Next-generation sequencing reveals novel resistance mechanisms and molecular heterogeneity in EGFR-mutant non-small cell lung cancer with acquired resistance to EGFR-TKIs

Single nucleotide and copy number variants of cancer driver genes inform drug response in multiple cancers

Due to the heterogeneity of cancer, precision medicine has been a major challenge for cancer treatment. Determining medication regimens based on patient genotypes has become a research hotspot in cancer genomics. In this study, we aim to identify key biomarkers for targeted therapies based on single nucleotide variants (SNVs) and copy number variants (CNVs) of genes. The experiment is carried out on 7 cancers on the Encyclopedia of Cancer Cell Lines (CCLE) dataset. Considering the high mutability of driver genes which result in abundant mutated samples, the effect of data sparsity can be eliminated to a large extent. Therefore, we focus on discovering the relationship between driver mutation patterns and three measures of drug response, namely area under the curve (AUC), half maximal effective concentration (EC50), and log2-fold change (LFC). First, multiple statistical methods are applied to assess the significance of difference in drug response between sample groups. Next, for each driver gene, we analyze the extent to which its mutations can affect drug response. Based on the results of multiple hypothesis tests and correlation analyses, our main findings include the validation of several known drug response biomarkers such as BRAF, NRAS, MAP2K1, MAP2K2, and CDKN2A, as well as genes with huge potential to infer drug responses. It is worth emphasizing that we identify a list of genes including SALL4, B2M, BAP1, CCDC6, ERBB4, FOXA1, GRIN2A, and PTPRT, whose impact on drug response spans multiple cancers and should be prioritized as key biomarkers for targeted therapies. Furthermore, based on the statistical p-values and correlation coefficients, we construct gene-drug sensitivity maps for cancer drug recommendation. In this work, we show that driver mutation patterns could be used to tailor therapeutics for precision medicine.

Temporal genomic heterogeneity guiding individualized therapy in recurrent non-small cell lung cancer

Introduction

Despite the benefit of adjuvant systemic therapy for patients with resected non-small cell lung cancer (NSCLC), the risk of postoperative recurrence remains high. Our objective was to characterize temporal genetic heterogeneity between primary resected and recurrent tumors, and its impact on treatment outcomes.

Methods

In this study, next-generation sequencing (NGS) testing was performed on tissue specimens and circulating tumor DNA (ctDNA) collected at postoperative recurrence, and results were compared to the genotypes of initial surgical specimens.

Results

Of forty-five patients with matched primary and post-operative recurrent tumors, EGFR status switched in 17 patients (37.8%) at post-operative recurrence and 28 patients (62.2%) had no genotype change (17 mutant, 11 wild-type). Based on the changes of EGFR status, patients were divided into 4 groups. Following subsequent treatment with EGFR TKI o chemotherapy: In group A, with sustained sensitive mutation, the percentage achieving partial response (PR) was the highest, at 72.2%, the median progression-free survival (PFS) was 17 months, and the median overall survival (OS) was 44.0 months respectively; In group B, with genotype changed from wild-type to mutant, 50% achieved PR, PFS was 10 months, and OS was 35 months; In group C, in which mutant status shifted to wild-type or new co-mutation emerged, the percentage achieving PR was 30%, PFS was 9 months, and OS was 35 months. In group D, with sustained wild type, the percentage achieving PR was 27.3%, PFS was 8 months, and OS was 22 months.

Discussion

Genotypic shift between paired primary and post-operative recurrent tumors was not infrequent, and this temporal genomic heterogeneity substantially impacted subsequent treatment outcomes.

Rare T263P epidermal growth factor receptor extracellular domain mutation of advanced non-small cell lung cancer in a Vietnamese male patient

T263P mutation is one of the rare EGFR mutations located on chromosome 7p11.2, which is a change in amino acid residue at position 263 of the epidermal growth factor receptor protein, where L-threonine has been replaced by L-proline. This missense mutation in the extracellular EGFR domain is not well-known in lung cancer. In this study, we first report a patient with advanced lung adenocarcinoma harbouring only a rare T263P EGFR mutation who benefited from first-line afatinib therapy in Vietnam. The patient achieved a partial response with a time-to-treatment failure of 5 months. The patient subsequently received several chemotherapy regimens as the disease progressed, with overall survival of 17 months. Non-small cell lung cancer with a rare T263P EGFR mutation responds to afatinib but has a poor prognosis. Further studies are needed to determine the efficacy of targeted therapies in this specific population.

Combining the amplification refractory mutation system and high-resolution melting analysis for KRAS mutation detection in clinical samples

The success of personalized medicine depends on the discovery of biomarkers that allow oncologists to identify patients that will benefit from a particular targeted drug. Molecular tests are mostly performed using tumor samples, which may not be representative of the tumor's temporal and spatial heterogeneity. Liquid biopsies, and particularly the analysis of circulating tumor DNA, are emerging as an interesting means for diagnosis, prognosis, and predictive biomarker discovery. In this study, the amplification refractory mutation system (ARMS) coupled with high-resolution melting analysis (HRMA) was developed for detecting two of the most relevant KRAS mutations in codon 12. After optimization with commercial cancer cell lines, KRAS mutation screening was validated in tumor and plasma samples collected from patients with pancreatic ductal adenocarcinoma (PDAC), and the results were compared to those obtained by Sanger sequencing (SS) and droplet digital polymerase chain reaction (ddPCR). The developed ARMS-HRMA methodology stands out for its simplicity and reduced time to result when compared to both SS and ddPCR but showing high sensitivity and specificity for the detection of mutations in tumor and plasma samples. In fact, ARMS-HRMA scored 3 more mutations compared to SS (tumor samples T6, T7, and T12) and one more compared to ddPCR (tumor sample T7) in DNA extracted from tumors. For ctDNA from plasma samples, insufficient genetic material prevented the screening of all samples. Still, ARMS-HRMA allowed for scoring more mutations in comparison to SS and 1 more mutation in comparison to ddPCR (plasma sample P7). We propose that ARMS-HRMA might be used as a sensitive, specific, and simple method for the screening of low-level mutations in liquid biopsies, suitable for improving diagnosis and prognosis schemes.

The significance of co-mutations in EGFR-mutated non-small cell lung cancer: Optimizing the efficacy of targeted therapies?

Non-small cell lung cancer (NSCLC) is the most common cause of cancer death worldwide. In non-squamous NSCLC, the identification of oncogenic drivers and the development of target-specific molecules led to remarkable progress in therapeutic strategies and overall survival over the last decade. Nevertheless, responses are limited by systematically acquired mechanisms of resistance early on after starting a targeted therapy. Moreover, mounting evidence has demonstrated that each oncogenic-driven cluster is actually heterogeneous in terms of molecular features, clinical behaviour, and sensitivity to targeted therapy. In this review, we aimed to examine the prognostic and predictive significance of oncogene-driven co-mutations, focusing mainly on EGFR and TP53. A narrative review was performed by searching MEDLINE databases for English articles published over the last decade (from January 2012 until November 2022). The bibliographies of key references were manually reviewed to select those eligible for the topic. The genetic landscape of EGFR-mutated NSCLC is more complicated than what is known so far. In particular, the occurrence of TP53 co-mutations stratify patients carrying EGFR mutations in terms of treatment response. The study provides a deeper understanding of the mechanisms underlying the variability of the genetic landscape of EGFR-mutated NSCLC and summarizes notably the clinical importance of TP53 co-mutations for an open avenue to more properly addressing the clinical decision-making in the near future.

Safety, efficacy, and pharmacokinetics of SH-1028 in EGFR T790M-positive advanced non-small cell lung cancer patients: A dose-escalation phase 1 study

BACKGROUND

SH-1028 is a new third-generation EGFR tyrosine kinase inhibitors (TKI) to benefit patients with EGFR T790M-mutated NSCLC. Here, the authors report its clinical safety, preliminary efficacy, and pharmacokinetic (PK) profile for the first time.

METHODS

Patients with EGFR T790M mutation, locally advanced non-small cell lung cancer (NSCLC), or metastatic NSCLC who had progressed after previous EGFR TKI therapy were eligible. Patients received SH-1028 at five oral dose levels (60 mg, 100 mg, 200 mg, 300 mg, and 400 mg) once daily until disease progression, unacceptable toxicity, or patient withdrawal. The primary end points were the safety, dose-limiting toxicity (DLT), maximum-tolerated dose (MTD), and PK profile. Secondary end points included objective response rate (ORR), disease control rate (DCR), progression-free survival (PFS), etc. RESULTS: Data cut off on December 31, 2020, a total of 20 patients were enrolled during the trial, two of three patients in 300 mg cohort experienced a DLT, and no DLT was observed in 240 mg cohort, 240 mg was determined to be the MTD of SH-1028. A total of 95.0% (19 of 20) of patients reported treatment-related adverse events (TRAEs), and the incidence of serious adverse events was 20.0% (4 of 20). The ORR and DCR of the 200 mg cohort were 75% (95% confidence interval [CI], 19.41-99.37) and 75.0% (95% CI, 19.41-99.37), respectively. The overall ORR was 40% (95% CI, 19.12-63.95), and DCR was 70.0% (95% CI, 45.72-88.11). According to the PK profile, the dosage regimen for future studies was determined as 200 mg once daily.

CONCLUSIONS

SH-1028 showed a manageable safety and promising antitumor activity in patients with EGFR T790M mutation at the dose of 200 mg once daily.

PLAIN LANGUAGE SUMMARY

Lung cancer has a high morbidity and mortality, with an estimated 1.8 million deaths in 2020. Non-small cell lung cancer accounts for approximately 85% of lung cancer. First- or second-generation EGFR TKIs' weak selectivity often led to the occurrence of treatment-related adverse events, such as interstitial lung disease, rash, diarrhea, etc., along with acquired drug resistance within approximately 1 year. A dose of 200 mg of SH-1028 once daily showed a preliminary antitumor activity with manageable safety in patients with EGFR T790M mutation.

Prevalence of highly actionable mutations among Indian patients with advanced non-small cell lung cancer: A systematic review and meta-analysis

BACKGROUND

Non-small cell lung cancer (NSCLC) remains a leading cause of cancer-related mortality in India. To clarify rates of actionable mutations, and thereby identify opportunities to improve the delivery of best available care for a large volume of patients, a comprehensive review of available data is warranted.

METHODS

Studies that reported prevalence of any actionable gene variant among adult Indian patients with advanced NSCLC were selected from three databases (PubMed, EMBASE, and Cochrane Library). Ranges in actionable variant prevalence were reported. Meta-analysis of proportions was completed among studies specifically evaluating mutational prevalence within ALK or EGFR. Sensitivity analyses were undertaken among populations sharing high heterogeneity.

RESULTS

Twenty-six studies were selected. Ranges in actionable mutational prevalence among NSCLC patients were as follows: ALK: 4.1-21.4%, BRAF: 1.5-3.5%, EGFR: 11.9-51.8%, HER2: 0-1.5%, KRAS: 4.5-6.4%, NTRK: 0-.7%, and ROS-1: 3.5-4.1%. Following sensitivity analysis, pooled ALK mutational prevalence rates were 8.3% (95% CIs: 6.6-10.4%) and 4.01% (95% CIs: 2.3-7.0) for adenocarcinoma and NSCLC patients, respectively. Pooled EGFR mutational prevalence rates were 28.7% (95% CIs: 23.5-34.6%) and 24.2% (95% CIs: 19.9-29.1%) for adenocarcinoma and NSCLC patients, respectively.

CONCLUSIONS

Nearly 40% of Indian patients with advanced adenocarcinoma and 30% with NSCLC share an actionable mutation in ALK or EGFR. Approximately one-half of adenocarcinoma patients have an actionable variant. Efforts should be directed toward efficiently identifying candidates for targeted agents and delivering such treatments.

Efficacy of erlotinib in NSCLC harboring rare EGFR extracellular domain mutation (T263P) and common mutations: Case report and literature review

The epidermal growth factor receptor (EGFR) typically contains an extracellular domain (ECD), a transmembrane (TM) domain, and an intracellular kinase (KD) domain. ECD mutations of EGFR in NSCLC may affect its normal function and intrinsic resistance to tyrosine kinase inhibitors (TKIs) and the effectiveness of drugs for these patients is unsatisfactory. Recently, we found an EGFR T263P mutation located at the ECD, which has never been reported in Chinese non-small cell lung cancer (NSCLC). Hence, we reported that a patient with advanced lung adenocarcinoma harboring the EGFR T263P mutation, L858R mutation and MET amplification was resistant to osimertinib but significantly benefited from erlotinib and capmatinib treatment. This patient achieved a partial response and had progression-free survival (PFS) for more than 19 months. In summary, we are the first researchers to report in detail on a Chinese patient carrying the T263P mutation and summarize all the ECD mutations in NSCLC. We believe this finding will enlighten us to treat patients with EGFR ECD mutations and more patients deserve further study.

High Tumor Mutation Burden Is Associated with Poor Clinical Outcome in EGFR-Mutated Lung Adenocarcinomas Treated with Targeted Therapy

This study aimed to determine the association between TMB and treatment outcomes in patients with epidermal growth factor receptor (EGFR)-mutated lung cancer that were treated with tyrosine kinase inhibitors (TKIs). The TMB was assessed using a 409-gene targeted next-generation sequencing panel. We compared the response rate (RR), progression-free survival (PFS), overall survival (OS), and frequency of secondary T790M mutations among the different TMB groups. The median TMB of the study population (n = 88) was 3.36/megabases. We divided 52 (59%) and 36 (41%) patients into the low and high TMB groups, respectively. A high TMB level was significantly associated with liver metastasis and more advanced stage (all p < 0.05). RR was significantly lower in the high TMB group than that of the low TMB group (50.0% vs. 80.7%, all p = 0.0384). In multivariate analysis, high TMB was independently associated with a shorter PFS (hazard ratio [HR] = 1.80, p = 0.0427) and shorter OS (HR = 2.05, p = 0.0397) than that of the low TMB group. Further, high TMB was independently associated with decreased T790M mutation development. These results suggest that high TMB may be a predictive biomarker for adverse treatment outcomes and represent a patients’ subgroup warranting tailored therapeutic approaches.

Osimertinib for lung cancer cells harboring low-frequency EGFR T790M mutation

Osimertinib, a third-generation EGFR tyrosine kinase inhibitor, shows significant benefit among patients with EGFR T790M mutation at disease progression. We analyzed the whole exome sequence of 48 samples obtained from 16 lung cancer patients with a longitudinal follow-up: treatment-naïve-baseline primary tumors positive for EGFR activating-mutations, paired re-biopsies upon disease progression but negative for EGFR T790M mutation based on qPCR, and their matched normal blood samples. Our Next generation sequencing (NGS) analysis identified an additional set of 25% re-biopsy samples to harbor EGFR T790M mutation occurring at a low-allele frequency of 5% or less, undetectable by conventional qPCR-based assays. Notably, the clinical utility of osimertinib among patients harboring low-allele frequency of EGFR T790M in tissue biopsy upon disease progression remains less explored. We established erlotinib-resistant PC-9R cells and twenty single-cell sub-clones from erlotinib-sensitive lung cancer PC-9 cells using in vitro drug-escalation protocol. NGS and allele-specific PCR confirmed the low-allele frequency of EGFR T790M present at 5% with a 100-fold higher resistance to erlotinib in the PC-9R cells and its sub-clones. Additionally, luciferase tagged PC-9, and PC-9R cells were orthotopically injected through the intercostal muscle into NOD-SCID mice. The orthotopic lung tumors formed were observed by non-invasive bioluminescence imaging. Consistent with in vitro data, osimertinib, but not erlotinib, caused tumor regression in mice injected with PC-9R cells, while both osimertinib and erlotinib inhibited tumors in mice injected with PC-9 cells. Taken together, our findings could extend the benefit of osimertinib treatment to patients with low EGFR T790M mutation allele frequency on disease progression.

Optimizing Patient Outcomes Through Sequential EGFR TKI Treatment in Asian Patients With EGFR Mutation-Positive NSCLC

Patients from Asia with non-small-cell lung cancer (NSCLC) often have mutations in the epidermal growth factor receptor (EGFR) gene. While an increasing number of EGFR tyrosine kinase inhibitors (TKIs) are now available for patients with EGFR mutation-positive NSCLC, most patients inevitably develop resistance to the treatment. Evidence from clinical studies suggests that treatment outcomes and resistance mechanisms vary depending on the choice of TKI therapy in the first-line setting. Hence, it is important to develop optimal treatment sequencing strategies that can provide maximum survival benefit for the patient. In this review we present clinical evidence in Asian patients with NSCLC for various EGFR TKIs, with the goal of supporting the optimization of treatment sequencing.

Comparison of T790M Acquisition After Treatment With First- and Second-Generation Tyrosine-Kinase Inhibitors: A Systematic Review and Network Meta-Analysis

Background

Lung adenocarcinoma is a common disease with a high mortality rate. Epidermal growth factor receptor (EGFR) mutations are found in adenocarcinomas, and oral EGFR-tyrosine kinase inhibitors (EGFR-TKIs) show good responses. EGFR-TKI therapy eventually results in resistance, with the most common being T790M. T790M is also a biomarker for predicting resistance to first- and second-generation EGFR-TKIs and is sensitive to osimertinib. The prognosis was better for patients with acquired T790M who were treated with osimertinib than for those treated with chemotherapy. Therefore, T790M mutation is important for deciding further treatment and prognosis. Previous studies based on small sample sizes have reported very different T790 mutation rates. We conducted a meta-analysis to evaluate the T790M mutation rate after EGFR-TKI treatment.

Methods

We systematic reviewed the electronic databases to evaluate the T790M mutation rate after treatment with first-generation (gefitinib, erlotinib, and icotinib) and second-generation (afatinib and dacomitinib) EGFR-TKIs. Random-effects network meta-analysis and single-arm meta-analysis were conducted to estimate the T790M mutation rate of the target EGFR-TKIs.

Results

A total of 518 studies were identified, of which 29 were included. Compared with afatinib, a higher odds ratio (OR) of the T790M mutation rate was observed after erlotinib [OR = 1.48; 95% confidence interval (CI):1.09–2.00] and gefitinib (OR = 1.45; 95% CI: 1.11–1.90) treatments. An even OR of the T790M mutation rate was noted after icotinib treatment (OR = 0.91, 95% CI: 0.46–1.79) compared with that after afatinib. The T790M mutation rate was significantly lower with afatinib (33%) than that with gefitinib (49%) and erlotinib treatments (47%) (p < 0.001). The acquired T790M mutation rate in all participants was slightly lower in Asians (43%) than that in Caucasians (47%).

Conclusions

Erlotinib and gefitinib had a higher OR for the T790M mutation than afatinib. The T790M mutation rate was significantly lower in afatinib than in gefitinib and erlotinib. T790M is of great significance because osimertinib shows a good prognosis in patients with T790M mutation.

Systematic Review Registration

PROSPERO, identifier CRD42021257824.

Targeting MERTK and AXL in EGFR Mutant Non-Small Cell Lung Cancer

MERTK and AXL are members of the TAM family of receptor tyrosine kinases and are abnormally expressed in 69% and 93% of non-small cell lung cancers (NSCLCs), respectively. Expression of MERTK and/or AXL provides a survival advantage for NSCLC cells and correlates with lymph node metastasis, drug resistance, and disease progression in patients with NSCLC. The TAM receptors on host tumor infiltrating cells also play important roles in the immunosuppressive tumor microenvironment. Thus, MERTK and AXL are attractive biologic targets for NSCLC treatment. Here, we will review physiologic and oncologic roles for MERTK and AXL with an emphasis on the potential to target these kinases in NSCLCs with activating EGFR mutations.

Targeted therapy moves to earlier stages of non-small-cell lung cancer: emerging evidence, controversies and future challenges

Lung cancer continues to be the leading cause of cancer mortality and a serious health problem despite the numerous advances made in the last decade and the rapid advance of research in this field. In recent years, there has been a decrease in mortality from lung cancer coinciding with the approval times of targeted therapy. To date, targeted therapy has been used in the context of advanced disease in clinical practice, with great benefits in survival and quality of life. The next step will be to incorporate targeted therapy into the treatment of earlier stages of non-small-cell lung cancer, and there is already a randomized trial showing a disease-free survival benefit. However, there are many questions that need to be resolved first. In the present review, the authors discuss the findings of published reports and ongoing clinical trials assessing the role of targeted therapies in nonmetastatic disease.

The role of molecular heterogeneity targeting resistance mechanisms to lung cancer therapies

Introduction: The treatment scenario of lung cancer is rapidly evolving through time. In parallel, growing evidence is accumulating on different mechanisms of treatment resistance. Inter- and intra-tumor heterogeneity define the spatial and temporal tumor clonal evolution, that is at the basis of tumor progression and resistance to anticancer treatments.Areas covered: This review summarizes the available evidence on molecular heterogeneity in lung cancer, from diagnosis to the occurrence of treatment resistance. The application of novel molecular diagnostic methods to detect molecular heterogeneity, and the implications of understanding heterogeneity for drug development strategies are discussed, with focus on clinical relevance and impact on patients' survival.Expert opinion: The current knowledge of molecular heterogeneity allows to identify different molecular subgroups of patients within the same conventional tumor type. Deeper understanding of heterogeneity determinants and the possibility to comprehensively investigate tumor molecular patterns will lead to the development of personalized treatment approaches, with the final goal to overcome resistance and prolong survival in lung cancer patients.

Identification of Hub Genes and Small Molecule Drugs Associated with Acquired Resistance to Gefitinib in Non-Small Cell Lung Cancer

Targeting EGFR, epidermal growth factor receptor tyrosine kinase inhibitors (EGFR TKIs), brings lights to the treatment of non-small cell lung cancer (NSCLC). Although T790M mutation responded as one of the main reasons of acquired resistance, still 15% of the resistance patients can't be explained by the known mechanisms. The purpose of this research was to identify some new mechanisms of gefitinib acquired resistance, and to predict small molecules drugs which may reverse drug resistance by integrated bioinformatics analysis. The GSE34228 data package containing the microarray data of acquired gefitinib-resistant cell line (PC9GR) and gefitinib-sensitive cell line (PC9) from the GEO database were downloaded, and gene co-expression networks by weighted gene co-expression network analysis (WGCNA) were constructed to identified key modules and key genes related to gefitinib resistance. Furthermore, the significantly differentially expressed genes (DEGs) between the two cell types were screened out, and a protein-protein interaction (PPI) network to obtain the key genes of DEGs was accordingly constructed. Through the above two methods, 4 hub genes, PI3, S100A8, AXL and PNPLA4 were mined as the most relevant to gefitinib resistance. Among them, PI3, S100A8 were down-regulated in PC9GR cell samples, while AXL, PNPLA4 were up-regulated. The gene set enrichment analysis (GSEA) for single gene showed that the four hub genes were mainly correlated with cell proliferation and cycle. Besides, small molecule drugs with the potential to overcome resistance, such as Emetine and cephaeline, were screened by CMap database. Consistent with this, in vitro experiments results have shown that emetine and cephaeline can increase the sensitivity of drug-resistant cells to gefitinib, and the mechanism may be related to the regulation of PI3 and S100A8. In conclusion, 4 hub genes were found to be related to the occurrence of gefitinib resistance in non-small cell lung cancer, and several small molecule drugs were screened out as potential therapeutic agents to overcome gefitinib resistance, which may lead a new way for the treatment of NSCLC of acquired resistance to gefitinib.

Identification of optimal dosing schedules of dacomitinib and osimertinib for a phase I/II trial in advanced EGFR-mutant non-small cell lung cancer

Despite the clinical success of the third-generation EGFR inhibitor osimertinib as a first-line treatment of EGFR-mutant non-small cell lung cancer (NSCLC), resistance arises due to the acquisition of EGFR second-site mutations and other mechanisms, which necessitates alternative therapies. Dacomitinib, a pan-HER inhibitor, is approved for first-line treatment and results in different acquired EGFR mutations than osimertinib that mediate on-target resistance. A combination of osimertinib and dacomitinib could therefore induce more durable responses by preventing the emergence of resistance. Here we present an integrated computational modeling and experimental approach to identify an optimal dosing schedule for osimertinib and dacomitinib combination therapy. We developed a predictive model that encompasses tumor heterogeneity and inter-subject pharmacokinetic variability to predict tumor evolution under different dosing schedules, parameterized using in vitro dose-response data. This model was validated using cell line data and used to identify an optimal combination dosing schedule. Our schedule was subsequently confirmed tolerable in an ongoing dose-escalation phase I clinical trial (NCT03810807), with some dose modifications, demonstrating that our rational modeling approach can be used to identify appropriate dosing for combination therapy in the clinical setting.

Progress of exosomes in the diagnosis and treatment of lung cancer

The incidence and mortality of lung cancer account for first place all over the world. Lung cancer lacks early diagnostic biomarkers; lung cancer patients are usually diagnosed in both middle and advanced stages and have poor treatment outcomes. It is more important to find the first diagnostic tools for lung cancer with high specificity and sensitivity. Besides, exosomes are usually nanometer-sized bi-layered lipid vesicles formed and produced by various types of cells. As one of the main modes of intercellular communication, they can deliver multiple functional biomolecules, such as DNA, microRNAs, messenger RNA (mRNA), long non-coding RNA, and proteins, and the events as mentioned above affects different physiological processes of recipient cells. It has been reported that exosomes are involved in different types of cancer, including lung cancer. Various studies proved that exosomes are involved in multiple cancer processes such as cell proliferation, metastasis, epithelial-mesenchymal transition (EMT), angiogenesis, and the tumor microenvironment in lung cancer. Tumor-derived exosomes (TEX) contain a variety of stimulatory and inhibitory factors involved in regulating immune response, which can affect the tumor microenvironment (TME) and thus participate in the formation and progression of lung cancer. This review's primary purpose to review the latest research progress of exosomes in diagnosing and treating lung cancer.

Analysis of the clinical effect of osimertinib on 90 cases with advanced lung adenocarcinoma

Background

Primary or secondary drug resistance of epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKI) is a new challenge in the treatment of advanced non-small cell lung cancer (NSCLC). Osimertinib is a third-generation EGFR-TKI, and its efficacy and safety in NSCLC patients with first-generation EGFR-TKI resistance, especially lung adenocarcinoma, are not yet clear. The purpose of this study was to observe the efficacy and adverse reactions of osimertinib in the treatment of patients with advanced lung adenocarcinoma.

Methods

From January 2017 to December 2018, 90 patients with advanced (stage IV) lung adenocarcinoma were diagnosed in Shanghai Chest Hospital. The disease of these patients (94.4%) progressed after first-line EGFR-TKI treatment, and 43.3% of patients received third-line or beyond third-line treatment. The efficacy and adverse reactions of osimertinib treatment were observed.

Results

Among 90 patients with advanced lung adenocarcinoma, 57 (63.3%) achieved partial response (PR), 27 (30.0%) had stable disease (SD), and 6 (6.7%) had progressive disease (PD). The objective response rate (ORR) was 63.3%, and the disease control rate (DCR) was 93.3%. The median progression-free time (mPFS) was 10.41 months (95% CI: 8.91–11.91 months), and the median overall survival (mOS) was 31.37 months (95% CI: 26.37–36.37 months). The incidence of adverse events of degree 3 and above was 7.78%. The main adverse events were diarrhea (28.9%) and rash (24.4%). After symptomatic treatment, the incidence of adverse events was significantly reduced.

Conclusions

Osimertinib has a definite curative effect in the treatment of patients with advanced lung adenocarcinoma, and the incidence of adverse reactions is low.

Making the case for EGFR TKI sequencing in EGFR mutation-positive NSCLC: a GioTag study US patient analysis

Aim: To assess time-to-treatment failure (TTF) in US patients with EGFR mutation-positive non-small-cell lung cancer (NSCLC) who received sequential afatinib-osimertinib treatment in the global, observational GioTag study. Patients & methods: Patients had EGFR T790M mutation-positive disease after first-line afatinib and subsequently received osimertinib. The primary outcome was TTF. Results: In 129 patients at US centers, median TTF was 28.4 months (90% CI: 27.0-34.1). Median overall survival was 47.6 months (90% CI: 35.5-51.5). Conclusion: Sequential afatinib-osimertinib in this US-treated population was associated with long median TTF and represents an effective, evidence-based treatment option for US patients with EGFR mutation-positive NSCLC not presenting with active brain metastases or de novo T790M. Clinical Trial Registration: NCT03370770 (ClinicalTrials.gov).

Technical Evaluation of Commercial Mutation Analysis Platforms and Reference Materials for Liquid Biopsy Profiling

Molecular profiling from liquid biopsy, in particular cell-free DNA (cfDNA), represents an attractive alternative to tissue biopsies for the detection of actionable targets and tumor monitoring. In addition to PCR-based assays, Next Generation Sequencing (NGS)-based cfDNA assays are now commercially available and are being increasingly adopted in clinical practice. However, the validity of these products as well as the clinical utility of cfDNA in the management of patients with cancer has yet to be proven. Within framework of the Innovative Medicines Initiative (IMI) program CANCER-ID we evaluated the use of commercially available reference materials designed for ctDNA testing and cfDNA derived from Diagnostic Leukaphereses (DLA) for inter- and intra-assay as well as intra- and inter-laboratory comparisons. In three experimental setups, a broad range of assays including ddPCR, MassARRAY and various NGS-based assays were tested. We demonstrate that both reference materials with predetermined VAFs and DLA samples are extremely useful for the performance assessment of mutation analysis platforms. Moreover, our data indicate a substantial variability of NGS assays with respect to sensitivity and specificity highlighting the importance of extensive validation of the test performance before offering these tests in clinical routine practice.

The miR‑625‑3p/AXL axis induces non‑T790M acquired resistance to EGFR‑TKI via activation of the TGF‑β/Smad pathway and EMT in EGFR‑mutant non‑small cell lung cancer

Gefitinib is currently the preferred treatment for non-small cell lung cancer (NSCLC) patients with epidermal growth factor receptor (EGFR)-activating mutation. However, some patients gradually develop acquired resistance after receiving treatment. In addition to secondary T790M mutation, the remaining mechanisms contributing to non-T790M mutations need to be explored. In the present study, NSCLC-derived HCC827 and PC-9 cells and the corresponding gefitinib-resistant cell lines (HCC827GR and PC9GR) were utilized. Next-generation DNA sequencing was performed on the HCC827GR and PC9GR cells. Under AXL receptor tyrosine kinase (AXL) knockdown or miR-625-3p overexpressing conditions, a cell growth inhibition assay was performed to evaluate gefitinib sensitivity. Wound healing and Transwell assays were used to examine the migratory and invasive abilities of the cells. Moreover, we also carried out western blot analysis to detect the altered downstream signaling pathway. Our study revealed markedly decreased miR-625-3p expression in the HCC827GR cell line, while its overexpression partly reversed gefitinib resistance. Integrated analysis based on Targetscan website showed that AXL can be potentially targeted by miR-625-3p and we further verified the hypothesis via dual-luciferase reporter assays. Mechanistic analysis revealed that TGF-β1-induced EMT may contribute to the miR-625-3p/AXL axis-mediated gefitinib resistance. Our data demonstrated that miR-625-3p contributes to the acquired resistance of gefitinib, which may provide novel insight to combat resistance to EGFR-TKIs.

Enhanced Expression of CD47 Is Associated With Off-Target Resistance to Tyrosine Kinase Inhibitor Gefitinib in NSCLC

Mutual interactions between cancer cells and the tumor microenvironment importantly contribute to the development of tyrosine kinase inhibitor (TKI) resistance in patients affected by EGFR-mutant NSCLC. In particular, immune recognition-associated proteins with impact on tumor cell clearance through phagocytosis, such as CD47 and calreticulin, could contribute to adaptive resistance and immune escape. Preclinical studies targeting the anti-phagocytic CD47 molecule showed promising results in different cancer types including lung cancer, but no data are available on its role in patients acquiring resistance to EGFR TKI treatment. We analyzed the functional contribution of CD47 and calreticulin to immune surveillance and evasion in a panel of NSCLC cell lines carrying sensitizing or resistant mutations in the EGFR gene, following treatment with the TKI gefitinib and after in vitro development of gefitinib resistance. While CD47 and calreticulin protein levels were markedly variable in both EGFR-mutant and wild-type cell lines, analysis of NSCLC transcriptomic dataset revealed selective overexpression of CD47 in patients carrying EGFR mutations. EGFR inhibition significantly reduced CD47 expression on the surface of pre-apoptotic cells, favoring more efficient engulfment of cancer cells by monocyte-derived dendritic cells. This was not necessarily associated with augmented surface exposure of calreticulin or other molecular markers of immunogenic cell death. Moreover, CD47 expression became up-regulated following in vitro drug resistance development, and blocking of this protein by a specific monoclonal antibody increased the clearance of EGFR-TKI resistant cells by phagocytes. Our study supports CD47 neutralization by specific monoclonal antibody as a promising immunotherapeutic option for naïve and resistant EGFR-mutant NSCLCs.

Molecular profiling for precision cancer therapies

The number of druggable tumor-specific molecular aberrations has grown substantially in the past decade, with a significant survival benefit obtained from biomarker matching therapies in several cancer types. Molecular pathology has therefore become fundamental not only to inform on tumor diagnosis and prognosis but also to drive therapeutic decisions in daily practice. The introduction of next-generation sequencing technologies and the rising number of large-scale tumor molecular profiling programs across institutions worldwide have revolutionized the field of precision oncology. As comprehensive genomic analyses become increasingly available in both clinical and research settings, healthcare professionals are faced with the complex tasks of result interpretation and translation. This review summarizes the current and upcoming approaches to implement precision cancer medicine, highlighting the challenges and potential solutions to facilitate the interpretation and to maximize the clinical utility of molecular profiling results. We describe novel molecular characterization strategies beyond tumor DNA sequencing, such as transcriptomics, immunophenotyping, epigenetic profiling, and single-cell analyses. We also review current and potential applications of liquid biopsies to evaluate blood-based biomarkers, such as circulating tumor cells and circulating nucleic acids. Last, lessons learned from the existing limitations of genotype-derived therapies provide insights into ways to expand precision medicine beyond genomics.

Investigation of efficacy and acquired resistance for EGFR-TKI plus bevacizumab as first-line treatment in patients with EGFR sensitive mutant non-small cell lung cancer in a Real world population

OBJECTIVES

We aimed to investigate the clinical efficacy of EGFR tyrosine kinase inhibitor (TKI, T) plus bevacizumab (an antiangiogenic therapy, A) in a real-world population and to provide insights into their mechanism of resistance.

METHODS

This study included 256 NSCLC patients harboring EGFR sensitizing mutations (EGFR 19del and L858R) who underwent nextgeneration sequencing (NGS) with 168-gene panel prior to treatment between Jan 2015 to Aug 2018. Cohort A included 60 patients treated with A + T; while cohort B consisted of 120 patients treated with EGFR-TKI monotherapy with the patients identified using Propensity Score Matching (Ratio of 1:2). Clinical outcomes and potential resistance mechanism were evaluated.

RESULTS

Baseline clinical characteristics were not significantly different between Cohort A and B. Compared with cohort B, cohort A had significantly better overall response rate (95% vs 74.2%, p = 0.001) and longer median progression-free survival (PFS, 16.5m vs.12.0 m, HR = 0.7, p = 0.001). Until Jan 2019, 31 and 103 patients in cohort A and B, respectively, were evaluated with progressive disease and underwent tissue re-biopsy and NGS profiling with 168-gene panel. In cohort B, T790M was the predominant acquired resistance mechanism, detected in 51.5% (53/103) of progressive tumors, followed by amplifications in EGFR (15.5%, 16/103) and MET (6.8%, 7/103). Contrastingly, cohort A had a significantly lower rate of T790 M mutation (35.5%, 11/31, p = 0.0003), followed by mutations in TP53 (29.0%, 9/31), RB1 (9.7%, 3/31), SMAD4 (3.2%, 1/31) and EGFR V834 L (3.2%, 1/31) and amplifications in EGFR (9.7%, 3/31), and MET(6.5%, 2/31).

CONCLUSION

Treatment with first-line A + T significantly extends the time to progression and increases the response rate with acceptable safety profile. T790 M was the most common acquired resistance mechanism but it was less common in patients who received A + T.

Predictive impact of low-frequency pretreatment T790M mutation in patients with EGFR-mutated non-small cell lung cancer treated with EGFR tyrosine kinase inhibitors

OBJECTIVES

Low-frequency epidermal growth factor receptor (EGFR) T790M mutation could be detected by ultrasensitive methods in EGFR tyrosine kinase inhibitor (TKI)-naïve non-small cell lung cancer (NSCLC). However, the impact of pretreatment T790M (preT790M) on the efficacy of EGFR-TKIs and on resistance remains unclear.

MATERIALS AND METHODS

Two independent cohorts consisting of advanced EGFR-mutated NSCLC patients treated with first-line EGFR-TKIs, a derivation cohort that started treatment between August 2013 and July 2016 (cohort A, n = 44) and a validation cohort between August 2016 and December 2017 (cohort B, n = 22), were examined in this study. Among these, 28 patients underwent re-biopsy at disease progression. DNAs from pretreatment tumor biopsy samples and re-biopsy samples were assessed to detect T790M by the Cobas EGFR Mutation Test v2 (Cobas) and for quantitating T790M by droplet digital polymerase chain reaction (ddPCR).

RESULTS

Detection rates of preT790M were 40.9% (18/44) in cohort A and 45.5% (10/22) in cohort B by ddPCR, and none by Cobas. A cutoff value of 0.3% for dividing into high- vs. low-preT790M allele frequency was determined by receiver operating characteristic curve analysis in cohort A. Progression-free survival (PFS) was significantly shorter in the high- preT790M group (n = 12) than in the low-preT790M (n = 6) and negative (n = 26) groups (combined low-preT790M) (median: 6.9 vs. 13.8 months, P =  0.00073). These observations were validated in cohort B [median: 6.2 (n = 5) vs. 15.3 months (n = 17), P =  0.0029]. In 28 paired biopsies, Cobas detected post-progression T790M in 60% (3/5) of the high-preT790M, in 57% (4/7) of the low-preT790M, and in 56% (9/16) of the negative-preT790M groups.

CONCLUSION

EGFR-mutated NSCLC with high preT790M had significantly shorter PFS on EGFR-TKIs. However, preT790M abundance may not necessarily confer post-TKI T790M resistance.

The prognostic value of tumor mutation burden in EGFR-mutant advanced lung adenocarcinoma, an analysis based on cBioPortal data base

Background

Tumor mutation burden (TMB) is novel biomarker of promising predict value in prediction of immune checkpoint inhibitors (ICPis) in non-small cell lung cancer (NSCLC). However, the distribution of TMB in epidermal growth factor receptor (EGFR)-mutant advanced lung adenocarcinoma (LUAD) patients and the impact on overall survival (OS) time are not well demonstrated.

Methods

Information regarding gene mutations and patients' survival time in advanced LUAD was downloaded from The Cancer Genome Atlas (TCGA) database. The diversity of TMB in different EGFR-mutant types was observed and the predicted value of TMB for OS as well as other co-mutations were analyzed. The diversity of TMB was also observed in another Chinese cohort of advanced LUAD patients.

Results

The median TMB values of EGFR wild-type, other types of EGFR mutations, exon 19 deletions and L858R were 6.12, 5.66, 3.77 and 4.72, differences between wild-type and EGFR sensitive mutations (exon 19 deletion or L858R) were significant (P<0.001 and P<0.01). OS time of high TMB group was inferior to that of the low TMB group (24.03 months vs. not reached, P=0.0020). TMB and TP53 together will make more accurate prediction of OS in EGFR-mutant advanced LUAD patients. Distribution of TMB in another Chinese cohort had the same trend.

Conclusions

In advanced LUAD patients, TMB was lower in patients with EGFR-mutant group than EGFR wild group. TMB was a negative prognostic biomarker of OS in EGFR-mutant LUAD patients, especially when TP53 was mutated together.

Impact of EGFR-TKIs combined with PD-L1 antibody on the lung tissue of EGFR-driven tumor-bearing mice

OBJECTIVES

EGFR-targeted tyrosine kinase inhibitors (TKIs) have been the standard treatment for non-small cell lung cancer patients with EGFR mutations. However, most patients eventually develop resistance. With the development of immune checkpoint inhibitors targeting the programmed cell death receptor/ligand 1 (PD-1/PD-L1), there is a growing interest in developing combination strategies. However, there are concerns that the combination of a PD-(L)1 inhibitor and EGFR-TKI may be associated with an increased risk of pneumonitis. Therefore, we utilized an established EGFR-driven tumor-bearing mouse model to investigate whether the combination would induce pneumonitis in mouse lung tissue.

MATERIALS AND METHODS

Mice were treated with monotherapy or combined therapy of PD-L1 antibody and EGFR-TKIs including first-generation gefitinib and third-generation osimertinib. Bronchoalveolar lavage fluids (BALFs) and lung tissues were collected for analysis at the end of treatment.

RESULTS AND CONCLUSION

The osimertinib and anti-PD-L1 combined treatment group had the highest inflammation scores in pathologic grades of H&E staining of lung tissue and had the highest percentages of myeloperoxidase positive cells. However, combining gefitinib and anti-PD-L1 treatment appeared to not increase the level of pneumonitis in mice. Total cell counts, neutrophil counts and total protein concentration in BALFs were also significantly increased in the osimertinib and anti-PD-L1 combined treatment group. We next evaluated proinflammatory factors in BALFs. The levels of IFN-γ, IL-2, IL-5, TNF-α and IL-12p70 were increased in osimertinib and anti-PD-L1 combined treatment group. Comparison of different sequences of drug administration demonstrated that mice treated with osimertinib followed by PD-L1 antibody did not show evident lung inflammation. Our findings indicate that osimertinib, rather than gefitinib combined with anti-PD-L1 treatment could lead to lung injury in an EGFR mutated tumor-bearing mouse model. The sequence and timing of combining EGFR-TKI and PD-L1 antibody may influence the severity of pneumonitis.

Perspective: Cellular and Molecular Profiling Technologies in Personalized Oncology

Cancer is a leading cause of death worldwide and therefore one of the most important public health concerns. In this contribution, we discuss recent key enabling technological innovations (and their challenges), including biomarker-based technologies, that potentially allow for decentralization (e.g., self-monitoring) with the increasing availability of point-of-care technologies in the near future. These technological innovations are moving the field one step closer toward personalized oncology.

Predicting pathologic response to neoadjuvant chemoradiation in resectable stage III non-small cell lung cancer patients using computed tomography radiomic features

OBJECTIVE

The use of a neoadjuvant chemoradiation followed by surgery in patients with stage IIIA NSCLC is controversial and the benefit of surgery is limited. There are currently no clinically validated biomarkers to select patients for such an approach. In this study we evaluate computed tomography (CT) derived intratumoral and peritumoral texture and nodule shape features in their ability to predict major pathological response (MPR). MPR being defined as ≤10% of residual viable tumor, assessed at the time of surgery.

MATERIAL AND METHODS

Ninety patients with stage III NSCLC treated with chemoradiation prior to surgical resection were selected. The patients were divided randomly into two equal sets, one for training and one for independent testing. The radiomic texture and shape features were extracted from within the nodule (intra) and from the parenchymal regions immediately surrounding the nodule (peritumoral). A univariate regression analysis was performed on the image and clinicopathologic variables and then included into a multivariable logistic regression (MLR) for binary outcome prediction of MPR. The radiomic signature risk-score was generated by using a multivariate Cox regression model and association of the signature with OS and DFS was also evaluated.

RESULTS

Thirteen stable and predictive intratumoral and peritumoral radiomic texture features were found to be predictive of MPR. The MLR classifier yielded an AUC of 0.90 ± 0.025 within the training set and a corresponding AUC = 0.86 in prediction of MPR within the test set. The radiomic signature was also significantly associated with OS (HR = 11.18, 95% CI = 3.17, 44.1; p-value = 0.008) and DFS (HR = 2.78, 95% CI = 1.11, 4.12; p-value = 0.0042) in the testing set.

CONCLUSION

Texture features extracted within and around the lung tumor on CT images appears to be associated with the likelihood of MPR, OS and DFS to chemoradiation.

Co-mutational assessment of circulating tumour DNA (ctDNA) during osimertinib treatment for T790M mutant lung cancer

Osimertinib is designed to target the secondary resistant EGFR T790M mutant and has shown outstanding clinical efficacy. However, the prognostic prediction of osimertinib patients is a big problem in clinical practice. The resistance mechanism of osimertinib is also not fully understood. NGS and a 1021 gene capture panel were used to analyse the somatic mutation profile of thirty‐six lung adenocarcinoma patients' serial ctDNA samples. Progression‐free survival of subgroup patients is analysed. Patients harbour TP53 mutations and patients with higher TMB value in pre‐treatment samples showed a shorter PFS. Moreover, compared to CT evaluation, ctDNA changes generally correlated with treatment responses in most patients. Novel resistance mechanisms are discovered including EGFR mutations and alternative activation pathway. Our results implied a broad potential of ctDNA as an adjuvant tool in practical clinical management of NSCLC patients. ctDNA could help with clinical practice during osimertinib treatment, regarding monitoring tumour response, detecting development of heterogeneity, identifying potential resistance mechanisms, predicting treatment efficacy and patient outcome.

Induction of Acquired Resistance towards EGFR Inhibitor Gefitinib in a Patient-Derived Xenograft Model of Non-Small Cell Lung Cancer and Subsequent Molecular Characterization

In up to 30% of non-small cell lung cancer (NSCLC) patients, the oncogenic driver of tumor growth is a constitutively activated epidermal growth factor receptor (EGFR). Although these patients gain great benefit from treatment with EGFR tyrosine kinase inhibitors, the development of resistance is inevitable. To model the emergence of drug resistance, an EGFR-driven, patient-derived xenograft (PDX) NSCLC model was treated continuously with Gefitinib in vivo. Over a period of more than three months, three separate clones developed and were subsequently analyzed: Whole exome sequencing and reverse phase protein arrays (RPPAs) were performed to identify the mechanism of resistance. In total, 13 genes were identified, which were mutated in all three resistant lines. Amongst them the mutations in NOMO2, ARHGEF5 and SMTNL2 were predicted as deleterious. The 53 mutated genes specific for at least two of the resistant lines were mainly involved in cell cycle activities or the Fanconi anemia pathway. On a protein level, total EGFR, total Axl, phospho-NFκB, and phospho-Stat1 were upregulated. Stat1, Stat3, MEK1/2, and NFκB displayed enhanced activation in the resistant clones determined by the phosphorylated vs. total protein ratio. In summary, we developed an NSCLC PDX line modelling possible escape mechanism under EGFR treatment. We identified three genes that have not been described before to be involved in an acquired EGFR resistance. Further functional studies are needed to decipher the underlying pathway regulation.

Quinalizarin, a specific CK2 inhibitor, can reduce icotinib resistance in human lung adenocarcinoma cell lines

The abnormal activation of the downstream signaling pathways of epidermal growth factor receptor (EGFR) that are independent of EGFR, contribute to the acquisition of EGFR-tyrosine kinase inhibitor (TKI) resistance in non-small cell lung cancer (NSCLC). The serine/threonine protein kinase casein kinase II (CK2) phosphorylates and modulates several members of the EGFR downstream signaling pathways. Thus, the purpose of the current study was to investigate the effects of the addition of quinalizarin (a specific CK2 inhibitor) to icotinib (an EGFR-TKI) on the proliferation and apoptosis of four NSCLC cell lines and its underlying mechanisms. The human lung adenocarcinoma cell lines HCC827, A549, H1650 and H1975 were employed to represent the EGFR-TKI-sensitive EGFR (EGFR-sensitive) mutation, wild-type EGFR and the EGFR-TKI-resistant EGFR (EGFR-resistant) mutations. The cell viability was determined by the MTT assay. Cell apoptosis was detected by flow cytom-etry using the Annexin V-enhanced green fluorescent protein Apoptosis Detection kit. The level of proteins in the EGFR downstream pathway was observed using a western blot assay. The results showed that the cells with the EGFR-sensitive mutation (HCC827, EGFR E716-A750del) were more sensitive to icotinib compared with those possessing the EGFR wild-type (A549) and the EGFR-resistant mutations (H1650, EGFR E716-A750del and PTEN lost; H1975, EGFR L858R+T790M). Quinalizarin inhibited proliferation and promoted apoptosis in the cells with the EGFR wild-type and resistant mutations, and the addition of quinalizarin to icotinib partially restored their sensitivity to icotinib. Quinalizarin and/or icotinib increased the apoptotic rates in the EGFR-TKI resistant cells, and the combination of these reduced the level of protein downstream of EGFR, including phosphorylated (p-AKT) and p-(ERK). In conclusion, quinalizarin may partially sensitize cells to icotinib by inhibiting proliferation and promoting apoptosis mediated by AKT and ERK in EGFR-TKI resistant NSCLC cell lines.

Exosome-based detection of activating and resistance EGFR mutations from plasma of non-small cell lung cancer patients

Non-small cell lung cancer (NSCLC) is the most prevalent form of lung cancer and its molecular landscape has been extensively studied. The most common genetic alterations in NSCLC are mutations within the epidermal growth factor receptor (EGFR) gene, with frequencies between 10-40%. There are several molecular targeted therapies for patients harboring these mutations.

Liquid biopsies constitute a flexible approach to monitor these mutations in real time as opposed to tissue biopsies that represent a single snap-shot in time. However, interrogating cell free DNA (cfDNA) has inherent biological limitations, especially at early or localized disease stages, where there is not enough tumor material released into the patient’s circulation.

We developed a qPCR- based test (ExoDx EGFR) that interrogates mutations within EGFR using Exosomal RNA/DNA and cfDNA (ExoNA) derived from plasma in a cohort of 110 NSCLC patients.

The performance of the assay yielded an overall sensitivity of 90% for L858R, 83% for T790M and 73% for exon 19 indels with specificities of 100%, 100%, and 96% respectively. In a subcohort of patients with extrathoracic disease (M1b and MX) the sensitivities were 92% (L858R), 95% (T790M), and 86% (exon 19 indels) with specificity of 100%, 100% and 94% respectively.

Re-biopsy and liquid biopsy for patients with non-small cell lung cancer after EGFR-tyrosine kinase inhibitor failure

Background

Re‐biopsy is important for exploring resistance mechanisms, especially for non‐small cell lung cancer (NSCLC) patients who develop resistance to EGFR‐tyrosine kinase inhibitors (TKIs). Liquid biopsy using circulating tumor DNA has come into use for this purpose. This retrospective study investigated the status of re‐biopsy and liquid biopsy in NSCLC patients with EGFR mutations and evaluated their effect on clinical strategies and prognosis.

Methods

Five hundred fifty‐five NSCLC patients with resistance to EGFR‐TKIs were included and divided into three groups: re‐biopsy, liquid biopsy, and no re‐biopsy. Amplification refractory mutation system (ARMS) PCR or super ARMS PCR was used to detect EGFR mutations.

Results

Three hundred eight (55.5%) patients underwent re‐biopsy; 45.5% (140/308) were positive for T790M. The most common re‐biopsy procedure was computed tomography‐guided percutaneous core needle biopsy (60.1%), followed by effusion drainage (29.5%) and superficial lymph node biopsy (6.5%). One hundred eighteen (21.3%) patients underwent liquid biopsy; the T790M detection rate was 41.5% (49/118.) Of the 308 patients who underwent re‐biopsy, 69 were examined for EGFR mutations with plasma. The concordance rate of T790M detection between tissue and plasma was 66.7%. A statistical difference in further treatment after EGFR‐TKI failure was observed among all groups (P = 0.014). Patients in the biopsy groups were more likely to receive third‐generation EGFR‐TKIs. Multivariate analysis showed that re‐biopsy had a significant impact on overall survival (P < 0.001).

Conclusion

Re‐biopsy plays a pivotal role in the management of patients with NSCLC and resistance to EGFR‐TKIs. Liquid biopsy may be an alternative if difficulties performing re‐biopsy exist.

20(S)-ginsenoside Rg3 sensitizes human non-small cell lung cancer cells to icotinib through inhibition of autophagy

Epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) have become a standard therapy for non-small cell lung cancer (NSCLC) patients with sensitive mutations. However, acquired resistance inevitably emerges after a median of 6-12 months. It has been demonstrated that autophagy plays an important role in EGFR-TKI resistance. 20(S)-ginsenoside Rg3 (Rg3) is proposed to sensitize the cancer cells to chemotherapy by inhibiting autophagy. We examined the ability of Rg3 to inhibit autophagy and increase the sensitivity of NSCLC cells to icotinib. We show that the induction of autophagy in response to icotinib contributes to the development of icotinib resistance. Rg3 is capable of inhibiting autophagic flux and enhancing the sensitivity of NSCLC cells to icotinib. The resistance to icotinib could also be reversed through Rg3-induced autophagy inhibition. Autophagy inhibition by Rg3 increases the therapeutic response in both icotinib-sensitive and icotinib-resistant NSCLC cells with an EGFR-activating mutation and may be an effective new treatment strategy for this disease.

Responses to crizotinib can occur in c-MET overexpressing nonsmall cell lung cancer after developing EGFR-TKI resistance

Evidence suggests that activation of the MET signaling pathway might be associated with EGFR-TKI resistance. EGFR TKI-resistant lung cancers often remain sensitive to inhibition of the EGFR pathway; thus, c-MET inhibitors are likely to be effective when combined with continued EGFR-TKI treatment. Here, we described a 56-year-old male who became refractory after first-line gefitinib therapy and was confirmed to have c-MET overexpression without a T790M mutation, c-MET amplification or MET exon 14 alterations. A complete response to crizotinib occurred in this patient. Our case report uncovered the underlying mechanism of c-MET overexpression in affecting EGFR-TKI sensitivity, and crizotinib may assist in overcoming this problem.

Exploration of resistance mechanisms for epidermal growth factor receptor-tyrosine kinase inhibitors based on plasma analysis by digital polymerase chain reaction and next-generation sequencing

Liquid biopsy offers a potential alternative to tissue biopsy for detection of genetic alterations in cancer, and it has been introduced into clinical practice to detect the tyrosine kinase inhibitor (TKI) resistance‐conferring T790M mutation of epidermal growth factor receptor (EGFR) in patients with non‐small‐cell lung cancer (NSCLC). We prospectively collected tumor and plasma samples from 25 NSCLC patients who harbored activating mutations of EGFR and experienced failure of treatment with afatinib. The samples were analyzed by digital PCR (dPCR) and next‐generation sequencing (NGS). T790M was detected in plasma with a respective sensitivity and specificity of 83.3% and 70.0% by dPCR and 50.0% and 70.0% by NGS relative to analysis of corresponding tumor samples. Quantitation of T790M based on the ratio of the number of T790M alleles to that of activating mutation alleles (T/A ratio) improved the specificity of plasma analysis to 100% for both dPCR and NGS without a reduction in sensitivity. Although several afatinib resistance mechanisms other than T790M—including copy number gain of NRAS or MET—were identified in tumor samples, the corresponding genetic alterations were not detected in plasma. TP53 mutations were frequently identified in plasma and tumor samples, with most such mutations also having been detected before afatinib treatment. The presence of de novo TP53 mutations was associated with reduced progression‐free survival. Quantitation of T790M in plasma is thus a clinically relevant approach to determine the T790M status of tumors. In addition, genetic alterations coexisting with EGFR mutations can affect the efficacy of EGFR‐TKI treatment.

Therapeutic approaches for T790M mutation positive non-small-cell lung cancer

INTRODUCTION

Epidermal growth factor receptor (EGFR) mutation positive non-small cell lung cancer (NSCLC) is a subset of lung cancer with demonstrated response to targeted therapies. However, resistance to the first targeted approach usually occurs within the first year, and it is associated in 50-60% of cases to the T790M resistance mutation. Areas covered: The review provides an overview on the significance of the presence of the T790M mutation, its detection, treatment options and subsequent mechanisms of resistance. Expert commentary: Osimertinib is the current treatment option for T790M mutation positive NSCLC after progression to first or second-generation EGFR TKIs, with activity also on brain metastasis. However, the scenario is in continuous evolution and results from clinical trials are awaited in first-line setting and in combination strategies.

Small Molecules Identified from a Quantitative Drug Combinational Screen Resensitize Cisplatin's Response in Drug-Resistant Ovarian Cancer Cells

Drug resistance to chemotherapy occurs in many ovarian cancer patients resulting in failure of treatment. Exploration of drug resistance mechanisms and identification of new therapeutics that overcome the drug resistance can improve patient prognosis. Following a quantitative combination screen of 6060 approved drugs and bioactive compounds in a cisplatin-resistant A2780-cis ovarian cancer cell line, 38 active compounds with IC₅₀s under 1 μM suppressed the growth of cisplatin-resistant ovarian cancer cells. Among these confirmed compounds, CUDC-101, OSU-03012, oligomycin A, VE-821, or Torin2 in a combination with cisplatin restored cisplatin's apoptotic response in the A2780-cis cells, while SR-3306, GSK-923295, SNX-5422, AT-13387, and PF-05212384 directly suppressed the growth of A2780-cis cells. One of the mechanisms for overcoming cisplatin resistance in these cells is mediated by the inhibition of epidermal growth factor receptor (EGFR), though not all the EGFR inhibitors are equally active. The increased levels of total EGFR and phosphorylated-EGFR (p-EGFR) in the A2780-cis cells were reduced after the combined treatment of cisplatin with EGFR inhibitors. In addition, a knockdown of EGFR mRNA reduced cisplatin resistance in the A2780-cis cells. Therefore, the top active compounds identified in this work can be studied further as potential treatments for cisplatin-resistant ovarian cancer. The quantitative combinational screening approach is a useful method for identifying effective compounds and drug combinations against drug-resistant cancer cells.

The long tail of molecular alterations in non-small cell lung cancer: a single-institution experience of next-generation sequencing in clinical molecular diagnostics

BACKGROUND

Molecular profiling of advanced non-small cell lung cancers (NSCLC) is essential to identify patients who may benefit from targeted treatments. In the last years, the number of potentially actionable molecular alterations has rapidly increased. Next-generation sequencing allows for the analysis of multiple genes simultaneously.

AIMS

To evaluate the feasibility and the throughput of next-generation sequencing in clinical molecular diagnostics of advanced NSCLC.

METHODS

A single-institution cohort of 535 non-squamous NSCLC was profiled using a next-generation sequencing panel targeting 22 actionable and cancer-related genes.

RESULTS

441 non-squamous NSCLC (82.4%) harboured at least one gene alteration, including 340 cases (63.6%) with clinically relevant molecular aberrations. Mutations have been detected in all but one gene (FGFR1) of the panel. Recurrent alterations were observed in KRAS, TP53, EGFR, STK11 and MET genes, whereas the remaining genes were mutated in <5% of the cases. Concurrent mutations were detected in 183 tumours (34.2%), mostly impairing KRAS or EGFR in association with TP53 alterations.

CONCLUSIONS

The study highlights the feasibility of targeted next-generation sequencing in clinical setting. The majority of NSCLC harboured mutations in clinically relevant genes, thus identifying patients who might benefit from different targeted therapies.