Detecting ALK, ROS1, and RET fusions and the METΔex14 splicing variant in liquid biopsies of non-small-cell lung cancer patients using RNA-based techniques.

ALK, ROS1, and RET fusions and MET∆ex14 variant associate with response to targeted therapies in non-small-cell lung cancer (NSCLC). Technologies for fusion testing in tissue must be adapted to liquid biopsies, which are often the only material available. In this study, circulating-free RNA (cfRNA) and extracellular vesicle RNA (EV-RNA) were purified from liquid biopsies. Fusion and MET∆ex14 transcripts were analyzed by nCounter (Nanostring) and digital PCR (dPCR) using the QuantStudio® System (Applied Biosystems). We found that nCounter detected ALK, ROS1, RET, or MET∆ex14 aberrant transcripts in 28/40 cfRNA samples from positive patients and 0/16 of control individuals (70% sensitivity). Regarding dPCR, aberrant transcripts were detected in the cfRNA of 25/40 positive patients. Concordance between the two techniques was 58%. Inferior results were obtained when analyzing EV-RNA, where nCounter often failed due to a low amount of input RNA. Finally, results of dPCR testing in serial liquid biopsies of five patients correlated with response to targeted therapy. We conclude that nCounter can be used for multiplex detection of fusion and MET∆ex14 transcripts in liquid biopsies, showing a performance comparable with next-generation sequencing platforms. dPCR could be employed for disease follow-up in patients with a known alteration. cfRNA should be preferred over EV-RNA for these analyses.

Cancer as an infective disease: the role of EVs in tumorigenesis.

Cancer is conventionally considered an evolutionary disease where tumor cells adapt to the environment and evolve eventually leading to the formation of metastasis through the seeding and growth of metastasis-initiating cells in distant organs. Tumor cell and tumor-stroma communication via soluble factors and extracellular vesicles (EVs) are essential for the success of the metastatic process. As the field of EVs advances, growing data support the role of tumor-derived EVs not only in modifying the microenvironment to facilitate tumor progression but also in inducing changes in cells outside the primary tumor that may lead to a malignant transformation. Thus, an alternative hypothesis has emerged suggesting the conceptualization of cancer as an 'infective' disease. Still, tackling EVs as a possible cancer treatment has not been widely explored. A major understanding is needed to unveil possible additional contributions of EVs in progression and metastasis, which may be essential for the development of novel approaches to treat cancer patients. Here, we review the contribution of EVs to cancer progression and the possible implication of these factors in the oncogenic transformation of indolent cells.

Molecular Divergence upon EGFR-TKI Resistance Could Be Dependent on the Exon Location of the Original EGFR-Sensitizing Mutation.

Tumor molecular profiling upon disease progression enables investigations of the tumor evolution. Next-generation sequencing (NGS) of liquid biopsies constitutes a noninvasive readily available source of tumor molecular information. In this study, 124 plasma samples from advanced EGFR-positive NSCLC patients, treated with a first-line EGFR tyrosine kinase inhibitor (EGFR-TKI) were collected upon disease progression. The circulating cell-free DNA (cfDNA) was sequenced using the Oncomine Pan-Cancer Cell-Free Assay™. Excluding EGFR mutations, the most frequently mutated gene was TP53 (57.3%), followed by APC (11.3%), FGFR3 (7.3%), and KRAS (5.6%). Different molecular alterations were observed upon disease progression depending on the location of the original EGFR-sensitizing mutation. Specifically, the detection of the p.T790M mutation was significantly associated with the presence of exon 19 mutations in EGFR (Fisher p-value: 0.028). All KRAS activating mutations (n = 8) were detected in tumors with EGFR mutations in exons 18 and 21 (Fisher p-value < 0.001). Similarly, mutations in NRAS and HRAS were more frequently detected in samples from tumors harboring mutations in exons 18 or 21 (Fisher p-value: 0.050 and Fisher p-value: 0.099, respectively). In conclusion, our data suggest that the mechanisms underlying EGFR-TKI resistance could be dependent on the exon location of the original EGFR-sensitizing mutation.

Circulating Tumor DNA as a Cancer Biomarker: An Overview of Biological Features and Factors That may Impact on ctDNA Analysis.

Cancer cells release nucleic acids, freely or associated with other structures such as vesicles into body fluids, including blood. Among these nucleic acids, circulating tumor DNA (ctDNA) has emerged as a minimally invasive biomarker for tumor molecular profiling. However, certain biological characteristics of ctDNA are still unknown. Here, we provide an overview of the current knowledge about ctDNA biological features, including size and structure as well as the mechanisms of ctDNA shedding and clearance, and the physio-pathological factors that determine ctDNA levels. A better understanding of ctDNA biology is essential for the development of new methods that enable the analysis of ctDNA.

Overall Survival and Biomarker Analysis of Neoadjuvant Nivolumab Plus Chemotherapy in Operable Stage IIIA Non-Small-Cell Lung Cancer (NADIM phase II trial).

PURPOSE: Neoadjuvant chemotherapy plus nivolumab has been shown to be effective in resectable non-small-cell lung cancer (NSCLC) in the NADIM trial (ClinicalTrials.gov identifier: NCT03081689). The 3-year overall survival (OS) and circulating tumor DNA (ctDNA) analysis have not been reported. METHODS: This was an open-label, multicenter, single-arm, phase II trial in which patients with stage IIIA NSCLC, who were deemed to be surgically resectable, were treated with neoadjuvant paclitaxel (200 mg/m2 once a day) and carboplatin (area under curve 6) plus nivolumab (360 mg) once on day 1 of each 21-day cycle, for three cycles, followed by adjuvant nivolumab monotherapy for 1 year (240 mg once every 2 weeks for 4 months, followed by 480 mg once every 4 weeks for 8 months). The 3-year OS and ctDNA analysis were secondary objectives of the trial. RESULTS: OS at 36 months was 81.9% (95% CI, 66.8 to 90.6) in the intention-to-treat population, rising to 91.0% (95% CI, 74.2 to 97.0) in the per-protocol population. Neither tumor mutation burden nor programmed cell death ligand-1 staining was predictive of survival. Conversely, low pretreatment levels of ctDNA were significantly associated with improved progression-free survival and OS (hazard ratio [HR], 0.20; 95% CI, 0.06 to 0.63, and HR, 0.07; 95% CI, 0.01 to 0.39, respectively). Clinical responses according to RECIST v1.1 criteria did not predict survival outcomes. However, undetectable ctDNA levels after neoadjuvant treatment were significantly associated with progression-free survival and OS (HR, 0.26; 95% CI, 0.07 to 0.93, and HR, 0.04; 95% CI, 0.00 to 0.55, respectively). The C-index to predict OS for ctDNA levels after neoadjuvant treatment (0.82) was superior to that of RECIST criteria (0.72). CONCLUSION: The efficacy of neoadjuvant chemotherapy plus nivolumab in resectable NSCLC is supported by 3-year OS. ctDNA levels were significantly associated with OS and outperformed radiologic assessments in the prediction of survival.

ALK-Fusion Transcripts Can Be Detected in Extracellular Vesicles (EVs) from Nonsmall Cell Lung Cancer Cell Lines and Patient Plasma: Toward EV-Based Noninvasive Testing.

BACKGROUND: ALK rearrangements are present in 5% of nonsmall cell lung cancer (NSCLC) tumors and identify patients who can benefit from ALK inhibitors. ALK fusions testing using liquid biopsies, although challenging, can expand the therapeutic options for ALK-positive NSCLC patients considerably. RNA inside extracellular vesicles (EVs) is protected from RNases and other environmental factors, constituting a promising source for noninvasive fusion transcript detection. METHODS: EVs from H3122 and H2228 cell lines, harboring EML4-ALK variant 1 (E13; A20) and variant 3 (E6a/b; A20), respectively, were successfully isolated by sequential centrifugation of cell culture supernatants. EVs were also isolated from plasma samples of 16 ALK-positive NSCLC patients collected before treatment initiation. RESULTS: Purified EVs from cell cultures were characterized by transmission electron microscopy (TEM), nanoparticle tracking analysis (NTA), and flow cytometry. Western blot and confocal microscopy confirmed the expression of EV-specific markers as well as the expression of EML4-ALK-fusion proteins in EV fractions from H3122 and H2228 cell lines. In addition, RNA from EV fractions derived from cell culture was analyzed by digital PCR (dPCR) and ALK-fusion transcripts were clearly detected. Similarly, plasma-derived EVs were characterized by NTA, flow cytometry, and the ExoView platform, the last showing that EV-specific markers captured EV populations containing ALK-fusion protein. Finally, ALK fusions were identified in 50% (8/16) of plasma EV-enriched fractions by dPCR, confirming the presence of fusion transcripts in EV fractions. CONCLUSIONS: ALK-fusion transcripts can be detected in EV-enriched fractions. These results set the stage for the development of EV-based noninvasive ALK testing.

A simple immunoassay for extracellular vesicle liquid biopsy in microliters of non-processed plasma.

BACKGROUND: Extracellular vesicles (EVs), released by most cell types, provide an excellent source of biomarkers in biological fluids. However, in order to perform validation studies and screenings of patient samples, it is still necessary to develop general techniques permitting rapid handling of small amounts of biological samples from large numbers of donors. RESULTS: Here we describe a method that, using just a few microliters of patient's plasma, identifies tumour markers exposed on EVs. Studying physico-chemical properties of EVs in solution, we demonstrate that they behave as stable colloidal suspensions and therefore, in immunocapture assays, many of them are unable to interact with a stationary functionalised surface. Using flocculation methods, like those used to destabilize colloids, we demonstrate that cationic polymers increase EV ζ-potential, diameter, and sedimentation coefficient and thus, allow a more efficient capture on antibody-coated surfaces by both ELISA and bead-assisted flow cytometry. These findings led to optimization of a protocol in microtiter plates allowing effective immunocapture of EVs, directly in plasma without previous ultracentrifugation or other EV enrichment. The method, easily adaptable to any laboratory, has been validated using plasma from lung cancer patients in which the epithelial cell marker EpCAM has been detected on EVs. CONCLUSIONS: This optimized high throughput, easy to automate, technology allows screening of large numbers of patients to phenotype tumour markers in circulating EVs, breaking barriers for the validation of proposed EV biomarkers and the discovery of new ones.

R-Score: A New Parameter to Assess the Quality of Variants' Calls Assessed by NGS Using Liquid Biopsies.

Next-generation sequencing (NGS) has enabled a deeper knowledge of the molecular landscape in non-small cell lung cancer (NSCLC), identifying a growing number of targetable molecular alterations in key genes. However, NGS profiling of liquid biopsies risk for false positive and false negative calls and parameters assessing the quality of NGS calls remains lacking. In this study, we have evaluated the positive percent agreement (PPA) between NGS and digital PCR calls when assessing EGFR mutation status using 85 plasma samples from 82 EGFR-positive NSCLC patients. According to our data, variant allele fraction (VAF) was significantly lower in discordant calls and the median of the absolute values of all pairwise differences (MAPD) was significantly higher in discordant calls (p < 0.001 in both cases). Based on these results, we propose a new parameter that integrates both variables, named R-score. Next, we sought to evaluate the PPA for EGFR mutation calls between two independent NGS platforms using a subset of 40 samples from the same cohort. Remarkably, there was a significant linear correlation between the PPA and the R-score (r = 0.97; p < 0.001). Specifically, the PPA of samples with an R-score ≤ -1.25 was 95.83%, whereas PPA falls to 81.63% in samples with R-score ≤ 0.25. In conclusion, R-score significantly correlates with PPA and can assist laboratory medicine specialists and data scientists to select reliable variants detected by NGS.

NGS-based liquid biopsy profiling identifies mechanisms of resistance to ALK inhibitors: a step toward personalized NSCLC treatment.

Despite impressive and durable responses, nonsmall cell lung cancer (NSCLC) patients treated with anaplastic lymphoma kinase (ALK) inhibitors (ALK-Is) ultimately progress due to development of resistance. Here, we have evaluated the clinical utility of circulating tumor DNA (ctDNA) profiling by next-generation sequencing (NGS) upon disease progression. We collected 26 plasma and two cerebrospinal fluid samples from 24 advanced ALK-positive NSCLC patients at disease progression to an ALK-I. These samples were analyzed by NGS and digital PCR. A tool to retrieve variants at the ALK locus was developed (VALK tool). We identified at least one resistance mutation in the ALK locus in ten (38.5%) plasma samples; the G1269A and G1202R mutations were the most prevalent among patients progressing to first- and second-generation ALK-Is, respectively. Overall, 61 somatic mutations were detected in 14 genes: TP53, ALK, PIK3CA, SMAD4, MAP2K1 (MEK1), FGFR2, FGFR3, BRAF, EGFR, IDH2, MYC, MET, CCND3, and CCND1. Specifically, a deletion in exon 19 in EGFR, a non-V600 BRAF mutation (G466V), and the F129L mutation in MAP2K1 were identified in four patients who showed no objective survival benefit from ALK-Is. Potential ALK-I-resistance mutations were also found in PIK3CA and IDH2. Finally, a c-MYC gain, along with a loss of CCND1 and FGFR3, was detected in a patient progressing on a first-line treatment with crizotinib. We conclude that NGS analysis of liquid biopsies upon disease progression identified different putative ALK-I-resistance mutations in most cases and could be a valuable approach for therapy decision making.

ctDNA from body fluids is an adequate source for EGFR biomarker testing in advanced lung adenocarcinoma.

OBJECTIVES: Epidermal growth factor receptor (EGFR) biomarker testing using blood-based liquid biopsies remains challenging due to the low concentration of circulating tumor DNA (ctDNA) in certain plasma samples. The aim of this study is to evaluate the usefulness for EGFR biomarker testing of ctDNA from pleural effusions, cerebrospinal fluids, ascites and pericardial effusions obtained during the clinical management of lung adenocarcinoma patients. METHODS: For comparison purposes, 23 paired plasma and body fluid samples were collected from 17 patients with EGFR-positive lung adenocarcinoma. After circulating free DNA (cfDNA) isolation, samples were evaluated for the initial EGFR-sensitizing mutation and the p.T790M resistance mutation by array-based digital PCR (dPCR). RESULTS: Body fluids had more cfDNA than plasma samples (1.90 vs. 0.36 ng/µL; p=0.0130), and more samples tested positive for EGFR mutations (21 vs. 16 samples), with a total of 28 vs. 22 variants detected. Furthermore, mutant allele frequencies (MAFs) observed in body fluids were significantly higher than those assessed in the paired plasma samples for EGFR-sensitizing mutations (median MAFs = 15.8 vs. 0.8%; p=0.0004) as well as for the p.T790M resistance mutation (median MAFs = 8.69 vs. 0.16%; p=0.0390). Importantly, two patients who had progressed on first-generation EGFR-tyrosine kinase inhibitors with a dubious result for p.T790M plasma (MAFs = 0.11%) had an indisputably positive result in their respective body fluid samples (MAFs = 10.25 and 9.66%). CONCLUSIONS: ctDNA derived from body fluids is an informative source for EGFR biomarker testing, with greater sensitivity than plasma samples.

ctDNA analysis reveals different molecular patterns upon disease progression in patients treated with osimertinib.

BACKGROUND: Several clinical trials have demonstrated the efficacy and safety of osimertinib in advanced non-small-cell lung cancer (NSCLC). However, there is significant unexplained variability in treatment outcome. METHODS: Observational prospective cohort of 22 pre-treated patients with stage IV NSCLC harboring the epidermal growth factor receptor (EGFR) p.T790M resistance mutation and who were treated with osimertinib. Three hundred and twenty-six serial plasma samples were collected and analyzed by digital PCR (dPCR) and next-generation sequencing (NGS). RESULTS: The median progression-free survival (PFS), since the start of osimertinib, was 8.9 [interquartile range (IQR): 4.6-18.0] months. The median treatment durations of sequential gefitinib + osimertinib, afatinib + osimertinib and erlotinib + osimertinib treatments were 30.1, 24.6 and 21.1 months, respectively. The p.T790M mutation was detected in 19 (86%) pre-treatment blood samples. Undetectable levels of the original EGFR-sensitizing mutation after 3 months of treatment were associated with superior PFS (HR: 0.2, 95% CI: 0.05-0.7). Likewise, re-emergence of the original EGFR mutation, alone or together with the p.T790M mutation was significantly associated with shorter PFS (HR: 8.8, 95% CI: 1.1-70.7 and HR: 5.9, 95% CI: 1.2-27.9, respectively). Blood-based monitoring revealed three molecular patterns upon progression to osimertinib: sensitizing+/T790M+/C797S+, sensitizing+/T790M+/C797S-, and sensitizing+/T790M-/C797S-. Median time to progression in patients showing the triplet pattern (sensitizing+/T790M+/C797S+) was 12.27 months compared with 4.87 months in patients in whom only the original EGFR sensitizing was detected, and 2.17 months in patients showing the duplet pattern (sensitizing+/T790M+). Finally, we found that mutations in exon 545 of the PIK3CA gene were the most frequent alteration detected upon disease progression in patients without acquired EGFR-resistance mutations. CONCLUSIONS: Different molecular patterns identified by plasma genotyping may be of prognostic significance, suggesting that the use of liquid biopsy is a valuable approach for tumor monitoring.

Next-generation sequencing to dynamically detect mechanisms of resistance to ALK inhibitors in ALK-positive NSCLC patients: a case report.

Tyrosine kinase inhibitors (TKIs) of the anaplastic lymphoma kinase gene (ALK) have significantly improved the quality of life and survival of non-small cell lung cancer (NSCLC) patients whose tumors harbor an ALK translocation. However, most of these patients relapse within 2 to 3 years as the tumor acquires resistance mutations. Unlike beaming and digital PCR (dPCR), which only allow a few mutations to be analyzed, next-generation sequencing (NGS) approaches enable the simultaneous screening of multiple genetic alterations even when the frequencies of the variants are very low. We present the case of a 52-year-old man who was diagnosed with an ALK-positive NSCLC and was treated with crizotinib and, subsequently, ceritinib. The analysis of serial liquid biopsies by NGS detected two asynchronous mutations arising in the ALK locus during disease progression, namely p.Gly1269Ala (c.3806G>C) and p.Gly1202Arg (c.3604G>A), that conferred resistance to crizotinib and ceritinib, respectively. The resistance mutations were detected independently at different times, and could be imputed to different metastatic lesions, thereby highlighting the importance of heterogeneity in advance disease. Plasma levels of ALK resistance mutations correlated well with tumor responses assessed by CT scans and bone scintigraphy, demonstrating that non-invasive tumor molecular profiling by NGS allows the efficient dynamic monitoring of ALK-positive NSCLC patients, and outperforms dPCR and beaming because more somatic mutations can be tracked over the course of the treatment. In conclusion, this case report illustrates the usefulness NGS to guide therapeutic decisions in ALK-positive NSCLC patients based tumor molecular profile upon disease progression.

Sex is a strong prognostic factor in stage IV non-small-cell lung cancer patients and should be considered in survival rate estimation.

BACKGROUND: Biological differences between the sexes have a major impact on disease and treatment outcome. In this paper, we evaluate the prognostic value of sex in stage IV non-small-cell lung cancer (NSCLC) in the context of routine clinical data, and compare this information with other external datasets. METHODS: Clinical data from stage IV NSCLC patients from Hospital Puerta de Hierro (HPH) were retrieved from electronic health records using big data analytics (N = 397). In addition, data from the Spanish Lung Cancer Group (GECP) Tumor Registry (N = 1382) and from a published study available from the cBioPortal (MSK) (N = 601) were analyzed. Survival curves were estimated using the Kaplan-Meier method. A Cox proportional hazards regression model was used to assess the prognostic value of sex. A meta-analysis to compare the outcome for males and females in terms of overall survival (OS) and progression free survival (PFS) was performed. RESULTS: The median OS time was 12 months for males and 19 months for females (overall HR = 0.77; 95% CI: 0.68-0.87; P < 0.001). Similarly, females with stage IV NSCLC harboring an EGFR-sensitizing mutation lived significantly longer than males (median OS: males, 19 months; females, 32 months) with a lower risk of death compared with males (overall HR = 0.75; 95% CI: 0.67-0.84). In addition, female patients benefited more from EGFR inhibitors in terms of PFS and OS (overall HR = 0.45; 95% CI: 0.32-0.64, and HR = 0.62; 95% CI: 0.48-0.80, respectively). Median PFS was 21 months in females and 12 months in males (P < 0.001). CONCLUSIONS: Using routine clinical data we confirmed the previous finding that among stage IV NSCLC patients, females had a significantly better prognosis than males. The effect size of the sex was notable, highlighting the fact that survival rates are usually estimated and patients are generally managed without considering the sexes separately, which may lead to suboptimal results.

Clinical utility of liquid biopsy for the diagnosis and monitoring of EML4-ALK NSCLC patients.

Background: Genomic rearrangement in anaplastic lymphoma kinase (ALK) gene occurs in 3-7% of patients with non-small-cell lung cancer (NSCLC). The detection of this alteration is crucial as ALK positive NSCLC patients benefit from ALK inhibitors, which improve both the patient's quality of life and overall survival (OS) compared to traditional chemotherapy. Content: In routine clinical practice, ALK rearrangements are detected using tissue biopsy. Nevertheless, the availability of tumor tissue is compromised in NSCLC patients due to surgical complications or difficult access to the cancer lesion. In addition, DNA quality and heterogeneity may impair tumor biopsies testing. These limitations can be overcome by liquid biopsy, which refers to non-invasive approaches for tumor molecular profiling. In this paper we review currently available technology for non-invasive ALK testing, in NSCLC patients, based on the analysis of circulating tumor DNA (ctDNA), circulating tumor RNA (ctRNA), circulating tumor cells (CTCs), tumor-educated platelets (TEPs) and extracellular vesicles (EVs) such as exosomes. Summary and outlook: Non-invasive tumor molecular profiling is crucial to improve outcomes and quality of life of NSCLC patients whose tumors harbor a translocation involving ALK locus.

Peritoneal washing is an adequate source for somatic BRCA1/2 mutation testing in ovarian malignancies.

Genetic screening for BRCA mutations should be offered to all women diagnosed with epithelial ovarian, fallopian tube, and/or peritoneal cancers given the implications for treatment options and cancer risk assessments. Yet, while germline breast cancer susceptibility gene 1 (BRCA1) and breast cancer susceptibility gene 2 (BRCA2) testing is commonly performed, BRCA1/2 somatic mutations testing is rather challenging since the poor quality of DNA extracted from formalin fixed paraffin embedded (FFPE) samples can significantly impair this process. Peritoneal lavage is routinely performed in surgeries of suspected ovarian malignancies. We have analyzed fresh tumor, peritoneal lavage and blood samples from ten patients and we have found an excellent agreement (88%) between fresh tumor and peritoneal lavage for BRCA mutation testing. Importantly, 112 of the 114 genomic alterations detected in fresh tumor samples were also found in peritoneal lavage fluids. Our data suggest that peritoneal washings can indeed streamline BRCA genes mutation testing procedures.