Basal-like breast cancer: a critical review

MELK as a potential target to control cell proliferation in triple-negative breast cancer MDA-MB-231 cells

Maternal embryonic leucine zipper kinase (MELK) is an important regulator in tumorigenesis of human breast cancer, and if silenced leads to programmed cell death in specific breast cancer cell lines, including MDA-MB-231 cells. In the present study, RNA interference, proliferation assay and semi-quantification of cell cycle relative proteins were performed to determine the effects of MELK in human breast cancer cells. Data demonstrated that the highest level of MELK protein in the MDA-MB-231 cell line among eight breast cancer cell lines. The sensitivity of MELK small interfering-RNA varied in different breast cancer cell lines, but MELK silencing resulted in marked suppression of proliferation of triple-negative breast cancer (TNBC) and non-TNBC cells. Specific silencing of MELK caused G2 arrest in TNBC MDA-MB-231 and HCC1143 cells, and G1 arrest in non-TNBC T47D and MCF7 cells. Notably, the knockdown of MELK did not induce apoptosis in HCC1143 cells, indicated by the lack of caspase-3 expression. In addition, in response to MELK silencing, cyclin B and cyclin D1 were downregulated in four breast cancer cell lines. Furthermore, the silencing of MELK resulted in the upregulation of p21, p27 and phosphorylated (p)-c-Jun N-terminal kinase (JNK) in HCC1143 TNBC cells, and downregulation of p21 and p-JNK in T47D non-TNBC cells. Additionally, MELK protein was markedly suppressed in non-TNBC cells in response to estrogen deprivation. The findings from the present study suggested that MELK may be a potential target in MDA-MB-231 cells, although genetic knockdown of MELK resulted in inhibitory effects on proliferation of TNBC and non-TNBC cells. MELK exert its effect on different breast cancer cells via arrest of different cell cycle phases and therefore mediated by different mediators, which may be involved in the crosstalk with MELK signaling and with the estrogen receptor signaling pathway.

Twist promotes tumor metastasis in basal-like breast cancer by transcriptionally upregulating ROR1

Rationale: Twist is a key transcription factor for induction of epithelial-mesenchymal transition (EMT), which promotes cell migration, invasion, and cancer metastasis, confers cancer cells with stem cell-like characteristics, and provides therapeutic resistance. However, the functional roles and targeted genes of Twist in EMT and cancer progression remain elusive. Methods: The potential targeted genes of Twist were identified from the global transcriptomes of T47D/Twist cells by microarray analysis. EMT phenotype was detected by western blotting and immunofluorescence of marker proteins. The dual-luciferase reporter and chromatin immunoprecipitation assays were employed to observe the direct transcriptional induction of ROR1 by Twist. A lung metastasis model was used to study the pro-metastatic role of Twist and ROR1 by injecting MDA-MB-231 cells into tail vein of nude mice. Bio-informatics analysis was utilized to measure the metastasis-free survival of breast cancer patients. Results: Twist protein was proved to directly activate the transcription of ROR1 gene, a receptor of Wnt5a in non-canonical WNT signaling pathway. Silencing of ROR1 inhibited EMT process, cell migration, invasion, and cancer metastasis of basal-like breast cancer (BLBC) cells. Knockdown of ROR1 also ameliorated the pro-metastatic effect of Twist. Furthermore, analyses of clinical specimens indicated that high expression of both ROR1 and Twist tightly correlates with poor metastasis-free survival of breast cancer patients. Conclusion: ROR1 is a targeted gene of Twist. Twist/ROR1 signaling is critical for invasion and metastasis of BLBC cells.

Circulating tumor cells in bladder cancer: Emerging technologies and clinical implications foreseeing precision oncology

CONTEXT

Circulating tumor cells (CTC) in peripheral blood of cancer patients provide an opportunity for real-time liquid biopsies capable of aiding early intervention, therapeutic decision, response to therapy, and prognostication. Nevertheless, the rare and potentially heterogeneous molecular nature of CTC has delayed the standardization of robust high-throughput capture/enrichment and characterization technologies.

OBJECTIVE

This review aims to systematize emerging solutions for CTC analysis in bladder cancer (BC), their opportunities and limitations, while providing key insights on specific technologic aspects that may ultimately guide molecular studies and clinical implementation.

EVIDENCE ACQUISITION

State-of-the-art screening for CTC technologies and clinical applications in BC was conducted in MEDLINE through PubMed.

EVIDENCE SYNTHESIS

From 200 records identified by the search query, 25 original studies and 1 meta-analysis met the full criteria for selection. A significant myriad of CTC technological platforms, including immunoaffinity, biophysical, and direct CTC detection by molecular methods have been presented. Despite their preliminary nature and irrespective of the applied technology, most studies concluded that CTC counts in peripheral blood correlated with metastasis. Associations with advanced tumor stage and grade and worst prognosis have been suggested. However, the unspecific nature, low sensitivity, and the lack of standardization of current methods still constitutes a major drawback. Moreover, few comprehensive molecular studies have been conducted on these poorly known class of malignant cells.

CONCLUSION

The current rationale supports the importance of moving the CTC field beyond proof of concept studies toward molecular-based solutions capable of improving disease management. The road has been paved for identification of highly specific CTC biomarkers and novel targeted approaches, foreseeing successful clinical applications.

Application of pharmacologically induced transcriptomic profiles to interrogate PI3K-Akt-mTOR pathway activity associated with cancer patient prognosis

The PI3K-Akt-mTOR signaling pathway has been identified as a key driver of carcinogenesis in several cancer types. As such, a major area of focus in cancer biology is the development of genomic biomarkers that can measure the activity level of the PI3K-Akt-mTOR pathway. In this study, we systematically estimate PI3K-Akt-mTOR pathway activity in breast primary tumor samples using transcriptomic profiles derived from drug treatment in MCF7 cell lines. We demonstrate that gene expression profiles derived from chemically-induced protein inhibition allows us to measure PI3K-Akt-mTOR pathway activity in patient tumor samples. With this approach, we predict prognosis and response to chemotherapy in cancer patients, and screen for potential pharmacological modulators of PI3K-Akt-mTOR pathway inhibitors.

Fibroblast growth factor receptor 4 (FGFR4) and fibroblast growth factor 19 (FGF19) autocrine enhance breast cancer cells survival

Basal-like breast cancer is an aggressive tumor subtype with poor prognosis. The discovery of underlying mechanisms mediating tumor cell survival, and the development of novel agents to target these pathways, is a priority for patients with basal-like breast cancer. From a functional screen to identify key drivers of basal-like breast cancer cell growth, we identified fibroblast growth factor receptor 4 (FGFR4) as a potential mediator of cell survival. We found that FGFR4 mediates cancer cell survival predominantly via activation of PI3K/AKT. Importantly, a subset of basal-like breast cancer cells also secrete fibroblast growth factor 19 (FGF19), a canonical ligand specific for FGFR4. siRNA-mediated silencing of FGF19 or neutralization of extracellular FGF19 by anti-FGF19 antibody (1A6) decreases AKT phosphorylation, suppresses cancer cell growth and enhances doxorubicin sensitivity only in the FGFR4⁺/FGF19⁺ breast cancer cells. Consistently, FGFR4/FGF19 co-expression was also observed in 82 out of 287 (28.6%) primary breast tumors, and their expression is strongly associated with AKT phosphorylation, Ki-67 staining, higher tumor stage and basal-like phenotype. In summary, our results demonstrated the presence of an FGFR4/FGF19 autocrine signaling that mediates the survival of a subset of basal-like breast cancer cells and suggest that inactivation of this autocrine loop may potentially serve as a novel therapeutic intervention for future treatment of breast cancers.

MOBCdb: a comprehensive database integrating multi-omics data on breast cancer for precision medicine

BACKGROUND

Breast cancer is one of the most frequently diagnosed cancers among women worldwide, characterized by diverse biological heterogeneity. It is well known that complex and combined gene regulation of multi-omics is involved in the occurrence and development of breast cancer.

RESULTS

In this paper, we present the Multi-Omics Breast Cancer Database (MOBCdb), a simple and easily accessible repository that integrates genomic, transcriptomic, epigenomic, clinical, and drug response data of different subtypes of breast cancer. MOBCdb allows users to retrieve simple nucleotide variation (SNV), gene expression, microRNA expression, DNA methylation, and specific drug response data by various search fashions. The genome-wide browser /navigation facility in MOBCdb provides an interface for visualizing multi-omics data of multi-samples simultaneously. Furthermore, the survival module provides survival analysis for all or some of the samples by using data of three omics. The approved public drugs with genetic variations on breast cancer are also included in MOBCdb.

CONCLUSION

In summary, MOBCdb provides users a unique web interface to the integrated multi-omics data of different subtypes of breast cancer, which enables the users to identify potential novel biomarkers for precision medicine.

Immunohistochemical Analysis of ER, PR, HER-2, CK 5/6, p63 and EGFR Antigen Expression in Medullary Breast Cancer

Aims and Background

Recent publications of breast cancer classification based on gene expression profile analyses indicate that medullary breast carcinomas (MBC) may be considered part of the basal-like carcinoma spectrum made up of ER-negative, PR-negative and HER-2-negative cells (“triple-negative phenotype”). On the other hand, there are also data showing that a proportion of MBC and atypical MBC (AMBC) is ER, PR and/or HER-2 positive. Therefore, we have decided to immunohistochemically analyze ER, PR, HER-2 and basal/myoepithelial markers CK5/6, p63 and EGFR expression in our archival paraffin-embedded MBC and AMBC samples from 48 patients.

Methods

Immunohistochemical evaluation of samples which were derived from patients operated on at our two hospitals between 1999 and 2005.

Results

Typical MBC was found in 39 patients and AMBC in 9 patients. The patients ranged in age from 32 to 84 years (median 55). Modified radical mastectomy with axillary dissection was performed in 30/48 patients (63%) while breast segmentectomy with axillary dissection was performed in 18/48 patients (37%). Metastases in axillary lymph nodes were observed in 15/48 patients (31%). ER positivity was present in 3/48 patients (6%), PR positivity in 8/48 (17%), and a positive HER-2 reaction was present in 14/48 patients (29%). CK 5/6 was positive in 20/48, p63 in 24/48 and EGFR in 8/48 patients. Adjuvant therapy was applied in all but 2 patients. Alive were 45/48 (94%) of patients. With the exception of PR expression, 39 patients with typical MBC and 9 patients with AMBC were comparable in the analyzed parameters. Positive HER-2 antigen expression in the analyzed sample was not found to be associated to a statistically significant degree with the MBC or AMBC histological tumor type, tumor size, axillary lymph node metastases, ER and PR status nor with patient survival.

Conclusions

The data from our study seem to be generally comparable with the relatively scarce published data on clinicopathological parameters of MBC and AMBC.

Osteopontin Expression According to Molecular Profile of Invasive Breast Cancer: A Clinicopathological and Immunohistochemical Study

Osteopontin (OPN) is a secreted, calcium-binding phosphorylated glycoprotein involved in several physiological and pathological events such as angiogenesis, apoptosis, inflammation, wound healing, vascular remodeling, calcification of mineralized tissues, and induction of cell proteases. There is growing interest in the role of OPN in breast cancer. In an attempt to obtain new insight into the pathogenesis of OPN-associated breast carcinomas, an immunohistochemical panel with 17 primary antibodies including cytokeratins and key regulators of the cell cycle was performed in 100 formalin-fixed paraffin-embedded samples of invasive breast carcinomas. OPN was expressed in 65% of tumors and was negatively correlated with estrogen (p=0.0350) and progesterone (p=0.0069) receptors, but not with the other markers and clinicopathological features evaluated including age, menstrual status, pathological grading, tumor size, and metastasis. There was no correlation between OPN expression and carcinomas of the basal-like phenotype (p=0.1615); however, OPN correlated positively with c-erbB-2 status (p=0.0286) and negatively with carcinomas of the luminal subtype (p=0.0353). It is well known that carcinomas overexpressing c-erbB-2 protein have a worse prognosis than luminal tumors. Here, we hypothesize that the differential expression of OPN in the first subtype of carcinomas may contribute to their more aggressive behavior.

Studies on DNA Damage Repair and Precision Radiotherapy for Breast Cancer

Radiotherapy acts as an important component of breast cancer management, which significantly decreases local recurrence in patients treated with conservative surgery or with radical mastectomy. On the foundation of technological innovation of radiotherapy setting, precision radiotherapy of cancer has been widely applied in recent years. DNA damage and its repair mechanism are the vital factors which lead to the formation of tumor. Moreover, the status of DNA damage repair in cancer cells has been shown to influence patient response to the therapy, including radiotherapy. Some genes can affect the radiosensitivity of tumor cell by regulating the DNA damage repair pathway. This chapter will describe the potential application of DNA damage repair in precision radiotherapy of breast cancer.

Expression of the glutamine metabolism-related proteins glutaminase 1 and glutamate dehydrogenase in canine mammary tumours

Glutamine metabolism is an important metabolic pathway for cancer cell survival, and there is a critical connection between tumour growth and glutamine metabolism. Because of their similarities, canine mammary carcinomas are useful for studying human breast cancer. Accordingly, we investigated the correlations between the expression of glutamine metabolism-related proteins and the pathological features of canine mammary tumours. We performed immunohistochemical and western blot analysis of 39 mammary tumour tissues. In immunohistochemical analysis, the expression of glutaminase 1 (GLS1) in the epithelial region increased according to the histological grade (P < .005). In the stromal region, complex-type tumours displayed significantly higher GLS1 intensity than simple-type tumours. However, glutamate dehydrogenase expression did not show the same tendencies as GLS1. The western blot results were consistent with the immunohistochemical findings. These results suggest that the expression of GLS1 is correlates with clinicopathological factors in canine mammary tumours and shows a similar pattern to human breast cancer.

The SIRT2 Deacetylase Stabilizes Slug to Control Malignancy of Basal-like Breast Cancer

Overabundance of Slug protein is common in human cancer and represents an important determinant underlying the aggressiveness of basal-like breast cancer (BLBC). Despite its importance, this transcription factor is rarely mutated in BLBC, and the mechanism of its deregulation in cancer remains unknown. Here, we report that Slug undergoes acetylation-dependent protein degradation and identify the deacetylase SIRT2 as a key mediator of this post-translational mechanism. SIRT2 inhibition rapidly destabilizes Slug, whereas SIRT2 overexpression extends Slug stability. We show that SIRT2 deacetylates Slug protein at lysine residue K116 to prevent Slug degradation. Interestingly, SIRT2 is frequently amplified and highly expressed in BLBC. Genetic depletion and pharmacological inactivation of SIRT2 in BLBC cells reverse Slug stabilization, cause the loss of clinically relevant pathological features of BLBC, and inhibit tumor growth. Our results suggest that targeting SIRT2 may be a rational strategy for diminishing Slug abundance and its associated malignant traits in BLBC.

Transforming Growth Factor-beta Regulation of Ephrin Type-A Receptor 4 Signaling in Breast Cancer Cellular Migration

Breast cancer consists of a range of tumor subtypes with different clinical characteristics, disease prognosis, and treatment-response. Luminal breast cancer has the best prognosis while basal-like breast cancer (BLBC) represents the worst subtype. Transforming growth factor-beta (TGFβ) plays a prominent role in stimulating the migration and invasion of malignant breast cancer cells contributing to tumor progression. In this study, we identified the Ephrin type-A receptor 4 (EPHA4) as a novel target of TGFβ in breast cancer. Moreover, we show that TGFβ induction of EPHA4 gene expression is specific to basal-like tumors and is required for TGFβ-mediated cell migration. We further addressed the mechanism and found EPHA4 to be required for TGFβ-mediated cell migration in breast cancer through TGFβ-induced short term and long term activation of RhoGTPases. Finally, our data revealed a strong association between high EPHA4 expression and advanced tumor stage, aggressive BLBC molecular subtype and poor prognosis. Importantly, we found significant co-expression of EPHA4 and the TGFβ receptor type-2 (TGFβR2) in breast cancer subtypes associated with increased tumor relapse and drug resistance. Together, this study highlight the important role of the TGFβ/EPHA4 signaling axis in mediating tumor aggressiveness and poor patient survival in human breast cancer.

Suppression of protein tyrosine phosphatase N23 predisposes to breast tumorigenesis via activation of FYN kinase

Zhang et al. identified PTPN23 as a suppressor of cell motility and invasion in mammary epithelial and breast cancer cells. They validated the underlying mechanism of PTPN23 function in breast tumorigenesis as that of a key phosphatase that normally suppresses the activity of FYN in two different models.

Disruption of the balanced modulation of reversible tyrosine phosphorylation has been implicated in the etiology of various human cancers, including breast cancer. Protein Tyrosine Phosphatase N23 (PTPN23) resides in chromosomal region 3p21.3, which is hemizygously or homozygously lost in some breast cancer patients. In a loss-of-function PTPome screen, our laboratory identified PTPN23 as a suppressor of cell motility and invasion in mammary epithelial and breast cancer cells. Now, our TCGA (The Cancer Genome Atlas) database analyses illustrate a correlation between low PTPN23 expression and poor survival in breast cancers of various subtypes. Therefore, we investigated the tumor-suppressive function of PTPN23 in an orthotopic transplantation mouse model. Suppression of PTPN23 in Comma 1Dβ cells induced breast tumors within 56 wk. In PTPN23-depleted tumors, we detected hyperphosphorylation of the autophosphorylation site tyrosine in the SRC family kinase (SFK) FYN as well as Tyr142 in β-catenin. We validated the underlying mechanism of PTPN23 function in breast tumorigenesis as that of a key phosphatase that normally suppresses the activity of FYN in two different models. We demonstrated that tumor outgrowth from PTPN23-deficient BT474 cells was suppressed in a xenograft model in vivo upon treatment with AZD0530, an SFK inhibitor. Furthermore, double knockout of FYN and PTPN23 via CRISPR/CAS9 also attenuated tumor outgrowth from PTPN23 knockout Cal51 cells. Overall, this mechanistic analysis of the tumor-suppressive function of PTPN23 in breast cancer supports the identification of FYN as a therapeutic target for breast tumors with heterozygous or homozygous loss of PTPN23.

Immunoexpression of P63 and SOX2 in triple-negative breast cancers, Indonesia

Background: Using immunohistochemical stains to target specific breast cancer markers has become indispensable for evaluation of small diagnostic tissue specimens, and therefore novel marker cocktails for specific breast cancers are required. This study was conducted to assess the immunoexpression of P63 and SOX2 in triple negative breast cancer (TNBC), and to evaluate the predictive diagnostic value of these markers for specific types of TNBC. Methods: Histological slides and paraffin blocks of TNBC cases were collected from Dr. Hasan Sadikin Hospital, Bandung, Indonesia from 5-years period (2011-2015). Each histological slide was subjected to immunohistochemical staining for P63 (nucleus and cytoplasm) and SOX2 (nucleus), with specific primer antibodies. Immunoexpression of P63 and SOX2 was evaluated using immunoreactivity scoring. Associations between P63 and SOX2 immunoexpression and TNBC types were assessed using Mann Whitney tests. In addition, the predictive diagnostic values of these markers were assessed. Results: Forty TNBC histological slides were included, and 23 (57.5%) were Basal-like type TNBC and 17 (42.5%) were Non basal-like type TNBC. Immunoexpression of P63 nucleus and SOX2 was not different between types of TNBC. However, immunoexpression of P63 in the cytoplasm in Basal-like type TNBC was significantly higher than in Non basal-like type TNBC ( p=0.021). Predictor diagnostic value analysis suggested that immunoexpression of P63 in cytoplasm had 56.5% sensitivity and 70.6% specificity for diagnosing Basal-like type TNBC, with area under curve of 0.64.    Conclusions: Immunoexpression of P63 in the cytoplasm has a relatively weak diagnostic value to discriminate Basal-like and Non basal-like types of TNBC.

MELK is not necessary for the proliferation of basal-like breast cancer cells

Thorough preclinical target validation is essential for the success of drug discovery efforts. In this study, we combined chemical and genetic perturbants, including the development of a novel selective maternal embryonic leucine zipper kinase (MELK) inhibitor HTH-01-091, CRISPR/Cas9-mediated MELK knockout, a novel chemical-induced protein degradation strategy, RNA interference and CRISPR interference to validate MELK as a therapeutic target in basal-like breast cancers (BBC). In common culture conditions, we found that small molecule inhibition, genetic deletion, or acute depletion of MELK did not significantly affect cellular growth. This discrepancy to previous findings illuminated selectivity issues of the widely used MELK inhibitor OTSSP167, and potential off-target effects of MELK-targeting short hairpins. The different genetic and chemical tools developed here allow for the identification and validation of any causal roles MELK may play in cancer biology, which will be required to guide future MELK drug discovery efforts. Furthermore, our study provides a general framework for preclinical target validation.

Active smoking and survival following breast cancer among African American and non-African American women in the Carolina Breast Cancer Study

PURPOSE

To examine racial differences in smoking rates at the time of breast cancer diagnosis and subsequent survival among African American and non-African American women in the Carolina Breast Cancer Study (Phases I/II), a large population-based North Carolina study.

METHODS

We interviewed 788 African American and 1,020 Caucasian/non-African American women diagnosed with invasive breast cancer from 1993 to 2000, to assess smoking history. After a median follow-up of 13.56 years, we identified 717 deaths using the National Death Index; 427 were breast cancer-related. We used Cox regression to examine associations between self-reported measures of smoking and breast cancer-specific survival within 5 years and up to 18 years after diagnosis conditional on 5-year survival. We examined race and estrogen receptor status as potential modifiers.

RESULTS

Current (vs never) smoking was not associated with 5-year survival; however, risk of 13 year conditional breast cancer-specific mortality was elevated among women who were current smokers at diagnosis (HR 1.54, 95% CI 1.06-2.25), compared to never smokers. Although smoking rates were similar among African American (22.0%) and non-African American (22.1%) women, risk of breast cancer-specific mortality was elevated among African American (HR 1.69, 95% CI 1.00-2.85), but only weakly elevated among non-African American (HR 1.22, 95% CI 0.70-2.14) current (vs. never) smokers (P Interaction = 0.30). Risk of breast cancer-specific mortality was also elevated among current (vs never) smokers diagnosed with ER- (HR 2.58, 95% CI 1.35-4.93), but not ER+ (HR 1.11, 95% CI 0.69-1.78) tumors (P Interaction = 0.17).

CONCLUSIONS

Smoking may negatively impact long-term survival following breast cancer. Racial differences in long-term survival, as related to smoking, may be driven by ER status, rather than by differences in smoking patterns.

Stabilization of the transcription factors slug and twist by the deubiquitinase dub3 is a key requirement for tumor metastasis

The epithelial-mesenchymal transition (EMT) represents a cellular de-differentiation process that provides cells with the increased plasticity required during embryonic development, tissue remodeling, wound healing and metastasis. Slug and Twist are two key EMT transcription factors (EMT-TFs) that are tightly regulated via ubiquitination and degradation. How Slug and Twist escape degradation and become stabilized in cancer cells remains unclear. One plausible mechanism of Slug and Twist stabilization involves removal of ubiquitin by deubiquitinases (DUBs). In this study, we identified Dub3 as a novel DUB for both Slug and Twist. We further found that Dub3 overexpression increased Slug and Twist protein levels in a dose-dependent manner, whereas Dub3-knockdown decreased their protein levels. Of importance, Dub3 interacted with Slug and Twist and prevented them from degradation, thereby promoting migration, invasion, and cancer stem cell (CSC)-like properties of breast cancer cells. Intriguingly, Dub3 was identified as an early response gene that was upregulated after exposure to inflammatory cytokines such as IL-6, which plays a critical role in the growth and metastasis of breast cancer cells, as well as the maintenance of breast CSCs. We found that Dub3 played an essential role in IL-6 induced EMT through stabilization of Slug and Twist. Our study has uncovered an IL-6-Dub3-Slug/Twist signaling axis during EMT and suggests potential approaches that could target Dub3 to prevent metastatic breast tumor.

Integrated diagnostic network construction reveals a 4-gene panel and 5 cancer hallmarks driving breast cancer heterogeneity

Breast cancer encompasses a group of heterogeneous diseases, each associated with distinct clinical implications. Dozens of molecular biomarkers capable of categorizing tumors into clinically relevant subgroups have been proposed which, though considerably contribute in precision medicine, complicate our understandings toward breast cancer subtyping and its clinical translation. To decipher the networking of markers with diagnostic roles on breast carcinomas, we constructed the diagnostic networks by incorporating 6 publically available gene expression datasets with protein interaction data retrieved from BioGRID on previously identified 1015 genes with breast cancer subtyping roles. The Greedy algorithm and mutual information were used to construct the integrated diagnostic network, resulting in 37 genes enclosing 43 interactions. Four genes, FAM134B, KIF2C, ALCAM, KIF1A, were identified having comparable subtyping efficacies with the initial 1015 genes evaluated by hierarchical clustering and cross validations that deploy support vector machine and k nearest neighbor algorithms. Pathway, Gene Ontology, and proliferation marker enrichment analyses collectively suggest 5 primary cancer hallmarks driving breast cancer differentiation, with those contributing to uncontrolled proliferation being the most prominent. Our results propose a 37-gene integrated diagnostic network implicating 5 cancer hallmarks that drives breast cancer heterogeneity and, in particular, a 4-gene panel with clinical diagnostic translation potential.

Validation of a Novel Diagnostic Kit Using the Semidry Dot-Blot Method to Detect Metastatic Lymph Nodes in Breast Cancer: Distinguishing Macrometastases From Nonmacrometastases

BACKGROUND

The semidry dot-blot method is a diagnostic procedure for detecting lymph node (LN) metastases using the presence of cytokeratin (CK) in lavage fluid from sectioned LNs. We evaluated 2 novel kits that use newly developed anti-CK-19 antibodies to diagnose LN metastases in breast cancer.

PATIENTS AND METHODS

We examined 159 LNs dissected that we sliced at 2-mm intervals and washed with phosphate-buffered saline. The suspended cells in the lavage were centrifuged and lysed to extract protein. This extracted protein was used with a low-power and a high-power kit to diagnose LN metastasis. Diagnoses on the basis of the kits were compared with pathological diagnoses.

RESULTS

Of the 159 LNs, 68 were assessed as positive and 91 as negative in permanent section examination. Sensitivity, specificity, and accuracy of the low-power kit for detecting LN metastases was 83.8%, 100%, and 93.1%, respectively. Those of the high-power kit were 92.6%, 92.3%, and 92.5%, respectively. Combining the low- and high-power kit results, those for distinguishing macrometastases were 94.5%, 95.2%, and 95.0%, respectively. Diagnosis was achieved in approximately 20 minutes, at a cost of less than $30 USD.

CONCLUSION

The kits were accurate, fast, and cost-effective in diagnosing LN metastases without the loss of LN tissue.

Mammography and ultrasound effective features in differentiating basal-like and normal-like subtypes of triple negative breast cancer

The aim of our study was to find effective features of mammography and ultrasound in differentiating Basal-like breast cancer (BBC) and Normal-like breast cancer (NBC), two subtypes of triple negative breast cancer (TNBC). From January 2014 to March 2017, we retrospectively reviewed 91 patients who were pathologically confirmed as TNBC. According to immunohistochemical cytokeratin 5/6 (CK5/6) and Epidermal Growth Factor Receptor (EGFR), TNBCs were classified into BBCs group and NBCs group. Both CK5/6 and EGFR were negative defined to be NBC, whereas if any of CK5/6 or EGFR was positive then defined as BBC. BBCs group concluded 65 (71.4%) cases and NBCs group concluded26 (28.6%) cases. Ultrasound images and mammograms were reevaluated by breast imaging experts according to the breast imaging reporting and data system (BI-RADS) 4th edition. On mammography, masses margins had significant differences between BBCs group and NBCs group (P = 0.024). Most BBCs margins exhibited microlobulated (30/64, 46.9%) or spiculated (25/64, 39.0%), whereas most NBCs margins exhibited microlobulated (17/23, 73.9%). On ultrasound, BBCs were more frequently to present as larger than 20mm lesions (52/65, 80.0%) and more likely to have angular or spiculated margins (35/65, 53.8%), additionally, compared with NBCs, BBCs were less likely to have calcification (1/65, 1.5%). Other mammography and ultrasound features showed no significant differences between the two groups. In conclusion, we have found some effective features of mammography and ultrasound that could be helpful in differentiating BBC and NBC, which will provide some useful references for clinical diagnosis and treatment.

Novel therapeutic strategies in the treatment of triple-negative breast cancer

Triple-negative breast cancer (TNBC) is a heterogeneous subtype of breast cancer that is defined by negative estrogen receptor (ER), progesterone receptor (PR) and human epidermal growth factor receptor 2 (HER2) status. Treating patients with TNBC remains clinically challenging, as patients are not candidates for endocrine or HER2-directed therapy. As a result, chemotherapy with traditional agents such as anthracyclines and taxanes remains the only available option with moderate success. Recent discoveries have revealed that TNBC is a heterogeneous disease at the clinical, histological and molecular levels. The use of biomarkers to identify distinct subsets of TNBC that derive the greatest benefit from presently approved as well as novel therapeutics has become the main focus of current research. The aim of this review is to explore the clinical and biological complexity of TNBC as well as identify novel therapeutic options that target the various molecular subsets of TNBC.

Identification of EGF-NF-κB-FOXC1 signaling axis in basal-like breast cancer

Background

The pathogenesis of human basal-like breast cancer (BLBC) is not well understood and patients with BLBC have a poor prognosis. Expression of the epidermal growth factor receptor (EGFR) and nuclear factor-κB (NF-κB) is well-known to be upregulated in BLBC. The forkhead box C1 (FOXC1) transcription factor, an important prognostic biomarker specific for BLBC, has been shown to be induced by EGF and is critical for EGF effects in breast cancer cells. How FOXC1 is transcriptionally activated in BLBC is not clear.

Methods

Luciferase reporter assays were performed to show that NF-κB-p65 enhances FOXC1 promoter activity in BLBC cells (MDA-MB-468). Electrophoretic mobility shift assay, biotinylated oligonucleotide precipitation assay, and chromatin immunoprecipitation assay were used to show that NF-κB interacts and binds to the promoter region of FOXC1.

Results

In this study, we demonstrate that NF-κB is a pivotal mediator of the EGF/EGFR regulation of FOXC1 expression by binding to the FOXC1 promoter to activate FOXC1 transcription. Loss or inhibition of NF-κB diminished FOXC1 expression.

Conclusion

Collectively, our findings reveal a novel EGFR-NF-κB-FOXC1 signaling axis that is critical for BLBC cell function, supporting the notion that intervention in the FOXC1 pathway may provide potential modalities for BLBC treatment.

Electronic supplementary material

The online version of this article (doi:10.1186/s12964-017-0180-3) contains supplementary material, which is available to authorized users.

SR-B1-targeted nanodelivery of anti-cancer agents: a promising new approach to treat triple-negative breast cancer

Patients with triple-negative breast cancer (TNBC) have a considerably less favorable prognosis than those with hormone-positive breast cancers. TNBC patients do not respond to current endocrine treatment and have a 5-year survival prognosis of <30%. The research presented here is intended to fill a void toward the much needed development of improved treatment strategies for metastatic TNBC. The overall goal of this research was to evaluate the effectiveness of reconstituted high-density lipoprotein (rHDL) nanoparticles (NPs) as delivery agents for anti-TNBC drugs. Using lapatinib and valrubicin as components of the rHDL/drug complexes resulted in a significantly better performance of the NP-transported drugs compared with their free (unencapsulated) counterparts. The enhancement of the therapeutic effect and the protection of normal cells (cardiomyocytes) achieved via the rHDL NPs were likely due to the overexpression of the high-density lipoprotein (HDL) (scavenger receptor class B type 1 [SR-B1]) receptor by the TNBC cells.

Do Histopathological Features and Microcalcification Affect the Elasticity of Breast Cancer?

OBJECTIVES

The aim of this study was to evaluate any association between histological grade, molecular subtypes of breast cancer, and strain elastography, and to investigate whether microcalcification affects the stiffness of tumor in breast cancers with the same histological grade.

METHODS

Between April 2015 and March 2016, 94 lesions of 94 patients with the diagnosis of invasive ductal carcinoma were included in the study. Strain elastography was performed on all patients before biopsy. Histological grades (Grades 1, 2, and 3), molecular subtypes (luminal A, luminal B, Her-2, and basal-like), and strain ratio (SR) were compared. In the same histological grades, patients were divided into two groups according to the presence of microcalcifications, and the groups were compared with each other.

RESULTS

Compared with Grades 1 (20.5) and 2 (23.7), Grade 3 (11.7) showed lower SR values (Grade 3-2, P = .01; Grade 3-1, P = .2). The groups with microcalcification had slightly higher SR in all histological grades, but not of statistical significance. In molecular subtypes, luminal A and B demonstrated higher SR, whereas HER2 and basal-like had lower SR (P > .05 for all group comparisons).

CONCLUSIONS

Grade 3 invasive ductal carcinomas are different from other grades with lower SR values. The presence of microcalcifications and molecular subtypes do not affect elasticity like a high histological grade does.

Role of postmastectomy radiotherapy in early-stage (T1-2N0-1M0) triple-negative breast cancer: a systematic review

Triple-negative breast cancer (TNBC), which represents 15%–20% of all breast cancers, is defined by the absence of estrogen receptor (ER) and progesterone receptor (PR) and overexpression of human epidermal growth factor receptor 2 (HER2). Owing to the absence of specific therapeutic targets and its aggressive biologic characteristics, TNBC patients often experience a high risk of disease progression and poor overall survival. Furthermore, TNBC exhibits an early pattern of recurrence with a peak recurrence risk at 2–3 years after surgery. Currently, chemotherapy continues to be the mainstay in TNBC patients; however, such treatment leaves them associated with a high rate of local and systemic relapses even in early-stage (T1–2N0–1M0). Therefore, in early-stage disease, greater emphasis is placed on locoregional treatments, based on radiation therapy (RT) after surgery, to reduce local and systemic relapses. However, there are no specific treatment guidelines for early-stage (T1–2N0–1M0) TNBC patients. In this review, we discuss the type of surgery received and the relevant adverse clinicopathologic factors and underlying BRCA1 mutation status regarding the influence of tailing postmastectomy radiotherapy (PMRT). In addition, we assess the role of PMRT in early-stage (T1–2N0–1M0) TNBC patients.

Breast cancer detection and tumor characteristics in BRCA1 and BRCA2 mutation carriers

PURPOSE

To describe imaging findings, detection rates, and tumor characteristics of breast cancers in a large series of patients with BRCA1 and BRCA2 mutations to potentially streamline screening strategies.

METHODS

An IRB-approved, HIPAA-compliant retrospective analysis of 496 BRCA mutation carriers diagnosed with breast carcinoma from 1999 to 2013 was performed. Institutional database and electronic medical records were reviewed for mammography and MRI imaging. Patient and tumor characteristics including age at diagnosis, tumor histology, grade, receptor, and nodal status were recorded.

RESULTS

Tumors in BRCA1 mutation carriers were associated exhibited significantly higher nuclear and histological grade compared to BRCA2 (p < 0.001). Triple-negative tumors were more frequent in BRCA1 mutation carriers, whereas hormone receptor-positive tumors were more frequent in BRCA2 mutation carriers (p < 0.001). BRCA2 mutation carriers more frequently presented with ductal carcinoma in situ (DCIS) alone 14% (35/246) and cancers more frequently exhibiting calcifications (p < 0.001). Mammography detected fewer cancers in BRCA1 mutation carriers compared to BRCA2 (p = 0.04): 81% (186/231) BRCA1 versus 89% (212/237) BRCA2. MRI detected 99% cancers in each group. Mammography detected cancer in two patients with false-negative MRI (1 invasive cancer, 1 DCIS). Detection rates on both mammography and MRI did not significantly differ for women over 40 years and women below 40 years.

CONCLUSIONS

Breast cancers in BRCA1 mutation carriers are associated with more aggressive tumor characteristics compared to BRCA2 and are less well seen on mammography. Mammography rarely identified cancers not visible on MRI. Thus, the omission of mammography in BRCA1 mutation carriers screened with MRI can be considered.

CRISPR/Cas9 mutagenesis invalidates a putative cancer dependency targeted in on-going clinical trials

The Maternal Embryonic Leucine Zipper Kinase (MELK) has been reported to be a genetic dependency in several cancer types. MELK RNAi and small-molecule inhibitors of MELK block the proliferation of various cancer cell lines, and MELK knockdown has been described as particularly effective against the highly-aggressive basal/triple-negative subtype of breast cancer. Based on these preclinical results, the MELK inhibitor OTS167 is currently being tested as a novel chemotherapy agent in several clinical trials. Here, we report that mutagenizing MELK with CRISPR/Cas9 has no effect on the fitness of basal breast cancer cell lines or cell lines from six other cancer types. Cells that harbor null mutations in MELK exhibit wild-type doubling times, cytokinesis, and anchorage-independent growth. Furthermore, MELK-knockout lines remain sensitive to OTS167, suggesting that this drug blocks cell division through an off-target mechanism. In total, our results undermine the rationale for a series of current clinical trials and provide an experimental approach for the use of CRISPR/Cas9 in preclinical target validation that can be broadly applied.

DOI:http://dx.doi.org/10.7554/eLife.24179.001

Like a person who is dependent on coffee to be productive, cancer cells are dependent on the products of certain genes in order to dominate their environment and grow. Cancer cells will stop growing and die when the activity of these gene products is blocked. These genes are known as cancer dependencies or “addictions”. As a result, researchers are constantly looking for cancer dependencies and developing drugs to block their activity.

It was previously believed that a gene called MELK was an addiction in certain types of breast cancer. In fact, pharmaceutical companies had developed a drug to block the activity of MELK, and this drug is currently being tested in human patients. However, Lin, Giuliano et al. have now taken a second look at the role of MELK in breast cancer, and have come to a different conclusion.

Using a gene editing technology called CRISPR/Cas9, Lin, Giuliano et al. removed MELK activity from several cancer cell lines. This did not stop cancer cells from multiplying, suggesting that MELK is not actually a cancer addiction.

Additionally, when breast cancer cells that do not produce MELK were exposed to the drug that is supposed to block MELK activity, the drug still stopped cell growth. Since the drug works when MELK is not present in the cell, the drug must be binding to other proteins. This suggests that MELK is not the actual target of the drug.

Lin, Giuliano et al. suggest that, in the future, CRISPR/Cas9 technology could be used to better identify cancer dependencies and drug targets before cancer drugs are given to human patients.

DOI:http://dx.doi.org/10.7554/eLife.24179.002

FOXC1: an emerging marker and therapeutic target for cancer

The Forkhead box C1 (FOXC1) transcription factor is involved in normal embryonic development and regulates the development and function of many organs. Most recently, a large body of literature has shown that FOXC1 plays a critical role in tumor development and metastasis. Clinical studies have demonstrated that elevated FOXC1 expression is associated with poor prognosis in many cancer subtypes, such as basal-like breast cancer (BLBC). FOXC1 is highly and specifically expressed in BLBC as opposed to other breast cancer subtypes. Its functions in breast cancer have been extensively explored. This review will summarize current knowledge on the function and regulation of FOXC1 in tumor development and progression with a focus on BLBC as well as the implications of these new findings in cancer diagnosis and treatment.

AKR1B1 promotes basal-like breast cancer progression by a positive feedback loop that activates the EMT program

The treatment of BLBC represents an unmet medical need. Wu et al. show that AKR1B1 facilitates BLBC progression through a positive feedback loop that activates the EMT program, suggesting that inhibition of AKR1B1 has the potential to become a valuable therapeutic strategy for BLBC.

Basal-like breast cancer (BLBC) is associated with high-grade, distant metastasis and poor prognosis. Elucidating the determinants of aggressiveness in BLBC may facilitate the development of novel interventions for this challenging disease. In this study, we show that aldo-keto reductase 1 member B1 (AKR1B1) overexpression highly correlates with BLBC and predicts poor prognosis in breast cancer patients. Mechanistically, Twist2 transcriptionally induces AKR1B1 expression, leading to nuclear factor κB (NF-κB) activation. In turn, NF-κB up-regulates Twist2 expression, thereby fulfilling a positive feedback loop that activates the epithelial–mesenchymal transition program and enhances cancer stem cell (CSC)–like properties in BLBC. AKR1B1 expression promotes, whereas AKR1B1 knockdown inhibits, tumorigenicity and metastasis. Importantly, epalrestat, an AKR1B1 inhibitor that has been approved for the treatment of diabetic complications, significantly suppresses CSC properties, tumorigenicity, and metastasis of BLBC cells. Together, our study identifies AKR1B1 as a key modulator of tumor aggressiveness and suggests that pharmacologic inhibition of AKR1B1 has the potential to become a valuable therapeutic strategy for BLBC.

Quercetin induces apoptosis and cell cycle arrest in triple-negative breast cancer cells through modulation of Foxo3a activity

Quercetin, a plant-derived flavonoid found in fruits, vegetables and tea, has been known to possess bioactive properties such as anti-oxidant, anti-inflammatory and anti-cancer. In this study, anti-cancer effect of quercetin and its underlying mechanisms in triple-negative breast cancer cells was investigated. MTT assay showed that quercetin reduced breast cancer cell viability in a time and dose dependent manner. For this, quercetin not only increased cell apoptosis but also inhibited cell cycle progression. Moreover, quercetin increased FasL mRNA expression and p51, p21 and GADD45 signaling activities. We also observed that quercetin induced protein level, transcriptional activity and nuclear translocation of Foxo3a. Knockdown of Foxo3a caused significant reduction in the effect of quercetin on cell apoptosis and cell cycle arrest. In addition, treatment of JNK inhibitor (SP 600125) abolished quercetin-stimulated Foxo3a activity, suggesting JNK as a possible upstream signaling in regulation of Foxo3a activity. Knockdown of Foxo3a and inhibition of JNK activity reduced the signaling activities of p53, p21 and GADD45, triggered by quercetin. Taken together, our study suggests that quercetin induces apoptosis and cell cycle arrest via modification of Foxo3a signaling in triple-negative breast cancer cells.

Prognostic impact of EGFR and cytokeratin 5/6 immunohistochemical expression in triple-negative breast cancer

Triple-negative breast cancer (TNBC) has an aggressive behavior and limited therapeutic options due to lack of targeted therapy. We aimed in this study to assess the immunohistochemical expression of EGFR and cytokeratin 5/6 and their ability to predict survival and response to neoadjuvant chemotherapy (NAC) among triple-negative breast cancer patients. Thirty-five cases with TNBC were studied by immunohistochemistry for EGFR and CK5/6 expression. Data on overall survival (OS), disease-free survival (DFS) and response to NAC were collected. The resulted data were statistically analyzed. Invasive carcinoma of no special type (NST) was the predominant histopathological type (80%). The commonest histological grade was grade II-III (88.6%). About 57.1% of TNBC cases were CK5/6-positive, and 71.4% were EGFR-positive. EGFR expression showed a significant association with tumor grade and axillary lymph node metastasis (p=0.006, 0.016 respectively). EGFR expression was related to unfavorable response to NAC (p=0.036), poor OS (p=0.002) and poor DFS (p=0.003). CK5/6 expression showed a significant association with tumor grade, unfavorable response to NAC, poor OS & DFS (p=0.007, 0.048, <0.001, 0.043 respectively). Immunohistochemical expression of EGFR and/or CK5/6 showed a high significant association with an unfavorable response to NAC, poor DFS &OS (p=0.010, 0.012, 0.030 respectively).

CONCLUSIONS

EGFR and CK5/6 are adverse prognostic markers in TNBC. EGFR and CK5/6 expression could serve as biomarkers for identifying TNBC patients with poor survival that are unlikely to benefit from neoadjuvant chemotherapy. So, targeted therapy against EGFR may be a hopeful therapy for TNBC with NAC resistance.

Integrative Comparison of mRNA Expression Patterns in Breast Cancers from Caucasian and Asian Americans with Implications for Precision Medicine

Asian Americans (AS) have significantly lower incidence and mortality rates of breast cancer than Caucasian Americans (CA). Although this racial disparity has been documented, the underlying pathogenetic factors explaining it are obscure. We addressed this issue by an integrative genomics approach to compare mRNA expression between AS and CA cases of breast cancer. RNA-seq data from the Cancer Genome Atlas showed that mRNA expression revealed significant differences at gene and pathway levels. Increased susceptibility and severity in CA patients were likely the result of synergistic environmental and genetic risk factors, with arachidonic acid metabolism and PPAR signaling pathways implicated in linking environmental and genetic factors. An analysis that also added eQTL data from the Genotype-Tissue Expression Project and SNP data from the 1,000 Genomes Project identified several SNPs associated with differentially expressed genes. Overall, the associations we identified may enable a more focused study of genotypic differences that may help explain the disparity in breast cancer incidence and mortality rates in CA and AS populations and inform precision medicine. Cancer Res; 77(2); 423-33. ©2016 AACR.

Splicing imbalances in basal-like breast cancer underpin perturbation of cell surface and oncogenic pathways and are associated with patients' survival

Despite advancements in the use of transcriptional information to understand and classify breast cancers, the contribution of splicing to the establishment and progression of these tumours has only recently starting to emerge. Our work explores this lesser known landscape, with special focus on the basal-like breast cancer subtype where limited therapeutic opportunities and no prognostic biomarkers are currently available. Using ExonArray analysis of 176 breast cancers and 9 normal breast tissues we demonstrate that splicing levels significantly contribute to the diversity of breast cancer molecular subtypes and explain much of the differences compared with normal tissues. We identified pathways specifically affected by splicing imbalances whose perturbation would be hidden from a conventional gene-centric analysis of gene expression. We found that a large fraction of them involve cell-to-cell communication, extracellular matrix and transport, as well as oncogenic and immune-related pathways transduced by plasma membrane receptors. We identified 247 genes in which splicing imbalances are associated with clinical patients’ outcome, whilst no association was detectable at the gene expression level. These include the signaling gene TGFBR1, the proto-oncogene MYB as well as many immune-related genes such as CCR7 and FCRL3, reinforcing evidence for a role of immune components in influencing breast cancer patients’ prognosis.

Triple-negative breast cancer: is there a treatment on the horizon?

Triple-negative breast cancer (TNBC), which accounts for 15-20% of all breast cancers, does not express estrogen receptor (ER) or progesterone receptor (PR) and lacks human epidermal growth factor receptor 2 (HER2) overexpression or amplification. These tumors have a more aggressive phenotype and a poorer prognosis due to the high propensity for metastatic progression and absence of specific targeted treatments. Patients with TNBC do not benefit from hormonal or trastuzumab-based targeted therapies because of the loss of target receptors. Although these patients respond to chemotherapeutic agents such as taxanes and anthracyclines better than other subtypes of breast cancer, prognosis remains poor. A group of targeted therapies under investigation showed favorable results in TNBC, especially in cancers with BRCA mutation. The lipid-lowering statins (3-hydroxy-3-methyl-glutaryl coenzyme A reductase inhibitors), including lovastatin and simvastatin, have been shown to preferentially target TNBC compared with non-TNBC. These statins hold great promise for the management of TNBC. Only with the understanding of the molecular basis for the preference of statins for TNBC and more investigations in clinical trials can they be reformulated into a clinically approved drug against TNBC.

Triple Negative Breast Cancer at the University Hospital Mohammed VI – Oujda

Introduction: The triple-negative breast cancer (TNBC), defined by the absence of receptors to oestrogen and progesterone and no histochemical expression of human epidermal receptor -2, is associated with a particularly aggressive behavior. The aim of our study was to determine the clinico-pathological, therapeutic and prognostic features associated with this type of breast cancer in Morocco. Methods: A cohort retrospective study, spread over 3 years, was conducted of 116 breast cancer patients, diagnosed between January 2009 and December 2011 at the Regional Center of Oncology. Epidemiological, clinical, histological and therapeutic data were analyzed. Survival curves at 3 years were estimated by Kaplan-Meier analysis with use of the log-rank test. Results: The proportion of triple-negative breast cancer in our series was 13.2%. The average age was 46.5 years and 20,7% had a previous history of familial breast cancer. Some 56,9% of tumors were greater than 3 cm in diameter. infiltrating ductal carcinoma being the histological type in the majority of cases (75.9%). TNBC was most often associated with a high grade, grade III accounting for 50.9%. Vascular invasion was found in 58.6% of cases. Regarding lymph node involvement, 42.2% had positive lymph nodes and 15.5% featured distant metastases. Neoadjuvant chemotherapy was administrated to 20% of patients with a 23.5% complete pathologic response. The rates for overall survival and disease-free-survival at 3 years for localized stages were 70 and 55.6%, respectively. With metastatic lesions, the figures were 27.5% and 10.3% respectively. Conclusion: The TNBC is correlated with a poor prognosis with a high mortality and early relapse requiring identification of new target therapies and markers for prediction of tumoral response to various treatments.

Aberrant DNA Double-strand Break Repair Threads in Breast Carcinoma: Orchestrating Genomic Insult Survival

Breast carcinoma is a heterogeneous disease that has exhibited rapid resistance to treatment in the last decade. Depending genotype and phenotype of breast cancer, there are discernible differences in DNA repair protein responses including DNA double strand break repair. It is a fact that different molecular sub-types of breast carcinoma activate these dedicated protein pathways in a distinct manner. The DNA double-strand damage repair machinery is manipulated by breast carcinoma to selectively repair the damage or insults inflicted by the genotoxic effects of chemotherapy or radiation therapy. The two DNA double-strand break repair pathways employed by breast carcinoma are homologous recombination and non-homologous end joining. In recent decades, therapeutic interventions targeting one or more factors involved in repairing DNA double-strand breaks inflicted by chemo/radiation therapy have been widely studied. Herein, this review paper summarizes the recent evidence and ongoing clinical trials citing potential therapeutic combinatorial interventions targeting DNA double-strand break repair pathways in breast carcinoma.

Both bulk and cancer stem cell subpopulations in triple-negative breast cancer are susceptible to Wnt, HDAC, and ERα coinhibition

Development of targeted therapies for triple-negative breast cancer (TNBC, a more aggressive subtype) is an unmet medical need. We analyzed data from 887 patients with invasive breast cancer and observed that increased Wnt and histone deacetylase (HDAC) activities are associated with estrogen receptor 1 (ESR1) and progesterone receptor (PGR) repression, poor survival, and increased relapse. The inverse correlation between Wnt signaling and repression of ESR1 and PGR expression was found to be magnified in cancer stem cell (CSC) subpopulations in TNBC cell lines. Cosuppression of Wnt, HDAC, and ESR1 using clinically relevant low-dose inhibitors effectively repressed both bulk and CSC subpopulations and converted CSCs to non-CSCs in TNBC cells without affecting MCF-10A mammary epithelial cells.

Mps1/TTK: a novel target and biomarker for cancer

Monopolar spindle1 (Mps1, also known as TTK) is the core component of the spindle assembly checkpoint, which functions to ensure proper distribution of chromosomes to daughter cells. Mps1 is hardly detectable in normal organs except the testis and placenta. However, high levels of Mps1 are found in many types of human malignancies, including glioblastoma, thyroid carcinoma, breast cancer, and other cancers. Several Mps1 inhibitors can inhibit the proliferation of cancer cells and exhibit demonstrable survival benefits. Mps1 can be utilized as a new immunogenic epitope, which is able to induce potent cytotoxic T lymphocyte activity against cancer cells while sparing normal cells. Some clinical trials have validated its safety, immunogenicity and clinical response. Thus, Mps1 may be a novel target for cancer therapy. Mps1 is differentially expressed between normal and malignant tissues, indicating its potential as a molecular biomarker for diagnosis. Meanwhile, the discovery that it clearly correlates with recurrence and survival time suggests it may serve as an independent prognostic biomarker as well.

HMMR antisense RNA 1, a novel long noncoding RNA, regulates the progression of basal-like breast cancer cells

Recently, accumulating evidence has suggested that long noncoding RNAs (lncRNAs) play crucial roles in carcinogenesis and cancer progression. Hyaluronan-mediated motility receptor (HMMR) is an essential cancer-related gene in basal-like breast cancer (BLBC). In our study, HMMR antisense RNA 1 (HMMR-AS1) was analyzed in BLBC patients through polymerase chain reaction analysis. Here, we found that the expression of HMMR was positively correlated with HMMR-AS1 (RP11-80G.1). When HMMR-AS1 (RP11-80G.1) was knocked down, the expression of HMMR markedly reduced. Furthermore, in MDA-MB-231 and MDA-MB-468 breast cancer cells, the proliferation and migration abilities were remarkably suppressed via knocking down HMMR-AS1 (RP11-80G.1) in vitro. The results showed that lncRNA HMMR-AS1 (RP11-80G.1) influenced the progression of BLBCs through regulating HMMR, suggesting that HMMR-AS1 (RP11-80G.1) could be regarded as a novel biomarker and therapeutic target in the treatment of BLBCs in future.

A phase II study of capecitabine plus cisplatin in metastatic triple-negative breast cancer patients pretreated with anthracyclines and taxanes

BACKGROUND

Cisplatin is an effective agent for triple-negative breast cancer (TNBC) and synergistic activity between cisplatin and capecitabine has been demonstrated by in vitro and in vivo studies. This study was designed as a prospective clinical trial to evaluate the efficacy and safety of capecitabine plus cisplatin (XP) regimen in metastatic TNBC patients pretreated with anthracyclines and taxanes.

PATIENTS AND METHODS

Thirty-three patients with metastatic TNBC who had anthracyclines and taxanes as prior therapy were treated with capecitabine 2000 mg/m(2) orally on day 1 through 14 plus cisplatin 75 mg/m(2) intravenously on day 1 of a 21-day cycle, followed by capecitabine maintenance medications after a maximum of 6 cycles. The primary end point was objective response rate (ORR) and the secondary end points included progression-free survival (PFS), overall survival (OS) and toxicity profiles.

RESULTS

A total of 162 cycles was given. ORR was 63.6%. Median PFS was 8.2 (95%CI: 4.8-11.6) months in the entire population and 10.8 (95%CI: 6.5-15.1) months in responding patients. Median OS was 17.8 (95%CI: 14.4-21.2) months in all enrolled patients and 25.8 (95%CI: 14.6-37.0) months in responding patients. Most adverse events were mild and manageable, with neutropenia and nausea/vomiting as the most common toxicities. Grade 3/4 toxicities included leukopenia (10, 30.3%), neutropenia (10, 30.3%), anemia (2, 6.1%), thrombocytopenia (1, 3.0%), nausea/vomiting (3, 9.1%), hand-foot syndrome (HFS; 1, 3.0%), and sensory neuropathy (1, 3.0%).

CONCLUSIONS

Capecitabine plus cisplatin demonstrated an excellent activity and an acceptable safety profile in metastatic TNBC patients pretreated with anthracyclines and taxanes.

[Breast cancer in Morocco: phenotypic profile of tumors]

Le cancer du sein est le plus fréquent chez la femme et figure parmi les principales causes de mortalité liées au cancer. La curabilité de ce type tumoral est en augmentation, grâce aux programmes de dépistage et aux progrès thérapeutiques, qui ont certes augmenté la survie des patients. Mais des défis restent à relever en rapport avec l’instabilité phénotypique des cellules cancéreuses. L’objectif de ce travail est d’étudier le profil phénotypique du cancer du sein chez les patients pris en charge au Centre Mohammed VI pour le traitement des Cancers, durant les années 2013-2014. Il s’agit d’une étude transversale sur deux années, incluant les cas du cancer du sein pris en charge au Centre. Le recueil des données était fait à partir des dossiers des patients et analysés par le logiciel Epi Info. 1277 patients ont été pris en charge au sein de notre centre. 99,5% des cas de sexe féminin, l’âge moyen était 50,20 ± 11,34 ans. Le type histologique le plus fréquent était le carcinome canalaire infiltrant (80,7% des cas). Le stade diagnostic était précoce (56,9%). Le phénotype moléculaire le plus fréquent était le luminal A (41,4% des cas). Le luminal B, le HER2 et les triples négatifs étaient dans respectivement 10,4%, 6,3%, 11,2% des cas. L’étude du phénotype tumoral des patients atteints du cancer du sein permet l’orientation du clinicien dans le choix du traitement, et des décideurs dans la planification de programmes de lutte contre cette pathologie.

"Triple negative breast cancer": Translational research and the (re)assembling of diseases in post-genomic medicine

The paper examines the debate about the nature and status of "Triple-negative breast cancer", a controversial biomedical entity whose existence illustrates a number of features of post-genomic translational research. The emergence of TNBC is intimately linked to the rise of molecular oncology, and, more generally, to the changing configuration of the life sciences at the turn of the new century. An unprecedented degree of integration of biological and clinical practices has led to the proliferation of bio-clinical entities emerging from translational research. These translations take place between platforms rather than between clinical and laboratory settings. The complexity and heterogeneity of TNBC, its epistemic and technical, biological and clinical dualities, result from its multiple instantiations via different platforms, and from the uneven distribution of biological materials, techniques, and objects across clinical research settings. The fact that TNBC comes in multiple forms, some of which seem to be incompatible or, at least, only partially overlapping, appears to be less a threat to the whole endeavor, than an aspect of an ongoing translational research project. Discussions of translational research that rest on a distinction between basic research and its applications fail to capture the dynamics of this new domain of activity, insofar as application is built-in from the very beginning in the bio-clinical entities that emerge from the translational research domain.

Identifying gene regulatory network rewiring using latent differential graphical models

Gene regulatory networks (GRNs) are highly dynamic among different tissue types. Identifying tissue-specific gene regulation is critically important to understand gene function in a particular cellular context. Graphical models have been used to estimate GRN from gene expression data to distinguish direct interactions from indirect associations. However, most existing methods estimate GRN for a specific cell/tissue type or in a tissue-naive way, or do not specifically focus on network rewiring between different tissues. Here, we describe a new method called Latent Differential Graphical Model (LDGM). The motivation of our method is to estimate the differential network between two tissue types directly without inferring the network for individual tissues, which has the advantage of utilizing much smaller sample size to achieve reliable differential network estimation. Our simulation results demonstrated that LDGM consistently outperforms other Gaussian graphical model based methods. We further evaluated LDGM by applying to the brain and blood gene expression data from the GTEx consortium. We also applied LDGM to identify network rewiring between cancer subtypes using the TCGA breast cancer samples. Our results suggest that LDGM is an effective method to infer differential network using high-throughput gene expression data to identify GRN dynamics among different cellular conditions.

SIAH and EGFR, Two RAS Pathway Biomarkers, are Highly Prognostic in Locally Advanced and Metastatic Breast Cancer

BACKGROUND

Metastatic breast cancer exhibits diverse and rapidly evolving intra- and inter-tumor heterogeneity. Patients with similar clinical presentations often display distinct tumor responses to standard of care (SOC) therapies. Genome landscape studies indicate that EGFR/HER2/RAS "pathway" activation is highly prevalent in malignant breast cancers. The identification of therapy-responsive and prognostic biomarkers is paramount important to stratify patients and guide therapies in clinical oncology and personalized medicine.

METHODS

In this study, we analyzed matched pairs of tumor specimens collected from 182 patients who received neoadjuvant systemic therapies (NST). Statistical analyses were conducted to determine whether EGFR/HER2/RAS pathway biomarkers and clinicopathological predictors, alone and in combination, are prognostic in breast cancer.

FINDINGS

SIAH and EGFR outperform ER, PR, HER2 and Ki67 as two logical, sensitive and prognostic biomarkers in metastatic breast cancer. We found that increased SIAH and EGFR expression correlated with advanced pathological stage and aggressive molecular subtypes. Both SIAH expression post-NST and NST-induced changes in EGFR expression in invasive mammary tumors are associated with tumor regression and increased survival, whereas ER, PR, and HER2 were not. These results suggest that SIAH and EGFR are two prognostic biomarkers in breast cancer with lymph node metastases.

INTERPRETATION

The discovery of incorporating tumor heterogeneity-independent and growth-sensitive RAS pathway biomarkers, SIAH and EGFR, whose altered expression can be used to estimate therapeutic efficacy, detect emergence of resistant clones, forecast tumor regression, differentiate among partial responders, and predict patient survival in the neoadjuvant setting, has a clear clinical implication in personalizing breast cancer therapy.

FUNDING

This work was supported by the Dorothy G. Hoefer Foundation for Breast Cancer Research (A.H. Tang); Center for Innovative Technology (CIT)-Commonwealth Research Commercialization Fund (CRCF) (MF14S-009-LS to A.H. Tang), and National Cancer Institute (CA140550 to A.H. Tang).