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Secondary trastuzumab resistance represents an evolutionary adaptation of HER2‐positive breast cancer during anti‐HER2 treatment. Most current studies have tended to prioritize HER2 and its associated signaling pathways, often overlooking broader but seemingly less relevant cellular processes, along with their associated genetic and epigenetic mechanisms. Here, transcriptome data is not only characterized but also examined epigenomic and 3D genome architecture information in both trastuzumab‐sensitive and secondary‐resistant breast cancer cells. The findings reveal that the global metabolic reprogramming associated with trastuzumab resistance may stem from genome‐wide alterations in both histone modifications and chromatin structure. Specifically, the transcriptional activities of key genes involved in lipid metabolism appear to be regulated by variant promoter H3K27me3 and H3K4me3 modifications, as well as promoter‐enhancer interactions. These discoveries offer valuable insights into how cancer cells adapt to anti‐tumor drugs and have the potential to impact future diagnostic and treatment strategies. [ABSTRACT FROM AUTHOR]

Simple Summary: tRF-27 has been identified as upregulated in both naïve trastuzumab-resistant HER2-positive breast cancer cells and patient samples, positioning it as a potential biomarker. However, the underlying mechanisms of this upregulation remain unclear. This study proposes that the abnormal transcription of specific tRNA-Cys-GCA isodecoders in naïve trastuzumab-resistant cells might contribute to the accumulation of tRF-27. Additionally, the reduction in H3K27me3 modifications at these tRNA genes, attributed to imbalances in histone modification enzymes, appears to influence tRNA transcription alterations. Building upon these findings, our research demonstrates that the application of a demethylase inhibitor may offer a potential strategy to overcome trastuzumab resistance. tRNA-derived fragments (tRFs) play crucial roles in cancer progression. Among them, tRF-27 has been identified as a key factor in promoting naïve trastuzumab resistance in HER2-positive breast cancer. However, the origin of tRF-27 remains uncertain. In this study, we propose that the upregulated expression of specific cysteine tRNAs may lead to the increased accumulation of tRF-27 in trastuzumab-resistant JIMT1 cells. Mechanistically, the reduced inhibitory H3K27me3 modification at the promoter regions of tRF-27-related tRNA genes in JIMT1 cells, potentially resulting from decreased EZH2 and increased KDM6A activity, may be a critical factor stimulating the transcriptional activity of these tRNA genes. Our research offers fresh insights into the mechanisms underlying elevated tRF-27 levels in trastuzumab-resistant breast cancer cells and suggests potential strategies to mitigate trastuzumab resistance in clinical treatments. [ABSTRACT FROM AUTHOR]

Simple Summary: While the prognosis of hormone receptor-positive (HR+) breast cancer has been significantly improved, tamoxifen resistance remains a challenge in the treatment of HR+ breast cancer. This study identified that tRF-16-K8J7K1B, a novel small ncRNA derived from the 3′-end of tRNAAla-TGC, was highly expressed in tamoxifen-resistant cells compared to parental cells. Moreover, extracellular tRF-16-K8J7K1B confers tamoxifen resistance via incorporation into exosomes and then degrades the expression of apoptosis-related proteins, reducing the proportion of drug-induced cell apoptosis. Therefore, we propose that exosomal tRF-16-K8J7K1B could be a potential predictive biomarker and therapeutic target for overcoming tamoxifen resistance. Tamoxifen resistance remains a challenge in hormone receptor-positive (HR+) breast cancer. Recent evidence suggests that transfer ribonucleic acid (tRNA)-derived fragments play pivotal roles in the occurrence and development of various tumors. However, the relationship between tRNA-derived fragments and tamoxifen resistance remains unclear. In this study, we found that the expression of tRF-16-K8J7K1B was upregulated in tamoxifen-resistant cells in comparison with tamoxifen-sensitive cells. Higher levels of tRF-16-K8J7K1B were associated with shorter disease-free survival in HR+ breast cancer. Overexpression of tRF-16-K8J7K1B promotes tamoxifen resistance. Moreover, extracellular tRF-16-K8J7K1B could be packaged into exosomes and could disseminate tamoxifen resistance to recipient cells. Mechanistically, exosomal tRF-16-K8J7K1B downregulates the expression of apoptosis-related proteins, such as caspase 3 and poly (ADP-ribose) polymerase, by targeting tumor necrosis factor-related apoptosis-inducing ligand in receptor cells, thereby reducing drug-induced cell apoptosis. Therapeutically, the inhibition of exosomal tRF-16-K8J7K1B increases the sensitivity of breast cancer cells to tamoxifen in vivo. These data demonstrate that exosomal tRF-16-K8J7K1B may be a novel therapeutic target to overcome tamoxifen resistance in HR+ breast cancer. [ABSTRACT FROM AUTHOR]

Background: Tyrosine kinase inhibitors (TKIs) are effective for treating human epidermal growth factor receptor 2 (HER2)-positive metastatic breast cancer. However, therapies subsequent to TKI progression remain controversial, and effective treatments for TKI resistance are urgently needed. We evaluate the practice of exchange of TKIs, which involves treatment with a different TKI following prior TKI failure. Specifically, this study investigated the efficacy of pyrotinib-based therapy in lapatinib-resistant HER2-positive metastatic breast cancer (NCT04899128). Methods: This real-world study included 76 patients diagnosed with HER2-positive metastatic breast cancer who received pyrotinib-based therapy after lapatinib progression at four Chinese institutions between August 2018 and March 2020. Progression-free survival (PFS), overall survival (OS), objective response rate (ORR), clinical benefit rate (CBR), and toxicity profiles were reported. Results: All patients received pyrotinib-based therapy in two or later line therapy. The median PFS was 8.0 months (95% CI 5.1–10.9). OS has not reached. The ORR and CBR were 17.1% and 60.5%, respectively. The median PFS was 7.1 months (95% CI 5.633–8.567) and intracranial ORR was 42.9% in patients who had brain metastasis (n = 14). Patients who benefited from lapatinib ⩾ 6.0 months prior exhibited a longer PFS (10.6 versus 6.0 months, p = 0.034, stratified hazard ratio (HR) 0.534, 95% CI 0.293–0.975). The most common adverse effects were diarrhea (n = 34, 44.7%) and hand-foot syndrome (n = 10, 13.2%). Conclusion: Pyrotinib-based therapy has the potential to improve survival in patients with lapatinib-resistant HER2-positive metastatic breast cancer, including those with brain metastases. Pyrotinib could provide a clinically significant increase in PFS for patients who benefited from prior lapatinib. [ABSTRACT FROM AUTHOR]

Background: With life span extending, breast cancer (BC) survivors may face the possibility of developing second primary cancer (SPC) and considerably shorten survivorship. However, little is known about multiple primary cancer (MPC) patients with nonmetastatic breast cancer as a first primary malignancy (BCFPM). Methods: Here, we retrospectively analyzed data on cancer survivors with BCFPM diagnosed between 2010 and 2015 from the Surveillance, Epidemiology, and End Results (SEER) database. The prognostic factors for breast cancer‐specific survival (BCSS) were ascertained by the stepwise regression analysis and a competing risk model, and were integrated to the establishment of prognostic nomogram, of which the accuracy was measured by the calibration curve and the concordance index (C‐index). Results: In total, 8616 patients were identified with 4.6% of 3‐year breast cancer‐ specific death (BCSD) and 8.6% of 5‐year BCSD. The most common SPC among BCFPM patients were female BC and lung cancer. Besides, the median latency time between BC and SPC was 22 months. At a ratio of 7:3, all patients were randomly categorized into a training cohort (n = 6032) and a validation cohort (n = 2584). By a proportional subdistribution hazards regression analysis, the following factors were considered to own independent prognostic abilities of BCSS: subtypes, grade, T classification, N classification, radiation, and sites of SPC. The nomogram could accurately predict 3‐year and 5‐year breast cancer‐associated survival of BCFPM patients with high internal and external validated C‐index, 0.715 (95% CI, 0.691–0.739), and 0.683 (95% CI, 0.642–0.724), respectively. Conclusions: BC survivors remained a high risk of developing SPC and considerably shortened survival time. In this study, a favorable nomogram was constructed to as a prediction model for 3‐year and 5‐year BCSS of BCFPM patients, largely intending to prolong the life of these patients by assisting clinicians to make individualized follow‐up plans. [ABSTRACT FROM AUTHOR]

Background: Anthracycline‐based chemotherapy (ABC) is one of the standard therapies against breast cancer. However, few guidelines are currently available to optimize the use of ABC. Therefore, the present analysis aimed at determining the profile and treatment patterns of ABC and the association of clinicopathological characteristics with ABC selection. Methods: We retrospectively analyzed the data of a nation‐wide multicenter epidemiological study, which collected the medical records of breast cancer patients receiving chemotherapy in different settings from seven geographic regions in China (NCT03047889). Results: In total, 3393 patients were included, with 2917 treated with ABC. Among them, 553 (89.8%), 2165 (81.7%), and 814 (25.7%) were subjected to ABC as neoadjuvant, adjuvant, and advanced chemotherapy, respectively. The most frequently used regimens were anthracycline‐taxane‐based combinations for neo‐ and adjuvant chemotherapy, along with taxanes and oral fluorouracils for the palliative stages. In the overall cohort, patients aged < 40 or 40‐65 (p < 0.001), in premenopause (p < 0.001), without comorbidities (p = 0.016), with invasive ductal carcinoma (p= 0.001), high lymph node involvement (p < 0.001), in the pTNM stage II, III, or IV versus stage I (p < 0.001), subjected to mastectomy (p < 0.001) or subjected to sentinel lymph node biopsy combined with axillary lymph node dissection (p = 0.044), or with a decreased disease‐free survival (p < 0.001) were more likely to be recommended to ABC. Conclusion: Taken together, ABC remained the mainstay of breast cancer treatment, especially in neo and adjuvant therapy. ABC was mainly used as a combination therapy, and the correlation between influencing factors and ABC choice varied during different settings, indicating the preference and different perspectives of medication considered by medical oncologists regarding the use ABC in China. [ABSTRACT FROM AUTHOR]

Cancer-associated fibroblasts (CAFs) are key components in tumor microenvironment (TME). The secreted products of CAFs play important roles in regulating tumor cells and further impacting clinical prognosis. This study aims to reveal the relationship between CAF-secreted cytokines and breast cancer (BC) by constructing the risk signature. We performed three algorithms to reveal CAF-related cytokines in the TCGA BC dataset and identified five prognosis-related cytokines. Then we used single-cell RNA sequencing (ScRNA-Seq) datasets of BC to confirm the expression level of these five cytokines in CAFs. METABRIC and other independent datasets were utilized to validate the findings in further analyses. Based on the identified five-cytokine signature derived from CAFs, BC patients with high-risk score (RS) had shorter overall survival than low-RS cases. Further analysis suggested that the high-RS level correlated with cell proliferation and mast cell infiltration in BCs of the Basal-like subtype. The results also indicated that the level of RS could discriminate the high-risk BC cases harboring driver mutations (i.e., PI3KCA, CDH1, and TP53). Additionally, the status of five-cytokine signature was associated with the frequency and molecular timing of whole genome duplication (WGD) events. Intratumor heterogeneity (ITH) analysis among BC samples indicated that the high-RS level was associated with the increase of tumor subclones. This work demonstrated that the prognostic signature based on CAF-secreted cytokines was associated with clinical outcome, tumor progression, and genetic alteration. Our findings may provide insights to develop novel strategies for early intervention and prognostic prediction of BC. [ABSTRACT FROM AUTHOR]

Objective: Axillary node status after neoadjuvant chemotherapy (NCT) in early breast cancer patients influences the axillary surgical staging procedure. This study was conducted for the identification of the likelihood of patients being node pathological complete response (pCR) post NCT. We aimed to recognize patients most likely to benefit from sentinel lymph node biopsy (SLNB) following NCT and to reduce the risk of missed detection of positive lymph nodes through the construction and validation of a clinical preoperative scoring prediction model. Methods: The existing data (from March 2010 to December 2018) of the Chinese Society of Clinical Oncology Breast Cancer Database (CSCO-BC) was used to evaluate the independent related factors of node pCR after NCT by Binary Logistic Regression analysis. A predictive model was established according to the score of considerable factors to identify ypN0. Model performance was confirmed in a cohort of NCT patients treated between January 2019 and December 2019 in Henan Cancer Hospital, and model discrimination was evaluated via assessing the area under the receiver operating characteristic (ROC) curve (AUC). Results: Multivariate regression analysis showed that the node stage before chemotherapy, the expression level of Ki-67, biologic subtype, and breast pCR were all independent related factors of ypN0 after chemotherapy. According to the transformation and summation of odds ratio (OR) values of each variable, the scoring system model was constructed with a total score of 1–5. The AUC for the ROC curves was 0.715 and 0.770 for the training and the validation set accordingly. Conclusions: A model was established and verified for predicting ypN0 after chemotherapy in newly diagnosed cN+ patients and the model had good accuracy and efficacy. The underlined effective model can suggest axillary surgical planning, and reduce the risk of missing positive lymph nodes by SLNB after NCT. It has great value for identifying initial cN+ patients who are more appropriate for SLNB post-chemotherapy. [ABSTRACT FROM AUTHOR]

Background: Clinical guidelines generally recommend endocrine therapy (ET) as first-line treatment of hormone receptor-positive advanced breast cancer (HR+ ABC) whereas chemotherapy (CT) should be considered in the presence of life-threatening disease or limited clinical benefit after three sequential ET regimens. However, it is unclear if real-world clinical practice is in accordance with the current guidelines. This study was to present the real-world treatment patterns and ET regimens among HR+ ABC patients in China. Methods: Using data from the Nation-wide Multicenter Retrospective Clinical Epidemiology Study of Female Advanced Breast Cancer in China (ClinicalTrials.gov identifier: NCT03047889), we investigated the clinicopathological characteristics, clinical profiles, and treatment patterns of HR+ ABC patients from January 2012 to December 2014. Results: A total of 2,342 patients with HR+ ABC were included in this study. Our findings revealed that, in comparisons with those receiving initial CT (n = 1445), patients initiated ET (n =402) were significantly older, later recurrent after adjuvant treatment, with a lower rate of visceral involvement and a decreasing quantity of metastatic sites. A total of 1,308 patients received palliative ET while only 18.9% patients (n = 247) reached three lines of ET. Among patients completing more than one line of ET, the median treatment duration was 8 months for the first line, 6 months for the second line, and 3 months for the third line for patients receiving ET. In the advanced setting, the choices of palliative ET regimens were diverse, yet aromatase inhibitor (AI) monotherapy was still the overall mainstay of ET; in contrast, patients were less accessible to everolimus plus AI regimen in this population. Conclusions: Less than one quarter of patients initiated palliative ET for HR+ ABC in routine clinical practice. Patients who received multi-lines of ET experienced successive shorter durations following each line of therapy. This real-life data provides a solid overview of ET for HR+ ABC from China, indicating unmet need for treatment options that improve the effectiveness of endocrine therapy. [ABSTRACT FROM AUTHOR]

PURPOSE: To examine the impact of a clinical decision support system (CDSS) on breast cancer treatment decisions and adherence to National Comprehensive Cancer Center (NCCN) guidelines. PATIENTS AND METHODS: A cross-sectional observational study was conducted involving 1,977 patients at high risk for recurrent or metastatic breast cancer from the Chinese Society of Clinical Oncology. Ten oncologists provided blinded treatment recommendations for an average of 198 patients before and after viewing therapeutic options offered by the CDSS. Univariable and bivariable analyses of treatment changes were performed, and multivariable logistic regressions were estimated to examine the effects of physician experience (years), patient age, and receptor subtype/TNM stage. RESULTS: Treatment decisions changed in 105 (5%) of 1,977 patients and were concentrated in those with hormone receptor (HR)–positive disease or stage IV disease in the first-line therapy setting (73% and 58%, respectively). Logistic regressions showed that decision changes were more likely in those with HR-positive cancer (odds ratio [OR], 1.58; P <.05) and less likely in those with stage IIA (OR, 0.29; P <.05) or IIIA cancer (OR, 0.08; P <.01). Reasons cited for changes included consideration of the CDSS therapeutic options (63% of patients), patient factors highlighted by the tool (23%), and the decision logic of the tool (13%). Patient age and oncologist experience were not associated with decision changes. Adherence to NCCN treatment guidelines increased slightly after using the CDSS (0.5%; P =.003). CONCLUSION: Use of an artificial intelligence–based CDSS had a significant impact on treatment decisions and NCCN guideline adherence in HR-positive breast cancers. Although cases of stage IV disease in the first-line therapy setting were also more likely to be changed, the effect was not statistically significant (P =.22). Additional research on decision impact, patient-physician communication, learning, and clinical outcomes is needed to establish the overall value of the technology. [ABSTRACT FROM AUTHOR]

Lapatinib, targeting the human epidermal growth factor receptor family members HER1 and HER2, has been approved by the US Food and Drug Administration for use in metastatic HER2-positive breast cancer. However, resistance to lapatinib remains a common challenge to HER2-positive metastatic breast cancer. Until now, the molecular mechanisms of acquired resistance to lapatinib (ALR) have remained unclear. With no definite biomarkers currently known, we aimed to screen for key biomarkers in ALR. In this research, we identified 55 differentially expressed genes (DEGs, 20 upregulated, 35 downregulated) through bioinformatic analysis using microarray datasets GSE16179, GSE38376, and GSE51889 from the Gene Expression Omnibus (GEO) database. The related gene function was explored using the Gene Ontology (GO) function and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis. The protein-protein interaction (PPI) network was constructed with the Search Tool for the Retrieval of Interacting Genes (STRING) and Cytoscape. The functional enrichment of the DEGs was analyzed, including negative regulation of the B cell apoptotic process, DNA replication, solute:proton symporter activity, synthesis, and degradation of ketone bodies, and metal sequestration by antimicrobial proteins. Analysis of seven hub genes revealed their concentration mainly in DNA replication and cell cycle. Survival analysis revealed that MCM10 and SPC24 may be related with poor prognosis in patients with ALR. Meanwhile, the prediction model of lapatinib sensitivity was constructed, and emerging role of the model was further analyzed using several webtools. In conclusion, hub genes are involved in the complex mechanisms underlying ALR in breast cancer and provide favorable support for treatment of ALR in future. [ABSTRACT FROM AUTHOR]

Background: Previous case reports have shown the promising antitumor activity of everolimus in solid tumors containing molecular aberrations in PI3K/ATK/mTOR pathway, however, whether it is effective in patients with breast cancer remains unknown. Therefore, we conducted this retrospective cohort study to compare the efficacy of molecularly matched targeted therapy with everolimus to conventional therapy in refractory breast cancer patients harboring PI3K/ATK/mTOR pathway activating mutations. Methods: Refractory metastatic breast cancer patients who have received molecular screening using next‐generation sequencing (NGS) between September 8, 2015 and October 30, 2017 in two sites were screened for this study. The primary outcome was progression‐free survival (PFS). The secondary outcomes were overall response rate (ORR), disease control rate (DCR), and safety profile. Results: A total of 78 patients were screened for analysis, amongst all, 52 (66.7%) had at least one gene mutation in PI3K/AKT/mTOR pathway. The most common mutation fell in PIK3CA (76.9%, 40/52) with a mutational prevalence of 51.3%. Of the 32 patients who were eligible for efficacy analysis, patients in the everolimus group (n = 19) exhibited shorter PFS than those in the conventional group (n = 13) (median, 1.9 vs 6.1 months; HR, 3.6; 95% CI, 1.48‐8.81; P = .0005). ORR was 15.4% (2/13) in the everolimus group and 23.1% (3/13) in the conventional group (P = 1.000), and DCR was 30.8% (4/13) and 100% (13/13) for each group, respectively (P = .000). The incidence of grade 3‐5 adverse events was relatively higher in the conventional group (38.5%, 5/13) than that in the everolimus group (26.3%, 5/19). Conclusions: Our findings suggested that everolimus might not be effective for cancer patients harboring mutations in PI3K/ATK/mTOR pathway and physicians should be cautious about its off‐label use in clinical practice. [ABSTRACT FROM AUTHOR]

Background: Although an immense effort has been made to develop a novel biomarker for response to trastuzumab, no reliable biomarkers are available to guide management, expect for HER2. The aim of this study was to examine the relationship between microRNA (miRNA) expression and resistance to trastuzumab. Methods: Differentially expressed miRNAs between trastuzumab‐resistant and trastuzumab‐sensitive cell lines were analyzed using microarrays. We performed Gene Ontology and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses to determine the functions of differentially expressed miRNA and their targeted genes. Furthermore, the protein–protein interactions (PPI) network was analyzed. Serum samples were collected from patients with HER2‐positive breast cancer who were treated with trastuzumab. We validated the miRNAs expression levels by quantitative reverse‐transcription polymerase chain reaction (qRT‐PCR) in these serums. Receiver operating characteristic (ROC) curve analysis was performed to evaluate the predictive performance of the miRNA. Results: Using miRNA microarrays, 151 miRNAs that significant differentially expressed between the trastuzumab‐resistant and sensitive cells were identified, including 46 upregulated and 105 downregulated miRNAs. Results of real‐time PCR confirmed seven miRNAs in cell lines. PI3K‐Akt signaling pathway was involved in regulating biological function according to KEGG analysis. Compared with the serums of trastuzumab‐sensitive patients, three miRNAs, namely miR‐200b, miR‐135b, and miR‐29a, were identified to be upregulated, and miR‐224 was downregulated in the trastuzumab‐resistant serums. ROC analysis showed that four miRNAs were correlated with trastuzumab resistance. Furthermore, three subnetwork modules of PPI network were obtained. Conclusion: The results indicated that miRNAs were reliable predictive biomarkers for response to trastuzumab. [ABSTRACT FROM AUTHOR]

PURPOSE: The aim of the current study was to assess treatment concordance and adherence to National Comprehensive Cancer Network breast cancer treatment guidelines between oncologists and an artificial intelligence advisory tool. PATIENTS AND METHODS: Study cases of patients (N = 1,977) who were at high risk for recurrence or who had metastatic disease and cell types for which the advisory tool was trained were obtained from the Chinese Society for Clinical Oncology cancer database (2012 to 2017). A cross-sectional observational study was performed to examine treatment concordance and guideline adherence among an artificial intelligence advisory tool and 10 oncologists with varying expertise—three fellows, four attending physicians, and three chief physicians. In a blinded fashion, each oncologist provided treatment advice on an average of 198 cases and the advisory tool on all cases (N = 1,977). Results are reported as rates and logistic regression odds ratios. RESULTS: Concordance for the recommended treatment was 0.56 for all physicians and higher for fellows compared with chief and attending physicians (0.68 v 0.54; 0.49; P =.001). Concordance differed by hormone receptor subtype–TNM stage, with the lowest for hormone receptor–positive human epidermal growth factor receptor 2/neu-positive cancers (0.48) and highest for triple-negative breast cancers (0.71) across most TNM stages. Adherence to National Comprehensive Cancer Network guidelines was higher for oncologists compared with the advisory tool (0.96 v 0.82; P <.003) and lower for fellows compared with attending physicians (0.93 v 0.98; 0.96; P =.04). CONCLUSION: Study findings reflect a complex breast cancer case mix, the limits of medical knowledge regarding optimum treatment, clinician practice patterns, and use of a tool that reflects expertise from one cancer center. Additional research in different practice settings is needed to understand the tool's scalability and its impact on treatment decisions and clinical and health services outcomes. [ABSTRACT FROM AUTHOR]

Background/Aims: Resistance to trastuzumab remains a common challenge to HER-2 positive breast cancer. Up until now, the underlying mechanism of trastuzumab resistance is still unclear. tRNA-derived small non-coding RNAs, a new class of small non-coding RNA (sncRNAs), have been observed to play an important role in cancer progression. However, the relationship between tRNA-derived fragments and trastuzumab resistance is still unknown. Methods: We detected the levels of tRNA-derived fragments expression in normal breast epithelial cell lines, trastuzumab-sensitive and -resistant breast cancer cell lines using high-throughput sequencing. qRT-PCR was conducted to validate the differentially expressed fragments in serums from trastuzumab-sensitive and -resistant patients. A receiver operating characteristic (ROC) curve analysis was performed to evaluate the power of specific tRNA-derived fragments. Progression-free survival (PFS) was analyzed using Cox-regression. Results: Our sequence results showed that tRNA-derived fragments were differentially expressed in the HBL-100, SKBR3, and JIMT-1 cell lines. tRF-30-JZOYJE22RR33 and tRF-27-ZDXPHO53KSN were found significantly upregulated in trastuzumab-resistant patients compared to sensitive individuals, and the ROC analysis showed that tRF-30-JZOYJE22RR33 and tRF-27-ZDXPHO53KSN were correlated with trastuzumab resistance. In a multivariate analysis, higher levels of tRF-30-JZOYJE22RR33 and tRF-27-ZDXPHO53KSN expression were associated with significantly shorter PFS in patients with metastatic HER-2 positive breast cancer. Conclusion: Our results suggest that tRF-30-JZOYJE22RR33 and tRF-27-ZDXPHO53KSN play important roles in trastuzumab resistance. Patients with high levels of tRF-30-JZOYJE22RR33 and tRF-27-ZDXPHO53KSN expression benefitted less from trastuzumab-based therapy than those that express lower-levels of these molecules. tRF-30-JZOYJE22RR33 and tRF-27-ZDXPHO53KSN may be potential biomarkers and intervention targets in the clinical treatment of trastuzumab-resistant breast cancer. [ABSTRACT FROM AUTHOR]

Placenta‐specific protein 1 (Plac1) is a cancer/testis antigen that plays a critical role in promoting cancer initiation and progression. However, the clinical significance and mechanism of Plac1 in cancer progression remain elusive. Here, we report that Plac1 is an important oncogenic and prognostic factor, which physically interacts with Furin to drive breast cancer invasion and metastasis. We have shown that Plac1 expression positively correlates with clinical stage, lymph node metastasis, hormone receptor status, and overall patient survival. Overexpression of Plac1 promoted invasion and metastasis of breast cancer cells in vitro and in vivo. Co‐immunoprecipitation and immunofluorescence cell staining assays revealed that interaction of Plac1 and Furin degraded Notch1 and generated Notch1 intracellular domain (NICD) that could inhibit PTEN activity. These findings are consistent with the results of microarray study in MDA‐MB‐231 cells overexpressing Plac1. A rescue study showed that inhibition of Furin and overexpression of PTEN in Plac1 overexpression cells blocked Plac1‐induced tumor cell progression. Taken together, our findings suggest that functional interaction between Plac1 and Furin enhances breast cancer invasion and metastasis and the Furin/NICD/PTEN axis may act as an important therapeutic target for breast cancer treatment. [ABSTRACT FROM AUTHOR]

Multidrug resistance (MDR) hinders treatment efficacy in cancer therapy. One typical mechanism contributing to MDR is the overexpression of permeability-glycoprotein (P-gp) encoded by ATP-binding cassette subfamily B member 1 (ABCB1). Basic helix-loop-helix family member e40 (BHLHE40) is a well-known transcription factor that has pleiotropic effects including the regulation of cancer-related processes. However, whether BHLHE40 regulates MDR is still unknown. Chromatin immunoprecipitation-seq study revealed BHLHE40 occupancy in the promoter of ABCB1 gene. Adriamycin (ADM)-resistant human chronic myeloid leukemia cells (K562/A) and human breast cancer cells (MCF-7/A) were established. BHLHE40 expression was downregulated in the ADM-resistant cell lines. Overexpression of BHLHE40 resensitized resistant cells to ADM, promoted cell apoptosis in vitro and suppressed tumor growth in vivo, whereas BHLHE40 knockdown induced resistance to ADM in parental cells. Moreover, we found that BHLHE40 regulated drug resistance by directly binding to the ABCB1 promoter (-1605 to -1597) and inactivating its transcription. In consistence, the expression of BHLHE40 was negatively correlated with ABCB1 in various cancer cells, while positively with cancer cell chemosensitivity and better prognosis of patients with breast cancer. The study reveals the role of BHLHE40 as a transcriptional suppressor on the expression of ABCB1, major ABC transporter in chemoresistance. The findings extend the function of BHLHE40 in tumor progression and provides a novel mechanism for the reversal of multidrug resistance. BHLHE40 inhibits multidrug resistance through directly binding to ABCB1 promoter. Model is proposed to illustrate our findings. When BHLHE40 binds to ABCB1 promoter, transcription of ABCB1 is suppressed in sensitive cells. When expression of BHLHE40 is inhibited, ABCB1 transcription initiates and translates to P-gp that pumps ADM out in resistant cells. [Display omitted] [ABSTRACT FROM AUTHOR]

Background/Aims: Androgen receptor (AR), a steroid hormone receptor, has recently emerged as prognostic and treatment-predictive marker in breast cancer. Previous studies have shown that AR is widely expressed in up to one-third of triple-negative breast cancer (TNBC). However, the role of AR in TNBC is still not fully understood, especially in mesenchymal stem- like (MSL) TNBC cells. Methods: MSL TNBC MDA-MB-231 and Hs578T breast cancer cells were exposed to various concentration of agonist 5-α-dihydrotestosterone (DHT) or nonsteroidal antagonist bicalutamide or untreated. The effects of AR on cell viability and apoptosis were determined by MTT assay, cell counting, flow cytometry analysis and protein expression of p53, p73, p21 and Cyclin D1 were analyzed by western blotting. The bindings of AR to p73 and p21 promoter were detected by ChIP assay. MDA-MB-231 cells were transplanted into nude mice and the tumor growth curves were determined and expression of AR, p73 and p21 were detected by Immunohistochemistry (IHC) staining after treatment of DHT or bicalutamide. Results: We demonstrate that AR agonist DHT induces MSL TNBC breast cancer cells proliferation and inhibits apoptosis in vitro. Similarly, activated AR significantly increases viability of MDA-MB-231 xenografts in vivo. On the contrary, AR antagonist, bicalutamide, causes apoptosis and exerts inhibitory effects on the growth of breast cancer. Moreover, DHTdependent activation of AR involves regulation in the cell cycle related genes, including p73, p21 and Cyclin D1. Further investigations indicate the modulation of AR on p73 and p21 mediated by direct binding of AR to their promoters, and DHT could make these binding more effectively. Conclusions: Our study demonstrates the tumorigenesis role of AR and the inhibitory effect of bicalutamide in AR-positive MSL TNBC both in vitro and in vivo, suggesting that AR inhibition could be a potential therapeutic approach for AR-positive TNBC patients. [ABSTRACT FROM AUTHOR]

Genetic variants in human microRNA (miRNA) genes may alter mature miRNA processing and/or target selection, and likely contribute to cancer susceptibility and disease progression. Previous studies have suggested that miR-101 may play important roles in the development of cancer by regulating key tumor-associated genes. However, the role of single nucleotide polymorphisms (SNPs) of miR-101 in breast cancer susceptibility remains unclear. In this study, we genotyped 11 SNPs of the miR-101 genes (including miR-101-1 and miR-101-2) in a case-control study of 1064 breast cancer cases and 1073 cancer-free controls. The results revealed that rs462480 and rs1053872 in the flank regions of pre-miR-101-2 were significantly associated with increased risk of breast cancer (rs462480 AC/CC vs AA: adjusted OR = 1.182, 95% CI: 1.030–1.357, P = 0.017; rs1053872 CG/GG vs CC: adjusted OR = 1.179, 95% CI: 1.040–1.337, P = 0.010). However, the remaining 9 SNPs were not significantly associated with risk of breast cancer. Additionally, combined analysis of the two high-risk SNPs revealed that subjects carrying the variant genotypes of rs462480 and rs1053872 had increased risk of breast cancer in a dose-response manner (Ptrend = 0.002). Compared with individuals with “0–1” risk allele, those carrying “2–4” risk alleles had 1.29-fold risk of breast cancer. In conclusion, these findings suggested that the SNPs rs462480 and rs1053872 residing in miR-101-2 gene may have a solid impact on genetic susceptibility to breast cancer, which may improve our understanding of the potential contribution of miRNA SNPs to cancer pathogenesis. [ABSTRACT FROM AUTHOR]

The molecular mechanisms that underpin invasive ductal breast cancer (IDC) invasion and metastasis are incompletely understood. The oncogene, mouse double minute 2 (MDM2), has been implicated in the pathogenesis of numerous cancers, where it stimulates the expression of matrix metalloproteinase 9 (MMP9), an important enzyme in the breakdown of the extracellular matrix. However, its role in breast cancer remains poorly understood. This study assessed the clinical significance of MDM2 expression in IDC and used in vitro expression assays to determine the molecular roles of MDM2. Immunohistochemical staining for MMP9 and MDM2 was performed using archived tumor blocks from 321 women who underwent surgical resection for IDC at the First Affiliated Hospital of Nanjing Medical University, China between January 2002 and December 2003. MCF-7 and MDA-MD-231 cell lines were transfected with siRNA targeted against MDM2, or MDM2 was overexpressed using transiently expressed vectors. The invasion, cell migration and proteolytic capabilities of cells that over- or underexpressed MDM2 was then assessed and compared against control cells, in addition to the consequent effects on MMP9 expression using RT-PCR. In vivo, 54.9% and 49.6% of samples were positive for MMP9 and MDM2 expression, respectively, and their expression was significantly correlated (r2 = 0.171, P = 0.012). Moreover, MDM2 expression was markedly correlated with disease-free survival (HR 2.56, 95% CI 1.02–6.40, P = 0.038). In vitro, MDM2 overexpression significantly enhanced cell invasion, migration and proteolysis compared with control cells, and the converse effects were observed after MDM2-siRNA treatment. MDM2 overexpression induced MMP9 expression in a dose-dependent manner. Taken together, these results suggest that high levels of MDM2 are associated with a poorer prognosis in IDC. This might result from increased tumor invasiveness due to enhanced MMP9 expression causing increased extracellular matrix breakdown. [ABSTRACT FROM AUTHOR]

Abstract: Vascular endothelial growth factor (VEGF) has been implicated in breast tumor angiogenesis. And tumor necrosis factor-α (TNF-α) is a positive regulator of VEGF. This study was aimed to identify the signalling pathway of TNF-α in VEGF expression regulation in breast cancer cell line MCF7. Using luciferase reporter assays, we demonstrated that TNF-α significantly increased activator protein-1 (AP-1) transcriptional activity in the MCF7 cells. The expression of the AP-1 family members c-Jun, c-Fos and JunB and phosphorylation levels of c-Jun were upregulated by TNF-α, whereas other AP-1 family members Fra-1, Fra-2, and JunD were unaffected. The activation of AP-1 was associated with the formation of p-c-Jun-c-Jun and p-c-Jun-JunB homodimers. Furthermore, the phosphorylation levels of c-Jun N-terminal kinase (JNK) but not P38 and ERK were elevated by TNF-α in MCF7 cells. TNF-α potently upregulated the mRNA and protein levels of VEGF, which were significantly reversed by JNK inhibitor SP600125. Finally using chromatin immunoprecipitation (CHIP) assays, we found that p-c-Jun bound to the VEGF promoter and regulated VEGF transcription directly. These data suggest that the pro-inflammatory cytokine TNF-α is a critical regulator of VEGF expression in breast cancer cells, at least partially via a JNK and AP-1 dependent pathway. [Copyright &y& Elsevier]

Background: Tucidinostat (formerly known as chidamide) is an oral subtype-selective histone deacetylase inhibitor. In an exploratory study, the combination of tucidinostat with exemestane showed preliminary signs of encouraging anti-tumour activity in patients with advanced hormone receptor-positive breast cancer. To build on these findings, we aimed to assess the efficacy and safety of this combination in a randomised trial in a larger population of postmenopausal patients with advanced, hormone receptor-positive breast cancer.Methods: We did the randomised, double-blind, placebo-controlled, phase 3 ACE trial at 22 specialist cancer centres in China. Eligible patients were postmenopausal women (aged ≥60 years or aged <60 years if their serum follicle-stimulating hormone and oestradiol concentrations were within postmenopausal ranges) with hormone receptor-positive, HER2-negative breast cancer, whose disease had relapsed or progressed after at least one endocrine therapy (either in advanced or metastatic or adjuvant setting), and who had at least one measurable lesion, adequate organ function, Eastern Cooperative Oncology Group (ECOG) performance status of 0-1, and adequate haematological and biochemical parameters. Endocrine therapy did not have to be the most recent therapy before randomisation, but recurrence or progression after the most recent therapy was a prerequisite. Patients were randomly assigned (2:1) by a dynamic randomisation scheme via an interactive web-response system to receive 30 mg oral tucidinostat or placebo twice weekly. All patients in both groups also received 25 mg oral exemestane daily. Randomisation was stratified according to the presence of visceral metastases (yes vs no). Patients, investigators, study site staff, and the sponsor were masked to treatment assignment. The primary endpoint was investigator-assessed progression-free survival. Efficacy analyses were done in the full analysis set population, comprising all patients who received at least one dose of any study treatment, and safety analyses were done in all patients who received at least one dose of any study treatment and for whom at least one safety case report form was available. This study is registered with ClinicalTrials.gov, number NCT02482753. The study has reached the required number of events for final analysis of the primary endpoint. The trial is no longer enrolling patients, but follow-up for investigation of overall survival is ongoing.Findings: Between July 20, 2015, and June 26, 2017, 365 patients were enrolled and randomly assigned, 244 to the tucidinostat group and 121 to the placebo group. The median duration of follow-up was 13·9 months (IQR 9·8-17·5). Investigator-assessed median progression-free survival was 7·4 months (95% CI 5·5-9·2) in the tucidinostat group and 3·8 months (3·7-5·5) in the placebo group (HR 0·75 [95% CI 0·58-0·98]; p=0·033). The most common grade 3 or 4 adverse events in either group were neutropenia (124 [51%] of 244 patients in the tucidinostat group vs three [2%] of 121 patients in the placebo group), thrombocytopenia (67 [27%] vs three [2%]), and leucopenia (46 [19%] vs three [2%]). Serious adverse events of any cause occurred in 51 (21%) of 244 patients in the tucidinostat group and seven (6%) of 121 patients in the placebo group. No treatment-related deaths were reported.Interpretation: Tucidinostat plus exemestane improved progression-free survival compared with placebo plus exemestane in patients with advanced, hormone receptor-positive, HER2-negative breast cancer that progressed after previous endocrine therapy. Grade 3-4 haematological adverse events were more common in the tucidinostat plus exemestane group than in the placebo plus exemestane group. Tucidinostat plus exemestane could represent a new treatment option for these patients.Funding: Chipscreen Biosciences. [ABSTRACT FROM AUTHOR]

The emergence of antibody-drug conjugates (ADCs) targeting trophoblast cell-surface antigen-2 (Trop-2) has reshaped the therapeutic landscape of advanced breast cancer. Accurate profiling of the Trop-2 status of tumor cells can facilitate the identification of patients who will benefit from Trop-2-targeting therapy; however limited analytical method has hindered this process. In this study, we have proposed a specific and sensitive biosensor for visual tracking of the Trop-2 status of breast cancer cells based on tetrahedral DNA nanostructure (TDN)-decorated Fe-based metal-organic framework nanoparticles (TDN-PCN-222 (Fe)). In the design, a dual-aptamer-assisted biomimetic capture strategy shows high capture efficiency while maintaining the viability and original phenotype of captured cells, ensuring the accurate profiling of the Trop-2 status. Meanwhile, by using the high intrinsic peroxidase activity and excellent targeting ability of Trop-2-specific aptamer-linked TDN-PCN-222 (Fe), specific detection of Trop-2-positive tumor cells can be achieved with a limit of detection (LOD) of 10 cells/mL, and the Trop-2 status of tumor cells can be visually tracked. Moreover, the proposed biosensor has been successfully used for tracking the Trop-2 status of tumor cells in breast cancer tissues, suggesting that our method has great promise for clinical applications. • Colorimetric sensor is fabricated to track Trop-2 status of breast cancer cells. • Specific and sensitive detection of Trop-2-positive tumor cells can be achieved. • The capture strategy can maintain the viability and phenotype of captured cells. • Visual profiling of Trop-2 status of tumor cells in cancer tissues is possible. [ABSTRACT FROM AUTHOR]

Breast cancer is one of the most common malignancies and bone is the commonest site of distant metastases. Evidences indicate that adequate supply of vitamin D will decrease the morbidity and mortality of breast cancer. However, the main role of vitamin D deficiency in breast cancer bone metastases remains unclear. In this study, the relationship between vitamin D and breast cancer bone metastases were evaluated. Results showed that 1,25(OH) 2 D 3 can not only inhibit the proliferation, migration and invasion of breast cancer cell TM40D in vitro, but also attenuate the breast cancer cell TM40D-induced bone destruction in vivo, whose underlying mechanism was at least partially through decreasing the number of the osteoclasts. To our knowledge, this is the first to use 1-alpha-hydroxylase [1α(OH)ase] knockout mice which characterized vitamin D deficiency to establish the breast cancer bone metastases model. Based on this model, we also found that vitamin D deficiency will accelerate the osteolytic lesions, and 1,25(OH) 2 D 3 supplement will restrain osteolytic lesions. Therefore, these findings suggest that vitamin D has the potential capacity to be a therapeutic agent for the breast cancer bone metastases. [ABSTRACT FROM AUTHOR]

Breast cancer is the most common cancer diagnosed and is the second leading cause of cancer death among women in the US. For breast cancer, early diagnosis and efficient therapy remains a significant clinical challenge. Therefore, it is necessary to identify novel tumor associated molecules to target for biomarker development and immunotherapy. In this regard, cancer testis antigens (CTAs) have emerged as a potential clinical biomarker targeting immunotherapy for various malignancies due to the nature of its characteristics. CTAs are a group of tumor associated antigens (TAAs) that display normal expression in immune-privileged organs, but display aberrant expression in several types of cancers, particularly in advanced cancers. Investigation of CTAs for the clinical management of breast malignancies indicates that these TAAs have potential roles as novel biomarkers, with increased specificity and sensitivity compared to those currently used in the clinic. Moreover, TAAs could be therapeutic targets for cancer immunotherapy. This review is an attempt to address the promising CTAs in breast cancer and their possible clinical implications as biomarkers and immunotherapeutic targets with particular focus on challenges and future interventions. [ABSTRACT FROM AUTHOR]

Abstract: Background: Leptin is a circulating peptide hormone, encoded by the obesity (ob) gene, acting as a regulator of food intake via hypothalamic-mediated effects. Recent studies have shown that leptin and leptin receptor (ObR) are involved in the carcinogenesis and development of breast cancer. In addition, functional cross talk between leptin and estrogen signaling has been registered. Here, we investigated the relation of leptin and ObR expression with survival in women with breast cancer treated with the anti-estrogen tamoxifen, and whether leptin can interfere with the estrogen receptor alpha (ERα) and the effect of tamoxifen in breast cancer cells. Methods: The protein expression of leptin and ObRb in 114 breast cancer samples was evaluated by immunohistochemistry, quantified by Immunoreactivity Score (IRS) and correlated to survival and other clinicopathological features. The expression of ObRb in ERα positive MCF-7 breast cancer cells was examined by immunofluorescence and western blot. Leptin effect on cell proliferation was determined by MTT assay. The interference of leptin with tamoxifen on ERα degradation was studied by western blot and immunofluorescence. Effects of leptin on the transcriptional activity of ERα were explored using luciferase reporter assays. Results: Positive staining (Immunoreactivity Score, IRS≥1) of leptin and ObR isoform ObRb in breast cancer tissues were seen in 79.8% and 85.1% of patients respectively. In overall and in tamoxifen-treated breast cancer patients, leptin expression (IRS≥1) correlated with poor prognosis, (log-rank test, P =0.016, overall; P =0.031, tamoxifen-treated). Overexpressed ObRb was found by western blotting andimmunofluorescence in MCF-7 as well as in MDA-MB-231, T47D, and MDA-MB-435 cell lines. Tamoxifen (1000μM) significantly inhibited the proliferation of MCF-7 cells, degraded ERα and reduced ERα-dependent transcription from estrogen response element-containing promoter. On the contrary, simultaneous treatment with leptin (100ng/ml) significantly attenuated these effects, similar to the effects of estradiol. Conclusions: Leptin correlated significantly with poor prognosis in overall and tamoxifen-treated breast cancer patients. Leptin interferes with the action of tamoxifen in MCF-7 cells, at least partly, through inducing increased nuclear expression of ERα. Thus, leptin may contribute to tamoxifen resistance and consequently, leptin suppression could be a novel way of circumventing resistance to anti-estrogen treatment. [Copyright &y& Elsevier]