Circulating tumor DNA and circulating tumor cells in metastatic triple negative breast cancer patients

The Combined Assessment of CTC and ESR1 Status in Liquid Biopsy Samples Enhances the Clinical Value of Prediction in Metastatic Breast Cancer

Monitoring of metastatic breast cancer (mBC) is an important issue in the clinical management of patients. Liquid biopsy has become a non-invasive method for detecting and monitoring cancer in body fluids. The presence of circulating tumor cells (CTCs) and circulating tumor DNA (ctDNA) in peripheral blood indicates poor prognosis and may contribute to early detection of progression, but assessment of these levels is still not routine clinical management. The main objective of this study was to estimate the frequency and clinical value of the ESR1 and PIK3CA mutations identified in circulating free DNA (cfDNA.) The second goal was to evaluate whether simultaneous evaluation of CTCs and mutation status in cfDNA increases the prognostic value of liquid biopsy. The results of the analysis of the CTC number and ESR1 and PIK3CA mutations in blood collected from 179 patients with metastatic breast cancer show that ESR1 mutations are more frequent in patients with advanced luminal breast cancer regardless of the type of the treatment. ESR1 mutations appear primarily during progression, as no mutations were found in primary tumor samples. The main conclusion of the study is that combined assessment of CTCs and ESR1 status in liquid biopsy may improve the prognostic value of liquid biopsy.

Next-generation biomarkers for prognostic and potential therapeutic enhancement in Triple negative breast cancer

Triple-negative breast carcinoma (TNBC) is one of the most challenging subtypes of breast carcinoma and it has very limited therapeutic options as it is highly aggressive. The prognostic biomarkers are crucial for early diagnosis of the tumor, it also helps in anticipating the trajectory of the illness and optimizing the therapy options. Several therapeutic biomarkers are being used. Among them, the next-generation biomarkers that include Circulating tumor (ct) DNA, glycogen, lipid, and exosome biomarkers provide intriguing opportunities for enhancing the prognosis of TNBC. Lipid and glycogen biomarkers serve as essential details on the development of the tumor along with the efficacy of the treatment, as it exhibits metabolic alteration linked to TNBC. Several types of biomarkers have predictive abilities in TNBC. Elevated levels are associated with worse outcomes. ctDNA being a noninvasive biomarker reveals the genetic composition of the tumor, as well as helps to monitor the progression of the disease. Traditional therapies are ineffective in TNBC due to a lack of receptors, targeted drug delivery provides a tailored approach to overcome drug resistance and site-specific action by minimizing the side effects in TNBC treatment. This enhances therapeutic outcomes against the aggressive nature of breast cancer. This paper includes all the recent biomarkers which has been researched so far in TNBC and the state of art for TNBC which is explored.

Early Evaluation of Risk Stratification and Clinical Outcomes for Patients with Advanced Breast Cancer through Combined Monitoring of Baseline Circulating Tumor Cells and DNA

PURPOSE

Early evaluation of tumor heterogeneity related to metastasis and outcomes is a major challenge in the management of advanced breast cancer (BCa) in the clinic. In this study, we introduced the value of baseline circulating tumor cells (CTC) and ctDNA for early differentiation of clinical stages, tumor heterogeneity, and prognosis in clinic.

EXPERIMENTAL DESIGN

A total of 292 patients with BCa were enrolled in this study, including 254 Stage IV and 38 Stage III patients, and examined the baseline levels of CTCs, CTC-clusters, and plasma ctDNA before initiating therapies. Outcomes including progression-free survival (PFS) and overall survival were evaluated using proportional hazards regression analysis.

RESULTS

The baseline CTCs, including HER2+ CTCs, in Stage IV patients were approximately 9.5 times higher than those detected in Stage III patients. Baseline CTC counts with a cutoff of 5 were significantly associated with the prognosis. Within each stage, patients with <5 CTCs had significantly longer PFS. Stage III patients with no CTCs exhibited the longest survival compared with patients with ≥1 CTC. CTC-clusters were only found in Stage IV patients, among whom 15 Stage IV patients with ≥5 CTC-clusters had the worst PFS compared with the 239 Stage IV patients with <5 CTC-clusters. Similar outcomes were observed in 28 out of 254 Stage IV patients who had at least one CTC-cluster detected, as these patients had shorter PFS compared with CTC-cluster negative group. The major differences in ctDNA mutations between patients with Stage III and Stage IV BCa were in PIK3CA and ESR1, which were associated with specific organ metastasis and worse outcomes.

CONCLUSIONS

Assessing the baseline levels of CTCs, CTC-clusters, and mutational ctDNA profile could reliably aid in differentiation of clinical stage and early prediction of metastasis and outcomes in advanced BCa.

Searching for the "Holy Grail" of breast cancer recurrence risk: a narrative review of the hunt for a better biomarker and the promise of circulating tumor DNA (ctDNA)

BACKGROUND

This paper is a narrative review of a major clinical challenge at the heart of breast cancer care: determining which patients are at risk of recurrence, which require systemic therapy, and which remain at risk in the survivorship phase of care despite initial therapy.

METHODS

We review the literature on prognostic and predictive biomarkers in breast cancer with a focus on detection of minimal residual disease.

RESULTS

While we have many tools to estimate and refine risk that are used to individualize local and systemic therapy, we know that we continue to over treat many patients and undertreat others. Many patients also experience what is, at least in hindsight, needless fear of recurrence. In this review, we frame this dilemma for the practicing breast oncologist and discuss the search for what we term the "holy grail" of breast cancer evaluation: the ideal biomarker of residual distant disease. We review the history of attempts to address this problem and the up-to-date science on biomarkers, circulating tumor cells and circulating tumor DNA (ctDNA).

CONCLUSION

This review suggests that the emerging promise of ctDNA may help resolve a crticical dilemma at the heart of breast cancer care, and improve prognostication, treatment selection, and outcomes for patients with breast cancer.

Metastatic progression of breast cancer along with decreased mitochondrial cell death priming of breast cancer cells: a case report

Metastatic breast cancer remains to be a major cause of cancer-related deaths in women. Exploring the molecular mechanisms to identify targetable alterations in progressing breast cancer and developing functional tools to predict therapy response in these patients are needed. In this report, we present a case of breast cancer patient who progressed following surgery and adjuvant endocrine therapy. Radiological and pathological analyses revealed metastasis to liver and brain. Paired liquid biopsies demonstrated acquired ERBB2 mutations in addition to TP53 and PIK3CA mutations, which were also present before progression. BH3 profiling test demonstrated decreased mitochondrial cell death priming in CTCs of the patient after progression. In conclusion, novel personalized treatment strategies are needed to monitor metastatic breast cancer patients for better clinical benefit.

Dynamic analysis of circulating tumor DNA to predict the prognosis and monitor the treatment response of patients with metastatic triple-negative breast cancer: A prospective study

Background

Limited data are available on applying circulating tumor DNA (ctDNA) in metastatic triple-negative breast cancer (mTNBC) patients. Here, we investigated the value of ctDNA for predicting the prognosis and monitoring the treatment response in mTNBC patients.

Methods

We prospectively enrolled 70 Chinese patients with mTNBC who had progressed after ≤2 lines of chemotherapy and collected blood samples to extract ctDNA for 457-gene targeted panel sequencing.

Results

Patients with ctDNA+, defined by 12 prognosis-relevant mutated genes, had a shorter progression-free survival (PFS) than ctDNA- patients (5.16 months vs. 9.05 months, p=0.001), and ctDNA +was independently associated with a shorter PFS (HR, 95% CI: 2.67, 1.2-5.96; p=0.016) by multivariable analyses. Patients with a higher mutant-allele tumor heterogeneity (MATH) score (≥6.316) or a higher ctDNA fraction (ctDNA%≥0.05) had a significantly shorter PFS than patients with a lower MATH score (5.67 months vs.11.27 months, p=0.007) and patients with a lower ctDNA% (5.45 months vs. 12.17 months, p<0.001), respectively. Positive correlations with treatment response were observed for MATH score (R=0.24, p=0.014) and ctDNA% (R=0.3, p=0.002), but not the CEA, CA125, or CA153. Moreover, patients who remained ctDNA +during dynamic monitoring tended to have a shorter PFS than those who did not (3.90 months vs. 6.10 months, p=0.135).

Conclusions

ctDNA profiling provides insight into the mutational landscape of mTNBC and may reliably predict the prognosis and treatment response of mTNBC patients.

Funding

This work was supported by the National Natural Science Foundation of China (Grant No. 81902713), Natural Science Foundation of Shandong Province (Grant No. ZR2019LZL018), Breast Disease Research Fund of Shandong Provincial Medical Association (Grant No. YXH2020ZX066), the Start-up Fund of Shandong Cancer Hospital (Grant No. 2020-PYB10), Beijing Science and Technology Innovation Fund (Grant No. KC2021-ZZ-0010-1).

Omics Technologies Improving Breast Cancer Research and Diagnostics

Breast cancer (BC) has yielded approximately 2.26 million new cases and has caused nearly 685,000 deaths worldwide in the last two years, making it the most common diagnosed cancer type in the world. BC is an intricate ecosystem formed by both the tumor microenvironment and malignant cells, and its heterogeneity impacts the response to treatment. Biomedical research has entered the era of massive omics data thanks to the high-throughput sequencing revolution, quick progress and widespread adoption. These technologies-liquid biopsy, transcriptomics, epigenomics, proteomics, metabolomics, pharmaco-omics and artificial intelligence imaging-could help researchers and clinicians to better understand the formation and evolution of BC. This review focuses on the findings of recent multi-omics-based research that has been applied to BC research, with an introduction to every omics technique and their applications for the different BC phenotypes, biomarkers, target therapies, diagnosis, treatment and prognosis, to provide a comprehensive overview of the possibilities of BC research.

Clinical Evidence of Circulating Tumor DNA Application in Aggressive Breast Cancer

Breast cancer is clinically and biologically heterogeneous and is classified into different subtypes according to the molecular landscape of the tumor. Triple-negative breast cancer is a subtype associated with higher tumor aggressiveness, poor prognosis, and poor response to treatment. In metastatic breast cancer, approximately 6% to 10% of new breast cancer cases are initially staged IV (de novo metastatic disease). The number of metastatic recurrences is estimated to be 20-30% of all existing breast tumor cases, whereby the need to develop specific genetic markers to improve the prognosis of patients suffering from these deadly forms of breast cancer. As an alternative, liquid biopsy methods can minutely identify the molecular architecture of breast cancer, including aggressive forms, which provides new perspectives for more precise diagnosis and more effective therapeutics. This review aimed to summarize the current clinical evidence for the application of circulating tumor DNA in managing breast cancer by detailing the increased usefulness of this biomarker as a diagnostic, prognostic, monitoring, and surveillance marker for breast cancer.

Searching for DNA methylation in patients triple-negative breast cancer: a liquid biopsy approach

INTRODUCTION

Liquid biopsies are proving to have diagnostic and prognostic value in many different cancers, and in breast cancer they have the potential to improve outcomes by providing valuable information throughout a patient's cancer journey. However, patients with triple negative breast cancer (TNBC) have received little benefit from such liquid biopsies due to underlying limitations in the discovery and utility of robust biomarkers. Here, we examine the development of DNA methylation-based liquid biopsy assays for breast cancer and how they pertain to TNBC.

AREAS COVERED

We conducted a systematic review of liquid biopsy assays for breast cancer and analyzed their relevance in TNBC. We show that the utility of DNA mutation-based assays is poor for TNBC due to the low mutational frequencies across the genome in this subtype. We offer a detailed review of mDETECT - a liquid biopsy specifically designed for assessing tumor burden in TNBC patients.

EXPERT OPINION

DNA methylation are foundational and robust events that occur in cancer evolution and may differentiate almost all forms of cancer, including TNBC. Longitudinal patient monitoring using DNA methylation-based liquid biopsies offers great potential for improving the detection and management of TNBC.

Clearance of ctDNA in triple-negative and HER2-positive breast cancer patients during neoadjuvant treatment is correlated with pathologic complete response

BACKGROUND

Although the standard of care is to perform surgery of primary breast cancer (BC) after neoadjuvant chemotherapy (NAC), for certain patients achieving clinical complete response (cCR) and pathologic complete response (pCR), omission of surgical treatment may be an option. Levels of circulating tumor DNA (ctDNA) during and after therapy could identify patients achieving minimal residual disease. In this study, we evaluated whether ctDNA clearance during NAC could be a correlate to effective response in human epidermal growth factor receptor 2 positive (HER2+) and triple-negative (TN) BC patients.

METHODS

A prospective study was conducted to identify patient-specific PIK3CA and TP53 mutations in tissue using next-generation sequencing, which could then be used to track the presence/absence of mutations prior to, during, and following NAC using Sysmex SafeSEQ technology. All patients underwent a surgical excision after NAC, and pCR was assessed.

RESULTS

A total of 29 TN and HER2+ BC patients were examined and 20 that carried mutations in the PIK3CA and/or TP53 genes were recruited. Overall, 19 of these 20 patients harbored at least one tumor-specific mutation in their plasma at baseline. After NAC, 15 patients (75.0%) achieved pCR according to the histopathologic evaluation of the surgical specimen, and 15 patients (75.0%) had a cCR; 18 of 20 patients (90.0%) had concordant pCR and cCR. The status of 'no mutation detected' (NMD) following NAC in cCR patients correctly identified the pCR in 14 of 15 patients (93.33%), as well as correctly ruled out pCR in three patients, with an accuracy of 89.47%. During the 12-month follow-up after surgery, 40 plasma samples collected from 15 patients all showed no detectable ctDNA (NMD), and no patient recurred.

CONCLUSION

These findings prompt further research of the value of ctDNA for non-invasive prediction of clinical/pathological response, raising the possibility of sparing surgery following NAC in selected BC patients.

Introduction of Nanomaterials to Biosensors for Exosome Detection: Case Study for Cancer Analysis

Exosomes have been gaining attention for early cancer diagnosis owing to their biological functions in cells. Several studies have reported the relevance of exosomes in various diseases, including pancreatic cancer, retroperitoneal fibrosis, obesity, neurodegenerative diseases, and atherosclerosis. Particularly, exosomes are regarded as biomarkers for cancer diagnosis and can be detected in biofluids, such as saliva, urine, peritoneal fluid, and blood. Thus, exosomes are advantageous for cancer liquid biopsies as they overcome the current limitations of cancer tissue biopsies. Several studies have reported methods for exosome isolation, and analysis for cancer diagnosis. However, further clinical trials are still required to determine accurate exosome concentration quantification methods. Recently, various biosensors have been developed to detect exosomal biomarkers, including tumor-derived exosomes, nucleic acids, and proteins. Among these, the exact quantification of tumor-derived exosomes is a serious obstacle to the clinical use of liquid biopsies. Precise detection of exosome concentration is difficult because it requires clinical sample pretreatment. To solve this problem, the use of the nanobiohybrid material-based biosensor provides improved sensitivity and selectivity. The present review will discuss recent progress in exosome biosensors consisting of nanomaterials and biomaterial hybrids for electrochemical, electrical, and optical-based biosensors.

Applications of Circulating Tumor Cells and Circulating Tumor DNA in Precision Oncology for Breast Cancers

Liquid biopsies allow for the detection of cancer biomarkers such as circulating tumor cells (CTCs) and circulating tumor DNA (ctDNA). Elevated levels of these biomarkers during cancer treatment could potentially serve as indicators of cancer progression and shed light on the mechanisms of metastasis and therapy resistance. Thus, liquid biopsies serve as tools for cancer detection and monitoring through a simple, non-invasive blood draw, allowing multiple longitudinal sampling. These circulating markers have significant prospects for use in assessing patients’ prognosis, monitoring response to therapy, and developing precision medicine. In addition, single-cell omics of these liquid biopsy markers can be potential tools for identifying tumor heterogeneity and plasticity as well as novel therapeutic targets. In this review, we focus on our current understanding of circulating tumor biomarkers, especially in breast cancer, and the scope of novel sequencing technologies and diagnostic methods for better prognostication and patient stratification to improve patient outcomes.

The Role of Circulating Tumor Cells in the Prognosis of Metastatic Triple-Negative Breast Cancers: A Systematic Review of the Literature

Breast cancer is one of the leading causes of death in women worldwide. One subtype of breast cancer is the triple-negative, which accounts for 15% of total breast cancer cases and is known for its poor prognosis. The main cause of death is due to metastasis. Circulating tumor cells (CTCs) play a key role in the metastatic process. CTCs arise either by detaching from the primary tumor or from cancer stem cells undergoing an epithelial-to-mesenchymal transition (EMT). This review aims to present up-to-date data concerning the role of CTC numbers in relation to the prognostic and treatment response in metastatic triple-negative breast cancer (mTNBC) patients, and also to discuss the methods used for CTCs’ identification. A search in the MEDLINE database was performed. A total of 234 articles were identified. The results of the 24 eligible studies showed that positive CTC status is associated with shorter overall survival (OS) and progression-free survival (PFS) in mTNBC patients. Furthermore, a decrease in number of CTCs during therapy seems to be a favorable prognostic factor, making CTCs’ detection an important prognostic tool before and during therapy in mTNBC patients. The methods used for CTC detection are still developing and need further improvement.

Randomised, open-label, multicentric phase III trial to evaluate the safety and efficacy of palbociclib in combination with endocrine therapy, guided by ESR1 mutation monitoring in oestrogen receptor-positive, HER2-negative metastatic breast cancer patients: study design of PADA-1

INTRODUCTION

The combination of a CDK4/6 inhibitor with an aromatase inhibitor (AI) has recently become the gold standard for AI-sensitive first line treatment of oestrogen receptor-positive (ER+) HER2-negative (HER2-) advanced breast cancer. However, most patients receiving this combination will ultimately progress and require further therapies.Several studies have demonstrated that the onset of a ESR1 gene mutation lead to AIs resistance in the advanced setting. ESR1 mutations can be detected in circulating tumour DNA (ctDNA) using a digital PCR assay. Our study aims to prove the clinical efficacy of periodic monitoring for emerging or rise of ESR1 mutations in ctDNA to trigger an early change from AI plus palbociclib to fulvestrant plus palbociclib treatment while assessing global safety.

METHODS

PADA-1 is a randomised, open-label, multicentric, phase III trial conducted in patients receiving AI and palbociclib as first line therapy for metastatic ER +HER2- breast cancer. 1000 patients will be included and treated with palbociclib in combination with an AI. Patients will be screened for circulating blood ESR1 mutation detection at regular intervals. Patients for whom a rising circulating ESR1 mutation is detected without tumour progression (up to N=200) will be randomised (1:1) between (1) Arm A: no modification of therapy; and (2) Arm B: palbociclib in combination with fulvestrant, a selective ER down-regulator. At tumour progression, an optional crossover will be offered to patients randomised in arm A. The coprimary endpoints are (1) Grade ≥3 haematological toxicities and their associations with baseline characteristics and (2) progression-free survival in randomised patients.

ETHICS AND DISSEMINATION

The study has been approved by the French medicines agency (ANSM) and by an ethics committee (ref 01/17_1 CPP Ouest-IV Nantes) in January 2017. The trial results will be published in academic conference presentations and international peer-reviewed journals.

TRIAL REGISTRATION NUMBERS

EudraCT: 2016-004360-18; NCT03079011.

Role of circulating tumor DNA and circulating tumor cells in breast cancer: History and updates

Circulating tumor DNA, cell-free DNA, and circulating tumor cells have been at the epitome of recent research in breast cancer. These forms of liquid biopsies have been used in monitoring disease progression, estimating the risk of relapse, and response to treatment. Much has been done in relation to serial monitoring of circulating tumor DNA in patients with primary breast cancer for detection of occult metastatic disease. Some studies have also explored their use in monitoring treatment response. As the field of liquid biopsies expands, more prospective studies are needed to tailor management in an individualistic approach. In this literature review, the authors explore the multiple uses of circulating tumor DNA and circulating tumor cells in breast cancer.

Diagnosis and treatment monitoring in breast cancer: how liquid biopsy can support patient management

Imaging and tissue biopsies represent the current gold standard for breast cancer diagnosis and patient management. However, these practices are time-consuming, expensive and require invasive procedures. Moreover, tissue biopsies do not capture spatial and temporal tumor heterogeneity. Conversely, liquid biopsy, which includes circulating tumor cells, circulating free nucleic acids and extracellular vesicles, is minimally invasive, easy to perform and can be repeated during a patient's follow-up. Increasing evidence also suggests that liquid biopsy can be used to efficiently screen and diagnose tumors at an early stage, and to monitor changes in the tumor molecular profile. In the present review, clinical applications and prospects are discussed.

High-Sensitivity Fluorescence Detection for lung cancer CYFRA21-1 DNA based on Accumulative Hybridization of Quantum Dots

Sensitive detection of circulating tumor DNA (ctDNA) in vitro has attracted growing attention owing to its potential application in diagnostics of cancer. In this study, we synthesized hydrophilic AgInS2@ZnS core-shell...

Computational challenges in detection of cancer using cell-free DNA methylation

Cell-free DNA(cfDNA) methylation profiling is considered promising and potentially reliable for liquid biopsy to study progress of diseases and develop reliable and consistent diagnostic and prognostic biomarkers. There are several different mechanisms responsible for the release of cfDNA in blood plasma, and henceforth it can provide information regarding dynamic changes in the human body. Due to the fragmented nature, low concentration of cfDNA, and high background noise, there are several challenges in its analysis for regular use in diagnosis of cancer. Such challenges in the analysis of the methylation profile of cfDNA are further aggravated due to heterogeneity, biomarker sensitivity, platform biases, and batch effects. This review delineates the origin of cfDNA methylation, its profiling, and associated computational problems in analysis for diagnosis. Here we also contemplate upon the multi-marker approach to handle the scenario of cancer heterogeneity and explore the utility of markers for 5hmC based cfDNA methylation pattern. Further, we provide a critical overview of deconvolution and machine learning methods for cfDNA methylation analysis. Our review of current methods reveals the potential for further improvement in analysis strategies for detecting early cancer using cfDNA methylation.

Direct Detection of Low Abundance Genes of Single Point Mutation

Cell-free DNA (cfDNA) analysis, specifically circulating tumor DNA (ctDNA) analysis, provides enormous opportunities for noninvasive early assessment of cancers. To date, PCR-based methods have led this field. However, the limited sensitivity/specificity of PCR-based methods necessitates the search for new methods. Here, we describe a direct approach to detect KRAS G12D mutated genes in clinical ctDNA samples with the utmost LOD and sensitivity/specificity. In this study, MutS protein was immobilized on the tip of an atomic force microscope (AFM), and the protein sensed the mismatched sites of the duplex formed between the capture probe on the surface and mutated DNA. A noteworthy LOD (3 copies, 0.006% allele frequency) was achieved, along with superb sensitivity/specificity (100%/100%). These observations demonstrate that force-based AFM, in combination with the protein found in nature and properly designed capture probes/blockers, represents an exciting new avenue for ctDNA analysis.

Multimodal liquid biopsy for early monitoring and outcome prediction of chemotherapy in metastatic breast cancer

Circulating tumor cells (CTCs) and circulating tumor DNA (ctDNA) are two cancer-derived blood biomarkers that inform on patient prognosis and treatment efficacy in breast cancer. We prospectively evaluated the clinical validity of quantifying both CTCs (CellSearch) and ctDNA (targeted next-generation sequencing). Their combined value as prognostic and early monitoring markers was assessed in 198 HER2-negative metastatic breast cancer patients. All patients were included in the prospective multicenter UCBG study COMET (NCT01745757) and treated by first-line chemotherapy with weekly paclitaxel and bevacizumab. Blood samples were obtained at baseline and before the second cycle of chemotherapy. At baseline, CTCs and ctDNA were respectively detected in 72 and 74% of patients and were moderately correlated (Kendall’s τ = 0.3). Only 26 (13%) patients had neither detectable ctDNA nor CTCs. Variants were most frequently observed in TP53 and PIK3CA genes. KMT2C/MLL3 variants detected in ctDNA were significantly associated with a lower CTC count, while the opposite trend was seen with GATA3 alterations. Both CTC and ctDNA levels at baseline and after four weeks of treatment were correlated with survival. For progression-free and overall survival, the best multivariate prognostic model included tumor subtype (triple negative vs other), grade (grade 3 vs other), ctDNA variant allele frequency (VAF) at baseline (per 10% increase), and CTC count at four weeks (≥5CTC/7.5 mL). Overall, this study demonstrates that CTCs and ctDNA have nonoverlapping detection profiles and complementary prognostic values in metastatic breast cancer patients. A comprehensive liquid-biopsy approach may involve simultaneous detection of ctDNA and CTCs.

Clinical and biological determinants of circulating tumor DNA detection and prognostication using a next-generation sequencing panel assay

Circulating tumor DNA (ctDNA) is utilized for molecular profiling of cancers, and is under investigation for a growing number of applications based on the assumption that ctDNA levels faithfully reflect disease burden. Our objective was to investigate whether patient and tumor characteristics may impact ctDNA detection or levels and the prognostic significance of ctDNA levels or mutations. We performed a retrospective cohort analysis of a comprehensively annotated cohort of 561 patients at a National Cancer Institute-designated comprehensive cancer center with advanced solid cancers who underwent ctDNA testing using a commercial targeted next-generation sequencing assay. ctDNA detection in advanced cancers was associated with older age, non-obese body mass index, and diabetes, but not with tumor diameter, volume, lesion number, or other pathological features. Regression models indicate that no more than 14.3% of the variance in ctDNA levels between patients was explained by known clinical factors and disease burden. Even after adjusting for established prognostic factors and tumor burden, ctDNA levels were associated with worse survival among patients without prior systemic therapy, while ctDNA mutations were associated with survival among patients who previously received systemic treatment. These findings uncover clinical factors that affect ctDNA detection in patients with advanced cancers and challenge the convention that ctDNA is a surrogate for tumor burden. Our study also indicates that the prognostic value of ctDNA levels and mutations are independent of tumor burden and dependent on treatment context.

Liquid Biopsy in Breast Cancer: A Focused Review

CONTEXT.—

The role of liquid biopsy in cancer management has been gaining increased prominence in the past decade, with well-defined clinical applications now being established in lung cancer. Recently, the US Food and Drug Administration also approved the Therascreen PIK3CA RGQ polymerase chain reaction assay as a companion diagnostic assay to detect PIK3CA mutations in breast cancer for both tissue and liquid biopsies, bringing the role of liquid biopsy in breast cancer management to the fore. Its utility in other aspects of breast cancer, however, is yet to be clearly defined.

OBJECTIVE.—

To review the studies that looked at liquid biopsies in breast cancer and examine their potential for clinical application in the areas of early diagnosis, prognostication, monitoring disease response, detecting minimal residual disease, and predicting risk of progression or relapse. We focus mainly on circulating tumor cells and circulating tumor DNA.

DATA SOURCES.—

Peer-reviewed articles in PubMed.

CONCLUSIONS.—

Liquid biopsies in breast cancers have yielded promising results, especially in the areas of monitoring treatment response and predicting disease progression or relapse. With further study, and hopefully coupled with continued improvements in technologies that isolate tumor-derived materials, liquid biopsies may go on to play a greater role in the breast cancer clinic.

The Emerging Role of Circulating Tumor DNA in the Management of Breast Cancer

With the incidence of breast cancer steadily rising, it is important to explore novel technologies that can allow for earlier detection of disease as well more a personalized and effective treatment approach. The concept of "liquid biopsies" and the data they provide have been increasingly studied in the recent decades. More specifically, circulating tumor DNA (ctDNA) has emerged as a potential biomarker for various cancers, including breast cancer. While methods such as mammography and tissue biopsies are the current standards for the detection and surveillance of breast cancer, ctDNA analysis has shown some promise. This review discusses the versatility of ctDNA by exploring its multiple emerging uses for the management of breast cancer. Its efficacy is also compared to current biomarkers and technologies.

BRCA Mutational Status is a Promising Predictive Biomarker for Platinum- based Chemotherapy in Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) can be distinguished from other breast malignancies by the lack of expression of estrogen receptors (ER), progesterone receptors (PR) as well as human epidermal growth factor receptor 2 (HER2). TNBC is associated with adverse clinical outcomes and high risk of metastasis. Currently, several clinical and translational reports are focusing on developing targeted therapies for this aggressive cancer. In addition to approved targeted drugs such as poly(ADP-ribose) polymerase inhibitors (PARPi) and immune-checkpoint inhibitors, platinum-based chemotherapy is still a cornerstone therapeutic option in TNBC. However, despite the observed improved outcomes with platinum- based chemotherapy in TNBC, there is still a large proportion of patients who do not respond to this treatment, hence, the need for predictive biomarkers to stratify TNBC patients and therefore, avoiding unwanted toxicities of these agents. With the emergence of genetic testing, several recent studies suggested mutations in breast cancer susceptibility gene (BRCA) in TNBC patients as important predictors of outcomes. These mutations alter the homologous recombination repair (HRR) mechanisms leading to genomic instability. Consequently, sensitivity to platinum-based treatments in this subpopulation of TNBC patients may be explained by cell death enhanced by deoxyribonucleic acid (DNA) damage induced by these potent anticancer drugs. Through this paper, we review several recent studies on this topic to better understand the mechanisms and discuss the potential of BRCA mutational status as a predictive biomarker of platinum-based chemotherapy in TNBC.

A DNA methylation-based liquid biopsy for triple-negative breast cancer

Here, we present a next-generation sequencing (NGS) methylation-based blood test called methylation DETEction of Circulating Tumour DNA (mDETECT) designed for the optimal detection and monitoring of metastatic triple-negative breast cancer (TNBC). Based on a highly multiplexed targeted sequencing approach, this assay incorporates features that offer superior performance and included 53 amplicons from 47 regions. Analysis of a previously characterised cohort of women with metastatic TNBC with limited quantities of plasma (<2 ml) produced an AUC of 0.92 for detection of a tumour with a sensitivity of 76% for a specificity of 100%. mDETECT_TNBC was quantitative and showed superior performance to an NGS TP53 mutation-based test carried out on the same patients and to the conventional CA15-3 biomarker. mDETECT also functioned well in serum samples from metastatic TNBC patients where it produced an AUC of 0.97 for detection of a tumour with a sensitivity of 93% for a specificity of 100%. An assay for BRCA1 promoter methylation was also incorporated into the mDETECT assay and functioned well but its clinical significance is currently unclear. Clonal Hematopoiesis of Indeterminate Potential was investigated as a source of background in control subjects but was not seen to be significant, though a link to adiposity may be relevant. The mDETECT_TNBC assay is a liquid biopsy able to quantitatively detect all TNBC cancers and has the potential to improve the management of patients with this disease.

Relationship between Stemness, Reactive Oxygen Species, and Epithelial-to-Mesenchymal Transition in Model Circulating Tumor Cells

Most cancer deaths are caused by secondary metastasized tumors. The cells that spread these tumors are known as circulating tumor cells (CTCs). They exist in a dynamic environment, including exposure to fluid shear stress (FSS) that makes them susceptible to reactive oxygen species (ROS) generation. There are questions about the similarities of CTCs to cancer stem cells (CSCs) and whether the stem cell-like characteristics of CTCs allow them to proliferate and spread despite the biophysical obstacles during the metastatic process. One of those qualities is the ability to undergo the epithelial-to-mesenchymal transition (EMT). Here, MDA-MB-231 and MCF7 were modeled as CTCs by prolonged exposure to FSS using a spinner flask. They were tested for ROS generation, CSC, EMT, and Hippo pathway gene and protein markers using qRT-PCR and flow cytometry. MDA-MB-231 did not show significant changes in CSC markers, but did show significant changes in ROS, EMT, and Hippo markers (p < 0.05). Similarly, MCF7 showed significant changes in ROS and EMT markers (p < 0.05). Furthermore, both cell lines demonstrated the reverse mesenchymal-to-epithelial transition signature when allowed to recover after FSS. These results suggest that the degree of their stemness or aggressiveness affects their responses to externally applied biophysical forces and demonstrates a potential link between mechanotransduction, the Hippo pathway, and the induction of EMT in breast cancer cells.

Detection Methods and Clinical Applications of Circulating Tumor Cells in Breast Cancer

Circulating Tumor Cells (CTCs) are cancer cells that split away from the primary tumor and appear in the circulatory system as singular units or clusters, which was first reported by Dr. Thomas Ashworth in 1869. CTCs migrate and implantation occurs at a new site, in a process commonly known as tumor metastasis. In the case of breast cancer, the tumor cells often migrate into locations such as the lungs, brain, and bones, even during the early stages, and this is a notable characteristic of breast cancer. Survival rates have increased significantly over the past few decades because of progress made in radiology and tissue biopsy, making early detection and diagnosis of breast cancer possible. However, liquid biopsy, particularly that involving the collection of CTCs, is a non-invasive method to detect tumor cells in the circulatory system, which can be easily isolated from human plasma, serum, and other body fluids. Compared to traditional tissue biopsies, fluid sample collection has the advantages of being readily available and more acceptable to the patient. It can also detect tumor cells in blood earlier and in smaller numbers, possibly allowing for diagnosis prior to any tumor detection using imaging methods. Because of the scarcity of CTCs circulating in blood vessels (only a few CTCs among billions of erythrocytes and leukocytes), thorough but accurate detection methods are particularly important for further clinical applications.

Phase II study of apatinib in combination with oral vinorelbine in heavily pretreated HER2-negative metastatic breast cancer and clinical implications of monitoring ctDNA

OBJECTIVE

Apatinib is an oral TKI targeting VEGFR-2. Single-agent apatinib treatment has been shown to produce an objective response in patients with pretreated mBC. Oral vinorelbine also holds promise as a treatment of choice in patients with mBC. This study aimed to investigate the efficacy and safety of the oral vinorelbine-apatinib combination in patients with pretreated mBC. In addition, we detected gene variants in ctDNA to explore the therapeutic implications.

METHODS

This study enrolled patients with HER2-negative mBC who were pretreated with anthracycline/taxanes. Patients were treated with apatinib at 500 mg/425 mg daily plus oral vinorelbine 60 mg/m2 on days 1, 8, and 15 of every cycle (3 weeks). The primary endpoint was PFS. The secondary endpoints were ORR, CBR, OS, and safety. Patients eligible for ctDNA detection were evaluated before and during treatment.

RESULTS

Forty patients were enrolled. The median PFS was 5.2 months (95% CI, 3.4-7.0 months), and the median OS was 17.4 months (95% CI, 8.0-27.0 months). The ORR was 17.1% (6/35), and the CBR was 45.7% (16/35). The most common AEs included gastrointestinal reaction, myelosuppression, and hypertension. In 20 patients, ctDNA was detected at baseline and during treatment. A significant difference was found in PFS for undetected vs. detected baseline ctDNA (13.9 months vs. 3.6 months, P = 0.018).

CONCLUSIONS

All-oral therapy with apatinib plus vinorelbine displayed objective efficacy in patients with heavily pretreated HER2-negative mBC, with acceptable and manageable toxicity profiles. Patients with no gene variant detected and lower variant allele frequencies in ctDNA at baseline showed longer PFS.

Clinical application of circulating tumor DNA in breast cancer

BACKGROUND

The recent advancement in massively parallel sequencing technologies has empowered liquid biopsies, in particular circulating tumor DNA (ctDNA) analysis, to be the new paradigm in personalized cancer management. Plasma ctDNA detection overcomes the current limitations in tumor tissue procurement and serves as a convenient and non-invasive method to capture tumor heterogeneity and genetic evolution along patients' cancer journey. In breast cancer, the current clinical application of ctDNA includes real-time monitoring of tumor response, detection of drug-resistant clones, assessing dynamic variations in tumor mutational landscape, identifying actionable mutations, detecting minimal residual disease and screening of early tumor.

PURPOSE

This review aims to summarize the current clinical evidence of ctDNA application in the management of breast cancer.

Association of Circulating Tumor DNA and Circulating Tumor Cells After Neoadjuvant Chemotherapy With Disease Recurrence in Patients With Triple-Negative Breast Cancer: Preplanned Secondary Analysis of the BRE12-158 Randomized Clinical Trial

Importance

A significant proportion of patients with early-stage triple-negative breast cancer (TNBC) are treated with neoadjuvant chemotherapy. Sequencing of circulating tumor DNA (ctDNA) after surgery, along with enumeration of circulating tumor cells (CTCs), may be used to detect minimal residual disease and assess which patients may experience disease recurrence.

Objective

To determine whether the presence of ctDNA and CTCs after neoadjuvant chemotherapy in patients with early-stage TNBC is independently associated with recurrence and clinical outcomes.

Design, Setting, and Participants

A preplanned secondary analysis was conducted from March 26, 2014, to December 18, 2018, using data from 196 female patients in BRE12-158, a phase 2 multicenter randomized clinical trial that randomized patients with early-stage TNBC who had residual disease after neoadjuvant chemotherapy to receive postneoadjuvant genomically directed therapy vs treatment of physician choice. Patients had blood samples collected for ctDNA and CTCs at time of treatment assignment; ctDNA analysis with survival was performed for 142 patients, and CTC analysis with survival was performed for 123 patients. Median clinical follow-up was 17.2 months (range, 0.3-58.3 months).

Interventions

Circulating tumor DNA was sequenced using the FoundationACT or FoundationOneLiquid Assay, and CTCs were enumerated using an epithelial cell adhesion molecule-based, positive-selection microfluidic device.

Main Outcomes and Measures

Primary outcomes were distant disease-free survival (DDFS), disease-free survival (DFS), and overall survival (OS).

Results

Among 196 female patients (mean [SD] age, 49.6 [11.1] years), detection of ctDNA was significantly associated with inferior DDFS (median DDFS, 32.5 months vs not reached; hazard ratio [HR], 2.99; 95% CI, 1.38-6.48; P = .006). At 24 months, DDFS probability was 56% for ctDNA-positive patients compared with 81% for ctDNA-negative patients. Detection of ctDNA was similarly associated with inferior DFS (HR, 2.67; 95% CI, 1.28-5.57; P = .009) and inferior OS (HR, 4.16; 95% CI,1.66-10.42; P = .002). The combination of ctDNA and CTCs provided additional information for increased sensitivity and discriminatory capacity. Patients who were ctDNA positive and CTC positive had significantly inferior DDFS compared with those who were ctDNA negative and CTC negative (median DDFS, 32.5 months vs not reached; HR, 5.29; 95% CI, 1.50-18.62; P = .009). At 24 months, DDFS probability was 52% for patients who were ctDNA positive and CTC positive compared with 89% for those who were ctDNA negative and CTC negative. Similar trends were observed for DFS (HR, 3.15; 95% CI, 1.07-9.27; P = .04) and OS (HR, 8.60; 95% CI, 1.78-41.47; P = .007).

Conclusions and Relevance

In this preplanned secondary analysis of a randomized clinical trial, detection of ctDNA and CTCs in patients with early-stage TNBC after neoadjuvant chemotherapy was independently associated with disease recurrence, which represents an important stratification factor for future postneoadjuvant trials.

Trial Registration

ClinicalTrials.gov Identifier: NCT02101385.

Circulating Tumor Cells and Bevacizumab Pharmacokinetics during Neoadjuvant Treatment Combining Chemotherapy and Bevacizumab for Early Breast Cancer: Ancillary Analysis of the AVASTEM Trial

The phase II AVASTEM trial explored the impact of chemotherapy-bevacizumab combination on breast cancer stem cells in the neoadjuvant setting. We aimed to identify biological features associated with preoperative chemotherapy efficacy and prognosis by analyses of circulating tumor cells (CTCs) and bevacizumab pharmacokinetics (PK). The main objective was to assess the prognostic (relapse-free survival and overall survival) and predictive (pathological complete response, pCR) values of CTCs (CellSearch technology) and bevacizumab PK (ELISA). Seventy-five patients were included. Out of them 50 received bevacizumab-chemotherapy and 25 received chemotherapy alone. CTC results were available for 60 patients and PK data for 29 patients in the experimental arm. The absence of CTC at inclusion was correlated to better outcome. Five-years overall survival (OS) was 91% for CTC-negative patients vs. 54% for CTC-positive cases (HR = 6.21; 95%CI (1.75-22.06), p = 0.001, log-rank test). Similar results were observed for RFS with 5 y-RFS of 78% vs. 44% (HR = 3.51; 95%CI (1.17-10.52), p = 0.017, log-rank test). However, CTC status at baseline was not predictive of pCR (p = 0.74). CTC status after one cycle was not a significant prognostic factor (HR = 1.56; 95%CI (0.19-12.67); p = 0.68 for OS and HR = 2.76; 95%CI (0.60-12.61); p = 0.17 for RFS, log-rank test). Bevacizumab serum levels could not predict pCR and survival. PK values were not associated with treatment-related toxicities. In conclusion, CTCs detection at baseline is a prognostic marker for breast cancer receiving a neoadjuvant chemotherapy-bevacizumab combination independently of tumor response.

The Polemic Diagnostic Role of TP53 Mutations in Liquid Biopsies from Breast, Colon and Lung Cancers

Being minimally invasive and thus allowing repeated measures over time, liquid biopsies are taking over traditional solid biopsies in certain circumstances such as those for unreachable tumors, very early stages or treatment monitoring. However, regarding TP53 mutation status analysis, liquid biopsies have not yet substituted tissue samples, mainly due to the lack of concordance between the two types of biopsies. This needs to be examined in a study-dependent manner, taking into account the particular type of liquid biopsy analyzed, that is, circulating tumor cells (CTCs) or cell-free DNA (cfDNA), its involvement in the tumor biology and evolution and, finally, the technology used to analyze each biopsy type. Here, we review the main studies analyzing TP53 mutations in either CTCs or cfDNA in the three more prevalent solid tumors: breast, colon and lung cancers. We evaluate the correlation for mutation status between liquid biopsies and tumor tissue, suggesting possible sources of discrepancies, as well as evaluating the clinical utility of using liquid biopsies for the analysis of TP53 mutation status and the future actions that need to be undertaken to make liquid biopsy analysis a reality for the evaluation of TP53 mutations.

Practical classification of triple-negative breast cancer: intratumoral heterogeneity, mechanisms of drug resistance, and novel therapies

Triple-negative breast cancer (TNBC) is not a unique disease, encompassing multiple entities with marked histopathological, transcriptomic and genomic heterogeneity. Despite several efforts, transcriptomic and genomic classifications have remained merely theoretic and most of the patients are being treated with chemotherapy. Driver alterations in potentially targetable genes, including PIK3CA and AKT, have been identified across TNBC subtypes, prompting the implementation of biomarker-driven therapeutic approaches. However, biomarker-based treatments as well as immune checkpoint inhibitor-based immunotherapy have provided contrasting and limited results so far. Accordingly, a better characterization of the genomic and immune contexture underpinning TNBC, as well as the translation of the lessons learnt in the metastatic disease to the early setting would improve patients' outcomes. The application of multi-omics technologies, biocomputational algorithms, assays for minimal residual disease monitoring and novel clinical trial designs are strongly warranted to pave the way toward personalized anticancer treatment for patients with TNBC.

Precision Medicine for Breast Cancer Utilizing Circulating Tumor DNA: It Is in the Blood

OPINION STATEMENT

Liquid biopsy using blood components to assess circulating tumor DNA (ctDNA) is rapidly becoming a new standard-of-care technology in many tumor types, including breast cancer, due to the potential to provide predictive and prognostic information. The minimally invasive and repeatable nature of plasma based mutational testing is appealing for patients and facilitates enhanced disease monitoring. It is important for the clinician to understand the benefits and limitations of this emerging assay and the potential applications in breast cancer. Multiple technologies have been employed to assess breast cancer ctDNA with high sensitivity and specificity leading to assays that have been useful in research trials and are entering widespread clinical application. ctDNA analysis of breast cancer is of clinical utility today in selecting targeted therapy for advanced breast cancer, most notably by assessing PIK3CA mutations in hormone receptor-positive, HER2-negative disease. It will be employed in the near future in a variety of clinical settings including early detection of primary breast cancer, minimal residual disease after initial therapy, and use in advanced breast cancer for prognosis, early identification of non-response, and monitoring genomic markers of resistance.

B7-H3 Immune Checkpoint Protein in Human Cancer

B7-H3 belongs to the B7 family of immune checkpoint proteins, which are important regulators of the adaptive immune response and emerging key players in human cancer. B7-H3 is a transmembrane protein expressed on the surface of tumor cells, antigen presenting cells, natural killer cells, tumor endothelial cells, but can also be present in intra- and extracellular vesicles. Additionally, B7-H3 may be present as a circulating soluble isoform in serum and other body fluids. B7-H3 is overexpressed in a variety of tumor types, in correlation with poor prognosis. B7-H3 is a promising new immunotherapy target for anti-cancer immune response, as well as a potential biomarker. Besides its immunoregulatory role, B7-H3 has intrinsic pro-tumorigenic activities related to enhanced cell proliferation, migration, invasion, angiogenesis, metastatic capacity and anti-cancer drug resistance. B7-H3 has also been found to regulate key metabolic enzymes, promoting the high glycolytic capacity of cancer cells. B7-H3 receptors are still not identified, and little is known about the molecular mechanisms underlying B7-H3 functions. Here, we review the current knowledge on the involvement of B7-H3 in human cancer.

Perspectives on Triple-Negative Breast Cancer: Current Treatment Strategies, Unmet Needs, and Potential Targets for Future Therapies

Triple-negative breast cancer (TNBC), characterized by the absence or low expression of estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor (HER2), is the most aggressive subtype of breast cancer. TNBC accounts for about 15% of breast cancer cases in the U.S., and is known for high relapse rates and poor overall survival (OS). Chemo-resistant TNBC is a genetically diverse, highly heterogeneous, and rapidly evolving disease that challenges our ability to individualize treatment for incomplete responders and relapsed patients. Currently, the frontline standard chemotherapy, composed of anthracyclines, alkylating agents, and taxanes, is commonly used to treat high-risk and locally advanced TNBC. Several FDA-approved drugs that target programmed cell death protein-1 (Keytruda) and programmed death ligand-1 (Tecentriq), poly ADP-ribose polymerase (PARP), and/or antibody drug conjugates (Trodelvy) have shown promise in improving clinical outcomes for a subset of TNBC. These inhibitors that target key genetic mutations and specific molecular signaling pathways that drive malignant tumor growth have been used as single agents and/or in combination with standard chemotherapy regimens. Here, we review the current TNBC treatment options, unmet clinical needs, and actionable drug targets, including epidermal growth factor (EGFR), vascular endothelial growth factor (VEGF), androgen receptor (AR), estrogen receptor beta (ERβ), phosphoinositide-3 kinase (PI3K), mammalian target of rapamycin (mTOR), and protein kinase B (PKB or AKT) activation in TNBC. Supported by strong evidence in developmental, evolutionary, and cancer biology, we propose that the K-RAS/SIAH pathway activation is a major tumor driver, and SIAH is a new drug target, a therapy-responsive prognostic biomarker, and a major tumor vulnerability in TNBC. Since persistent K-RAS/SIAH/EGFR pathway activation endows TNBC tumor cells with chemo-resistance, aggressive dissemination, and early relapse, we hope to design an anti-SIAH-centered anti-K-RAS/EGFR targeted therapy as a novel therapeutic strategy to control and eradicate incurable TNBC in the future.

Circulating Tumor Cells in Metastatic Breast Cancer: From Genome Instability to Metastasis

The emergence of clinical resistance in repeatedly treated cancers extends from the primary tumor's capability to exploit genome instability to adapt, escape, and progress. Triple negative breast cancer serves as a good example of such a response demonstrating poor clinical outcome due to a high rate of cellular heterogeneity resulting in metastatic relapse. The capability to effectively track the emergence of therapeutic resistance in real-time and adapt the clinical response is the holy grail for precision medicine and has yet to be realized. In this review we present liquid biopsy using CTCs and ctDNA as a potential replacement and/or addition to the current diagnostic tests to deliver personalized therapies to patients with advanced breast cancer. We outline current uses of liquid biopsy in the metastatic breast cancer setting and discuss their limitations. In addition, we provide a detailed overview of common genome instability events in patients with metastatic breast cancer and how these can be tracked using liquid biopsy.

Biomarkers in Triple-Negative Breast Cancer: State-of-the-Art and Future Perspectives

Triple-negative breast cancer (TNBC) is a heterogeneous group of tumors characterized by aggressive behavior, high risk of distant recurrence, and poor survival. Chemotherapy is still the main therapeutic approach for this subgroup of patients, therefore, progress in the treatment of TNBC remains an important challenge. Data derived from molecular technologies have identified TNBCs with different gene expression and mutation profiles that may help developing targeted therapies. So far, however, only a few of these have shown to improve the prognosis and outcomes of TNBC patients. Robust predictive biomarkers to accelerate clinical progress are needed. Herein, we review prognostic and predictive biomarkers in TNBC, discuss the current evidence supporting their use, and look at the future of this research field.

A Review on the Role of Nanosensors in Detecting Cellular miRNA Expression in Colorectal Cancer

BACKGROUND

Colorectal cancer (CRC) is one of the leading causes of death across the globe. Early diagnosis with high sensitivity can prevent CRC progression, thereby reducing the condition of metastasis.

OBJECTIVE

The purpose of this review is (i) to discuss miRNA based biomarkers responsible for CRC, (ii) to brief on the different methods used for the detection of miRNA in CRC, (iii) to discuss different nanobiosensors so far found for the accurate detection of miRNAs in CRC using spectrophotometric detection, piezoelectric detection.

METHODS

The keywords for the review like micro RNA detection in inflammation, colorectal cancer, nanotechnology, were searched in PubMed and the relevant papers on the topics of miRNA related to CRC, nanotechnology-based biosensors for miRNA detection were then sorted and used appropriately for writing the review.

RESULTS

The review comprises a general introduction explaining the current scenario of CRC, the biomarkers used for the detection of different cancers, especially CRC and the importance of nanotechnology and a general scheme of a biosensor. The further subsections discuss the mechanism of CRC progression, the role of miRNA in CRC progression and different nanotechnology-based biosensors so far investigated for miRNA detection in other diseases, cancer and CRC. A scheme depicting miRNA detection using gold nanoparticles (AuNPs) is also illustrated.

CONCLUSION

This review may give insight into the different nanostructures, like AuNPs, quantum dots, silver nanoparticles, MoS2derived nanoparticles, etc., based approaches for miRNA detection using biosensors.

Potential treatment strategy for the rare osimertinib resistant mutation EGFR L718Q

Epidermal growth factor receptor (EGFR) L718Q is a rare resistant mutation which independently leads to third-generation tyrosine kinase inhibitor (TKI) resistance. Although a few studies have examined its resistance mechanisms, no effective treatment strategy has yet been proposed for patients with this mutation. Here, we report an effective treatment strategy for the rare EGFR L718Q mutation for the first time. A 44-year-old Chinese male patient initially presented with the sensitizing EGFR L858R mutation, and the progression-free survival (PFS) time after initial icotinib treatment was 9 months. When the progression of the disease (PD) and the EGFR T790M mutation were identified, he did not respond to the osimertinib treatment. Through comprehensive next-generation sequencing (NGS) of the surgical specimen, the rare EGFR L718Q mutation was eventually identified as having a frequency of 68.84%, together with an EGFR amplification with a copy number of 11.54. The previous treatment response was retrospectively explained, and the patient faced the challenge of not being able to benefit from any targeted therapy. Following chemotherapy with a personalized regimen which effectively modified the proportion of sensitive and resistant cells, significant response to osimertinib re-challenge was observed, and another PFS of 4.7 months was achieved. Unfortunately, four EGFR mutations, EGFR L858, T790M, L718Q, and C797S, were simultaneously detected in his late stage, and led to further progression of disease.

53BP1 Accumulation in Circulating Tumor Cells Identifies Chemotherapy-Responsive Metastatic Breast Cancer Patients

Evidence suggests that the DNA end-binding protein p53-binding protein 1 (53BP1) is down-regulated in subsets of breast cancer. Circulating tumor cells (CTCs) provide accessible “biopsy material” to track cell traits and functions and their alterations during treatment. Here, we prospectively monitored the 53BP1 status in CTCs from 67 metastatic breast cancer (MBC) patients with HER2- CTCs and known hormone receptor (HR) status of the primary tumor and/or metastases before, during, and at the end of chemotherapeutic treatment with Eribulin. Nuclear 53BP1 staining and genomic integrity were evaluated by immunocytochemical and whole-genome-amplification-based polymerase chain reaction (PCR) analysis, respectively. Comparative analysis of CTCs from patients with triple-negative and HR+ tumors revealed elevated 53BP1 levels in CTCs from patients with HR+ metastases, particularly following chemotherapeutic treatment. Differences in nuclear 53BP1 signals did not correlate with genomic integrity in CTCs at baseline or with nuclear γH2AX signals in MBC cell lines, indicating that 53BP1 detected features beyond DNA damage. Kaplan–Meier analysis revealed an increasing association between nuclear 53BP1-positivity and progression-free survival (PFS) during chemotherapy until the final visit. Our data suggest that 53BP1 detection in CTCs could be a useful marker to capture dynamic changes of chemotherapeutic responsiveness in triple-negative and HR+ MBC.

Morphologic and Genomic Heterogeneity in the Evolution and Progression of Breast Cancer

: Breast cancer is a remarkably complex and diverse disease. Subtyping based on morphology, genomics, biomarkers and/or clinical parameters seeks to stratify optimal approaches for management, but it is clear that every breast cancer is fundamentally unique. Intra-tumour heterogeneity adds further complexity and impacts a patient's response to neoadjuvant or adjuvant therapy. Here, we review some established and more recent evidence related to the complex nature of breast cancer evolution. We describe morphologic and genomic diversity as it arises spontaneously during the early stages of tumour evolution, and also in the context of treatment where the changing subclonal architecture of a tumour is driven by the inherent adaptability of tumour cells to evolve and resist the selective pressures of therapy.

Molecular profiling in breast cancer—ready for clinical routine?

The herald of genomic testing opened novel diagnostic and therapeutic possibilities for many tumor entities. For breast cancer, molecular profiling has become an integral part of disease management on multiple levels. Genetic testing allows for the identification of hereditary cancer syndromes in patients with a family history of malignancies and contributes to the successful prevention of breast cancer. In early breast cancer, several prospective randomized trials demonstrated the prognostic significance of commercially available mRNA-based gene expression analyses, which now have become part of standard of care in the adjuvant setting. In advanced breast cancer, testing for targetable mutations ensures personalized cancer treatment. Poly-ADP-ribose polymerase (PARP) inhibitors provide the first targeted alternative for patients with BRCA 1/2-associated breast cancer. In advanced breast cancer of luminal type, the detection of Phosphatidylinositol-4,5-Bisphosphate 3-Kinase Catalytic Subunit Alpha (PIK3CA) mutations provides a novel treatment option with alpelisib, a PIK3CA inhibitor. Further targetable mutations include NTRK3 in rare cases of secretory breast carcinoma and human epidermal growth factor receptor 2 (HER2). Recent data support the importance of the analysis of circulating tumor cells and cell-free DNA. These “liquid biopsies” open novel possibilities of molecular profiling. However, clinical benefit of such analyses remains to be confirmed.

Prognostic and Predictive Value of Circulating and Disseminated Tumor Cells in Breast Cancer: A National Cancer Database (NCDB) Analysis

IMPORTANCE

Our understanding of the utility of circulating tumor cells (CTCs) and disseminated tumor cells (DTCs) as clinical biomarkers continues to evolve.

OBJECTIVE

This study evaluated (1) clinicopathologic factors associated with the presence of CTCs or DTCs, (2) the prognostic value of CTCs or DTCs by disease stage, 3), the value of these biomarkers in predicting the benefit of chemotherapy.

DESIGN

This is a retrospective analysis of patients with breast cancer (BC) diagnosed between 2004 and 2016 using the National Cancer Database (NCDB). To evaluate variables associated with the presence of CTCs or DTCs at the univariate level, we used chi-squared and Wilcoxon rank-sum tests. Multivariate logistic regression models were then constructed using significant variables. Consequently, we included CTC or DTC status (i.e. positive or negative) in multivariate, stage-by-stage Cox regression analyses for overall survival (OS). After stratifying by receptor status and staging, we used the Kaplan-Meier method to explore chemotherapy efficacy in CTC- or DTC-positive vs. CTC- or DTC-negative subsets.

RESULTS

Factors significantly associated with CTCs were race, progesterone receptor status, HER2 status, histology and AJCC N- and M-staging. Factors associated with DTCs were race, HER2 status, histology and AJCC N-staging. CTCs were associated with poor OS in late-stage (III and IV) but not early-stage (0-II) BC. DTCs were not significantly associated with OS in either context. In hormone receptor (HR)-positive disease, chemotherapy was associated with better OS when CTC status was positive, both in early-stage and late-stage disease. In a subset of patients without CTCs, however, chemotherapy conferred no survival benefit. DTC status was not a significant predictor of chemotherapy efficacy in early or late-stage, HR+ disease.

CONCLUSIONS

This study suggests that CTC-status is a significant prognostic factor at later stages of BC; yet it can also help guide management of early-stage disease as it appears predictive for chemotherapy benefit.

Know your enemy: Genetics, aging, exposomic and inflammation in the war against triple negative breast cancer

Triple negative breast cancer (TNBC) is one of the most biologically aggressive and very often lethal breast disease. It is one of the most puzzling women malignancies, and it currently appears not to be a good candidate to a standardized, unanimously accepted and sufficiently active therapeutic strategy. Fast proliferating and poorly differentiated, it is histopathologically heterogeneous, and even more ambiguous at the molecular level, offering few recurrent actionable targets to the clinicians. It is a formidable and vicious enemy that requires a huge investigational effort to find its vital weak spots. Here, we provide a broad review of "old but gold" biological aspects that taken together may help in finding new TNBC management strategies. A better and updated knowledge of the origins, war-like tactics, refueling mechanisms and escape routes of TNBC, will help in moving the decisive steps towards its final defeat.

Translational Application of Circulating DNA in Oncology: Review of the Last Decades Achievements

In recent years, the introduction of new molecular techniques in experimental and clinical settings has allowed researchers and clinicians to propose circulating-tumor DNA (ctDNA) analysis and liquid biopsy as novel promising strategies for the early diagnosis of cancer and for the definition of patients' prognosis. It was widely demonstrated that through the non-invasive analysis of ctDNA, it is possible to identify and characterize the mutational status of tumors while avoiding invasive diagnostic strategies. Although a number of studies on ctDNA in patients' samples significantly contributed to the improvement of oncology practice, some investigations generated conflicting data about the diagnostic and prognostic significance of ctDNA. Hence, to highlight the relevant achievements obtained so far in this field, a clearer description of the current methodologies used, as well as the obtained results, are strongly needed. On these bases, this review discusses the most relevant studies on ctDNA analysis in cancer, as well as the future directions and applications of liquid biopsy. In particular, special attention was paid to the early diagnosis of primary cancer, to the diagnosis of tumors with an unknown primary location, and finally to the prognosis of cancer patients. Furthermore, the current limitations of ctDNA-based approaches and possible strategies to overcome these limitations are presented.

Unravelling tumour heterogeneity by single-cell profiling of circulating tumour cells

Single-cell technologies have contributed to unravelling tumour heterogeneity, now considered a hallmark of cancer and one of the main causes of tumour resistance to cancer therapies. Liquid biopsy (LB), defined as the detection and analysis of cells or cell products released by tumours into the blood, offers an appealing minimally invasive approach that allows the characterization and monitoring of tumour heterogeneity in individual patients. Here, we will review and discuss how circulating tumour cell (CTC) analysis at single-cell resolution provides unique insights into tumour heterogeneity that are not revealed by analysis of circulating tumour DNA (ctDNA) derived from LBs. The molecular analysis of CTCs provides complementary information to that of genomic aberrations determined using ctDNA to fully describe many different cellular components (for example, DNA, RNA, proteins and metabolites) that can influence tumour heterogeneity.

Detection of TP53 and PIK3CA Mutations in Circulating Tumor DNA Using Next-Generation Sequencing in the Screening Process for Early Breast Cancer Diagnosis

Circulating tumor DNA (ctDNA) has emerged as a non-invasive "liquid biopsy" for early breast cancer diagnosis. We evaluated the suitability of ctDNA analysis in the diagnosis of early breast cancer after mammography findings, comparing PIK3CA and TP53 mutations between tumor biopsies and pre-biopsy circulating DNA. Matched plasma and frozen fresh tissue biopsies from patients with Breast Imaging-Reporting and Data System (BIRADS) 4c/5 mammography findings and subsequent diagnosis of primary breast cancer were analyzed using NGS TruSeq Custom Amplicon Low Input Panel (Illumina) and plasma SafeSEQ (Sysmex Inostics). The same plasma and tumor mutations were observed in eight of 29 patients (27.6%) with four in TP53 and five in PIK3CA mutations. Sequencing analysis also revealed four additional ctDNA mutations (three in TP53 and one in PIK3CA) previously not identified in three patients tissue biopsy. One of these patients had mutations in both genes. Age, tumor grade and size, immunohistochemical (IHC) subtype, BIRADS category, and lymph node positivity were significantly associated with the detectability of these blood tumor-derived mutations. In conclusion, ctDNA analysis could be used in early breast cancer diagnosis, providing critical clinical information to improve patient diagnosis.

Liquid biopsy for the detection and management of surgically resectable tumors

BACKGROUND

Traditional biopsies have numerous limitations in the developing era of precision medicine, with cancer treatment that relies on biomarkers to guide therapy. Tumor heterogeneity raises the potential for sampling error with the use of traditional biopsy of the primary tumor. Moreover, tumors continuously evolve as new clones arise in the natural course of the disease and under the pressure of treatment. Since traditional biopsy is invasive, it is neither feasible nor practical to perform serial biopsies to guide treatment in real time.

PURPOSE

The current manuscript will review the most commonly used types of liquid biopsy and how these apply to surgical patients in terms of diagnosis, prediction of outcome, and guiding therapy.

CONCLUSIONS

Liquid biopsy has the potential to overcome many of the limitations of traditional biopsy as a highly tailored, minimally invasive, and cost-effective method to screen and monitor response to treatment. However, many challenges still need to be overcome before liquid biopsy becomes a reliable and widely available option.