Biological Subtypes of Triple-Negative Breast Cancer

Possible Beneficial Effects of N-Acetylcysteine for Treatment of Triple-Negative Breast Cancer

N-acetylcysteine (NAC) is a widely used antioxidant with therapeutic potential. However, the cancer-promoting effect of NAC observed in some preclinical studies has raised concerns regarding its clinical use. Reactive oxygen species (ROS) can mediate signaling that results in both cancer-promoting and cancer-suppressing effects. The beneficial effect of NAC may depend on whether the type of cancer relies on ROS signaling for its survival and metastasis. Triple-negative breast cancer (TNBC) has aggressive phenotypes and is currently treated with standard chemotherapy as the main systemic treatment option. Particularly, basal-like TNBC cells characterized by inactivated BRCA1 and mutated TP53 produce high ROS levels and rely on ROS signaling for their survival and malignant progression. In addition, the high ROS levels in TNBC cells can mediate the interplay between cancer cells and the tissue microenvironment (TME) to trigger the recruitment and conversion of stromal cells and induce hypoxic responses, thus leading to the creation of cancer-supportive TMEs and increased cancer aggressiveness. However, NAC treatment effectively reduces the ROS production and ROS-mediated signaling that contribute to cell survival, metastasis, and drug resistance in TNBC cells. Therefore, the inclusion of NAC in standard chemotherapy could probably provide additional benefits for TNBC patients.

Expression of PD-L1 using SP142 CDx in triple negative breast cancer

Triple negative breast cancer (TNBC) represents a small subtype of breast cancer yet it has the worst outcome. Immunotherapy using immune checkpoint inhibitors combined with chemotherapy was recently approved by the FDA raising the hope for an improved outcome. The approval was based on demonstration of a positive PD-L1 expression using the SP142 CDx assay ¹. We aimed to study a cohort of TNBC patients in terms of prevalence of the PD-L1 expression using the approved assay and to investigate its association with clinicopathological variables. This is a single center retrospective study consisting of 49 TNBC patients who had available archived paraffin-embedded tissue blocks from the primary tumors. All blocks were stained using the SP142 CDx assay as per the manufacture's instruction. Clinicopathological data were collected from medical records. Eighteen of the 49 (36.7%) patients were found to have a score of 1% or more by the immune cell-scoring algorithm. PDL-1 expression was significantly associated with the degree of tumor infiltrating lymphocytes (TILs). No additional significant relationship was found between PD-L1 expression and any of the other investigated clinicopathological variables. Although a trend of favorable prognostic association with PD-L1 expression was noted. The overall and event free survival were significantly related to pathological response to neoadjuvant therapy. Conclusion: Our PD-L1 rate of 36.7% is close to the results of the previously reported 40.9% in the IMpassion 130 trial. There were no significant association between positive PD-L1 expression and clinicopathological variables however a trend of a favorable outcome was observed.

Fabatin-loaded silica nanoparticle-induced apoptosis via mitochondrial dysfunction: targeting the PI3K/AKT molecular pathway as a therapeutic implication against triple negative breast cancer

Mechanism induced by F-SNP on inducing apoptosis in triple negative breast cancer.

A Mechanistic Investigation on the Anticancer Properties of SYA013, a Homopiperazine Analogue of Haloperidol with Activity against Triple Negative Breast Cancer Cells

Triple-negative breast cancer (TNBC) is one of the most malignant cancers associated with early metastasis, poor clinical prognosis, and high recurrence rate. TNBC is a distinct subtype of breast cancer that lacks estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor 2 receptors (HER2). Development of effective TNBC therapies has been limited partially due to the lack of specific molecular targets and chemotherapy involving different cytotoxic drugs suffers from significant side effects and drug-resistance development. Therefore, there is an unmet need for the development of novel and efficient therapeutic drugs with reduced side effects to treat TNBC. We have previously reported that certain analogues of haloperidol (a typical antipsychotic drug used for treating mental/mood disorders such as schizophrenia and bipolar disorder) suppress the viability of a variety of solid tumor cell lines, and we have identified 4-(4-(4-chlorophenyl)-1,4-diazepan-1-yl)-1-(4-fluoro-phenyl)butan-1-one (SYA013) with such antiproliferative properties. Interestingly, unlike haloperidol, SYA013 shows moderate selectivity toward σ2 receptors. In this study, we explored the potential of SYA013 in modulating the important biological events associated with cell survival and progression as well as the mechanistic aspects of apoptosis in a representative TNBC cell line (MDA-MB-231). Our results indicate that SYA013 inhibits the proliferation of MDA-MB-231 cells in a concentration-dependent manner and suppresses cell migration and invasion. Apoptotic studies were also conducted in MDA-MB-468 cells (cells derived from a 51-year old Black female with metastatic adenocarcinoma of the breast.). In addition, we have demonstrated that SYA013 induces MDA-MB-231 cell death through the intrinsic apoptotic pathway and may suppress tumor progression and metastasis. Taken together, our study presents a mechanistic pathway of the anticancer properties of SYA013 against TNBC cell lines and suggests a potential for exploring SYA013 as a lead agent for development against TNBC.

Breast Cancer Stem Cells: Biomarkers, Identification and Isolation Methods, Regulating Mechanisms, Cellular Origin, and Beyond

Despite recent advances in diagnosis and treatment, breast cancer (BC) is still a major cause of cancer-related mortality in women. Breast cancer stem cells (BCSCs) are a small but significant subpopulation of heterogeneous breast cancer cells demonstrating strong self-renewal and proliferation properties. Accumulating evidence has proved that BCSCs are the driving force behind BC tumor initiation, progression, metastasis, drug resistance, and recurrence. As a heterogeneous disease, BC contains a full spectrum of different BC subtypes, and different subtypes of BC further exhibit distinct subtypes and proportions of BCSCs, which correspond to different treatment responses and disease-specific outcomes. This review summarized the current knowledge of BCSC biomarkers and their clinical relevance, the methods for the identification and isolation of BCSCs, and the mechanisms regulating BCSCs. We also discussed the cellular origin of BCSCs and the current advances in single-cell lineage tracing and transcriptomics and their potential in identifying the origin and lineage development of BCSCs.

Triple-Negative Breast Cancer Comparison With Canine Mammary Tumors From Light Microscopy to Molecular Pathology

Many similar characteristics in human and dog cancers including, spontaneous development, clinical presentation, tumor heterogeneity, disease progression, and response to standard therapies have promoted the approval of this comparative model as an alternative to mice. Breast cancer represents the second most frequent neoplasm in humans after lung cancer. Triple-negative breast cancers (TNBC) constitute around 15% of all cases of breast cancer and do not express estrogen receptor (ER), progesterone receptor (PR), and do not overexpress human epidermal growth factor receptor 2 (HER2). As a result, they do not benefit from hormonal or trastuzumab-based therapy. Patients with TNBC have worse overall survival than patients with non-TNBC. Lehmann and collaborators described six different molecular subtypes of TNBC which further demonstrated its transcriptional heterogeneity. This six TNBC subtype classification has therapeutic implications. Breast cancer is the second most frequent neoplasm in sexually intact female dogs after skin cancer. Canine mammary tumors are a naturally occurring heterogeneous group of cancers that have several features in common with human breast cancer (HBC). These similarities include etiology, signaling pathway activation, and histological classification. Molecularly CMTs are more like TNBCs, and therefore dogs are powerful spontaneous models of cancer to test new therapeutic approaches, particularly for human TNBCs. More malignant tumors of the breast are more often ER and PR negative in both humans and dogs. Promising breast cancer biomarkers in both humans and canines are cancer-associated stroma (CAS), circulating tumor cells and tumor DNA (ctDNA), exosomes and miRNAs, and metabolites.

NGS Panel Testing of Triple-Negative Breast Cancer Patients in Cyprus: A Study of BRCA-Negative Cases

Simple Summary

In Cyprus, approximately 9% of triple-negative (negative in common breast cancer receptors—estrogen, progesterone, and human epidermal growth factor receptor 2 (HER2) receptors) breast cancer (TNBC) patients carry inherited mutations in the BRCA1/2 breast cancer (BC) susceptibility genes. These mutations increase the risk of BC. However, the contribution of other BC susceptibility genes has not yet been determined. To this end, we aimed to investigate the prevalence of mutations in BRCA1/2-negative TNBC patients in Cyprus. Ninety-five cancer susceptibility genes were sequenced for 163 TNBC patients. The frequency of non-BRCA mutations and especially PALB2 in TNBC patients in Cyprus appears to be higher compared to other populations, and half of the mutation-positive patients were diagnosed over the age of 60 years. Based on these results, we believe that PALB2 and TP53 along with BRCA1/2 genetic testing could be beneficial for a large proportion of TNBC patients in Cyprus, irrespective of their age of diagnosis.

Abstract

In Cyprus, approximately 9% of triple-negative (estrogen receptor-negative, progesterone receptor-negative, and human epidermal growth factor receptor 2-negative) breast cancer (TNBC) patients are positive for germline pathogenic variants (PVs) in BRCA1/2. However, the contribution of other genes has not yet been determined. To this end, we aimed to investigate the prevalence of germline PVs in BRCA1/2-negative TNBC patients in Cyprus, unselected for family history of cancer or age of diagnosis. A comprehensive 94-cancer-gene panel was implemented for 163 germline DNA samples, extracted from the peripheral blood of TNBC patients. Identified variants of uncertain clinical significance were evaluated, using extensive in silico investigation. Eight PVs (4.9%) were identified in two high-penetrance TNBC susceptibility genes. Of these, seven occurred in PALB2 (87.5%) and one occurred in TP53 (12.5%). Interestingly, 50% of the patients carrying PVs were diagnosed over the age of 60 years. The frequency of non-BRCA PVs (4.9%) and especially PALB2 PVs (4.3%) in TNBC patients in Cyprus appears to be higher compared to other populations. Based on these results, we believe that PALB2 and TP53 along with BRCA1/2 genetic testing could be beneficial for a large proportion of TNBC patients in Cyprus, irrespective of their age of diagnosis.

Remarkable response to combined immunochemotherapy in patients with metastatic triple-negative breast cancer

Background: Progress in immunotherapy (IT) has shifted treatment paradigms for multiple malignancies. In March 2019, the combination of nab-paclitaxel and atezolizumab was approved by the US FDA for patients with PD-L1 positive metastatic triple-negative breast cancer based on positive results of the Impassion130 trial. Although numerous studies have examined the prognostic role of PD-L1, the value of this test remains controversial. Results: Here, we presented the cases of three heavily pretreated women with metastatic triple-negative breast cancer who exhibited remarkable responses to combined IT and chemotherapy despite undetectable PD-L1. Conclusion: In our opinion, the current FDA-approved assessment for PD-L1 expression is a reasonable tool for deciding whether to start IT. However, because this approach has many limitations, patients with undetectable PD-L1 expression should still be considered for IT.

Prognostic Role of Immune Markers in Triple Negative Breast Carcinoma

Tumor immune microenvironment (TIME) is a significant prognostic parameter for triple negative breast carcinomas (TNBC) due to being a target for immunotherapeutic agents and its essential role during the cancer immunoediting process. In this study, CD8, FOXP3, CD163, PD-L1/SP142 and PD-L1/SP263 antibodies were examined in a sample of 51 TNBC cases. Patients who received neoadjuvant therapy were excluded. CD8, FOXP3 and CD163 antibodies were evaluated separately in intratumoral area (ITA) and tumor stroma (TS). PD-L1 status was also examined in tumor cells (TC) and immune cells (IC) using both SP142 and SP263 antibodies. In multivariate Cox regressions, the only antibody that was found to be significantly associated with survival was SP142. SP142-positivity in TC and IC was related to increased overall survival. Higher CD163 expression in ITA and SP263-positivity in IC were associated with younger age. Lymphatic/angioinvasion was more frequent in cases with negative/low CD8 and FOXP3 expressions. Moreover, metastatic axillary lymph node(s) was associated with negative/low FOXP3 expression in TS. CD8, FOXP3, CD163, SP142 and SP263 expressions were positively correlated with each other, except a mild discordance caused by CD163 in ITA. Although PD-L1 status with both SP142 and SP263 antibodies were concordant in the majority of cases, 33.3% and 13.7% of the cases showed SP142-negative/SP263-positive pattern in TC and IC respectively. In conclusion, we suggest that composition, density and localization of the immune cells and the check point molecules are important prognostic parameters in TNBC. Immunohistochemistry can be used as an accessible and less expensive tool to demonstrate TIME.

Machine learning analysis identifies genes differentiating triple negative breast cancers

Triple negative breast cancer (TNBC) is one of the most aggressive form of breast cancer (BC) with the highest mortality due to high rate of relapse, resistance, and lack of an effective treatment. Various molecular approaches have been used to target TNBC but with little success. Here, using machine learning algorithms, we analyzed the available BC data from the Cancer Genome Atlas Network (TCGA) and have identified two potential genes, TBC1D9 (TBC1 domain family member 9) and MFGE8 (Milk Fat Globule-EGF Factor 8 Protein), that could successfully differentiate TNBC from non-TNBC, irrespective of their heterogeneity. TBC1D9 is under-expressed in TNBC as compared to non-TNBC patients, while MFGE8 is over-expressed. Overexpression of TBC1D9 has a better prognosis whereas overexpression of MFGE8 correlates with a poor prognosis. Protein-protein interaction analysis by affinity purification mass spectrometry (AP-MS) and proximity biotinylation (BioID) experiments identified a role for TBC1D9 in maintaining cellular integrity, whereas MFGE8 would be involved in various tumor survival processes. These promising genes could serve as biomarkers for TNBC and deserve further investigation as they have the potential to be developed as therapeutic targets for TNBC.

An immune-centric exploration of BRCA1 and BRCA2 germline mutation related breast and ovarian cancers

Background

BRCA1/2 germline mutation related cancers are candidates for new immune therapeutic interventions. This study was a hypothesis generating exploration of genomic data collected at diagnosis for 19 patients. The prominent tumor mutation burden (TMB) in hereditary breast and ovarian cancers in this cohort was not correlated with high global immune activity in their microenvironments. More information is needed about the relationship between genomic instability, phenotypes and immune microenvironments of these hereditary tumors in order to find appropriate markers of immune activity and the most effective anticancer immune strategies.

Methods

Mining and statistical analyses of the original DNA and RNA sequencing data and The Cancer Genome Atlas data were performed. To interpret the data, we have used published literature and web available resources such as Gene Ontology, The Cancer immunome Atlas and the Cancer Research Institute iAtlas.

Results

We found that BRCA1/2 germline related breast and ovarian cancers do not represent a unique phenotypic identity, but they express a range of phenotypes similar to sporadic cancers. All breast and ovarian BRCA1/2 related tumors are characterized by high homologous recombination deficiency (HRD) and low aneuploidy. Interestingly, all sporadic high grade serous ovarian cancers (HGSOC) and most of the subtypes of triple negative breast cancers (TNBC) also express a high degree of HRD.

Conclusions

TMB is not associated with the magnitude of the immune response in hereditary BRCA1/2 related breast and ovarian cancers or in sporadic TNBC and sporadic HGSOC. Hereditary tumors express phenotypes as heterogenous as sporadic tumors with various degree of “BRCAness” and various characteristics of the immune microenvironments. The subtyping criteria developed for sporadic tumors can be applied for the classification of hereditary tumors and possibly also characterization of their immune microenvironment. A high HRD score may be a good candidate biomarker for response to platinum, and potentially PARP-inhibition.

Trial registration

Phase I Study of the Oral PI3kinase Inhibitor BKM120 or BYL719 and the Oral PARP Inhibitor Olaparib in Patients With Recurrent TNBC or HGSOC (NCT01623349), first posted on June 20, 2012. The design and the outcome of the clinical trial is not in the scope of this study.

Breast-conserving surgery vs. total mastectomy in patients with triple negative breast cancer in early stages: A propensity score analysis

BACKGROUND

Breast-conserving surgery (BCS) as an alternative to total mastectomy (TM) in patients with early-stage triple-negative breast cancer (TNBC) is not widely spread.

OBJECTIVE

We aimed to compare the overall survival (OS) and disease-free survival (DFS) between both surgical approaches in early-stage TNBC patients at 10 years.

METHODS

We conducted a retrospective cohort study in TNBC female patients with stage I-IIa, treated at a single-center during the period of 2000-2014. We estimated and compared the survival rates with the Kaplan Meier and Long-rank test. Propensity scores were calculated with the generalized boosted regression model and were used in the multivariate Cox regression analysis with the covariate adjustment method.

RESULTS

We included 288 patients, 111 in the BCS vs. 177 in the TM group. The median follow-up was 102 months. Moreover, the patients in the BCS group had superior OS (85% vs. 81%, p = 0.56) and DFS (83% vs. 80%, p = 0.42) at 10 years. In the multivariate Cox analysis, BCS decreased the mortality risk (HR: 0.79, 95% CI: 0.37-1.67, p = 0.538), and the locoregional or distant recurrence risk (HR: 0.67, 95% CI: 0.32-1.41, p = 0.294), albeit with no statistical significance.

CONCLUSION

BCS is a safe alternative to TM in Latin-American patients with early-stage TNBC.

α-Santalol functionalized chitosan nanoparticles as efficient inhibitors of polo-like kinase in triple negative breast cancer

Polo-like kinase 1 (PLK-1) is a protein kinase that plays a significant role in the initiation, maintenance, and completion of mitotic processes in the cell cycle.

Heterogeneity of breast cancer: The importance of interaction between different tumor cell populations

INTRODUCTION

Breast cancer is the most common cancer and the second leading cause of cancer-related death in women worldwide. Despite the early detection of breast cancer and increasing knowledge of its biology and chemo-resistance, metastatic breast cancer is largely incurable disease. We provide a review of the intertumor and intratumor heterogeneity, explain the differences between triple-negative breast cancer subtypes. Also, we describe the interaction of breast tumor cells with their microenvironment cells and explain how this interaction contributes to the tumor progression, metastasis formation and resistance to the treatment.

DISCUSSION

One of the main causes that complicate the treatment is tumor heterogeneity. It is observed among patients (intertumor heterogeneity) and in each individual tumor (intratumor heterogeneity). In the case of intratumor heterogeneity, the tumor consists of different phenotypical cell populations. During breast cancer subtype identification, a small piece of solid tumor tissue does not necessarily represent all the tumor composition. Breast tumor cell phenotypical differences may appear due to cell localization in different tumor sites, unique response to the treatment, cell interaction with tumor microenvironment or tumor cell interaction with each other. This heterogeneity may lead to breast cancer aggressiveness and challenging treatment.

CONCLUSION

Understanding the molecular and cellular mechanisms of tumor heterogeneity that are relevant to the development of treatment resistance is a major area of research. Identification of differences between populations and their response to anticancer drugs would help to predict the potential resistance to chemotherapy and thus would help to select the most suitable anticancer treatment.

Triple-negative breast cancer: current perspective on the evolving therapeutic landscape

Triple-negative breast cancer (TNBC) is known to have a poor prognosis and limited treatment options, namely chemotherapy. Different molecular studies have recently classified TNBC into different subtypes opening the door to potential new-targeted treatment options. In this review, we discuss the current standard of care in the treatment of TNBC in the neoadjuvant, adjuvant and metastatic settings. In addition, we summarize the ongoing phase III clinical trials evaluating different associations between the 3 pillars of anticancer treatment: chemotherapy, targeted therapy and immunotherapy.

Platinum Salts in Patients with Breast Cancer: A Focus on Predictive Factors

Breast cancer (BC) is the most frequent oncologic cause of death among women and the improvement of its treatments is compelling. Platinum salts (e.g., carboplatin, cisplatin, and oxaliplatin) are old drugs still used to treat BC, especially the triple-negative subgroup. However, only a subset of patients see a concrete benefit from these drugs, raising the question of how to select them properly. Therefore, predictive biomarkers for platinum salts in BC still represent an unmet clinical need. Here, we review clinical and preclinical works in order to summarize the current evidence about predictive or putative platinum salt biomarkers in BC. The association between BRCA1/2 gene mutations and platinum sensitivity has been largely described. However, beyond the mutations of these two genes, several other proteins belonging to the homologous recombination pathways have been linked to platinum response, defining the concept of BRCAness. Several works, here reviewed, have tried to capture BRCAness through different strategies, such as homologous recombination deficiency (HRD) score and genetic signatures. Moreover, p53 and its family members (p63 and p73) might also be used as predictors of platinum response. Finally, we describe the mounting preclinical evidence regarding base excision repair deficiency as a possible new platinum biomarker.

Absence of estrogen receptor is associated with worse oncologic outcome in patients who were received neoadjuvant chemotherapy for breast cancer

BACKGROUND/OBJECTIVE

Neoadjuvant chemotherapy (NAC) is a standard treatment for locally advanced breast cancer, especially for HER2-positive or triple negative breast cancer which shows good response to chemotherapy. However, because a result of biomarkers is, occasionally, changed after NAC, the treatment strategy should be differently applied for patients with locally advanced breast cancer. We compared the results of biomarkers before and after NAC to evaluate the association with disease prognosis and oncologic results.

METHODS

Fifty-seven patients with locally advanced breast cancer underwent NAC and the immunohistochemical (IHC) staining results were compared between before and after NAC. And the association between oncologic outcomes and biomarkers was analyzed.

RESULTS

Negative status of estrogen receptor (ER) was associated with locoregional recurrence and distant metastasis both before and after NAC (p = 0.021, 0.019; p = 0.018, 0.036). And the negative status of progesterone receptor (PR) and triple negative status before neoadjuvant chemotherapy were also associated with death and distant metastasis, respectively. However, the changes of biomarkers after NAC in breast cancer were not directly associated with any oncologic outcomes.

CONCLUSION

The absence of ER in breast cancer before and after NAC would be a significant prognostic factor for local recurrence and distant metastasis. Therefore, the absence of ER should be considered as important factor in determining the treatment strategy.

Molecular characteristics of breast cancer according to clinicopathological factors

The purpose of the present study was to evaluate the correlation between molecular factors such as BRCA1 DNA repair associated (BRCA1), checkpoint kinase 2 (CHEK2) and nucleotide binding oligomerization domain containing 2 (NOD2) gene mutations and clinicopathological factors in patients with breast cancer (BC). Prognostic factors were analyzed in BC patients with confirmed BRCA1 (n=73), CHEK2 (n=51) and NOD2 (n=31) mutations. The control group was selected from BC patients without mutations (n=392). The BRCA-associated cancer cases were significantly more often triple negative compared with sporadic cancer (62% vs. 14%; P=0.0001). Luminal B HER2-positive and HER2-positive non-luminal subtypes were observed more often in the control group (33 and 17%). The luminal A subtype was detected in 53% of CHEK2 mutation carriers and 45% of NOD2 mutation carriers. A lower histological grade was observed significantly more often in patients with CHEK2 mutations in comparison with the control group (88 vs. 69%; P=0.003). Lymph nodes without metastases were reported more frequently in NOD2 mutation carriers (74 vs. 54%; P=0.038), in BRCA1 mutations (73 vs. 54%; P=0.004) and, although not significantly, in CHEK2 mutation carriers (69 vs. 54%; P=0.071) compared with the control group. In conclusion, BRCA1 mutation was associated with TNBC and the luminal B HER2 (-) subtype. HER2-positive subtypes were characteristic of the control group. CHEK2 and NOD2 mutation carriers had a more favorable profile of prognostic factors.

LncRNA HOTAIR up-regulation is strongly related with lymph nodes metastasis and LAR subtype of Triple Negative Breast Cancer

Triple-negative breast cancers (TNBCs) represent a heterogeneous disease characterized by several molecular subtypes with different prognoses and responses to therapy. For a correct clinical management of TNBC patients the knowledge of the gene regulation mechanisms related to tumor progression and drug response has become fundamental.

LncRNAs regulate gene expression through various processes, including chromatin modification, transcription and post-transcription and they are emerging as important cancer biomarkers being involved in tumor pathogenesis, metastatic progression and drug resistance.

In this study we aimed to analyze the expression of the lncRNA HOTAIR, mainly involved in breast cancer disease, in a large case series of TNBC patients. We used ISH methods by a RNA probe to better define its staining in tumor tissues and its relation with clinical-pathological parameters and outcomes of patients.

Our results show that high HOTAIR expression in tumor tissues is strongly correlated with lymph nodes metastasis (LNM) (p=0.039), as reported also for other tumor types, and has a direct strong association with Androgen Receptor (AR) expression (p= 0.019).

These data confirm the prognostic role of HOTAIR in TNBC, and, its involvement in the regulation of AR pathway, suggests the possibility to establish new therapeutic strategies for AR+TNBC patients.

A Multigene Assay Determines Risk of Recurrence in Patients with Triple-Negative Breast Cancer

Approximately 40% of patients with stage I-III triple-negative breast cancer (TNBC) recur after standard treatment, whereas the remaining 60% experience long-term disease-free survival (DFS). There are currently no clinical tests to assess the risk of recurrence in TNBC patients. We previously determined that TNBC patients with MHC class II (MHCII) pathway expression in their tumors experienced significantly longer DFS. To translate this discovery into a clinical test, we developed an MHCII Immune Activation assay, which measures expression of 36 genes using NanoString technology. Preanalytical testing confirmed that the assay is accurate and reproducible in formalin-fixed paraffin-embedded (FFPE) tumor specimens. The assay measurements were concordant with RNA-seq, MHCII protein expression, and tumor-infiltrating lymphocyte counts. In a training set of 44 primary TNBC tumors, the MHCII Immune Activation Score was significantly associated with longer DFS (HR = 0.17; P = 0.015). In an independent validation cohort of 56 primary FFPE TNBC tumors, the Immune Activation Score was significantly associated with longer DFS (HR = 0.19; P = 0.011) independent of clinical stage. An Immune Activation Score threshold for identifying patients with very low risk of relapse in the training set provided 100% specificity in the validation cohort. The assay format enables adoption as a standardized clinical prognostic test for identifying TNBC patients with a low risk of recurrence. Correlative data support future studies to determine if the assay can identify patients in whom chemotherapy can be safely deescalated and patients likely to respond to immunotherapy. SIGNIFICANCE: The MHCII Immune Activation assay identifies TNBC patients with a low risk of recurrence, addressing a critical need for prognostic biomarker tests that enable precision medicine for TNBC patients.

Metformin reverses PARP inhibitors-induced epithelial-mesenchymal transition and PD-L1 upregulation in triple-negative breast cancer

Poly (ADP-ribose) polymerase (PARP) inhibitors have emerged as promising targeted therapies for BRCA-mutated cancers by blocking repair of DNA double-strand breaks. However, resistance to PARP inhibitors (PARPi) has been described in some patients lowering the overall response rates. To investigate the underlying mechanisms of PARPi resistance, we developed the adaptive resistant clones in triple-negative breast cancer cell lines. We identified epithelial-mesenchymal transition (EMT) and upregulation of programmed death-ligand 1 (PD-L1) in resistant cells and further demonstrated the important role of Akt S473 phosphorylation in PARPi resistance. In addition, PARPi mediated EMT is independent of PD-L1 upregulation. Blocking the p-Akt S473 axis by metformin reversed EMT and PD-L1 expression which sensitized PARPi-resistant cells to cytotoxic T cells. Thus, a combination of metformin and PARP inhibitors may be a promising therapeutic strategy to increase the efficacy of PARP inhibitors and tumor sensitivity to immunotherapy.

S-nitrosylation and its role in breast cancer angiogenesis and metastasis

S-nitrosylation, the modification by nitric oxide of free sulfhydryl groups in cysteines, has become an important regulatory mechanism in carcinogenesis and metastasis. S-nitrosylation of targets in tumor cells contributes to metastasis regulating epithelial to mesenchymal transition, migration and invasion. In the tumor environment, the role of S-nitrosylation in endothelium has not been addressed; however, the evidence points out that S-nitrosylation of endothelial proteins may regulate angiogenesis, adhesion of tumor cells to the endothelium, intra and extravasation of tumor cells and contribute to metastasis.

Triple Negative Breast Cancer Depends on Sphingosine Kinase 1 (SphK1)/Sphingosine-1-Phosphate (S1P)/Sphingosine 1-Phosphate Receptor 3 (S1PR3)/Notch Signaling for Metastasis

Background

Triple negative breast cancer (TNBC) has a more aggressive recurrence. Previous reports have demonstrated that sphingosine kinase 1 (SphK1) is a crucial regulator of breast cancer progression. However, the correlation of SphK1 with clinical prognosis has been poorly investigated. Thus, we aimed to elaborate the role of SphK1 in TNBC metastasis.

Material/Methods

We first determined the level of SphK1 in breast cancer tissue samples and breast cancer cells. Furthermore, the expression of HER2 and phosphor-SphK1 (pSphK1) in human breast cancer tissue samples was determined by immunohistochemical analysis. Associations between SphK1 and clinical parameters of tumors were analyzed. The activity of SphK1 was measured by fluorescence analysis. Extracellular sphingosine-1-phosphate (S1P) was detected using an ELISA kit. Associations between SphK1 and metastasis potential were analyzed by Transwell assay.

Results

Levels of SphK1 in TNBC patients were significantly higher than levels in other patients with other breast tumors. The expression of SphK1 was positively correlated with poor overall survival (OS) and progression-free survival (PFS), as well as poor response to 5-FU and doxorubicin. The depression of SphK1 thus could repress the Notch signaling pathway, reduce migration, and invasion of TNBC cells in vivo and in vitro. Furthermore, silencing of SphK1 by Ad-SPHK1-siRNA or SphK1 inhibitor PF543 sensitized TNBCs to 5-FU and doxorubicin. Our results also indicated that SphK1 inhibition could effectively counteracts tumors metastasis via Notch signaling pathways, indicating a potentially anti-tumor strategy in TNBC.

Conclusions

We found that elevated levels of pSphK1 were positive correlation with high expression of S1P, which in turn promoted metastasis of TNBC through S1P/S1PR3/Notch signaling pathway.

Breast cancer in Africa: prevalence, treatment options, herbal medicines, and socioeconomic determinants

Breast cancer is the leading cause of cancer-related deaths in women worldwide. GLOBOCAN estimated about 1.7 million new cases of breast cancer diagnoses worldwide and about 522,000 deaths in 2012. The burden of breast cancer mortality lies in the developing low-income and middle-income countries, where about 70% of such deaths occur. The incidence of breast cancer is also rising in low-income and middle-income countries in Africa as trend towards urbanization, and adoption of Western lifestyles increases. In general, the triple-negative breast cancer (TNBC) subtype tends to be frequent in women of African ancestry. What are the factors contributing to this prevalence? Are there genetic predispositions to TNBC in African women? This review addresses these questions and provides an update on the incidence, survival, and mortality of breast cancer in Africans, with a focus on sub-Saharan Africans. We have also addressed factors that could account for ethical disparities in incidence and mortality. Further, we have highlighted challenges associated with access to essential drug and to healthcare treatment in some African countries and outlined alternative/herbal treatment methods that are increasingly implemented in Africa and other developing nations.