Clinical Translatability of "Identified" Circulating miRNAs for Diagnosing Breast Cancer: Overview and Update

Beyond the Genome: Deciphering the Role of MALAT1 in Breast Cancer Progression

The MALAT1, a huge non-coding RNA, recently came to light as a multifaceted regulator in the intricate landscape of breast cancer (BC) progression. This review explores the multifaceted functions and molecular interactions of MALAT1, shedding light on its profound implications for understanding BC pathogenesis and advancing therapeutic strategies. The article commences by acknowledging the global impact of BC and the pressing need for insights into its molecular underpinnings. It is stated that the core lncRNA MALAT1 has a range of roles in both healthy and diseased cell functions. The core of this review unravels MALAT1's multifaceted role in BC progression, elucidating its participation in critical processes like resistance, invasion, relocation, and proliferating cells to therapy. It explores the intricate mechanisms through which MALAT1 modulates gene expression, interacts with other molecules, and influences signalling pathways. Furthermore, the paper emphasizes MALAT1's clinical significance as a possible prognostic and diagnostic biomarker. Concluding on a forward-looking note, the review highlights the broader implications of MALAT1 in BC biology, such as its connections to therapy resistance and metastasis. It underscores the significance of deeper investigations into these intricate molecular interactions to pave the way for precision medicine approaches. This review highlights the pivotal role of MALAT1 in BC progression by deciphering its multifaceted functions beyond the genome, offering profound insights into its implications for disease understanding and the potential for targeted therapeutic interventions.

Diagnostic value of circulating miR-155 for breast cancer: a meta-analysis

Backgrounds

The value of circulating microRNA (miR)-155 for breast cancer (BC) diagnosis may differ in different studies. Therefore, we conducted this systematic review and meta-analysis to evaluate the potential application of circulating miR-155 in the diagnosis of BC.

Methods

Articles published before December 2023 and in English were searched in these databases: PubMed, Web of Science, Medline, EMBASE and Google Scholar. A summary of sensitivity, specificity, positive likelihood ratios (PLR), negative likelihood ratios (NLR), and diagnostic odds ratio (DOR) were calculated from the true positive (TP), true negative (TN), false positive (FP) and false negative (FN) of each study. Additionally, the summary receive-operating characteristics (SROC) curve was constructed to summarize the TP and FP rates.

Results

The pooled parameters calculated were as follows: sensitivity, 0.93 (95% CI: 0.83-0.97); specificity, 0.85 (95% CI: 0.74-0.92); PLR, 6.4 (95% CI: 3.4-11.9); NLR, 0.09 (95% CI: 0.04-0.20); and DOR, 74 (95% CI: 22-247). The analysis showed a significant heterogeneity (sensitivity, I2 = 95.19%, p < 0.001; specificity, I2 = 95.29%, p < 0.001; DOR, I2 = 92.9%, p < 0.001). The SROC curve was with an area under curve (AUC) of 0.95 (95% CI: 0.93-0.97).

Conclusion

Circulating miR-155 has a potential in the diagnosis of BC.

Role of MicroRNA in Hypoxic Tumours and their Potential as Biomarkers for Early Detection of Cancer

Hypoxia is a pathophysiological condition characterized by oxygen deficiency in tissues, which negatively affects normal biological functions. It is a typical microenvironment character of almost all solid tumours. Noncoding RNA are small functional RNA molecules that regulate gene expression at chromatin and posttranscriptional levels. Micro-RNAs (miRNAs) are a type of noncoding RNA and are ~12-22 nucleotides long that are crucial in regulating gene expression by partnering with the mRNAs of protein-coding genes. It is widely reported that miRs play an important role in various key processes and pathways during tumour formation, as well as advancement in hypoxic tumors by influencing the HIF pathway. The role of miRNAs in hypoxic tumours, namely in pancreatic, kidney, breast, lung and colorectal, are described. These miRNAs have immense potential as diagnostic and prognostic biomarkers for early cancer detection.

Characterization of a miRNA Signature with Enhanced Diagnostic and Prognostic Power for Patients with Bladder Carcinoma

Bladder carcinoma is globally among the most prevalent cancers and is associated with a high mortality rate at advanced stages. Its detection relies on invasive diagnostic methods that are unpleasant for the patient. Non-invasive molecular biomarkers, such as miRNAs, could serve as alternatives for early detection and prognosis of this malignancy. We designed a computational approach that combines transcriptome profiling, survival analyses, and calculation of diagnostic power in order to isolate miRNA signatures with high diagnostic and prognostic utility. Our analysis of TCGA-BLCA data from 429 patients yielded one miRNA signature, consisting of five upregulated and three downregulated miRNAs with cumulative diagnostic power that outperforms current diagnostic methods. The same miRNAs have a strong prognostic significance since their expression is associated with the overall survival of bladder cancer patients. We evaluated the expression of this signature in 19 solid cancer types, supporting its unique diagnostic utility for bladder carcinoma. We provide computational evidence regarding the functional implications of this miRNA signature in cell cycle regulation, demonstrating its abundance in body fluids, including peripheral blood and urine. Our study characterized a novel miRNA signature with the potential to serve as a non-invasive method for bladder cancer diagnosis and prognosis.

Evaluating the Role of Circulating MicroRNAs in Predicting Long-Term Survival Outcomes in Breast Cancer: A Prospective, Multicenter Clinical Trial

BACKGROUND

While long-term outcomes have improved for patients with breast cancer, 20% to 30% will still develop recurrence, and identifying these patients remains a challenge. MicroRNAs (miRNAs) are small, noncoding molecules that modulate genetic expression and affect oncogenesis.

STUDY DESIGN

This prospective, multicenter trial (ICORG10/11-NCT01722851) recruited patients undergoing neoadjuvant chemotherapy across 8 Irish centers. Predetermined miRNAs were quantified from patient whole blood using quantitative reverse transcriptase polymerase chain reaction. Venous sampling was performed at diagnosis (timepoint 1) and midway during neoadjuvant chemotherapy (timepoint 2 [T2]). miRNA expression profiles were correlated with recurrence-free survival (RFS), disease-free survival (DFS), and overall survival. Data analysis was performed using R v3.2.3.

RESULTS

A total of 124 patients were recruited with a median age of 55.0 years. The median follow-up was 103.1 months. Increased miR-145 expression at T2 was associated with improved RFS (hazard ratio 0.00; 95% confidence interval [CI] 0.00 to 0.99; p = 0.050). Using survival regression tree analysis, a relative cutoff of increased miR-145 expression greater than 0.222 was associated with improved RFS (p = 0.041). Increased miR-145 expression at T2 trended towards significance in predicting improved DFS (hazard ratio 0.00; 95% CI 0.00 to 1.42; p = 0.067). Using survival regression tree analysis, a relative cutoff of increased miR-145 expression greater than 0.222 was associated with improved DFS (p = 0.012). No miRNAs correlated with overall survival.

CONCLUSIONS

ICORG10/11 is the first Irish multicenter, translational research trial evaluating circulatory miRNAs as biomarkers predictive of long-term survival and correlated increased miR-145 expression with enhanced outcomes in early-stage breast cancer. Validation of these findings is required in the next generation of translational research trials.

Circulating microRNAs as Reliable Tumor Biomarkers: Opportunities and Challenges Facing Clinical Application

MicroRNAs (miRNAs) are involved in the development of human malignancies, and cells have the ability to secrete these molecules into extracellular compartments. Thus, cell-free miRNAs (circulating miRNAs) can potentially be used as biomarkers to evaluate pathophysiological changes. Although circulating miRNAs have been proposed as potential noninvasive tumor biomarkers for diagnosis, prognosis, and response to therapy, their routine application in the clinic is far from being achieved. This review focuses on the recent progress regarding the value of circulating miRNAs as noninvasive biomarkers, with specific consideration of their relevant clinical applications. In addition, we provide an in-depth analysis of the technical challenges that impact the assessment of circulating miRNAs. We also highlight the significance of integrating circulating miRNAs with the standard laboratory biomarkers to boost sensitivity and specificity. The current status of circulating miRNAs in clinical trials as tumor biomarkers is also covered. These insights and general guidelines will assist researchers in experimental practice to ensure quality standards and repeatability, thus improving future studies on circulating miRNAs. SIGNIFICANCE STATEMENT: Our review will boost the knowledge behind the inconsistencies and contradictory results observed among studies investigating circulating miRNAs. It will also provide a solid platform for better-planned strategies and standardized techniques to optimize the assessment of circulating cell-free miRNAs.

Addressing the Clinical Feasibility of Adopting Circulating miRNA for Breast Cancer Detection, Monitoring and Management with Artificial Intelligence and Machine Learning Platforms

Detecting breast cancer (BC) at the initial stages of progression has always been regarded as a lifesaving intervention. With modern technology, extensive studies have unraveled the complexity of BC, but the current standard practice of early breast cancer screening and clinical management of cancer progression is still heavily dependent on tissue biopsies, which are invasive and limited in capturing definitive cancer signatures for more comprehensive applications to improve outcomes in BC care and treatments. In recent years, reviews and studies have shown that liquid biopsies in the form of blood, containing free circulating and exosomal microRNAs (miRNAs), have become increasingly evident as a potential minimally invasive alternative to tissue biopsy or as a complement to biomarkers in assessing and classifying BC. As such, in this review, the potential of miRNAs as the key BC signatures in liquid biopsy are addressed, including the role of artificial intelligence (AI) and machine learning platforms (ML), in capitalizing on the big data of miRNA for a more comprehensive assessment of the cancer, leading to practical clinical utility in BC management.

Urinary miRNAs as a Diagnostic Tool for Bladder Cancer: A Systematic Review

Bladder cancer is the 10th most common cancer type worldwide. Cystoscopy represents the gold standard for bladder cancer diagnosis, but this procedure is invasive and painful, hence the need to identify new biomarkers through noninvasive procedures. microRNAs (miRNAs) are considered to be promising diagnostic molecules, because they are very stable in biological fluids (including urine) and easily detectable. This systematic review analyses the power of urine miRNAs as bladder cancer diagnostic markers. We conducted this systematic review according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. A total of 293 records related to miRNAs and their diagnostic significance in BC were retrieved from the PubMed and Embase databases. A systematic search of the literature was performed, and a total of 25 articles (N = 4054 participants) were identified and reviewed. Although many of the selected studies were of high scientific quality, the results proved to be quite heterogeneous, because we did not identify a univocal consensus for a specific miRNA signature but only isolated the signatures. We did not identify a univocal consensus for a specific diagnostic miRNA signature but only isolated the signatures, some of them with better diagnostic power compared to the others.

Discovering Common miRNA Signatures Underlying Female-Specific Cancers via a Machine Learning Approach Driven by the Cancer Hallmark ERBB

Big data processing, using omics data integration and machine learning (ML) methods, drive efforts to discover diagnostic and prognostic biomarkers for clinical decision making. Previously, we used the TCGA database for gene expression profiling of breast, ovary, and endometrial cancers, and identified a top-scoring network centered on the ERBB2 gene, which plays a crucial role in carcinogenesis in the three estrogen-dependent tumors. Here, we focused on microRNA expression signature similarity, asking whether they could target the ERBB family. We applied an ML approach on integrated TCGA miRNA profiling of breast, endometrium, and ovarian cancer to identify common miRNA signatures differentiating tumor and normal conditions. Using the ML-based algorithm and the miRTarBase database, we found 205 features and 158 miRNAs targeting ERBB isoforms, respectively. By merging the results of both databases and ranking each feature according to the weighted Support Vector Machine model, we prioritized 42 features, with accuracy (0.98), AUC (0.93–95% CI 0.917–0.94), sensitivity (0.85), and specificity (0.99), indicating their diagnostic capability to discriminate between the two conditions. In vitro validations by qRT-PCR experiments, using model and parental cell lines for each tumor type showed that five miRNAs (hsa-mir-323a-3p, hsa-mir-323b-3p, hsa-mir-331-3p, hsa-mir-381-3p, and hsa-mir-1301-3p) had expressed trend concordance between breast, ovarian, and endometrium cancer cell lines compared with normal lines, confirming our in silico predictions. This shows that an integrated computational approach combined with biological knowledge, could identify expression signatures as potential diagnostic biomarkers common to multiple tumors.

Circulating miRNAs in Breast Cancer Diagnosis and Prognosis

Great improvement has been made in the diagnosis and therapy of breast cancer patients. However, the identification of biomarkers for early diagnosis, prognosis, therapy assessment and monitoring, including drug resistance and the early detection of micro-metastases, is still lacking. Recently, circulating microRNAs (miRNAs), circulating freely in the blood stream or entrapped in extracellular vesicles (EVs), have been shown to have a potential diagnostic, prognostic or predictive power. In this review, recent findings are summarized, both at a preclinical and clinical level, related to miRNA applicability in the context of breast cancer. Different aspects, including clinical and technical challenges, are discussed, describing the potentialities of miRNA use in breast cancer. Even though more methodological standardized studies conducted in larger and selected patient cohorts are needed to support the effective clinical utility of miRNA as biomarkers, they could represent novel and accessible tools to be transferred into clinical practice.

Combinatorial Power of cfDNA, CTCs and EVs in Oncology

Liquid biopsy is a promising technique for clinical management of oncological patients. The diversity of analytes circulating in the blood useable for liquid biopsy testing is enormous. Circulating tumor cells (CTCs), cell-free DNA (cfDNA) and extracellular vesicles (EVs), as well as blood cells and other soluble components in the plasma, were shown as liquid biopsy analytes. A few studies directly comparing two liquid biopsy analytes showed a benefit of one analyte over the other, while most authors concluded the benefit of the additional analyte. Only three years ago, the first studies to examine the value of a characterization of more than two liquid biopsy analytes from the same sample were conducted. We attempt to reflect on the recent development of multimodal liquid biopsy testing in this review. Although the analytes and clinical purposes of the published multimodal studies differed significantly, the additive value of the analytes was concluded in almost all projects. Thus, the blood components, as liquid biopsy reservoirs, are complementary rather than competitive, and orthogonal data sets were even shown to harbor synergistic effects. The unmistakable potential of multimodal liquid biopsy testing, however, is dampened by its clinical utility, which is yet to be proven, the lack of methodical standardization and insufficiently mature reimbursement, logistics and data handling.

The miR-200 Family of microRNAs: Fine Tuners of Epithelial-Mesenchymal Transition and Circulating Cancer Biomarkers

The miR-200 family of microRNAs (miRNAs) includes miR-200a, miR-200b, miR-200c, miR-141 and miR-429, five evolutionarily conserved miRNAs that are encoded in two clusters of hairpin precursors located on human chromosome 1 (miR-200b, miR-200a and miR-429) and chromosome 12 (miR-200c and miR-141). The mature -3p products of the precursors are abundantly expressed in epithelial cells, where they contribute to maintaining the epithelial phenotype by repressing expression of factors that favor the process of epithelial-to-mesenchymal transition (EMT), a key hallmark of oncogenic transformation. Extensive studies of the expression and interactions of these miRNAs with cell signaling pathways indicate that they can exert both tumor suppressor- and pro-metastatic functions, and may serve as biomarkers of epithelial cancers. This review provides a summary of the role of miR-200 family members in EMT, factors that regulate their expression, and important targets for miR-200-mediated repression that are involved in EMT. The second part of the review discusses the potential utility of circulating miR-200 family members as diagnostic/prognostic biomarkers for breast, colorectal, lung, ovarian, prostate and bladder cancers.

Biological Role and Clinical Implications of microRNAs in BRCA Mutation Carriers

Women with pathogenic germline mutations in BRCA1 and BRCA2 genes have an increased risk to develop breast and ovarian cancer. There is, however, a high interpersonal variability in the modality and timing of tumor onset in those subjects, thus suggesting a potential role of other individual’s genetic, epigenetic, and environmental risk factors in modulating the penetrance of BRCA mutations. MicroRNAs (miRNAs) are small noncoding RNAs that can modulate the expression of several genes involved in cancer initiation and progression. MiRNAs are dysregulated at all stages of breast cancer and although they are accessible and evaluable, a standardized method for miRNA assessment is needed to ensure comparable data analysis and accuracy of results. The aim of this review was to highlight the role of miRNAs as potential biological markers for BRCA mutation carriers. In particular, biological and clinical implications of a link between lifestyle and nutritional modifiable factors, miRNA expression and germline BRCA1 and BRCA2 mutations are discussed with the knowledge of the best available scientific evidence.

miRNA-Based Therapeutics in Breast Cancer: A Systematic Review

Background

Breast cancer (BC) is the most common cancer in females and despite advances in treatment, it represents the leading cause of cancer mortality in women worldwide. Conventional therapeutic modalities have significantly improved the management of BC patients, but subtype heterogeneity, drug resistance, and tumor relapse remain the major factors to hamper the effectiveness of therapy for BC. In this scenario, miRNA(miR)-based therapeutics offer a very attractive area of study. However, the use of miR-based therapeutics for BC treatment still represents an underdeveloped topic. Therefore, this systematic review aims at summarizing current knowledge on promising miR-based therapeutics for BC exploring original articles focusing on in vivo experiments.

Methods

The current systematic review was performed according to PRISMA guidelines. PubMed and EMBASE databases were comprehensively explored to perform the article search.

Results

Twenty-one eligible studies were included and analyzed: twelve focused on antitumor miR-based therapeutics and nine on metastatic miR-based therapeutics. We found 18 different miRs tested as potential therapeutic molecules in animal model experiments. About 90% of the selected studies evaluate the efficiency and the safety of miRs as therapeutic agents in triple-negative (TN)-BC mouse models. Among all founded miR-based therapeutics, miR-21 emerged to be the most investigated and proposed as a potential antitumoral molecule for TNBC treatment. Besides, miR-34a and miR-205a appeared to be successful antitumoral and antimetastatic molecules.

Conclusions

Our analysis provides a snapshot of the current scenario regarding the miRs as therapeutic molecules in BC. Nevertheless, despite many efforts, none of the selected studies goes beyond preclinical studies, and their translatability in the clinical practice seems quite premature.

A highly sensitive electrochemical microRNA-21 biosensor based on intercalating methylene blue signal amplification and a highly dispersed gold nanoparticles/graphene/polypyrrole composite

Numerous clinical studies suggest that microRNAs (miRNAs) are indicative biomolecules for the early diagnosis of cancer. This work aims to develop a cost-effective and label-free electrochemical biosensor to detect miRNA-21, a biomarker of breast cancer. An electrochemical sensor is fabricated using a nanocomposite, consisting of graphene (GP), polypyrrole (PPY) and gold nanoparticles (AuNPs), modified onto a screen-printed carbon electrode (SPCE) to improve electron transfer properties and increase the degree of methylene blue (MB) intercalation for signal amplification. The GP/PPY-modified electrode offers good electrochemical reactivity and high dispersibility of AuNPs, resulting in excellent sensor performance. Peak current of the MB redox process, which is proportional to miRNA-21 concentration on the electrode surface, is monitored by differential pulse voltammetry (DPV). Under optimal conditions, this sensor is operated by monitoring the MB signal response due to the amount of hybridization products between miRNA-21 target molecules and DNA-21 probes immobilized on the electrode. The proposed biosensor reveals a linear range from 1.0 fM to 1.0 nM with a low detection limit of 0.020 fM. In addition, the miRNA-21 biosensor provides good selectivity, high stability, and satisfactory reproducibility, which shows promising potential in clinical research and diagnostic applications.

Impact of COVID-19 pandemic on the oncologic care continuum: urgent need to restore patients care to pre-COVID-19 era

Background:

Globally, cancer is the second leading cause of death, and it is estimated that over 18·1 million new cases are diagnosed annually. The COVID-19 pandemic has significantly impacted almost every aspect of the provision and management of cancer care worldwide. The time-critical nature of COVID-19 diagnosis and the large number of patients requiring hospitalisation necessitated the rerouting of already limited resources available for cancer services and programmes to the care of COVID-19 patients. Furthermore, the stringent social distancing, restricted in-hospital visits and lockdown measures instituted by various governments resulted in the disruption of the oncologic continuum including screening, diagnostic and prevention programmes, treatments and follow-up services as well as research and clinical trial programmes.

Materials and Methods:

We searched several databases from October 2020 to January 2021 for relevant studies published in English between 2020 and 2021 and reporting on the impact of COVID-19 on the cancer care continuum. This narrative review paper describes the impact of the COVID-19 pandemic on the cancer patient care continuum from screening and prevention to treatments and ongoing management of patients.

Conclusions:

The COVID-19 pandemic has profoundly impacted cancer care and the management of cancer services and patients. Nevertheless, the oncology healthcare communities worldwide have done phenomenal work with joint and collaborative efforts, utilising best available evidence-based guidelines to continue to give safe and effective treatments for cancer patients while maintaining the safety of patients, healthcare professionals and the general population. Nevertheless, several healthcare centres are now faced with significant challenges with the management of the backlog of screening, diagnosis and treatment cases. It is imperative that governments, leaders of healthcare centres and healthcare professionals take all necessary actions and policies focused on minimising further system-level delays to cancer screening, diagnosis, treatment initiation and clearing of all backlogs cases from the COVID-19 pandemic in order to mitigate the negative impact on cancer outcomes.

Angiogenesis regulation by microRNAs and long non-coding RNAs in human breast cancer

MicroRNAs (miRNAs) and long non-coding RNAs (lncRNAs) are capable of regulating gene expression post-transcriptionally. Since the past decade, a number of in vitro, in vivo, and clinical studies reported the roles of these non-coding RNAs (ncRNAs) in regulating angiogenesis, an important cancer hallmark that is associated with metastases and poor prognosis. The specific roles of various miRNAs and lncRNAs in regulating angiogenesis in breast cancer, with particular focus on the downstream targets and signalling pathways regulated by these ncRNAs will be discussed in this review. In light of the recent trend in exploiting ncRNAs as cancer therapeutics, the potential use of miRNAs and lncRNAs as biomarkers and novel therapeutic agent against angiogenesis was also discussed.

miRNA-195 expression in the tumor tissues of female Brazilian breast cancer patients with operable disease

OBJECTIVE

This study aimed to assess miRNA-195 expression in the tumor tissues from a cohort of Brazilian female breast cancer patients undergoing neoadjuvant chemotherapy (NAC) and evaluate its correlation with various clinicopathological markers.

METHODS

Quantitative reverse transcription polymerase chain reaction (qRT-PCR) was used to evaluate the miRNA-195 expression in tumor tissues from a cohort of female breast cancer patients undergoing NAC. This expression was then correlated with the occurrence of several distinct breast cancer molecular subtypes and other clinicopathological variables.

RESULTS

A total of 55 patients were included in this study, 28 (50.9%) of whom were treated using NAC. Tumor miRNA-195 expression was suppressed in breast cancer patients, regardless of their exposure to systemic treatments, histological grade, size, nodal status, and tumor-node-metastasis (TNM) staging. This was more pronounced in luminal and triple-negative patients, and patient's response to NAC was correlated with an increase in miRNA-195 expression.

CONCLUSION

miRNA-195 is downregulated in the tumor tissues of Brazilian breast cancer patients regardless of NAC exposure; this reinforces its role as a tumor suppressor and a potential biomarker for chemotherapy response.

The role of tumor suppressor short non-coding RNAs on breast cancer

Characterized by remarkable levels of aggression and malignancy, BC remains one of the leading causes of death in females world wide. Accordingly, significant efforts have been made to develop early diagnostic tools, increase treatment efficacy, and improve patient prognosis. Hopefully, many of the molecular mechanisms underlying BC have been detected and show promising targeting potential. In particular, short and long non-coding RNAs (ncRNAs) are a class of endogenous BC controllers and include a number of different species including microRNAs, Piwi-interacting RNAs, small nucleolar RNA, short interfering RNAs, and tRNA-derivatives. In this review, we discuss the tumor suppressing roles of ncRNAs in the context of BC, and the mechanisms by which ncRNAs target tumor hallmarks, including apoptosis, proliferation, invasion, metastasis, epithelial-mesenchymal transition, angiogenesis, and cell cycle progression, in addition to their diagnostic and prognostic significance in cancer treatment.

Five microRNAs in Serum Are Able to Differentiate Breast Cancer Patients From Healthy Individuals

Breast cancer is the cancer with the most incidence and mortality in women. microRNAs are emerging as novel prognosis/diagnostic tools. Our aim was to identify a serum microRNA signature useful to predict cancer development. We focused on studying the expression levels of 30 microRNAs in the serum of 96 breast cancer patients vs. 92 control individuals. Bioinformatic studies provide a microRNA signature, designated as a predictor, based on the expression levels of five microRNAs. Then, we tested the predictor in a group of 60 randomly chosen women. Lastly, a proteomic study unveiled the overexpression and downregulation of proteins differently expressed in the serum of breast cancer patients vs. that of control individuals. Twenty-six microRNAs differentiate cancer tissue from healthy tissue, and 16 microRNAs differentiate the serum of cancer patients from that of the control group. The tissue expression of miR-99a, miR-497, miR-362, and miR-1274, and the serum levels of miR-141 correlated with patient survival. Moreover, the predictor consisting of miR-125b, miR-29c, miR-16, miR-1260, and miR-451 was able to differentiate breast cancer patients from controls. The predictor was validated in 20 new cases of breast cancer patients and tested in 60 volunteer women, assigning 11 out of 60 women to the cancer group. An association of low levels of miR-16 with a high content of CD44 protein in serum was found. Circulating microRNAs in serum can represent biomarkers for cancer prediction. Their clinical relevance and the potential use of the predictor here described are discussed.

Mirna21 Expression in the Breast Cancer Tumor Tissue is Independent of Neoadjuvant Chemotherapy

Introduction

MicroRNA-21 (miRNA-21) has been described as one of the most significantly upregulated miRNAs in human breast cancer. However, limited knowledge exists on miRNA-21 expression in breast cancer tissue after neoadjuvant chemotherapy (NAC).

Purpose

The aim of this study was to assess miRNA-21 expression in the tumor tissues of Brazilian patients with breast cancer who underwent NAC and its correlation with clinicopathological variables.

Patients and Methods

Utilizing qRT-PCR, miRNA-21 expression in tumor tissue was measured in a cohort of female patients with breast cancer who underwent NAC. The correlation of miRNA-21 expression with breast cancer molecular subtypes and other clinicopathological variables was also assessed.

Results

A total of 55 patients were included in the study, and 28 (50.9%) underwent NAC. miRNA-21 was upregulated in patients with breast cancer, regardless of previous exposure to chemotherapy, molecular subtypes, tumor-node-metastasis (TNM) staging and lymph node status of the axilla. miRNA-21 expression did not differ between patients with breast cancer who achieved a pathologic complete response after NAC and healthy controls.

Conclusion

miRNA-21 was upregulated in the tumor tissue of Brazilian patients with breast cancer regardless of NAC treatment, which reinforces its role as an “oncomiR” and a potential biomarker.

Circulating miRNAs in HER2-Positive and Triple Negative Breast Cancers: Potential Biomarkers and Therapeutic Targets

Breast cancer is one of the most prevalent diseases among women worldwide and is highly associated with cancer-related mortality. Of the four major molecular subtypes, HER2-positive and triple-negative breast cancer (TNBC) comprise more than 30% of all breast cancers. While the HER2-positive subtype lacks estrogen and progesterone receptors and overexpresses HER2, the TNBC subtype lacks estrogen, progesterone and HER2 receptors. Although advances in molecular biology and genetics have substantially ameliorated breast cancer disease management, targeted therapies for the treatment of estrogen-receptor negative breast cancer patients are still restricted, particularly for TNBC. On the other hand, it has been demonstrated that microRNAs, miRNAs or small non-coding RNAs that regulate gene expression are involved in diverse biological processes, including carcinogenesis. Moreover, circulating miRNAs in serum/plasma are among the most promising diagnostic/therapeutic tools as they are stable and relatively easy to quantify. Various circulating miRNAs have been identified in several human cancers including specific breast cancer subtypes. This review aims to discuss the role of circulating miRNAs as potential diagnostic and prognostic biomarkers as well as therapeutic targets for estrogen-receptor negative breast cancers, HER2+ and triple negative.

Prognostic and Clinicopathological Significance of MiR-155 in Breast Cancer: A Systematic Review

There is an unmet need for novel non-invasive prognostic molecular tumour markers for breast cancer (BC). Accumulating evidence shows that miR-155 plays a pivotal role in tumorigenesis. Generally, miR-155 is considered an oncogenic miRNA promoting tumour growth, angiogenesis and aggressiveness of BC. Therefore, many researchers have focused on its use as a prognostic biomarker and therapeutic target. However, its prognostic value for BC patients remains controversial. To address this issue, the present systematic review aims to summarize the available evidence and give a picture of a prognostic significance of miR-155 in BC pathology. All eligible studies were searched on PubMed and EMBASE databases through various search strategies. Starting from 289 potential eligible records, data were examined from 28 studies, comparing tissue and circulating miR-155 expression levels with clinicopathological features and survival rates in BC patients. We discuss the pitfalls and challenges that need to be assessed to understand the power of miR-155 to respond to real clinical needs, highlighting the consistency, robustness or lack of results obtained to sate in translating this molecule to clinical practice. Our paper suggests that the prognostic role of miR-155 in the management of BC needs to be further verified.

Integrated analysis of circRNA-miRNA-mRNA regulatory network identifies potential diagnostic biomarkers in diabetic foot ulcer

Diabetic foot ulcer (DFU) is a common and serious complication of diabetes mellitus, which influences patients’ quality of life. Recently, circRNA regulated the mRNA levels by functioning as miRNA sponge in various disease, including diabetes mellitus. Nevertheless, the circRNA-miRNA-mRNA regulatory network involved in DFU remains obscure. The aim of this study is to construct a competing endogenous RNA (ceRNA) network and screen biological indicators as diagnostic factors in DFU.

All the differentially expressed circRNAs, miRNAs and mRNAs were derived from Gene Expression Omnibus database. Furthermore, circRNAs identified by cytoHubba analysis and miRNAs obtained by human miRNA-disease database were used to construct DFU-specific ceRNA network with intersection of mRNAs. Functional enrichment analysis displayed the function and pathway of dysregulated mRNAs. Hub genes with high diagnostic value were screened by ClusterONE, GO semantic similarity and receiver operating characteristic (ROC) curve.

Here, the ceRNA network consisted of 8 circRNAs, 11 miRNAs and 91 mRNAs. Functional enrichment analysis demonstrated diabetic complications-related pathway including TGF-beta, FoxO and Wnt signaling pathway. GO semantic similarity and ROC curve analysis showed 6 hub genes with high diagnostic value (the area under the ROC curve ≥ 0.8) in patients with DFU, including BCL2, CCND1, IRAK4, SMAD4, SP1 and SUFU, which were identified as potential target genes for DFU diagnosis. In conclusion, the present study looked at a circRNA-miRNA-mRNA regulatory network with DFU and screened the potential function of mRNA, then identified novel diagnostic biomarkers and therapeutic targets for patients with DFU.

Plasma-based microRNA signatures in early diagnosis of breast cancer

Background

MicroRNAs (miRNAs) play an important role in the development and progression of breast cancer (BC). The purpose of the present study was to identify plasma miRNAs enabling early diagnosis of BC.

Materials and Methods

Expression levels of seven plasma miRNAs (miR‐23a‐3p, miR‐29b‐2‐5p, miR‐130a‐5p, miR‐144‐3p, miR‐148a‐3p, miR‐152‐3p, and miR‐182‐5p) in 106 patients with newly diagnosed BC and 96 healthy participants were analyzed by qRT‐PCR. We also evaluated the relationship between the expression levels of these miRNAs and clinicopathological features of patients with BC.

Results

Compared with healthy controls, we found that miR‐23a‐3p (p = .025), miR‐130a‐5p (p = .006), miR‐144‐3p (p = .040), miR‐148a‐3p (p = .023), and miR‐152‐3p (p = .019) were downregulated in the plasma of patients with BC. MiR‐130a‐5p, miR‐144‐3p, and miR‐152‐3p were downexpressed in BC tissues as well as plasma. The expression of the miR‐23a‐3p, miR‐144‐3p, and miR‐152‐3p was related to ER positive and PR positive. Besides, miR‐23a‐3p, miR‐144‐3p, and miR‐152‐3p did show the significant difference in the staging compromised to the control, especially in stage I‐II. Moreover, we also found that miR‐144‐3p and miR‐148a‐3p were associated with lymph node invasion.

Conclusions

The expression levels of the miR‐23a‐3p, miR‐130a‐5p, miR‐144‐3p, miR‐148a‐3p, and miR‐152‐3p were lower in patients with BC compared to healthy controls and were associated with ex hormone receptor, clinical stage, and lymph node metastasis, indicating the diagnostic potential of these miRNAs in BC.