Can plasma DNA monitoring be employed in personalized chemotherapy for patients with advanced lung cancer?

Using cfDNA and ctDNA as Oncologic Markers: A Path to Clinical Validation

The detection of circulating tumor DNA (ctDNA) in liquid biopsy samples as an oncological marker is being used in clinical trials at every step of clinical management. As ctDNA-based liquid biopsy kits are developed and used in clinics, companies work towards increased convenience, accuracy, and cost over solid biopsies and other oncological markers. The technology used to differentiate ctDNA and cell-free DNA (cfDNA) continues to improve with new tests and methodologies being able to detect down to mutant allele frequencies of 0.001% or 1/100,000 copies. Recognizing this development in technology, the FDA has recently given pre-market approval and breakthrough device designations to multiple companies. The purpose of this review is to look at the utility of measuring total cfDNA, techniques used to differentiate ctDNA from cfDNA, and the utility of different ctDNA-based liquid biopsy kits using relevant articles from PubMed, clinicaltrials.gov, FDA approvals, and company newsletters. Measuring total cfDNA could be a cost-effective, viable prognostic marker, but various factors do not favor it as a monitoring tool during chemotherapy. While there may be a place in the clinic for measuring total cfDNA in the future, the lack of standardization means that it is difficult to move forward with large-scale clinical validation studies currently. While the detection of ctDNA has promising standardized liquid biopsy kits from various companies with large clinical trials ongoing, their applications in screening and minimal residual disease can suffer from lower sensitivity. However, researchers are working towards solutions to these issues with innovations in technology, multi-omics, and sampling. With great promise, further research is needed before liquid biopsies can be recommended for everyday clinical management.

Evaluation of cfDNA as an early detection assay for dense tissue breast cancer

A cell-free DNA (cfDNA) assay would be a promising approach to early cancer diagnosis, especially for patients with dense tissues. Consistent cfDNA signatures have been observed for many carcinogens. Recently, investigations of cfDNA as a reliable early detection bioassay have presented a powerful opportunity for detecting dense tissue screening complications early. We performed a prospective study to evaluate the potential of characterizing cfDNA as a central element in the early detection of dense tissue breast cancer (BC). Plasma samples were collected from 32 consenting subjects with dense tissue and positive mammograms, 20 with positive biopsies and 12 with negative biopsies. After screening and before biopsy, cfDNA was extracted, and whole-genome next-generation sequencing (NGS) was performed on all samples. Copy number alteration (CNA) and single nucleotide polymorphism (SNP)/insertion/deletion (Indel) analyses were performed to characterize cfDNA. In the positive-positive subjects (cases), a total of 5 CNAs overlapped with 5 previously reported BC-related oncogenes (KSR2, MAP2K4, MSI2, CANT1 and MSI2). In addition, 1 SNP was detected in KMT2C, a BC oncogene, and 9 others were detected in or near 10 genes (SERAC1, DAGLB, MACF1, NVL, FBXW4, FANK1, KCTD4, CAVIN1; ATP6V0A1 and ZBTB20-AS1) previously associated with non-BC cancers. For the positive–negative subjects (screening), 3 CNAs were detected in BC genes (ACVR2A, CUL3 and PIK3R1), and 5 SNPs were identified in 6 non-BC cancer genes (SNIP1, TBC1D10B, PANK1, PRKCA and RUNX2; SUPT3H). This study presents evidence of the potential of using cfDNA somatic variants as dense tissue BC biomarkers from a noninvasive liquid bioassay for early cancer detection.

Circulating free DNA as a marker of response to chemoradiation in locally advanced head and neck squamous cell carcinoma

Context

Liquid biopsy has moved from bench to bedside as a non-invasive biomarker for early diagnosis and monitoring treatment response.

Objective

This study investigated the role of circulating free DNA (cfDNA) as a diagnostic marker in locally advanced head and neck squamous cell carcinoma (HNSCC) and in monitoring response to chemoradiation therapy.

Materials and Methods

Serum was collected from treatment naïve, histopathologically diagnosed tumors in 24 HNSCC cases and 16 normal controls. CfDNA levels were quantified using β globin gene amplification.

Results

The cfDNA level was significantly elevated in HNSCC (992.67 ± 657.43 ng/mL) as compared to healthy controls (60.65 ± 30.42 ng/mL, P = <0.001). The levels of cfDNA did not significantly correlate with TNM stage, lymph node involvement and grade. In responders, percentage decrease in cfDNA levels was 9.57% and 29.66%, whereas in nonresponders percentage increase was 13.28% and 24.52% at the end of three months of follow-up.

Conclusion

Our study adds to the evidence that cfDNA levels are significantly higher in HNSCC cases and provides some evidence that levels increase with tumor progression. CfDNA may be a promising prospective non-invasive marker to predict response in patients undergoing chemo-radiotherapy.

Utilization of circulating cell-free DNA profiling to guide first-line chemotherapy in advanced lung squamous cell carcinoma

Rationale: Platinum-based chemotherapy is one of treatment mainstay for patients with advanced lung squamous cell carcinoma (LUSC) but it is still a "one-size fits all" approach. Here, we aimed to investigate the predictive and monitoring role of circulating cell-free DNA (cfDNA) profiling for the outcome of first-line chemotherapy in patients with advanced LUSC. Methods: Peripheral blood samples of 155 patients from a phase IV trial and 42 cases from an external real-world cohort were prospectively collected. We generated a copy number variations-based classifier via machine learning algorithm to integrate molecular profiling of cfDNA, named RESPONSE SCORE (RS) to predict the treatment outcome. To monitor the treatment efficacy, cfDNA samples collected at different time points were subjected to an ultra-deep sequencing platform. Results: The results showed that patients with high RS showed substantially higher objective response rate than those with low RS in training set (P < 0.001), validation set (P < 0.001) and real-world cohort (P = 0.019). Furthermore, a significant difference was observed in both progression-free survival (training set, P < 0.001; validation set: P < 0.001; real-world cohort: P = 0.019) and overall survival (training set, P < 0.001; validation set: P = 0.037) between high and low RS group. Notably, variant allele frequency (VAF) calculated from an ultra-deep sequencing platform significantly reduced in patients experienced a complete or partial response after 2 cycles of chemotherapy (P < 0.001), while it significantly increased in these of non-responder (P < 0.001). Moreover, VAF undetectable after 2 cycles of chemotherapy was correlated with markedly better objective response rate (P < 0.001) and progression-free survival (P < 0.001) than those with detectable VAF. Conclusions: These findings indicated that the RS, a circulating cfDNA sequencing-based stratification index, could help to guide first-line chemotherapy in advanced LUSC. The change of VAF is valuable to monitor the treatment response.

Value of dynamic plasma cell-free DNA monitoring in septic shock syndrome: A case report

BACKGROUND

Mortality due to septic shock is relatively high. The dynamic monitoring of plasma cell-free DNA (cfDNA) can guide the treatment of septic shock.

CASE SUMMARY

Herein, we present a typical case of septic shock syndrome caused by the bacilli Acinetobacter baumannii and Pantoea. The patient complained of abdominal pain, fever and chills upon admission to the Emergency Department. Marked decreases in white blood cells and procalcitonin (PCT) were observed after the patient received continuous renal replacement and extracorporeal membrane oxygenation. Plasma cfDNA levels were consistently high, peaking at 1366.40 ng/mL, as measured by a duplex real-time PCR assay with an internal control, which was developed as a novel method for the accurate quantification of cfDNA. The patient died of septic shock on HD 8, suggesting that cfDNA could be used to monitor disease progression more effectively than PCT and the other inflammatory factors measured in this case.

CONCLUSION

CfDNA may be a promising marker that complements other inflammatory factors to monitor disease progression in patients with septic shock.

Mutational Landscape of cfDNA Identifies Distinct Molecular Features Associated With Therapeutic Response to First-Line Platinum-Based Doublet Chemotherapy in Patients with Advanced NSCLC

Rationale To investigate whether the mutational landscape of circulating cell-free DNA (cfDNA) could predict and dynamically monitor the response to first-line platinum-based chemotherapy in patients with advanced non-small-cell lung cancer (NSCLC). Methods Eligible patients were included and blood samples were collected from a phase III trial. Both cfDNA fragments and fragmented genomic DNA were extracted for enrichment in a 1.15M size panel covering exon regions of 1,086 genes. Molecular mutational burden (MMB) was calculated to investigate the relationship between molecular features of cfDNA and response to chemotherapy. Results In total, 52 eligible cases were enrolled and their blood samples were prospectively collected at baseline, every cycle of chemotherapy and time of disease progression. At baseline, alterations of 17 genes were found. Patients with partial response (PR) had significantly lower baseline MMB of these genes than those patients with either stable disease (SD) (P = 0.0006) or progression disease (PD) (P = 0.0074). Further analysis revealed that the mutational landscape of cfDNA from pretreatment blood samples were distinctly different among patients with PR vs. SD/PD. For patients with baseline TP53 mutation, those with PR experienced a significant reduction in MMB whereas patients with SD or PD experienced an increase after two, three or four cycles of chemotherapy. Furthermore, patients with low MMB had superior response rate and significantly longer progression-free survival than those with high MMB. Conclusion This study indicated that the mutational landscape of cfDNA has potential clinical value to predict the therapeutic response to first-line platinum-based doublet chemotherapy in NSCLC patients. At the single gene level, dynamic change of molecular mutational burden of TP53 is valuable to monitor efficacy (and, therefore, might aid in early recognition of resistance and relapse) in patients harboring this mutation at baseline.

Quantification of circulating cell-free DNA to predict patient survival in non-small-cell lung cancer

We used computed tomography (CT) to explore the prognostic value of cell-free (cf) DNA quantification and its predictive efficacy over time after chemotherapy in non-small-cell lung cancer (NSCLC) patients. In total, 177 NSCLC patients were enrolled in a prospective biomarker trial. Consecutive paired blood collection was performed to determine cfDNA concentrations at baseline CT and throughout serial follow-ups. The best cfDNA cut-off value to predict progression-free and overall survival was determined using X-tile analysis. Among 112 chemo-naive patients with stage IV adenocarcinoma, 43 were available for follow-up analysis. Cox regression multivariate analysis indicated that a high cfDNA concentration was an independent negative prognostic factor for progression-free survival (hazard ratio: 2.60; 95% confidence interval: 1.65-4.10; p = 0.008) and overall survival (hazard ratio: 2.63; 95% confidence interval: 1.66-4.17; p < 0.001). However, cfDNA concentration changes during treatment did not correlate with radiological CT responses at first follow-up or best response. No pattern was noted in the percent change in the cfDNA concentration from baseline or subsequently measured level to progression. The serum cfDNA concentration is thus associated with NSCLC patient prognosis, but does not appear to be a clinically valid marker for tumor responses.

Plasma cell-free DNA and survival in non-small-cell lung cancer: A meta-analysis

In recent years, plasma cell-free DNA (cfDNA) has been attracting increasing attention as a potential tumor marker, as this method is easily applied and minimally invasive. A series of studies have confirmed the association between the level of cfDNA and overall survival (OS) in non-small-cell lung cancer (NSCLC), but the findings remain inconclusive. We herein conducted a meta-analysis of published articles evaluating the correlation between the level of cfDNA and OS. A total of 9 studies enrolling 1,170 patients were included. For the overall population, a high level of cfDNA was found to be significantly correlated with worse OS [hazard ratio (HR) = 1.57, 95% confidence interval (CI): 1.18–2.10] in NSCLC. The subgroup analysis suggested that a high cfDNA level was associated with worse outcome in stage III–IV patients (HR=1.53, 95% CI: 1.07–2.19). However, the level of cfDNA and OS were not found to be significantly associated in the subgroup of patients with tumor stage I–II. The present meta-analysis revealed that a high level of cfDNA may be correlated with poor OS in NSCLC.

Early Change in FDG-PET Signal and Plasma Cell-Free DNA Level Predicts Erlotinib Response in EGFR Wild-Type NSCLC Patients

INTRODUCTION: Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) are a treatment option in the second- or third-line palliative setting in EGFR wild-type (wt) non–small cell lung cancer (NSCLC) patients. However, response rates are low, and only approximately 25% will achieve disease control. Early prediction of treatment resistance could accelerate discontinuation of ineffective treatment and reduce unnecessary toxicity. In this study, we evaluated early changes on 18F-fluoro-D-glucose (F-18-FDG) positron emission tomography/computed tomography (PET/CT) and in total plasma cell-free DNA (cfDNA) as markers of erlotinib response in EGFR-wt patients. METHODS: F-18-FDG-PET/CT scans and blood samples were obtained prior to erlotinib initiation and were repeated after 1 week (PET/CT) and 1 to 4 weeks (blood sample) of treatment. Level of cfDNA was measured by droplet digital polymerase chain reaction. Percentage change (%∆) in SUL_peak and total lesion glycolysis (TLG) on FDG-PET/CT and in plasma cfDNA was correlated to radiological response, progression-free survival (PFS), and overall survival (OS). RESULTS: Fifty patients were prospectively enrolled. A significant correlation was found between CT response and %∆TLG (P = .003). All patients with early metabolic progression showed radiological progression. Increased %∆TLG and %∆cfDNA were significantly correlated with shorter PFS (P = .002 and P = .004, respectively) and OS (P = .009 and P = .009, respectively). Multivariate analysis indicated %∆cfDNA to be the strongest predictor of OS. CONCLUSION: Early increase in TLG on F-18-FDG-PET/CT correlates with radiological progression, and shorter PFS and OS. Early increase in cfDNA predicts shorter PFS and OS. Both assessments are promising tools for early detection of nonresponders and reduced OS in TKI-treated EGFR-wt NSCLC patients.

Real-time monitoring efficiency and toxicity of chemotherapy in patients with advanced lung cancer

Background

The Response Evaluation Criteria in Solid Tumors (RECIST) guideline and Common Terminology Criteria for Adverse Events (CTCAE) criteria are used to assess chemotherapy efficiency and toxicity in patients with advanced lung cancer. However, no real-time, synchronous indicators that can evaluate chemotherapy outcomes are available. We wanted to evaluate tumor response and toxicity in advanced lung cancer chemotherapy by using a novel synchronous strategy.

Results

We enrolled 316 patients with advanced lung cancer who were treated with cisplatin-based therapy and followed up them for 3 years. Plasma was obtained before and after every chemotherapy cycle. We quantitative assayed total plasma DNA and methylation of the APC/RASSF1A genes. Four parameters were assessed: methylation level before chemotherapy (meth_0 h), methylation level 24 h after chemotherapy (meth_24 h), total plasma DNA concentration before chemotherapy (DNA_0 h), and total plasma DNA concentration 24 h after chemotherapy (DNA_24 h). When meth_24 h > meth_0 h of at least one gene was used to predict tumor response, the correct prediction rate was 82.4 %. Additionally, patients for whom DNA_24 h/DNA_0 h ≤ 2 had mild toxicities. Therefore, meth_24 h > meth_0 h and DNA_24 h/DNA_0 h ≤ 2 were defined as criteria for better tumor response and fewer adverse events with a high correct prediction rate (84.7 %).

Conclusions

Quantitative analysis of total plasma DNA and plasma APC/RASSF1A methylation provide a real-time synchronous rapid monitoring indicator for therapeutic outcomes of advanced lung cancer, which could be a reference or supplementary guidelines in evaluating chemotherapy effects.

Electronic supplementary material

The online version of this article (doi:10.1186/s13148-015-0150-9) contains supplementary material, which is available to authorized users.

A prospective study of total plasma cell-free DNA as a predictive biomarker for response to systemic therapy in patients with advanced non-small-cell lung cancers

BACKGROUND

While previous studies have reported on the prognostic value of total plasma cell-free deoxyribonucleic acid (cfDNA) in lung cancers, few have prospectively evaluated its predictive value for systemic therapy response.

PATIENTS AND METHODS

We conducted a prospective study to evaluate the association between changes in total cfDNA and radiologic response to systemic therapy in patients with stage IIIB/IV non-small-cell lung cancers (NSCLCs). Paired blood collections for cfDNA and computed tomography (CT) assessments by RECIST v1.0 were performed at baseline and 6-12 weeks after therapy initiation. Total cfDNA levels were measured in plasma using quantitative real-time polymerase chain reaction. Associations between changes in cfDNA and radiologic response, progression-free survival (PFS), and overall survival (OS) were measured using Kruskal-Wallis and Kaplan-Meier estimates.

RESULTS

A total of 103 patients completed paired cfDNA and CT response assessments. Systemic therapy administered included cytotoxic chemotherapy in 57% (59/103), molecularly targeted therapy in 17% (17/103), and combination therapy in 26% (27/103). Median change in cfDNA from baseline to response assessment did not significantly differ by radiologic response categories of progression of disease, stable disease and partial response (P = 0.10). However, using radiologic response as continuous variable, there was a weak positive correlation between change in radiologic response and change in cfDNA (Spearman's correlation coefficient 0.21, P = 0.03). Baseline cfDNA levels were not associated with PFS [hazard ratio (HR) = 1.06, 95% confidence interval (CI) 0.93-1.20, P = 0.41] or OS (HR = 1.04, 95% CI 0.93-1.17, P = 0.51), neither were changes in cfDNA.

CONCLUSIONS

In this large prospective study, changes in total cfDNA over time did not significantly predict radiologic response from systemic therapy in patients with advanced NSCLC. Pretreatment levels of total cfDNA were not prognostic of survival. Total cfDNA level is not a highly specific predictive biomarker and future investigations in cfDNA should focus on tumor-specific genomic alterations using expanded capabilities of next-generation sequencing.

Cell-free circulating tumor DNA in plasma/serum of non-small cell lung cancer

Non-small cell lung cancer (NSCLC) is the common type of lung cancer, which is the leading cause of cancer death throughout the world. Most patients were diagnosed too late for curative treatment. So, it is necessary to develop a minimal invasive method to identify NSCLC at an early stage. In recent years, cell-free circulating tumor DNA (ctDNA) has attracted increasing attention as a potential tumor marker for its minimal invasive, convenient, and easily accepted properties. The amount of ctDNA in plasma or serum was significantly higher in NSCLC patients than that in healthy controls or patients with benign diseases. Furthermore, many studies have proved an association among tumor stage, tumor grade, lymph node involvement, the number of metastatic sites, tumor response, survival outcome, and the ctDNA levels. Many genetic changes, such as gene mutation, loss of heterozygosity, microsatellite instability, and gene methylation were also found in ctDNA in NSCLC patients. These findings demonstrated that the ctDNA could serve as a viable tool to monitor NSCLC and prompted us to find more sensitive and specific biomarkers for clinical practice, especially monitor these cases with at least one known gene abnormality. Here, we reviewed the evidence of ctDNA in NSCLC and consider possible future applications in patient management.