Long noncoding RNA DLEU2 and ROR1 pathway induces epithelial-to-mesenchymal transition and cancer stem cells in breast cancer.

Breast cancer (BC) patient who receives chemotherapy for an extended length of time may experience profound repercussions in terms of metastases and clinical outcomes due to the involvement of the epithelial-to-mesenchymal transition (EMT) mechanism and enriched cancer stem cells (CSCs). BC cells that express high levels of lncRNA deleted in lymphocytic leukemia-2 (lncRNA DLEU2) and type I tyrosine kinase-like orphan receptor ROR1 (ROR1) may play roles in the enhanced ability of the activation EMT and CSC induction. Here we find that lncRNA DLEU2 and ROR1 are specifically upregulated in tumor tissues compared to their normal counterparts in TCGA, PubMed GEO datasets, and samples from archived breast cancer tumor tissues. Following chemotherapy, lncRNA DLEU2 and ROR1 were enhanced in BC tumor cells, coupled with the expression of CSCs, EMT-related genes, and BMI1. Mechanistically, ROR1 and lncRNA DLEU2 overexpression led to enhanced tumor cell proliferation, inhibition of apoptosis, cell-cycle dysregulation, chemoresistance, as well as BC cell's abilities to invade, migrate, develop spheroids. These findings imply that the role of lncRNA DLEU2 and ROR1 in BC therapeutic failure is largely attributed to EMT, which is intricately linked to enriched CSCs. In conclusion, our findings indicate that a lncRNA DLEU2 and ROR1-based regulatory loop governs EMT and CSC self-renewal, implying that targeting this regulatory pathway may improve patients' responses to chemotherapy and survival.

High AUF1 level in stromal fibroblasts promotes carcinogenesis and chemoresistance and predicts unfavorable prognosis among locally advanced breast cancer patients.

BACKGROUND: Locally advanced breast cancer (LABC), the most aggressive form of the disease, is a serious threat for women's health worldwide. The AU-rich RNA-binding factor 1 (AUF1) promotes the formation of chemo-resistant breast cancer stem cells. Thereby, we investigated the power of AUF1 expression, in both cancer cells and their stromal fibroblasts, as predictive biomarker for LABC patients' clinical outcome following neoadjuvant treatment. METHODS: We have used immunohistochemistry to assess the level of AUF1 on formalin-fixed paraffin-embedded tissues. Immunoblotting was utilized to show the effect of AUF1 ectopic expression in breast stromal fibroblasts on the expression of various genes both in vitro and in orthotopic tumor xenografts. Cytotoxicity was evaluated using the WST1 assay, while a label-free real-time setting using the xCELLigence RTCA technology was utilized to assess the proliferative, migratory and invasive abilities of cells. RESULTS: We have shown that high AUF1 immunostaining (≥ 10%) in both cancer cells and their adjacent cancer-associated fibroblasts (CAFs) was significantly associated with higher tumor grade. Kaplan-Meier univariate analysis revealed a strong correlation between high AUF1 level in CAFs and poor patient's survival. This correlation was highly significant in patients with triple negative breast cancer, who showed poor disease-free survival (DFS) and overall survival (OS). High expression of AUF1 in CAFs was also associated with poor OS of ER+/Her2- patients. Similarly, AUF1-positive malignant cells tended to be associated with shorter DFS and OS of ER+/Her2+ patients. Interestingly, neoadjuvant therapy downregulated AUF1 to a level lower than 10% in malignant cells in a significant number of patients, which improved both DFS and OS. In addition, ectopic expression of AUF1 in breast fibroblasts activated these cells and enhanced their capacity to promote, in an IL-6-dependent manner, the epithelial-to-mesenchymal transition and stemness processes. Furthermore, these AUF1-expressing cells enhanced the chemoresistance of breast cancer cells and their growth in orthotopic tumor xenografts. CONCLUSIONS: The present findings show that the CAF-activating factor AUF1 has prognostic/predictive value for breast cancer patients and could represent a great therapeutic target in order to improve the precision of cancer treatment.

High DNMT1 Expression in Stromal Fibroblasts Promotes Angiogenesis and Unfavorable Outcome in Locally Advanced Breast Cancer Patients.

Background: Active breast cancer-associated fibroblasts (CAFs) play a leading role in breast carcinogenesis through promoting angiogenesis and resistance to therapy. Consequently, these active stromal cells have significant influence on patient outcome. Therefore, we explored here the role of the DNA methyltransferase 1 (DNMT1) protein in CAF-dependent promotion of angiogenesis as well as the prognostic power of DNMT1 level in both cancer cells and their adjacent CAFs in locally advanced breast cancer patients. Methods: We applied immunohistochemistry to evaluate the level of DNMT1 in breast cancer tissues and their adjacent normal counterparts. Quantitative RT-PCR and immunoblotting were performed to investigate the role of DNMT1 in regulating the expression of pro-angiogenic genes in active CAFs and also their response to the DNMT1 inhibitors decitabine (DAC) as well as eugenol. Results: We have shown that DNMT1 controls the pro-angiogenic potential of CAFs both in vitro and in vivo through positive regulation of the expression/secretion of 2 important pro-angiogenic factors VEGF-A and IL-8 as well as their upstream effectors mTOR and HIF-1α. To confirm this, we have shown that these DNMT1-related pro-angiogenic effects were suppressed by 2 DNMT1 inhibitors decitabine and eugenol. Interestingly, in a cohort of 100 tumors from locally advanced breast cancer patients (LABC), we have shown that high expression of DNMT1 in tumor cells and their adjacent stromal fibroblasts is correlated with poor survival of these patients. Conclusion: DNMT1 upregulation in breast stromal fibroblasts promotes angiogenesis via IL-8/VEGF-A upregulation, and correlates well with poor survival of LABC patients.

Association Between Obesity and Clinicopathological Profile of Patients with Newly Diagnosed Non-Metastatic Breast Cancer in Saudi Arabia.

Purpose: Obesity is prevalent in Saudi Arabia and is associated with adverse clinical features and poor breast cancer (BC) outcomes. We determined the distribution of body mass index (BMI) and evaluated its association with disease characteristics and outcomes in women with non-metastatic BC. Patients and Methods: We conducted a retrospective analysis of a prospectively collected database of consecutive patients treated for non-metastatic BC between 2002 and 2014. Patients were categorized into the following groups: underweight/normal weight (BMI <25 kg/m2), overweight (BMI 25-29.9 kg/m2), and obese (BMI ≥30 kg/m2). Regression analysis was used to evaluate clinicopathological factors associated with BMI and clinical stage. Results: A total of 2212 patients were enrolled. The median age was 45 years (interquartile range [IQR], 39-52 years), and the median BMI was 30 kg/m2 (IQR, 26-34 kg/m2). Most patients were premenopausal (63.6%), nearly half of the patients had stage III disease, and 11.2% were screen-detected. The prevalence of obesity was 53.4%, with a significant difference between the peri/premenopausal (49.4%) and postmenopausal (61.7%) groups (p < 0.001). Obese patients were more likely to be aged >40 years, be postmenopausal, have a history of oral contraceptive pills, have advanced-stage disease, and have undergone radiation therapy, and were less likely to have human epithelial growth factor 2 (HER2)+ disease than non-obese patients. Premenopausal obese women had fewer hormone receptor-positive and more triple-negative cancers than postmenopausal obese women did. Obesity, non-screening-detected BC, and HER+ status were independent prognostic factors for advanced-stage presentation. Conclusion: The prevalence of obesity and its significant association with advanced BC justify the upscaling of screening services and instituting weight-reduction strategies.

Translational Implications of Dysregulated Pathways and microRNA Regulation in Quadruple-Negative Breast Cancer.

Triple-negative breast cancers (HER2-, ER-, PR-) continue to present a unique treatment challenge and carry unfavorable prognoses. The elucidation of novel therapeutic targets has necessitated the re-evaluation of stratification approaches to best predict prognosis, treatment response and theranostic and prognostic markers. Androgen receptor expression and function have important implications on proliferation, tumor progression, immunity and molecular signaling in breast cancer. Accordingly, there has been increasing support for classification of androgen receptor-negative triple-negative breast cancer or quadruple-negative breast cancer (QNBC). QNBC has unique molecular, signaling and expression regulation profiles, particularly those affected by microRNA regulatory networks. microRNAs are now known to regulate AR-related targets and pathways that are dysregulated in QNBC, including immune checkpoint inhibitors (ICIs), SKP2, EN1, ACSL4 and EGFR. In this review, we explore and define the QNBC tumor subtype, its molecular and clinical distinctions from other subtypes, miRNA dysregulation and function in QNBC, and knowledge gaps in the field. Potential insights into clinical and translational implications of these dysregulated networks in QNBC are discussed.

Peripheral blood eosinophil count is associated with response to chemoimmunotherapy in metastatic triple-negative breast cancer.

Introduction: There is evidence for an association between peripheral blood eosinophil count (PBEC) and response to cancer immunotherapy; however, such data is limited in metastatic triple-negative breast cancer (mTNBC). Patients & methods: This report presents patients (n = 14) who received a combination of durvalumab and paclitaxel for mTNBC (NCT02628132). Results: There was a statistically significant correlation (p = 0.028) between an increase in PBEC (>300/mm3) during treatment and response to the combination therapy. Survival analysis showed a statistically significant association between progression-free survival and increased PBEC, after therapy (p = 0.005). A similar trend existed for overall survival, although it did not reach statistical significance (p = 0.167). Conclusion: This is the first study to report on eosinophilia in mTNBC treated with chemoimmunotherapy and supports a role for eosinophils in immunotherapy for mTNBC.

Plain language summary Previous reports have shown that an increase in peripheral blood eosinophil count is associated with a good response to cancer immunotherapy; however, data on this association is limited in a subtype of breast cancer called metastatic triple-negative breast cancer (mTNBC). The eosinophil count in patients who received the combination of an immunotherapeutic agent, durvalumab and a chemotherapeutic agent, paclitaxel, in mTNBC was assessed. There was a statistically significant association between an increase in eosinophils during treatment and the response to therapy. The progression of the disease was slower or less likely to occur in patients with increased eosinophils. This study supports the role of eosinophils in immunotherapy for mTNBC.

Using the Appropriate Formula for QT Measurement Can Save Lives.

CDK 4/6 inhibitors, in combination with endocrine therapy, are the standard of care for patients with endocrinesensitive advanced breast cancer. This class of drug, however, is associated with QT prolongation, which serves as a surrogate marker for Torsades de Pointes (TdP), a cause of life-threatening ventricular arrhythmias and sudden cardiac death. The ICH E14 guidance document uses the Bazett formula for reporting of cardio-dynamic and safety ECG data in clinical trials. While there is substantial familiarity with the Bazett (QTcB) formula (QT/(RR) 1/2), the Fridericia (QTcF) formula (QT/(RR) 1/3 ) is preferred in the cancer population as it is often more accurate at heart rate extreme. Accordingly, the Fridericia formula is currently the standard adopted by the FDA when submitting QT data for review. At the King Faisal Specialist Hospital and Research Center, a total of 82 patients with advanced breast cancer, had a baseline ECG on day 1 before the initiation of ribociclib based therapy. Of the enrolled 82 patients, 19 (23%) were initially excluded from receiving ribociclib based due to a prolonged QTc >450ms, however, when the QTc-interval was manually measured and recalculated using Fridericia and Framingham formulae using MDCalC (https://www.mdcalc.com),17 of 19 patients successfully received their treatment without any arrhythmogenic effects. Repeat ECG on day14, and day 1 of cycle 2 demonstrated that none of these patients had QTc exceeding 480 ms. Our data highlights the complexities of evaluating the QT interval in oncology patients and the utility of the Fridericia/Framingham formulae in this population. Given these findings, we recommend the adoption of the Fridericia or Framingham formulae for measurement of QTc in all cancer patients exposed to potentially QT-prolonging cancer therapy.

Weekly Paclitaxel given concurrently with Durvalumab has a favorable safety profile in triple-negative metastatic breast cancer.

Therapeutic anti-PD-L1 antibodies are safe as a monotherapy, albeit with minimal efficacy in triple-negative breast cancer (TNBC). This trial aimed to test the safety and efficacy of Durvalumab and Paclitaxel in metastatic TNBC. In this open-label, one-arm trial, five cycles of weekly paclitaxel were delivered intravenously (IV) concurrent with Durvalumab that was given IV every 2 weeks. The combination was preceded by one cycle of paclitaxel alone, for immunological priming, followed by Durvalumab solo until disease progression or unacceptable toxicity. Between 2017 and 2019, 14 patients received at least one cycle of the combination therapy. The therapy was safe with no-dose limiting toxicity, except one case of skin lesions. Adverse events (AEs) were reported in 71% of patients, and there was no death due to the combination therapy. Regardless of grade, the most common AEs were headache and peripheral neuropathy, as each happened in four patients (29%), followed by fatigue and skin rash in three patients (21%) each. Grade 3/4 AEs were experienced by three patients (21%), with the most common being headache and anemia, which happened in two patients (14%). The confirmed objective response rate (ORR) was observed in five patients with a median duration of 10.0 months. Median Progression-free survival (PFS) and overall survival (OS) were 5 and 20.7 months, respectively. The combination of Durvalumab and Paclitaxel is safe, leaving room for additional agents. This is the first report on the combination of Durvalumab and Paclitaxel in the treatment of TNBC (NCT02628132).

Ribociclib-Induced Pneumonitis: A Case Report.

BACKGROUND: Cyclin-dependent kinase 4/6 (CDK 4/6) inhibitors have been a significant breakthrough in the management of hormone receptor-positive, HER2-negative metastatic breast cancer based on the results of several large phase III randomized trials. The most common reported toxicity is myelosuppression due to disease such as leukopenia, neutropenia, and thrombocytopenia. Other toxicities associated with CDK 4/6 inhibitors include mucositis, fatigue, gastrointestinal side effects, hepatic toxicities, and QTc prolongation. Despite a good toxicity profile in pivotal studies, the increased rates of use in clinical practice may show less prevalent but lethal toxicity such as lung injury. CASE PRESENTATION: Here, we describe a female patient with metastatic hormone receptor-positive/human epidermal growth factor 2-negative breast cancer who developed lung toxicity while on ribociclib. DISCUSSION: Lung injury is a possible side effect of CDK 4/6 inhibitors and there is an increasing need to understand the management of this side effect.

Higher PD-L1 Immunohistochemical Detection Signal in Frozen Compared to Matched Paraffin-Embedded Formalin-Fixed Tissues.

PURPOSE: Response to anti-PD-L1/PD-1 immunotherapy correlates with PD-L1 expression in breast cancer. However, the prevalence of PD-L1 positive breast cancer is variable, which could be due to differences in the population/cohort of patients tested or the preservation/detection technology used. To investigate this variability, we examined the effect of two tissue preservation methods on PD-L1 immunohistochemical detection in breast cancer. METHODS: We compared PD-L1 expression in patient-matched frozen (FR) and formalin-fixed paraffin-embedded (FFPE) tissues of breast cancer patients. PD-L1 expression was assessed using tumor proportion score (TPS, simply PD-L1 score), and case positivity was determined with PD-L1 score ≥5. RESULTS: In FFPE tissues, PD-L1 was positive in 7-10% of tested patients, depending on the antibody used. In patient-matched FR tissues, the same antibodies showed positive PD-L1 expression in 20-30% of cases. The impact of the antibody tested on the rate of PD-L1 positivity (% of PDL1 positive cases) was minor, as evident in the near perfect concordance between PD-L1 score obtained using the different antibodies whether tested in FR or FFPE tissues. However, there was a systematic drop by an average of 13-20% in the PD-L1 score obtained in FFPE tissues compared to their patient-matched FR tissues. CONCLUSIONS: In the tested patient-matched cohort, there was consistently a higher PD-L1 score in FR than FFPE tissues, regardless of the antibody used, demonstrating a significant effect on PD-L1 detection due to the preservation method. These findings should inspire further work to improve the sensitivity of PD-L1 detection and possibly search for more sensitive antibodies in FFPE tissues.

Clinical Identification of Dysregulated Circulating microRNAs and Their Implication in Drug Response in Triple Negative Breast Cancer (TNBC) by Target Gene Network and Meta-Analysis.

Resistance to therapy is a persistent problem that leads to mortality in breast cancer, particularly triple-negative breast cancer (TNBC). MiRNAs have become a focus of investigation as tissue-specific regulators of gene networks related to drug resistance. Circulating miRNAs are readily accessible non-invasive potential biomarkers for TNBC diagnosis, prognosis, and drug-response. Our aim was to use systems biology, meta-analysis, and network approaches to delineate the drug resistance pathways and clinical outcomes associated with circulating miRNAs in TNBC patients. MiRNA expression analysis was used to investigate differentially regulated circulating miRNAs in TNBC patients, and integrated pathway regulation, gene ontology, and pharmacogenomic network analyses were used to identify target genes, miRNAs, and drug interaction networks. Herein, we identified significant differentially expressed circulating miRNAs in TNBC patients (miR-19a/b-3p, miR-25-3p, miR-22-3p, miR-210-3p, miR-93-5p, and miR-199a-3p) that regulate several molecular pathways (PAM (PI3K/Akt/mTOR), HIF-1, TNF, FoxO, Wnt, and JAK/STAT, PD-1/PD-L1 pathways and EGFR tyrosine kinase inhibitor resistance (TKIs)) involved in drug resistance. Through meta-analysis, we demonstrated an association of upregulated miR-93, miR-210, miR-19a, and miR-19b with poor overall survival outcomes in TNBC patients. These results identify miRNA-regulated mechanisms of drug resistance and potential targets for combination with chemotherapy to overcome drug resistance in TNBC. We demonstrate that integrated analysis of multi-dimensional data can unravel mechanisms of drug-resistance related to circulating miRNAs, particularly in TNBC. These circulating miRNAs may be useful as markers of drug response and resistance in the guidance of personalized medicine for TNBC.

Trastuzumab, Pertuzumab, and Docetaxel as the First Line for HER-2-Positive Metastatic Breast Cancer among Arabs.

INTRODUCTION: Human epidermal growth factor receptor 2 (HER-2) targeted therapy regimens can improve tumor response in HER-2-positive metastatic breast cancer (MBC), with overall survival benefits. OBJECTIVE: We evaluated the efficacy of dual HER-2 blockade combined with chemotherapy for HER-2-positive MBC patients as a first-line therapy in our patient population. PATIENTS AND METHODS: We identified 75 patients at King Faisal Specialist Hospital and Research Center that received trastuzumab, pertuzumab, and docetaxel as a first-line therapy in HER-2 positive MBC in 2013-2016. RESULTS: Median age at diagnosis was 45 years; 54.7% were estrogen receptor (ER)-positive. 10% of patients presented with only bone metastasis. The median follow-up time was 36 months with an objective response rate of 74.7% (complete response [CR] 18.7%; partial response [PR] 56%). The 5-year progression-free survival (PFS) and overall survival (OS) were 21% and 71.9% respectively, with a median PFS of 36 months (95% confidence interval [CI] 23.6-48.4). The 5-year OS for ER-negative and ER-positive patients was 93.9% and 59.4% respectively (p = 0.189); 23 patients experienced grade 1/2 toxicity and 2 patients had grade 3/4 toxicity. In terms of OS and PFS, the site of metastasis did not make any significant difference. CONCLUSIONS: First line pertuzumab, trastuzumab, and docetaxel for HER-2-positive MBC patients was found to be an effective and safe therapy in the Saudi population. This finding was consistent with the results seen in the CLEOPATRA trials.

Impact of Pathologic Complete Response following Neoadjuvant Chemotherapy ± Trastuzumab in Locally Advanced Breast Cancer.

PURPOSE: This study was designed to examine the relationship between breast cancer molecular subtypes and pathological response to neoadjuvant chemotherapy (NAC) ± trastuzumab, in locally advanced breast cancer (LABC). METHODS: Female patients with LABC (T2-T4, N0-N2, and M0) who received neoadjuvant chemotherapy + trastuzumab if HER2+ subtype, followed by surgery and radiotherapy ± hormonal therapy, were identified. The primary endpoint was pathologic complete response (pCR) in the breast and axilla (ypT0/ypN0), with final analysis on disease-free survival (DFS) and overall survival (OS). RESULTS: Six hundred eighty-one patients with a median age of 44 years, premenopausal: 70%, median tumour size: 7.0 cm (range 4-11 cm), stage II B: 27% and III A/III B: 73%, ER+/HER2-: 40.8%, ER-/HER2-: 23%, ER+/HER2+: 17.7%, and ER-/HER2+: 18.5%. Overall pCR (ypT0/ypN0) was 23%. The pCR rates based on molecular subtypes were ER+/HER2-: 9%; ER+/HER2+: 29%; ER-/HER2-: 31%; and ER-/HER2+: 37%. At median follow-up of 61 months, ER+/HER2+ and ER+/HER2- subtypes had the best 5-year DFS and OS; meanwhile, ER-/HER2+ and ER-/HER2- subtypes had the worst. CONCLUSION: Women with ER+/HER2- disease are the least likely to achieve pCR, with the highest rates in HER2+ and triple-negative subgroups. Degree of response is associated with OS; despite the comparatively higher likelihood of achieving pCR in ER-/HER2+ and triple-negative, these subgroups experience a survival detriment. We are consistent with the published data that patients who attain the pathological complete response defined as ypT0/ypN0 have improved outcomes.

Association Between Neutrophil-Lymphocyte Ratio and Oncotype Dx Recurrence Score in Early-Stage Hormonal Receptor-Positive, HER2-Negative, Node-Negative Breast Cancer.

PURPOSE: The correlation between the preoperative neutrophil-to-lymphocyte ratio (NLR) and Oncotype DX® (ODX) recurrence score (RS) has not yet been established. We aimed to investigate the association between NLR and ODX RS in patients with hormone receptor-positive (HR+) and human epidermal growth factor receptor 2-negative (HER2-) early-stage breast cancer (BC). PATIENTS AND METHODS: This retrospective study included consecutive patients with HR+/HER2-, node-negative primary BC who underwent surgical tumor resection from 2011 to 2019. Receiver operating characteristic curve analysis was used to obtain an optimal NLR cutoff value. Logistic regression analyses were used to estimate associations between various parameters and ODX RS. Furthermore, the factors significantly associated with the ODX RS in multivariable analysis were incorporated in a separate model and estimated using logistic regression. RESULTS: A total of 160 patients were enrolled. The optimal preoperative NLR cutoff was 2.15. Multivariable analysis revealed that NLR and tumor grade (G1/G2 vs G3) were independent predictive factors of high RS cutoff (≥26). Moreover, including the two variables yielded a stronger association; patients with low NLR and low-grade tumors were unlikely to have high RS (≥26; odds ratio [OR] = 0.03, 95% confidence interval [CI]: 0.006-0.154; p < 0.001). Conversely, the presence of any of the following factors made patients unlikely to have low RS (<16; OR = 0.34, 95% CI: 0.16-0.73; p = 0.006): high NLR, high grade, or high Ki-67 levels (>20). CONCLUSION: NLR is a promising independent predictor of RS. Furthermore, in addition to tumor grade and Ki-67 level, they together are also a potential indicator of high and low RS. However, further studies are required to validate this hypothesis.

Tocilizumab potentiates cisplatin cytotoxicity and targets cancer stem cells in triple-negative breast cancer.

Triple-negative breast cancer (TNBC) is a very aggressive subtype with high recurrence rate and no molecular targets for therapies. This subtype is characterized by high expression/secretion of the proinvasive/metastatic interleukin-6 (IL-6) cytokine. In the present study, we have shown that tocilizumab inhibits the IL-6/STAT3 signaling and suppresses the cancer/inflammatory epigenetic IL-6/STAT3/NF-κB positive feedback loop. Furthermore, tocilizumab inhibited the proliferative and the migratory/invasiveness capacities as well as the epithelial-to-mesenchymal transition (EMT) process in TNBC cells. Importantly, tocilizumab suppressed the stemness-related characteristics of TNBC cells, through the inhibition of the Wnt/ß-catenin breast cancer stem cell-related pathway. Additionally, we have shown that tocilizumab suppresses the paracrine activation of normal breast stromal fibroblasts to myofibroblats. Moreover, tocilizumab sensitized TNBC cells to the cytotoxic effect of cisplatin in vitro. Furthermore, pharmacological inhibition of IL-6 by tocilizumab had great inhibitory effect on tumor growth and the EMT process in humanized orthotopic breast tumors in mice. In addition, tocilizumab potentiated the proapoptotic effect of cisplatin in humanized breast tumors. Together, these findings indicate that tocilizumab can suppress the prometastatic capacity of TNBC cells and enhances the cytotoxic effect of cisplatin against these cells. Therefore, tocilizumab could be of great therapeutic value for these hard-to-treat TNBC patients.

Clinical and functional significance of tumor/stromal ATR expression in breast cancer patients.

BACKGROUND: Most breast cancer-associated fibroblasts (CAFs) are active and important cancer-promoting cells, with significant impact on patient prognosis. Therefore, we investigated here the role of the protein kinase ATR in breast stromal fibroblasts in the prognosis of locally advanced breast cancer patients. METHODS: We have used immunohistochemistry to assess the level of ATR in breast cancer tissues and their adjacent normal tissues. Immunoblotting as well as quantitative RT-PCR were utilized to show the role of breast cancer cells and IL-6 as well as AUF-1 in downregulating ATR in breast stromal fibroblasts. Engineered human breast tissue model was also used to show that ATR-deficient breast stromal fibroblasts enhance the growth of breast cancer cells. RESULTS: We have shown that the protein kinase ATR is downregulated in cancer cells and their neighboring CAFs in breast cancer tissues as compared to their respective adjacent normal tissues. The implication of cancer cells in ATR knockdown in CAFs has been proven in vitro by showing that breast cancer cells downregulate ATR in breast fibroblasts in an IL-6/STAT3-dependent manner and via AUF-1. In another cohort of 103 tumors from locally advanced breast cancer patients, we have shown that absence or reduced ATR expression in tumoral cells and their adjacent stromal fibroblasts is correlated with poor overall survival as well as disease-free survival. Furthermore, ATR expression in CAFs was inversely correlated with tumor recurrence and progression. CONCLUSION: ATR downregulation in breast CAFs is frequent, procarcinogenic, and correlated with poor patient survival.

Does the Timing of Surgery after Neoadjuvant Therapy in Breast Cancer Patients Affect the Outcome?

BACKGROUND: There is a paucity of literature examining the impact of timing of surgery after neoadjuvant chemotherapy. OBJECTIVE: This study aimed to analyze the impact of the time taken to initiate surgical treatment following completion of neoadjuvant chemotherapy on patients' outcomes by evaluating their pathological response, overall survival (OS), and disease-free survival (DFS). METHODS: This is a retrospective review of 611 patients diagnosed with stage II and III breast cancer that received neoadjuvant chemotherapy and surgery between January 2004 and December 2014. The data was collected from a prospectively gathered registry. The patients were stratified into three cohorts according to the time of surgery after neoadjuvant chemotherapy: <4 weeks, 4-7 weeks, or ≥8 weeks. Outcomes were assessed using Kaplan-Meier curves, and the variables were compared using log-rank statistics. RESULTS: The 5-year OS rate was 89.6% and the 5-year DFS rate was 74%. OS and DFS were not significantly different when stratified according to timing of surgery; however, the trends of OS and DFS were poor when surgery was delayed for ≥8 weeks. Median OS and median DFS have not yet been reached. Of the 17% of patients that had surgery after ≥8 weeks, 12.9% had pathological complete response (pCR), while among those that received surgery 4-7 weeks and <4 weeks after neoadjuvant chemotherapy, 26% and 21% had pCR, respectively (p = 0.02). ER+/HER-2+ patients had a statistically significant decrease in pCR if surgery was performed after ≥8 weeks. CONCLUSION: Our patients showed improved pCR if surgery was performed within 8 weeks, especially for ER+/HER-2+ patients. All patients had better OS and DFS trends if surgery was performed between 4 and 7 weeks after neoadjuvant chemotherapy.

Complete Response of Chemo-Refractory Metastatic Metaplastic Breast Cancer to Paclitaxel-Immunotherapy Combination.

BACKGROUND Metaplastic breast cancer (MPBC) is a rare subtype of breast cancer that is difficult to manage and is resistant to therapy. Immunotherapy is becoming a promising option for care of several types of cancers including triple negative breast cancer. CASE REPORT We present a case of a patient with chemo-refractory metastatic metaplastic-type of breast cancer with failures to 3 active lines of chemotherapy. The patient achieved a complete and sustained response to chemo-immunotherapy combination with acceptable tolerability and minimal adverse events. The treatment was a combination of anti-PD-L1 antibody (durvalumab) immunotherapy in combination with the chemotherapeutic agent, paclitaxel. CONCLUSIONS This is the first case reporting the successful use of durvalumab and paclitaxel combination for treatment of triple negative breast cancer in general, and in metastatic MPBC in specific.

ß1 Integrin is essential for fascin-mediated breast cancer stem cell function and disease progression.

Breast cancer remains the second cause of tumor-related mortality in women worldwide mainly due to chemoresistance and metastasis. The chemoresistance and metastasis are attributed to a rare subpopulation with enriched stem-like characteristics, thus called Cancer Stem Cells (CSCs). We have previously reported aberrant expression of the actin-bundling protein (fascin) in breast cancer cells, which enhances their chemoresistance, metastasis and enriches CSC population. The intracellular mechanisms that link fascin with its downstream effectors are not fully elucidated. Here, loss and gain of function approaches in two different breast cancer models were used to understand how fascin promotes disease progression. Importantly, findings were aligned with expression data from actual breast cancer patients. Expression profiling of a large breast cancer dataset (TCGA, 530 patients) showed statistically significant correlation between fascin expression and a key adherence molecule, ß1 integrin (ITGB1). In vitro manipulation of fascin expression in breast cancer cells exhibited its direct effect on ITGB1 expression. Fascin-mediated regulation of ITGB1 was critical for several breast cancer cell functions including adhesion to different extracellular matrix, self-renewability and chemoresistance. Importantly, there was a significant relationship between fascin and ITGB1 co-expression and short disease-free as well as overall survival in chemo-treated breast cancer patients. This novel role of fascin effect on ITGB1 expression and its outcome on cell self-renewability and chemoresistance strongly encourages for dual targeting of fascin-ITGB1 axis as a therapeutic approach to halt breast cancer progression and eradicate it from the root.