Purpose: Up to 30% of patients with breast cancer relapse after primary treatment. There are no sensitive and reliable tests to monitor these patients and detect distant metastases before overt recurrence. Here, we demonstrate the use of personalized circulating tumor DNA (ctDNA) profiling for detection of recurrence in breast cancer.Experimental Design: Forty-nine primary patients with breast cancer were recruited following surgery and adjuvant therapy. Plasma samples (n ¼ 208) were collected every 6 months for up to 4 years. Personalized assays targeting 16 variants selected from primary tumor whole-exome data were tested in serial plasma for the presence of ctDNA by ultradeep sequencing (average >100,000X).Results: Plasma ctDNA was detected ahead of clinical or radiologic relapse in 16 of the 18 relapsed patients (sensitivity of 89%); metastatic relapse was predicted with a lead time of up to 2 years (median, 8.9 months; range, 0.5-24.0 months). None of the 31 nonrelapsing patients were ctDNA-positive at any time point across 156 plasma samples (specificity of 100%). Of the two relapsed patients who were not detected in the study, the first had only a local recurrence, whereas the second patient had bone recurrence and had completed chemotherapy just 13 days prior to blood sampling.Conclusions: This study demonstrates that patientspecific ctDNA analysis can be a sensitive and specific approach for disease surveillance for patients with breast cancer. More importantly, earlier detection of up to 2 years provides a possible window for therapeutic intervention. Personalized profiling detects rising ctDNA ahead of clinical relapse. A-E, Plasma levels of ctDNA across serial plasma time points for five patients with breast cancer (one per panel). Mean VAFs are denoted by a dark blue circle, and solid lines represent the average VAF profile over time. The lead time is calculated as the time interval between clinical relapse (red triangle) and molecular relapse (blue triangle). CA 15-3 levels are graphed over time (teal circle), and the baseline levels (32 U/mL) are marked in light blue. F, Summary of percent VAF and number of targets detected at molecular and clinical relapse for all ctDNA-positive samples. Data are from 13 relapsed patients, excluding three patients with only one plasma time point. Coombes et al.

Purpose: The purpose of this study was to directly compare mutation profiles in multiple single circulating tumor cells (CTC) and cell-free DNA (cfDNA) isolated from the same blood samples taken from patients with metastatic breast cancer (MBC). We aimed to determine whether cfDNA would reflect the heterogeneity observed in 40 single CTCs.Experimental Design: CTCs were enumerated by CELL-SEARCH. CTC count was compared with the quantity of matched cfDNA and serum CA15-3 and alkaline phosphatase (ALP) in 112 patients with MBC. In 5 patients with !100 CTCs, multiple individual EpCAM-positive CTCs were isolated by DEPArray and compared with matched cfDNA and primary tumor tissue by targeted next-generation sequencing (NGS) of about 2,200 mutations in 50 cancer genes.Results: In the whole cohort, total cfDNA levels and cell counts (!5 CTCs) were both significantly associated with overall survival, unlike CA15-3 and ALP. NGS analysis of 40 individual EpCAMpositive CTCs from 5 patients with MBC revealed mutational heterogeneity in PIK3CA, TP53, ESR1, and KRAS genes between individual CTCs. In all 5 patients, cfDNA profiles provided an accurate reflection of mutations seen in individual CTCs. ESR1 and KRAS gene mutations were absent from primary tumor tissue and therefore likely either reflect a minor subclonal mutation or were acquired with disease progression.Conclusions: Our results demonstrate that cfDNA reflects persisting EpCAM-positive CTCs in patients with high CTC counts and therefore may enable monitoring of the metastatic burden for clinical decision-making.

BackgroundBreast cancer (BC) is the most common cancer in women, and despite the introduction of new screening programmes, therapies and monitoring technologies, there is still a need to develop more useful tests for monitoring treatment response and to inform clinical decision making.The purpose of this study was to compare circulating cell-free DNA (cfDNA) and circulating tumour cells (CTCs) with conventional breast cancer blood biomarkers (CA15-3 and alkaline phosphatase (AP)) as predictors of response to treatment and prognosis in patients with metastatic breast cancer (MBC).MethodsOne hundred ninety-four female patients with radiologically confirmed MBC were recruited to the study. Total cfDNA levels were determined by qPCR and compared with CELLSEARCH® CTC counts and CA15-3 and alkaline phosphatase (AP) values. Blood biomarker data were compared with conventional tumour markers, treatment(s) and response as assessed by RECIST and survival.Non-parametric statistical hypothesis tests were used to examine differences, correlation analysis and linear regression to determine correlation and to describe its effects, logistic regression and receiver operating characteristic curve (ROC curve) to estimate the strength of the relationship between biomarkers and clinical outcomes and value normalization against standard deviation to make biomarker values comparable. Kaplan–Meier estimator and Cox regression models were used to assess survival. Univariate and multivariate models were performed where appropriate.ResultsMultivariate analysis showed that both the amount of total cfDNA (p value = 0.024, HR = 1.199, CI = 1.024–1.405) and the number of CTCs (p value = 0.001, HR = 1.243, CI = 1.088–1.421) are predictors of overall survival (OS), whereas total cfDNA levels is the sole predictor for progression-free survival (PFS) (p value = 0.042, HR = 1.193, CI = 1.007–1.415) and disease response when comparing response to non-response to treatment (HR = 15.917, HR = 12.481 for univariate and multivariate analysis, respectively). Lastly, combined analysis of CTCs and cfDNA is more informative than the combination of two conventional biomarkers (CA15-3 and AP) for prediction of OS.ConclusionMeasurement of total cfDNA levels, which is a simpler and less expensive biomarker than CTC counts, is associated with PFS, OS and response in MBC, suggesting potential clinical application of a cheap and simple blood-based test.

BACKGROUND: Breast cancer tissues are heterogeneous and show diverse somatic mutations and somatic copy number alterations (CNAs). We used a novel targeted next generation sequencing (NGS) panel to examine cellfree DNA (cfDNA) to detect somatic mutations and gene amplification in women with metastatic breast cancer (MBC).

Cell-free DNA (cfDNA) analysis represents a promising method for the diagnosis, treatment selection and clinical follow-up of cancer patients. Although its general methodological feasibility and usefulness has been demonstrated, several issues related to standardisation and technical validation must be addressed for its routine clinical application in cancer. In this regard, most cfDNA clinical applications are still limited to clinical trials, proving its value in several settings. In this paper, we review the current clinical trials involving cfDNA/ctDNA analysis and highlight those where it has been useful for patient stratification, treatment follow-up or development of novel approaches for early diagnosis. Our query included clinical trials, including the terms ‘cfDNA’, ‘ctDNA’, ‘liquid biopsy’ AND ‘cancer OR neoplasm’ in the FDA and EMA public databases. We identified 1370 clinical trials (FDA = 1129, EMA = 241) involving liquid-biopsy analysis in cancer. These clinical trials show promising results for the early detection of cancer and confirm cfDNA as a tool for real-time monitoring of acquired therapy resistance, accurate disease-progression surveillance and improvement of treatment, situations that result in a better quality of life and extended overall survival for cancer patients.

Improving early detection of colorectal cancer (CRC) is a key public health priority as adenomas and stage I cancer can be treated with minimally invasive procedures. Population screening strategies based on detection of occult blood in the feces have contributed to enhance detection rates of localized disease, but new approaches based on genetic analyses able to increase specificity and sensitivity could provide additional advantages compared to current screening methodologies. Recently, circulating cell-free DNA (cfDNA) has received much attention as a cancer biomarker for its ability to monitor the progression of advanced disease, predict tumor recurrence and reflect the complex genetic heterogeneity of cancers. Here, we tested whether analysis of cfDNA is a viable tool to enhance detection of colon adenomas. To address this, we assessed a cohort of patients with adenomas and healthy controls using droplet digital PCR (ddPCR) and mutation-specific assays targeted to trunk mutations. Additionally, we performed multiregional, targeted next-generation sequencing (NGS) of adenomas and unmasked extensive heterogeneity, affecting known drivers such as APC, KRAS and mismatch repair (MMR) genes. However, tumor-related mutations were undetectable in patients’ plasma. Finally, we employed a preclinical mouse model of Apc-driven intestinal adenomas and confirmed the inability to identify tumor-related alterations via cfDNA, despite the enhanced disease burden displayed by this experimental cancer model. Therefore, we conclude that benign colon lesions display extensive genetic heterogeneity, that they are not prone to release DNA into the circulation and are unlikely to be reliably detected with liquid biopsies, at least with the current technologies.

Breast cancer (BC) is a common cancer in women worldwide. Despite advances in treatment, up to 30% of women eventually relapse and die of metastatic breast cancer. Liquid biopsy analysis of circulating cell-free DNA fragments in the patients' blood can monitor clonality and evolving mutations as a surrogate for tumour biopsy. Next generation sequencing platforms and digital droplet PCR can be used to profile circulating tumour DNA from liquid biopsies; however, they are expensive and time consuming for clinical use. Here, we report a novel strategy with proof-of-concept data that supports the usage of loop-mediated isothermal amplification (LAMP) to detect PIK3CA c.3140 A > G (H1047R), a prevalent BC missense mutation that is attributed to BC tumour growth. Allele-specific primers were designed and optimized to detect the p.H1047R variant following the USS-sbLAMP method. The assay was developed with synthetic DNA templates and validated with DNA from two breast cancer cell-lines and two patient tumour tissue samples through a qPCR instrument and finally piloted on an ISFET enabled microchip. This work sets a foundation for BC mutational profiling on a Lab-on-Chip device, to help the early detection of patient relapse and to monitor efficacy of systemic therapies for personalised cancer patient management.Breast cancer (BC) has a lifetime incidence risk of 12%, with an overall survival of more than 70% of reported cases when early detection is possible 1,2 . Although surgery is capable of removing the primary tumour, minimal residual disease (MRD)/micrometastases may persist resulting in eventual resistance to therapy and recurrence 3 . MRD can often persist even after adjuvant therapy and can grow and spread overtime, remaining undetectable through mammograms, MRI scans and current tumour marker blood tests, such as CA-15-3 and CA 27.29 antigen assays 4 . These current tumour marker blood tests work as a cost-effective method to measure disease progression but do not provide information about mutational changes and heterogeneity of the primary tumour or MRD. With the development of new, non-cross-resistant treatments for breast cancer, early detection of MRD/micrometastases and mutational profiling of circulating tumour DNA (ctDNA) provides an attractive, cost-effective alternative approach to the detection of early signs of relapse and treatment switching.Previous research has proven that circulating free DNA (cfDNA) contains DNA fragments from cancer cells (ctDNA) that are released in blood, showing somatic mutations that reflect the original cancer and evolved clonal subtypes 5 . In particular, recent efforts have established that hotspot mutations in PIK3CA, a gene mutated in 20-40% of metastatic BC, are also commonly observed in screen-detected stage-1 BCs 6 . The PI3K protein is involved in the AKT/mTOR pathway and, when deregulated, leads to tumour-cell growth 7 . Investigation has

Here we will provide a brief overview of the potential clinical utility of cfDNA profiling for detection and monitoring of patients with breast cancer. The review was conducted in English using PubMed and search terms including 'breast cancer', 'plasma DNA', 'circulating cell free DNA' and 'circulating tumour DNA'. Expert commentary: Liquid biopsies through circulating tumor DNA (ctDNA) enable monitoring of patients with breast cancer. The challenge ahead will be to incorporate cfDNA mutation profiling into routine clinical practice to provide patients with the most appropriate and timely treatment.