Markers In Triple-negative Breast Cancer Research Articles

Role of CD44 as cancer stem cell marker in triple-negative breast cancer and its association with histological grade and angiogenesis

Cancer stem cells (CSC) within the tumors play a central role in tumorigenesis. It is, thus, of utmost importance to identify these cells to develop effective cancer therapy. Triple-Negative Breast Cancer (TNBC) is an aggressive molecular subtype of breast cancer associated with poor patient outcomes. The role of CD44 immunohistochemistry (IHC) as a putative CSC in breast carcinomas, particularly of the TNBC-subtype is ambiguous, with equivocal results. The present study aims to assess the role of CSC in breast carcinoma by immunohistochemical analysis of CD44 expression in TNBC. The association of TNBC expressing CSC with histological grade as well as with angiogenesis (using CD34 IHC) has been studied. Biopsy samples from 58 patients with infiltrating ductal carcinoma, NST were studied. The histology of the tumor was sub-classified into grades 1-3. Based on immunohistochemical analysis (ER, PR, HER2/Neu), the cases were divided into TNBC and NTNBC groups. The tissue sections were also subjected to analysis for CD44 to identify the CSC-phenotype and CD34 to evaluate angiogenesis, to determine the microvascular density (MVD). Out of the 58 cases in the study, 28 were TNBC and 30 were NTNBC. CSC phenotype (CD44 positive) was expressed significantly higher in the TNBC (78%) versus the NTNBC (53%) (p-value 0.043). The MVD estimated using CD34 IHC was lower in the TNBC group in our study, though the difference was not statistically significant. A larger proportion of cases in TNBC showed a higher histological grade (35%) in comparison to NTNBC (27%). However, statistically, it was not significant. Our study demonstrated that CD44 as a CSC marker is seen significantly more in the TNBC category of invasive ductal carcinomas. Further large-scale studies, to confirm these findings, will be of potential therapeutic and prognostic value.

Expression of neuroendocrine markers predicts increased survival in triple-negative breast cancer patients.

The significance of neuroendocrine (NE) markers in triple-negative breast cancer (TNBC) patients has not been investigated. This study aims to clarify the incidence and prognostic significance of NE marker expression in TNBC, determine its association with other clinicopathological parameters, and further explore the pathological features and potential treatment options for TNBC patients expressing NE markers. Clinicopathological data were collected from 396 TNBC patients undergoing radical breast cancer surgery at Peking Union Medical College Hospital from January 2002 to December 2014, with a final follow-up in July 2019. Immunohistochemistry (IHC) staining was performed for NE markers including chromogranin A (CgA) and synaptophysin (Syn). For TNBC patients with positive NE marker expression, IHC staining was then performed for alpha-thalassemia/mental retardation X-linked (ATRX), O(6)-methylguanine-methyltransferase (MGMT), somatostatin receptor 2 (SSTR2), and programmed death receptor-ligand 1 (PD-L1). The chi-square or Fisher exact test was used to evaluate the correlations between NE marker expression and other parameters. Survival curves were plotted using the Kaplan-Meier (K-M) method to assess the prognostic significance of NE markers in TNBC. NE marker-positive staining was observed in 7.6% (30/396) of all TNBC cases. Only 0.5% (2/396) cases had ≥ 90% neoplastic cells expressing NE markers. Positive NE marker expression was associated with negative basal-like marker expression. K-M survival analysis showed that the NE marker-positive TNBC patients had higher disease-free survival (DFS) rates than the NE marker-negative patients at the same stage. Among the 30 NE marker-positive TNBC cases, 13.3% and 26.7% showed negative IHC staining for ATRX and MGMT, respectively, while 13.3% had a 3+ score for SSTR2 IHC staining. For PD-L1 IHC staining, 13.3% of the 30 TNBC cases were higher than 10 scores in Combined Positive Score (CPS), and 10.0% were higher than 10% in Tumor Cell Proportion Score (TPS). There was a small proportion of TNBC patients expressing NE markers. TNBC patients with positive NE marker expression had a better prognosis than the negative group at the same stage. TNBC cases with positive NE marker expression may potentially benefit from immunotherapy or somatostatin analogue treatment.

Evaluation of CDC6 Expression in Triple-Negative Breast Cancer and its Prognostic Significance

ABSTRACT Background: Triple-negative breast cancer (TNBC) leads to high morbidity and poor prognosis due to high proliferation and metastasis. Cell division cycle 6 (CDC6) is one of the genes involved in cell division and is significantly upregulated in TNBC. There is not much information available to understand whether CDC6 can be used as a prognostic marker in TNBC. Methods: In this study, BC-GenExMiner, NetworkAnalyst, GeneMania, GEPIA, COSMIC, cBioPortal, STRING, and FunRich were used to investigate the expression of CDC6 gene. Furthermore, survival analysis to correlate the gene expression was carried out using the Kaplan-Meier plotter. Results: The results showed that mRNA levels of CDC6 were significantly higher in TNBC compared to healthy and other types of breast cancer, and high expression levels were also associated with increased TNBC proliferation. The survival analysis showed that increased mRNA levels of CDC6 in all TNBC patients were associated with a poor prognosis for relapse-free survival. Conclusion: The findings of the current study indicate that CDC6 may be used as a possible prognostic biomarker for TNBC. However, further studies are required to check the effects of CDC6 on the progression and pathogenesis of TNBC.

Abstract C036: Correlation of Kaiso and androgen receptor expression in women of African ancestry with triple-negative breast cancer

Abstract Breast cancer (BCa) is the most frequently diagnosed female cancer and a leading cause of female deaths worldwide, regardless of increased awareness and improved therapies. Triple-negative breast cancer (TNBC) is one of the most challenging BCa subtypes as it is highly heterogeneous, metastatic in nature and has limited targeted therapies. TNBC is most prevalent in young women of African ancestry (WAA), who despite having lower BCa rates, have a disproportionately higher mortality rate compared to women of European ancestry (WEA). However, the cause for this racial disparity is currently unknown, thus highlighting the importance of unraveling the genetic and molecular factors that contribute to TNBC in WAA. Our lab previously showed that the transcription factor Kaiso may be linked to this disparity as it contributes to increased metastasis and mortality in WAA TNBC patients. Interestingly, multiple studies have indicated that WAA TNBC tissues also express less Androgen Receptor (AR) than WEA TNBC tissues, supporting the existence of a novel BCa subtype – quadruple-negative breast cancer (QNBC). Notably, in silico analysis revealed several Kaiso binding sites in the AR promoter region, and that high Kaiso and low AR expression correlated with poorer overall survival in BCa patients. Thus, we hypothesized that high Kaiso and low AR expression could be contributing to the increased mortality in WAA with TNBC. This study seeks to examine the relationship between Kaiso and AR, the clinical significance of this relationship and its role, if any, in TNBC racial disparities. Using tissue microarrays (TMAs) and immunohistochemistry (IHC), we found reduced and cytoplasmic AR expression in WAA compared to WEA. Moreover, preliminary findings from western blot analyses showed an increase in AR expression in response to Kaiso depletion in TNBC cells. These findings suggest that AR could be a bona fide Kaiso target gene and that there may be clinical relevance of high Kaiso, and low AR expression in BCa survival, especially in patients with an African heritage. Ongoing experiments are focused on determining if Kaiso directly associates with the endogenous AR promoter region and discerning the link between high Kaiso and low AR expression in TNBC racial disparities. A significant correlation between Kaiso and AR expression will help to validate the existence of QNBC in WAA and support Kaiso and AR as clinically relevant prognostic markers for TNBC, especially in WAA. Citation Format: Stephanie Ali Fairbairn, Robert Cowan, Juliet M. Daniel, Shawn M. Hercules. Correlation of Kaiso and androgen receptor expression in women of African ancestry with triple-negative breast cancer [abstract]. In: Proceedings of the 15th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2022 Sep 16-19; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2022;31(1 Suppl):Abstract nr C036.

Clinical Utility of Predictive Markers in Triple Negative Breast Cancer

Background & Objective: Triple negative breast cancer (TNBC) is an aggressive disease and visceral metastasis occurs due to unavailability of targeted therapy. This study was undertaken to evaluate incidence of predictive markers in TNBC which further guide to select adjuvant treatment. Method: This study evaluated androgen receptor (AR), PI3K, mTOR, c-myc and TLE3 expression by immunohistochemistry on tumor tissues of 50 untreated TNBC. The protein expression of markers was correlated with clinicopathological parameters and disease status. The data was analysed statistically using SPSS software version 20. Results: The incidence of expression of AR (18%) and TLE3 (22%) was found lower and c-myc (88%), PI3K (74%) and mTOR (86%) was found higher in TNBC. 82% were quadruple negative breast cancer. PI3K expression was seen higher in post-menopausal patients and mTOR expression was significantly higher in smaller tumor size and high BR score tumors with a trend in younger patients. Overexpression of c-myc was associated with post-menopausal status, early stage disease and high BR score tumors. These markers when intercorrelated, a significant positive correlation was noted of PI3K with mTOR, and mTOR with c-myc. Further, c-myc emerged as significant prognosticator predicting higher relapse rate in quadruple negative breast cancer, and death rate in total patients and quadruple negative breast cancer in multivariate analyses. Interpretation & Conclusion: Identification of potentially actionable targets is essential to plan adjuvant therapy for better patient management of TNBC. Keywords: predictive markers, c-myc, PI3K, mTOR, TNBC

HDAC7 inhibits cell proliferation via NudCD1/GGH axis in triple-negative breast cancer.

Triple-negative breast cancer (TNBC) is the most malignant subtype of breast cancer. In the absence of effective molecular markers for TNBC, there is an urgent clinical need for promising therapeutic target for TNBC. Histone deacetylases (HDACs), key regulators for chromatin remodeling and gene expression, have been suggested to play critical roles in cancer development. However, little is known ~the functions and implications of HDACs in TNBC treatment in the future. By analyzing the expression and prognostic significance of HDAC family members in TNBC through TCGA and METABRIC databases, HDAC7 was found to be downregulated in TNBC samples and the survival of patients with lower expression of HDAC7 was shorter. Furthermore, HDAC7 was negatively associated with NudC domain containing 1 (NudCD1) and γ-glutamyl hydrolase (GGH). Loss of NudCD1 or GGH predicted improved overall survival time (OS) of patients with TNBC. In vitro experiments showed that silencing of HDAC7 enhanced TNBC cell proliferation, while overexpression HDAC7 inhibited TNBC cell proliferation. The results of functional experiments confirmed that HDAC7 negatively modulated GGH and NudCD1 expression. Furthermore, decrease of NudCD1 or GGH inhibited cell proliferation. Notably, the HDAC7-NudCD1/GGH axis was found to be associated with NK cell infiltration. Overall, the present study revealed a novel role of HDAC7-NudCD1/GGH axis in TNBC, which might provide a promising treatment strategy for patients with TNBC.

Intercellular Communication Reveals Therapeutic Potential of Epithelial-Mesenchymal Transition in Triple-Negative Breast Cancer.

(1) Background: Triple-negative breast cancer (TNBC) is an aggressive subtype of breast cancer with high intra-tumoral heterogeneity. The epithelial-mesenchymal transition (EMT) is one of the inducers of cancer metastasis and migration. However, the description of the EMT process in TNBC using single-cell RNA sequencing (scRNA-seq) remains unclear. (2) Methods: In this study, we analyzed 8938 cellular gene expression profiles from five TNBC patients. We first scored each malignant cell based on functional pathways to determine its EMT characteristics. Then, a pseudo-time trajectory analysis was employed to characterize the cell trajectories. Furthermore, CellChat was used to identify the cellular communications. (3) Results: We identified 888 epithelium-like and 846 mesenchyme-like malignant cells, respectively. A further pseudo-time trajectory analysis indicated the transition trends from epithelium-like to mesenchyme-like in malignant cells. To characterize the potential regulators of the EMT process, we identified 10 dysregulated transcription factors (TFs) between epithelium-like and mesenchyme-like malignant cells, in which overexpressed forkhead box protein A1 (FOXA1) was recognized as a poor prognosis marker of TNBC. Furthermore, we dissected the cell-cell communications via ligand-receptor (L-R) interactions. We observed that tumor-associated macrophages (TAMs) may support the invasion of malignant epithelial cells, based on CXCL-CXCR2 signaling. The tumor necrosis factor (TNF) signaling pathway secreted by TAMs was identified as an outgoing communication pattern, mediating the communications between monocytes/TAMs and malignant epithelial cells. Alternatively, the TNF-related ligand-receptor (L-R) pairs showed promising clinical implications. Some immunotherapy and anti-neoplastic drugs could interact with the L-R pairs as a potential strategy for the treatment of TNBC. In summary, this study enhances the understanding of the EMT process in the TNBC microenvironment, and dissections of EMT-related cell communications also provided us with potential treatment targets.

Circ-TRIO promotes TNBC progression by regulating the miR-432-5p/CCDC58 axis

Numerous studies have shown that circRNAs are aberrantly expressed in various cancers and play a significant role in tumor progression. However, the molecular mechanisms of circRNAs in triple-negative breast cancer (TNBC) remain ambiguous. By intersecting throughput data and qRT-PCR results from tissues and cell lines, circ-TRIO was identified as a potential oncogenic regulator of TNBC. Moreover, circ-TRIO expression was detected in TNBC tissues and was correlated with the recurrence and prognosis of TNBC patients. The circular characteristics of circ-TRIO were verified by RNase R and CHX assays. Functionally, the knockdown of circ-TRIO inhibited the proliferation, migration and invasion of TNBC cells, while the overexpression of circ-TRIO resulted in the opposite impacts. Mechanistically, a dual luciferase reporter assay and RNA immunoprecipitation were performed and indicated that circ-TRIO could combine with miR-432-5p to regulate the expression of coiled-coil domain containing 58 (CCDC58). In summary, our study illustrates that circ-TRIO plays an important role in the progression of TNBC by regulating the miR-432-5p/CCDC58 axis, which could broaden our insight into the underlying mechanisms and provide a novel prognostic marker of TNBC in the clinic.

Особливості експресії молекул клітинної адгезії Е-кадгерину в різних молекулярних підтипах інвазивного протокового раку грудної залози

The purpose of the study was to determine the role of E-cadherin in the development and progression of molecular subtypes of invasive ductal breast cancer by assessing the expression of E-cadherin in various clinical and pathological prognostic parameters. Materials and methods. We demonstrated a comprehensive morphological, including immunohistochemical study of 193 cases of invasive ductal breast cancer with the molecular phenotype definition. General histological processing of samples was performed according to standard methods. Immunohistochemical studies for E-cadherin, ER, PR, c-erbB2, Ki-67 were performed according to standardized analytically validated protocols with the necessary controls. The grade of malignancy was determined according to the modified scheme of P. Scarff, H. Bloom and W. Richardson. E-cadherin expression level was quantified in 86 observations using the Qureshi counting system. Comparison of E-cadherin expression in different clinical and pathological parameters was evaluated using Pearson's test χ2. For all types of analysis, differences were considered significant at p <0.05. Results and discussion. E-cadherin expression in ductal breast cancer tissue is significantly lower in cases with lymph node metastases than without metastatic lymph node involvement (χ2 = 4.55, p = 0.031). Low expression of E-cadherin or its absence was associated with pT3 tumors, clinical stage 3, with G2 and G3 malignancies. Loss of E-cadherin expression has an unfavorable prognostic value. E-cadherin expression is associated with the molecular type of invasive breast ductal carcinoma. High E-cadherin expression was common in ER-positive tumors of the luminal A phenotype and was determined in patients of both premenopausal and postmenopausal age, suggesting that ER-positive expression may be involved in the regulation of E-cadherin expression. Low tumor activity of cells of invasive ductal breast cancer of the luminal subtype is accompanied by an increase in the adhesive properties of these cells due to the high level of expression of E-cadherin. E-cadherin is considered an independent marker of triple-negative breast cancer and is characterized by an unfavorable prognosis and short life expectancy. Triple-negative cancer was associated with a significant predominance of patients with low and negative E-cadherin expression (p = 0.011). Conclusion. Thus, E-cadherin is a potent tumor suppressor of breast cancer. According to this role in the progression of breast cancer, it was found that partial or complete loss of E-cadherin expression correlates with an unfavorable prognosis in patients

Abstract 149: The roles of PIM1 and PIM2 kinases in the progression and metastasis of triple negative breast cancer

Abstract Breast cancers are often evaluated by their expression of estrogen, progesterone and HER2/Neu receptors. Triple negative breast cancers (TNBC), which do not have upregulation of any of these receptors, lack directed therapies and therefore, are associated with a worse prognosis. The lack of directed therapies for TNBC and high incidence of relapse and drug resistance found in all breast cancers underscores the need for identification of additional therapeutic targets. The analysis of gene expression data revealed that PIM1 and PIM2 kinases are upregulated in triple negative breast cancer. PIM kinases are a family of serine/threonine kinases that activate cell division, promote cell growth, and inhibit apoptosis. Due to PIM1/2’s effect on these cellular processes and PIM1/2 being upregulated in TNBC, we hypothesized that PIM1/2 play an important role in progression of triple negative breast cancer. Knockdown of PIM1 significantly inhibited the proliferation, migration, and invasion of TNBC cells, including MDA-231, BT-20, HCC-1806, and MDA-468 cells. To study the in vivo roles of PIM1/2 in breast cancer progression and metastasis, we crossed the highly metastatic MMTV-PyMT breast cancer mouse model with PIM1/2 knockout mice. Deletion of PIM1 or PIM2 alone significantly inhibited tumor growth and reduced lung metastasis in these mice. Dual deletion of PIM1 and PIM2 significantly reduced tumor growth and almost completely blocked lung metastasis in these mice. A major advantage of the MMTV-PyMT model over xenograft models is that the immune system is intact in these mice, and that enabled us to perform immune cell profiling on the tumors. Tumor associated macrophages (TAMs) have been shown to promote tumor metastasis and are a poor prognostic marker for TNBC. Deletion of PIM1 alone and combined PIM1 and PIM2 deletion resulted in a significant reduction in the number of TAMs, indicating PIM1/2 play a significant role in regulating the immune milieu of these tumors. To understand the underlying mechanism by which PIM1 and PIM2 contribute to these processes, we performed biochemical analysis. Western blot analysis of PIM1 knockdown in MDA-231 cells showed a decrease in phosphorylation of CXCR4, S6 ribosomal protein, and 4EBP1 and increased expression of cell cycle regulator p27. Additionally, we performed RNA-seq analysis to identify which pathways were affected by PIM1/2 deletion in MMTV-PyMT tumors. GSEA analysis showed a significant enrichment of genes related to inflammatory response, extracellular matrix, EMT and metastasis in PyMT tumors and those were significantly reduced in PIM1/2 double knockout tumors. These results suggest that PIM1 and PIM2 play a significant role in the progression and metastasis of triple negative breast cancer and indicate that PIM1/2 inhibition could be a useful therapeutic approach for TNBC. Citation Format: Patrick Faughnan, Golam Mohi, Chandrajeet Singh. The roles of PIM1 and PIM2 kinases in the progression and metastasis of triple negative breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 149.

Expression of SOX10 and GATA3 in breast cancer and their significance

Objective: To investigate the expression characteristics of SOX10 and GATA3 in breast cancer and the value of their combination. Methods: A total of 360 breast cancer specimens with SOX10 immunohistochemical staining were collected from the Department of Pathology in Shenzhen People's Hospital from 2018 to 2021, including 268 cases with simultaneous SOX10 and GATA3 staining. The expression of SOX10 and GATA3 in primary and metastatic breast cancer was detected, and the correlations between SOX10 and GATA3 and the molecular types and clinicopathological features of breast cancer were compared, and the distribution differences among each group were statistically analyzed. Results: The overall expression of SOX10 and GATA3 in breast cancer were 25.8%(93/360) and 81.7%(219/268), and that in triple negative breast cancer (TNBC) were 83.3%(80/96) and 42.7%(32/75), respectively. SOX10 was strongly associated with TNBC (P<0.001), whereas GATA3 was highly expressed in luminal A, luminal B and HER2 over expression breast cancers (P<0.001). The expression of SOX10 and GATA3 was negatively correlated in TNBC, and the combined expression rates of SOX10 and GATA3 in breast cancer and TNBC could reach 97.8% (262/268) and 94.7%(71/75), respectively. In addition, the expression of SOX10 was closely correlated with high histological grade, high Ki-67 proliferation index and lymph node metastasis, and negatively correlated with AR. The expression of GATA3 was correlated with low histological grade and lymph node metastasis, and positively correlated with AR, and the difference was statistically significant. Conclusions: SOX10 is a sensitive marker of TNBC, while GATA3 is highly expressed in non-triple negative breast cancer. The two complementary, combined application of SOX10-GATA3 can improve the detection rate of breast cancer, especially TNBC. SOX10 is associated with malignant characteristics of the tumor, suggesting that SOX10 can be used as a prognostic marker and potential therapeutic target for breast cancer.

Stem Cell Marker Aldehyde Dehydrogenase 1A1 Expression in Triple-negative Breast Carcinoma

Background: Increasing evidence has proposed that tumor contains tumor initiating cells or cancer stem cells (CSCs) are responsible for its progression and relapse. Aldehyde dehydrogenase 1A1 (ALDH1A1) has recently been identified as a marker for cancer stem cells in some human malignancies including breast cancer.Triple negative breast carcinomas (TNBCs) are group of primary breast tumors with aggressive clinical behavior that have no targeted therapy at present.&#x0D; Aim: The assessment of immunohistochemical expression of ALDH1A1 in triple negative breast carcinoma and its correlation with the clinicopathological features of TNBC.&#x0D; Material and Methods: This study consisted of 60 cases of TNBC. Immunohistochemical reactions were carried out by using ALDH1A1 monoclonal antibody. A total score of ALDH1A1 expression is obtained by multiplying the score of staining intensity &amp; percentage of stained cells to obtain score ranging from 0 up to 300. Due to the relatively large number of positive cases, a statistical analysis was performed with a negative (score ≤ 10) and positive (score &gt; 10) cutoff [1].&#x0D; Results: Evaluation of the results of immunostaining for ALDH1A1 showed 88.3% of totalcases (53 cases) having a positive cytoplasmic reactivity. Statistical analysis for a possible correlation between ALDH1A1 expression and prognostic clinicopathological parameters; age, size, tumor grade, histologic subtypes, lymphovascular invasion, intraductal components, tumor infiltrating lymphocytes and TNM stage grouping revealed a non-significant correlation.&#x0D; Conclusion: ALDH1A1 couldn’t be used solely as a diagnostic or prognostic marker In TNBCs. Further research combining with other biomarkers and with a greater number of patients is necessary to confirm the role of ALDH1A1 in TNBC.&#x0D; Key words: Cancer stem cells (CSCs), Aldehyde dehydrogenase 1A1 (ALDH1A1), Triple Negative Breast cancer (TNBC).

Pretreatment neutrophil-to-lymphocyte ratio predicts lymph node metastasis in triple-negative breast cancer.

The purpose of the study was to investigate the value of pretreatment neutrophil-to-lymphocyte ratio (NLR) as a prognostic marker in triple-negative breast cancer (TNBC) and to see its bearing on the clinical and pathological stage of the disease. This was a retrospective analysis of cases of TNBC treated at our center from 2006 to 2013. The pretreatment complete blood count was recorded from which the NLR was calculated as the percentage of neutrophils divided by the percentage of lymphocytes. The association between pretreatment NLR with the stage of the disease, clinical and pathological lymph node status, and disease-specific survival was analyzed. A total of 208 patients were eligible for the analysis. The median follow-up period was 48 months. The NLR was found to have a strong correlation with the pathological nodal status and the clinical stage (75% cases node-positive in the high NLR group versus 36% in the low NLR group; P < 0.01). At the time of analysis, 74% of our study population was alive and well. There was no significant correlation between the NLR and the overall survival. Based on our study, we conclude that the pretreatment NLR is strongly associated with lymph node metastasis and clinical stage in TNBC patients. It is probably not useful as a prognostic marker, as it does not seem to have any significant bearing on the overall survival.

Current State of Knowledge on the Immune Checkpoint Inhibitors in Triple-Negative Breast Cancer Treatment: Approaches, Efficacy, and Challenges.

Triple-negative breast cancer (TNBC) is the most aggressive breast cancer subtype with limited treatment options. Recently, there has been a growing interest in immunotherapy with immune checkpoint inhibitors (ICIs) in TNBC, leading to extensive preclinical and clinical research. This review summarizes the current state of knowledge on ICIs efficacy and their predictive markers in TNBC and highlights the areas where the data are still limited. Currently, the only approved ICI-based regimen for TNBC is pembrolizumab with chemotherapy. Its advantage over chemotherapy alone was confirmed for non-metastatic TNBC regardless of programmed death-ligand 1 (PD-L1) expression (KEYNOTE-522) and for metastatic, PD-L1-positive TNBC (KEYNOTE-355). Pembrolizumab’s efficacy was also evaluated in monotherapy, or in combination with niraparib and radiation therapy, showing potential efficacy and acceptable safety profile in phase 2 clinical trials. Atezolizumab + nab-paclitaxel increased the overall survival (OS) over placebo + nab-paclitaxel in early TNBC, regardless of PD-L1 status (IMpassion031). In IMpassion130 (untreated, advanced TNBC), the OS improvement was not statistically significant in the intention-to-treat population but clinically meaningful in the PD-L1 positive cohort. The durvalumab–anthracycline combination showed an increased response durability over placebo anthracycline in early TNBC (GeparNuevo). Several phase 1 clinical trials also showed a potential efficacy of atezolizumab and avelumab monotherapy in metastatic TNBC. ICIs appear to be applicable in both neoadjuvant and adjuvant settings, and are both pretreated and previously untreated patients. Further research is necessary to determine the most beneficial drug combinations and optimize patient selection. It is essential to identify the predictive markers for ICIs and factors affecting their expression.

FOXC1.

Few studies have investigated the features of FOXC1 protein expression in invasive breast cancer subtypes as defined by immunohistochemistry (IHC)-based surrogate molecular classification. To investigate the diagnostic utility of the IHC-based FOXC1 test in breast cancer subtyping and to evaluate the correlation between FOXC1 expression and clinicopathologic parameters in triple-negative breast cancer (TNBC). FOXC1 expression was evaluated with IHC in a large cohort of 2443 patients with breast cancer. Receiver operating characteristic (ROC) curves were used to assess the diagnostic ability of FOXC1 expression to predict the triple-negative phenotype and to identify the best cutoff value. FOXC1 expression was correlated with the clinicopathologic parameters of TNBC. The expression rate of FOXC1 in TNBC was significantly higher than in other subtypes. The area under the ROC curve confirmed the high diagnostic value of FOXC1 for the prediction of the triple-negative phenotype. The cutoff value of 1% showed a maximized sum of sensitivity and specificity. In TNBC, FOXC1 expression was significantly associated with aggressive tumor phenotypes. Furthermore, FOXC1 expression was primarily observed in invasive breast carcinoma of no special type and metaplastic carcinoma but rarely in invasive carcinoma with apocrine differentiation. Correspondingly, FOXC1 expression was significantly associated with the expression of basal markers but was negatively correlated with apocrine-related markers in TNBC. In conclusion, FOXC1 is a highly specific marker for the triple-negative phenotype. Moreover, IHC detection of FOXC1 expression can be used as an additional diagnostic tool for the triple-negative phenotype and subclassification in TNBC.

Focal pyroptosis-related genes AIM2 and ZBP1 are prognostic markers for triple-negative breast cancer with brain metastases.

BackgroundExtensive research has shown the role of pyroptosis in the occurrence, progression, and prognosis of breast cancer. The study sought to screen important pyroptosis-related genes and their role in the prognosis of triple-negative breast cancer (TNBC) patients with brain metastasis (BM).MethodsThe Gene Expression Omnibus database was used to obtain transcriptome data from primary TNBC and from TNBC BM patients. Differentially expressed genes (DEGs) between the primary tumors and BMs were analyzed, and the expression, prognostic significance, immune infiltration, function, and drug sensitivity of the pyroptosis genes in the DEGs were analyzed.ResultsIn both data sets, 456 genes differed between primary TNBC and TNBC BM. Absent in melanoma 2 (AIM2) and Z-deoxyribonucleic acid-binding protein 1 (ZBP1) were found to be important pyroptosis genes in DEGs, and significant differences in their expression in primary lesions and BMs were observed. Patients with a high expression of AIM2 had a worse prognosis than low expression, while patients with a high expression of ZBP1 had a better prognosis than low expression. AIM2 and ZBP1 were positively correlated with the infiltration of most immune cells; however, AIM2 was negatively correlated with the infiltration of neural cell adhesion molecule 1 (CD56) bright natural killer cells and central memory cluster of differentiation 8 (CD8) T cells. Increased expression of ZBP1 is negatively correlated with high infiltration levels of central memory CD8 T cells and memory B cells.ConclusionsOur findings suggest that AIM2 and ZBP1 increase immune cell infiltration and may be potential targets for predicting and treating TNBC BM.

Ganglioside GD2: a novel therapeutic target in triple-negative breast cancer.

Triple-negative breast cancer (TNBC) is a heterogeneous disease characterized by lack of hormone receptor expression and is known for high rates of recurrence, distant metastases, and poor clinical outcomes. TNBC cells lack targetable receptors; hence, there is an urgent need for targetable markers for the disease. Breast cancer stem-like cells (BCSCs) are a fraction of cells in primary tumors that are associated with tumorigenesis, metastasis, and resistance to chemotherapy. Targeting BCSCs is thus an effective strategy for preventing cancer metastatic spread and sensitizing tumors to chemotherapy. The CD44hi CD24lo phenotype is a well-established phenotype for identification of BCSCs, but CD44 and CD24 are not targetable markers owing to their expression in normal tissues. The ganglioside GD2 has been shown to be upregulated in primary TNBC tumors compared with normal breast tissue and has been shown to identify BCSCs. In this review, we discuss GD2 as a BCSC- and tumor-specific marker in TNBC; epithelial-to-mesenchymal transition and the signaling pathways that are upstream and downstream of GD2 and the role of these pathways in tumorigenesis and metastasis in TNBC; direct and indirect approaches for targeting GD2; and ongoing clinical trials and treatments directed against GD2 as well as future directions for these strategies.

ERβ in Triple-Negative Breast Cancer: Emerging Concepts and Therapeutic Possibilities

Despite the improvements in diagnostic and therapeutic approaches, breast cancer still remains one of the world’s leading causes of death among women. Particularly, triple negative breast cancer (TNBC) is characterized by aggressiveness, metastatic spreading, drug resistance and a very high percentage of death in patients. Nowadays, identification of new targets in TNBC appears very compelling. TNBC are considered negative for the estrogen receptor alpha (ERα) expression. Nevertheless, they often express ERβ and its variants. As such, this TNBC subtype still responds to estrogens. While the ERβ1 variant seems to act as a tumor-suppressor, the two variants ERβ2 and 5 exhibit pro-oncogenic activities in TNBC. Thus, ERβ1 activation might be used to limit the growth and spreading as well as to increase the drug sensitivity of TNBC. In contrast, the pro-oncogenic properties of ERβ2 and ERβ5 suggest the possible development and clinical use of specific antagonists in TNBC treatment. Furthermore, the role of ERβ might be regarded in the context of the androgen receptor (AR) expression, which represents another key marker in TNBC. The relationship between AR and ERβ as well as the ability to modulate the receptor-mediated effects through agonists/antagonists represent a challenge to develop more appropriate therapies in clinical management of TNBC patients. In this review, we will discuss the most recent data in the field. Therapeutic implications of these findings are also presented in the light of the discovery of specific ERβ modulators.

Low KIBRA Expression Is Associated with Poor Prognosis in Patients with Triple-Negative Breast Cancer

Background and Objectives: Kidney and brain protein (KIBRA) is a protein encoded by the WW and C2 domain containing 1 (WWC1) gene and is involved in the Hippo signaling pathway. Recent studies have revealed the prognostic value of KIBRA expression; however, its role in breast cancer remains unclear. The aim of this study was to examine KIBRA expression in relation to the clinical and pathological characteristics of patients with breast cancer and to disease outcomes. Materials and Methods: We analyzed the expression of KIBRA and its correlation with event-free survival (EFS) outcomes in resected samples from 486 patients with breast cancer. Results: KIBRA expression was significantly different among the molecular subgroups (low KIBRA expression: luminal A, 46.7% versus 50.0%, p = 0.641; luminal B, 32.7% versus 71.7%, p < 0.001; human epidermal growth factor receptor 2 (HER2)-enriched, 64.9% versus 45.5%. p = 0.001; triple-negative, 73.6% versus 43.8%, p < 0.001). Low KIBRA expression was also associated with high nuclear grade (60.4% versus 37.8%, p < 0.001), high histologic grade (58.7% versus 37.0%, p < 0.001), and estrogen receptor (ER) negativity (54.2% versus 23.6%, p < 0.001). Low KIBRA expression was significantly associated with poor EFS (p = 0.041; hazard ratio (HR) 1.658; 95% confidence interval (CI), 1.015–2.709). Low KIBRA expression was an independent indicator of poor prognosis (p = 0.001; HR = 3.952; 95% CI = 1.542–10.133) in triple-negative breast cancer (TNBC). Conclusion: Low KIBRA expression was associated with higher histological grade, ER negativity and poor EFS of breast cancer. In particular, our data highlight KIBRA expression status as a potential prognostic marker for TNBC.

CXCL13 expression in mouse 4T1 breast cancer microenvironment elicits antitumor immune response by regulating immune cell infiltration.

Breast cancer is the most commonly diagnosed cancer type and the leading cause of cancer-related deaths among women worldwide. Previous studies have reported contradictory performance of chemokine CXC motif ligand 13 (CXCL13) in breast cancer. In this study, The Cancer Genome Atlas database analysis revealed that CXCL13 was overexpressed in various human cancers including breast carcinoma, and associated with good clinical prognosis in breast cancer. Flow cytometry detection also found upregulated intracellular CXCL13 expression in human breast cancer cell lines. To explore the possible role of CXCL13 in the breast cancer microenvironment, mouse triple negative breast cancer (TNBC) was lentivirally transfected to stably overexpress mouse CXCL13 (4T1-CXCL13). Both parental 4T1 and 4T1-CXCL13 strains showed no in vitro or in vivo endogenous cell surface CXCR5 expression. In immune-competent BALB/c mice, the in vivo tumor growth of 4T1-CXCL13 was significantly inhibited and even completely eradicated, accompanied with increased infiltrations of CD4+, CD8+ T lymphocytes and CD11b+CD11c+ DCs. Further investigations showed that CXCL13 expression in the 4T1 tumor microenvironment elicited long-term antitumor immune memory, and rejection of distal parental tumor. The antitumor activity of CXCL13 was remarkedly impaired in BALB/cA-nu nude mice, or in BALB/c mice with CD8+ T lymphocyte or NK cell depletion. Our investigation indicated that CXCL13 expression in TNBC triggered effective antitumor immunity by chemoattracting immune cell infiltrations and could be considered as a novel prognostic marker for TNBC.