and cell migration. TLR4-, TLR3- or IFNγ-induced M1 macrophage activity was less dependent on PDLIM2. Finally, analysis of publicly available breast cancer datasets showed that high PDLIM2 expression is associated with increased M2 macrophage infiltration. We conclude that PDLIM2 expression influences the tumour associated stroma and, in particular, M2 macrophage infiltration that may contribute to the progression of TNBC or other subsets of breast cancer.

Subpathway Analysis of Transcriptome Profiles Reveals New Molecular Mechanisms of Acquired Chemotherapy Resistance in Breast Cancer.

Simple SummaryThe use of diverse omics platforms and small sample sizes in current studies of cancer chemoresistance limits consensus regarding the molecular mechanisms underlying chemoresistance and the applicability of those study findings. We built transcriptome data for chemotherapy-resistant breast cancer samples for two cohorts and conducted pathway and subpathway analyses that revealed the activation of several molecular pathways associated with chemoresistance in Cushing’s syndrome, human papillomavirus infection, proteoglycans in cancer, fluid shear stress, and focal adhesion that have not been reported in the resistance of breast cancer to chemotherapy. However, analysis of a subset of triple-negative breast cancer samples revealed activation of the identical chemoresistance pathways.Chemoresistance has been a major challenge in the treatment of patients with breast cancer. The diverse omics platforms and small sample sizes reported in the current studies of chemoresistance in breast cancer limit the consensus regarding the underlying molecular mechanisms of chemoresistance and the applicability of these study findings. Therefore, we built two transcriptome datasets for patients with chemotherapy-resistant breast cancers—one comprising paired transcriptome samples from 40 patients before and after chemotherapy and the second including unpaired samples from 690 patients before and 45 patients after chemotherapy. Subsequent conventional pathway analysis and new subpathway analysis using these cohorts uncovered 56 overlapping upregulated genes (false discovery rate [FDR], 0.018) and 36 downregulated genes (FDR, 0.016). Pathway analysis revealed the activation of several pathways in the chemotherapy-resistant tumors, including those of drug metabolism, MAPK, ErbB, calcium, cGMP-PKG, sphingolipid, and PI3K-Akt, as well as those activated by Cushing’s syndrome, human papillomavirus (HPV) infection, and proteoglycans in cancers, and subpathway analysis identified the activation of several more, including fluid shear stress, Wnt, FoxO, ECM-receptor interaction, RAS signaling, Rap1, mTOR focal adhesion, and cellular senescence (FDR < 0.20). Among these pathways, those associated with Cushing’s syndrome, HPV infection, proteoglycans in cancer, fluid shear stress, and focal adhesion have not yet been reported in breast cancer chemoresistance. Pathway and subpathway analysis of a subset of triple-negative breast cancers from the two cohorts revealed activation of the identical chemoresistance pathways.