Gefitinib-sensitizing EGFR mutations in lung cancer activate anti-apoptotic pathways

A Ras destabilizer KYA1797K overcomes the resistance of EGFR tyrosine kinase inhibitor in KRAS-mutated non-small cell lung cancer

The epidermal growth factor receptor (EGFR) inhibitors such as erlotinib and gefitinib are widely used for treatment of non-small cell lung cancer (NSCLC), but they have shown limited efficacy in an unselected population of patients. The KRAS mutations, which are identified in approximately 20% of NSCLC patients, have shown to be associated with the resistance to the EGFR tyrosine kinase inhibitors (TKIs). Currently, there is no clinically available targeted therapy which can effectively inhibit NSCLC tumors harboring KRAS mutations. This study aims to show the effectiveness of KYA1797K, a small molecule which revealed anti-cancer effect in colorectal cancer by destabilizing Ras via inhibiting the Wnt/β-catenin pathway, for the treatment of KRAS-mutated NSCLC. While erlotinib fail to have anti-transforming effect in NSCLC cell lines harboring KRAS mutations, KYA1797K effectively inhibited the Ras-ERK pathway in KRAS-mutant NSCLC cell lines. As a result, KYA1797K treatment suppressed the growth and transformation of KRAS mutant NSCLC cells and also induced apoptosis. Furthermore, KYA1797K effectively inhibited Kras-driven tumorigenesis in the Kras^LA2 mouse model by suppressing the Ras-ERK pathway. The destabilization of Ras via inhibition of the Wnt/β-catenin pathway is a potential therapeutic strategy for KRAS-mutated NSCLC that is resistant to EGFR TKI.

Prognostic impact of pleural effusion in EGFR-mutant non-small cell lung cancer patients without brain metastasis

Background

In epidermal growth factor receptor (EGFR)‐mutant non‐small cell lung cancer (NSCLC), brain metastasis is known as a poor prognosis factor. However, prognostic factors in the patients without brain metastasis remain unclear. In this study, we aimed to clarify the differences between metastatic site and prognosis in common EGFR‐mutant NSCLC patients without brain metastasis.

Methods

Chemotherapy‐naïve, advanced EGFR‐mutant NSCLC patients without brain metastasis diagnosed between January 2010 and March 2016 were enrolled. We evaluated prognosis according to the presence or absence of bone metastases, liver metastasis, and pleural effusion.

Results

A total of 50 EGFR‐mutant NSCLC patients without brain metastasis were enrolled. The median progression‐free survival and overall survival were significantly shorter in patients with pleural effusion than in those patients without (progression‐free survival 7.0 months, 95% confidence interval [CI] 3.7–13.0 vs. 13.0 months, 95% CI 9.1–21.7, hazard ratio [HR] 2.29, 95% CI 1.11–4.73, P = 0.020; overall survival 19.5 months, 95% CI 5.7–28.8 vs. 55.3 months, 95% CI 24.0–not evaluable, HR 3.00, 95% CI 1.35–6.68, P = 0.005). Pleural effusion was an independent factor of poor prognosis for progression‐free survival (HR 3.44, 95% CI 1.50–7.88, P = 0.003) and overall survival (HR 2.34, 95% CI 1.00–5.44, P = 0.049).

Conclusion

Pleural effusion might be a poor prognosis factor for advanced EGFR‐mutant NSCLC patients without brain metastasis treated with first‐generation EGFR‐tyrosine kinase inhibitors. Further precision medicine according to the metastatic site is required.

Resistance to molecularly targeted therapy in non-small-cell lung cancer

The discovery of oncogenic driver gene mutations, including epidermal growth factor receptor (EGFR) mutation, anaplastic lymphoma kinase (ALK) fusion, ROS proto-oncogene 1 (ROS1) fusion, and ret proto-oncogene (RET) fusion, has led to the development of molecularly targeted therapy for non-small-cell lung cancer (NSCLC). This therapy has changed the standard of care for NSCLC. Despite the dramatic response to molecularly targeted therapy, almost all patients ultimately develop resistance to the drugs. To understand the mechanisms of resistance to molecularly targeted agents, it is essential to understand the molecular pathways of NSCLC. Here, we review the mechanisms of resistance to molecularly targeted therapy and discuss strategies to overcome drug resistance.

MicroRNAs as a drug resistance mechanism to targeted therapies in EGFR-mutated NSCLC: Current implications and future directions

The introduction of EGFR-tyrosine kinase inhibitors (TKIs) has revolutionized the treatment and prognosis of non-small cell lung cancer (NSCLC) patients harboring epidermal growth factor receptor (EGFR) mutations. However, these patients display disease progression driven by the onset of acquired mechanisms of drug resistance that limit the efficacy of EGFR-TKI to no longer than one year. Moreover, a small fraction of EGFR-mutated NSCLC patients does not benefit from this targeted treatment due to primary (i.e. intrinsic) mechanisms of resistance that preexist prior to TKI drug treatment. Research efforts are focusing on deciphering the distinct molecular mechanisms underlying drug resistance, which should prompt the development of novel antitumor agents that surmount such chemoresistance modalities. The capability of microRNAs (miRNAs) to regulate the expression of many oncogenic pathways and their central role in lung cancer progression, provided new directions for research on prognostic biomarkers, as well as innovative tools for predicting patients' response to systemic therapies. Recent evidence suggests that modulation of key miRNAs may also reverse oncogenic signaling pathways, and potentiate the cytotoxic effect of anti-cancer therapies. In this review, we focus on the putative emerging role of miRNAs in modulating drug resistance to EGFR-TKI treatment in EGFR-mutated NSCLC. Moreover, we discuss the current implications of miRNAs analyses in the clinical setting, using both tissue and liquid biopsies, as well as the future potential use of miRNA-based therapies in overcoming resistance to targeted agents like TKIs.

Bronchioloalveolar lung tumors induced in “mice only” by non-genotoxic chemicals are not useful for quantitative assessment of pulmonary adenocarcinoma risk in humans

Chemicals classified as known human carcinogens by International Agency for Research on Cancer (IARC) show a low level of concordance between rodents and humans for induction of pulmonary carcinoma. Rats and mice exposed via inhalation for 2 years show a low level of concordance in both tumor development and organ site location. In 2-year inhalation studies using rats and mice, when pulmonary tumors are seen in only male or female mice or both, but not in either sex of rat, there is a high probability that the murine pulmonary tumor has been produced via Clara cell or club cell (CC) metabolism of the inhaled chemical to a cytotoxic metabolite. Cytotoxicity-induced mitogenesis increases mutagenesis via amplification of the background mutation rate. If the chemical being tested is also negative in the Ames Salmonella mutagenicity assay, and only mouse pulmonary tumors are induced, the probability that this pulmonary tumor is not relevant to human lung cancer risk goes even higher. Mice have a larger percentage of CCs in their distal airways than rats, and a much larger percentage than in humans. The CCs of mice have a much higher concentration of metabolic enzymes capable of metabolizing xenobiotics than CCs in either rats or humans. A principal threat to validity of extrapolating from the murine model lies in the unique capacity of murine CCs to metabolize a significant spectrum of xenobiotics which in turn produces toxicants not seen in rat or human pulmonary pathophysiology.

Genetic and epigenetic contribution to astrocytic gliomas pathogenesis

Astrocytic gliomas are the most common and lethal form of intracranial tumors. These tumors are characterized by a significant heterogeneity in terms of cytopathological, transcriptional, and (epi)genomic features. This heterogeneity has made these cancers one of the most challenging types of cancers to study and treat. To uncover these complexities and to have better understanding of the disease initiation and progression, identification, and characterization of underlying cellular and molecular pathways related to (epi)genetics of astrocytic gliomas is crucial. Here, we discuss and summarize molecular and (epi)genetic mechanisms that provide clues as to the pathogenesis of astrocytic gliomas.

The lonely driver or the orchestra of mutations? How next generation sequencing datasets contradict the concept of single driver checkpoint mutations in solid tumours - NSCLC as a scholarly example

Driver mutations are considered to be responsible for the majority of cancers and several of those mutations provide targets in order to set up personalized therapies. So far the generally accepted opinion had been that driver mutations occur as stand-alone factors, but novel sequencing technologies induced an essential rethink. Next generation sequencing approaches have shown that double, triple or multiple concurrent mutations could occur within the same tumour and may by interaction influence sensitivity to anticancer drugs and therapy success. This review focusses on this novel concept and discusses the challenges for molecular pathology and laboratory diagnostics while providing putative solutions to overcome the present pitfalls, thereby taking NSCLC as an example.

Essential roles of mitochondrial and heme function in lung cancer bioenergetics and tumorigenesis

Contrary to Warburg’s hypothesis, mitochondrial oxidative phosphorylation (OXPHOS) contributes significantly to fueling cancer cells. Several recent studies have demonstrated that radiotherapy-resistant and chemotherapy-resistant cancer cells depend on OXPHOS for survival and progression. Several cancers exhibit an increased risk in association with heme intake. Mitochondria are widely known to carry out oxidative phosphorylation. In addition, mitochondria are also involved in heme synthesis. Heme serves as a prosthetic group for several proteins that constitute the complexes of mitochondrial electron transport chain. Therefore, heme plays a pivotal role in OXPHOS and oxygen consumption. Further, lung cancer cells exhibit heme accumulation and require heme for proliferation and invasion in vitro. Abnormalities in mitochondrial biogenesis and mutations are implicated in cancer. This review delves into mitochondrial OXPHOS and lesser explored area of heme metabolism in lung cancer.

Oxytetracycline have the therapeutic efficiency in CD133+ HCC population through suppression CD133 expression by decreasing of protein stability of CD133

Cancer stem cells (CSCs) are considered a serious sub-population in cancer tissues because of their strong resistance to conventional chemotherapy and radiotherapy. Thus, the current advancements in the use of liver cancer stem cells (LCSC) to develop efficient and organized means to an antitumor agent is quickly gaining recognition as a novel goal. Previously, we characterized CSCs in primary hepatocellular carcinoma (HCC) and identified CD133 as a CSC cell-surface marker. In this study, we proposed to use non-target based high throughput screening (HTS) approach to specifically target AFP⁺/CD133⁺ HCC present in mixed populations of HCC cells with hepatocytes. Through screening, we identified oxytetracycline, which showed significant inhibition activity of LCSC population without damage on hepatocytes. To determine whether oxytetracycline targets LCSC, we examined whether oxytetracycline treatment could change the CD133 expression, spheroid forming ability as well as the levels of stem cell-related markers. Treatment of spheroid-forming LCSC with oxytetracycline effectively decreased the spheroid formation and the CD133⁺ cell population. oxytetracycline could suppress expression of CD133 without changing of expression of other stem cell-related markers. Importantly, these series of phenomena by oxytetracycline occurs because of alteration of CD133 protein stability by oxytetracycline. Alterations in the malignant properties of AFP⁺/CD133⁺ HCC by oxytetracycline were also investigated by xenograft assay in nude mice. Treatment of oxytetracycline significantly attenuated tumor formation and CD133⁺ cell population in xenograft mice. These results indicate that the oxytetracycline suppresses stemness and malignancies in HCC cells through destabilization of CD133 in LCSC population, providing novel therapeutic strategies targeting specifically cancer stem-like cells.

Inhibiting Epidermal Growth Factor Receptor Dimerization and Signaling Through Targeted Delivery of a Juxtamembrane Domain Peptide Mimic

Overexpression and deregulation of the epidermal growth factor receptor (EGFR) are implicated in multiple human cancers and therefore are a focus for the development of therapeutics. Current strategies aimed at inhibiting EGFR activity include monoclonal antibodies and tyrosine kinase inhibitors. However, activating mutations severely limit the efficacy of these therapeutics. There is thus a growing need for novel methods to inhibit EGFR. One promising approach involves blocking the association of the cytoplasmic juxtamembrane (JM) domain of EGFR, which has been shown to be essential for receptor dimerization and kinase function. Here, we aim to improve the selectivity and efficacy of an EGFR JM peptide mimic by utilizing the pH(low) insertion peptide (pHLIP), a unique molecule that can selectively target cancer cells solely based on their extracellular acidity. This delivery strategy potentially allows for more selective targeting to tumors than current methods and for anchoring the peptide mimic to the cytoplasmic leaflet of the plasma membrane, increasing its local concentration and thus efficacy. We show that the conjugated construct is capable of inhibiting EGFR phosphorylation and downstream signaling and of inducing concentration- and pH-dependent toxicity in cervical cancer cells. We envision that this approach could be expanded to the modulation of other single-span membrane receptors whose activity is mediated by JM domains.

Arsenic circumvents the gefitinib resistance by binding to P62 and mediating autophagic degradation of EGFR in non-small cell lung cancer

Non-small cell lung cancer (NSCLC) is characterized by hyperexpression and/or gain-of-function mutations of the epidermal growth factor receptor (EGFR), resulting in an elevated overall kinase activity. Gefitinib is remarkably effective in patients with the L858R or ΔE746-A750-mutated of EGFR. However, drug resistance tends to develop because of the emergence of T790M mutation on EGFR. New strategies other than repressing kinase activity are thus required to treat NSCLC, thereby circumventing the resistance. In this study, arsenic trioxide (ATO) at 2 μM significantly inhibited the proliferation of the gefitinib-resistant NCI-H1975 cells of the EGFR L858R/T790M mutant compared with a modest inhibition in the gefitinib-sensitive HCC827 cells of ΔE746-A750 mutant and A549 cells of wild-type EGFR. Moreover, ATO significantly inhibited the overall kinase activity of EGFR primarily through quantitatively diminishing the EGFR in NCI-H1975 cells to an extent comparable with that reached by gefitinib in HCC827 cells. Furthermore, ATO promoted autophagic degradation of EGFR in NSCLC cells by directly binding to P62, which interacted with EGFR, preferentially the L858R/T790M mutant providing a plausible explanation for a more favorable effect of ATO on NCI-H1975 cells. Accordingly, the effect of ATO was further confirmed in the NSCLC xenograft mouse models. Our results reveal a new target for ATO with a unique molecular mechanism, i.e., ATO suppresses the overall catalytic potential of EGFR, significantly those with the L858R/T790M mutant in NCI-H1975 cells, through an autophagic degradation by interacting with P62. This study potentially offers an innovative therapeutic avenue for the NSCLC with L858R/T790M-mutated EGFR.

Oligosaccharyltransferase Inhibition Overcomes Therapeutic Resistance to EGFR Tyrosine Kinase Inhibitors

Asparagine (N)-linked glycosylation is a posttranslational modification essential for the function of complex transmembrane proteins. However, targeting glycosylation for cancer therapy has not been feasible due to generalized effects on all glycoproteins. Here, we perform sensitivity screening of 94 lung cancer cell lines using NGI-1, a small-molecule inhibitor of the oligosaccharyltransferase (OST) that partially disrupts N-linked glycosylation, and demonstrate a selective loss of tumor cell viability. This screen revealed NGI-1 sensitivity in just 11 of 94 (12%) cell lines, with a significant correlation between OST and EGFR inhibitors. In EGFR-mutant non-small cell lung cancer with EGFR tyrosine kinase inhibitor (TKI) resistance (PC9-GR, HCC827-GR, and H1975-OR), OST inhibition maintained its ability to induce cell-cycle arrest and a proliferative block. Addition of NGI-1 to EGFR TKI treatment was synthetic lethal in cells resistant to gefitinib, erlotinib, or osimertinib. OST inhibition invariably disrupted EGFR N-linked glycosylation and reduced activation of receptors either with or without the T790M TKI resistance mutation. OST inhibition also dissociated EGFR signaling from other coexpressed receptors like MET via altered receptor compartmentalization. Translation of this approach to preclinical models was accomplished through synthesis and delivery of NGI-1 nanoparticles, confirmation of in vivo activity through molecular imaging, and demonstration of significant tumor growth delay in TKI-resistant HCC827 and H1975 xenografts. This therapeutic strategy breaks from kinase-targeted approaches and validates N-linked glycosylation as an effective target in tumors driven by glycoprotein signaling.Significance:EGFR-mutant NSCLC is incurable despite the marked sensitivity of these tumors to EGFR TKIs. These findings identify N-linked glycosylation, a posttranslational modification common to EGFR and other oncogenic signaling proteins, as an effective therapeutic target that enhances tumor responses for EGFR-mutant NSCLC. Cancer Res; 78(17); 5094-106. ©2018 AACR.

The Network of Non-coding RNAs in Cancer Drug Resistance

Non-coding RNAs (ncRNAs) have been implicated in most cellular functions. The disruption of their function through somatic mutations, genomic imprinting, transcriptional and post-transcriptional regulation, plays an ever-increasing role in cancer development. ncRNAs, including notorious microRNAs, have been thus proposed to function as tumor suppressors or oncogenes, often in a context-dependent fashion. In parallel, ncRNAs with altered expression in cancer have been reported to exert a key role in determining drug sensitivity or restoring drug responsiveness in resistant cells. Acquisition of resistance to anti-cancer drugs is a major hindrance to effective chemotherapy and is one of the most important causes of relapse and mortality in cancer patients. For these reasons, non-coding RNAs have become recent focuses as prognostic agents and modifiers of chemo-sensitivity. This review starts with a brief outline of the role of most studied non-coding RNAs in cancer and then highlights the modulation of cancer drug resistance via known ncRNAs based mechanisms. We identified from literature 388 ncRNA-drugs interactions and analyzed them using an unsupervised approach. Essentially, we performed a network analysis of the non-coding RNAs with direct relations with cancer drugs. Within such a machine-learning framework we detected the most representative ncRNAs-drug associations and groups. We finally discussed the higher integration of the drug-ncRNA clusters with the goal of disentangling effectors from downstream effects and further clarify the involvement of ncRNAs in the cellular mechanisms underlying resistance to cancer treatments.

Calpain 2 knockdown promotes cell apoptosis and restores gefitinib sensitivity through epidermal growth factor receptor/protein kinase B/survivin signaling

Gefitinib, an epidermal growth factor receptor (EGFR)-specific drug, is effective for ~1 year, after which resistance is inevitable. Calpain 2 (CAPN2) is known to serve a role in the drug response and resistance in certain cancer therapies. However, the full function of CAPN2, particularly in non-small cell lung cancer, has not yet been elucidated. In the present study, CAPN2 expression in gefitinib-resistant lung adenocarcinoma cells was investigated. CAPN2 function in these cells was further evaluated using gene knockdown both in vitro and in vivo. The results demonstrated that CAPN2 was strongly associated with gefitinib-resistance, and CAPN2 mRNA and protein expression levels were significantly increased in gefitinib-resistant cell lines. Furthermore, CAPN2 knockdown inhibited gefitinib-resistant cell proliferation in vitro and in vivo. CAPN2 conferred gefitinib-resistance by inhibiting cell apoptosis and arresting the cell cycle. CAPN2 knockdown also induced caspase activation and mitochondrial dysfunction, and its function in gefitinib resistance appeared to be largely mediated by EGFR/protein kinase B/survivin signaling pathway activation. These results suggest that CAPN2 is responsible for EGFR-tyrosine kinase inhibitor resistance, and CAPN2 inhibition may be used to provide therapeutic benefits in the treatment of gefitinib resistance.

Hallmarks of Cancer in the Reading Room: A Guide for Radiologists

OBJECTIVE

The hallmarks of cancer are mechanisms that cells develop to undergo malignant transformation. The targeting of these hallmarks by newer cancer therapies results in new mechanisms of response, toxicity, and resistance. The purpose of this article is to review these hallmarks, their associated targeted therapies, imaging features of responses, and toxicities.

CONCLUSION

Ten hallmarks, among them proliferative signaling, angiogenesis, immune response, and genome instability, are reviewed. Molecular targeted therapies, including antiangiogenic factors and immune checkpoint inhibitors, target these hallmarks.

Gossypol Inhibits Non-small Cell Lung Cancer Cells Proliferation by Targeting EGFRL858R/T790M

Background: Overexpression of epidermal growth factor receptor (EGFR) has been reported to be implicated in the pathogenesis of non-small cell lung cancer (NSCLC). Several EGFR inhibitors have been used in clinical treatment of NSCLC, but the emergence of EGFRL858R/T790M resistant mutation has reduced the efficacy of the clinical used EGFR inhibitors. There is an urgent need to develop novel EGFRL858R/T790M inhibitors for better NSCLC treatment. Methods: By screening a natural product library, we have identified gossypol as a novel potent inhibitor targeting EGFRL858R/T790M. The activity of gossypol on NSCLC cells was evaluated by cell proliferation, cell apoptosis and cell migration assays. Kinase activity inhibition assay and molecular docking were used to study the inhibition mechanism of gossypol to EGFRL858R/T790M. Western blotting was performed to study the molecular mechanism of gossypol inhibiting the downstream pathways of EGFR. Results: Gossypol inhibited the cell proliferation and cell migration of NSCLC cells, and induced caspase-dependent cell apoptosis of NSCLC cells by upregulating the expression of pro-apoptotic protein BAD. Molecular docking revealed that gossypol could bind to the kinase domain of EGFRL858R/T790M with good binding affinity through hydrogen bonds and hydrophobic interactions. Gossypol inhibited the kinase activity of EGFRL858R/T790M with EC50 of 150.1 nM. Western blotting analysis demonstrated that gossypol inhibited the phosphorylation of EGFR and its downstream signal pathways in a dose-dependent manner. Conclusion: Gossypol inhibited cell proliferation and induced apoptosis of NSCLC cells by targeting EGFRL858R/T790M. Our findings provided a basis for developing novel EGFRL858R/T790M inhibitors for treatment of NSCLC.

Management of Brain Metastases in Epidermal Growth Factor Receptor Mutant Non-Small-Cell Lung Cancer

Lung cancer remains a leading cause of mortality with 1.69 million deaths worldwide. Activating mutations in epidermal growth factor receptor (EGFR), predominantly exon 19 deletions and exon 21 L858R mutations, are known oncogenic drivers identified in 20-40% of non-small-cell lung cancers (NSCLC). 70% of EGFR-mutant NSCLC patients develop brain metastases (BM), compared to 38% in EGFR wild-type patients. First-generation tyrosine kinase inhibitors (TKIs), such as erlotinib and gefitinib have proven to be superior to chemotherapy in the front-line treatment of EGFR-mutant NSCLC, as has afatinib, a second-generation TKI. The most common acquired resistance mechanism is the development of a gatekeeper mutation in exon 20 T790M. Osimertinib has emerged as a third-generation EGFR TKI with proven activity in the front-line setting as well as in patients with a T790M acquired resistance mutation with remarkable CNS activity. As long-term survival outcomes in EGFR-mutant NSCLC continue to improve, the burden of BM becomes a greater challenge. Here, we review the literature related to the management of BM in EGFR-mutant NSCLC including the role of the three generations of EGFR TKIs, immunotherapy, and brain radiation.

Bioinformatics Identification of Drug Gene Modules: Application to Clear Cell Carcinoma of the Ovary

Targeted therapy is a treatment that targets the cancer's specific genes, proteins, or the tissue environment that contributes to cancer growth and survival. Identification of therapeutics targets is a very challenging problem in bioinformatics. An integrative and iterative approach for the identification of drug-gene modules (i.e., groups of genes and drugs such that genes in the same module may regulate each other and are targets of some of the drugs in the same module) is developed. Application to clear cell carcinoma of the ovary data reveals several drug-gene modules and a target network that may play important roles in treating this disease.

Personalized medicine in non-small cell lung cancer: a review from a pharmacogenomics perspective

Non-small cell lung cancer is a prevalent and rapidly-expanding challenge to modern medicine. While generalized medicine with traditional chemotherapy yielded comparatively poor response rates and treatment results, the cornerstone of personalized medicine using genetic profiling to direct treatment has exalted the successes seen in the field and raised the standard for patient treatment in lung and other cancers. Here, we discuss the current state and advances in the field of personalized medicine for lung cancer, reviewing several of the mutation-targeting strategies that are approved for clinical use and how they are guided by patient genetic information. These classes include inhibitors of tyrosine kinase (TKI), anaplastic lymphoma kinase (ALK), and monoclonal antibodies. Selecting from these treatment plans and determining the optimal dosage requires in-depth genetic guidance with consideration towards not only the underlying target genes but also other factors such as individual metabolic capability and presence of resistance-conferring mutations both directly on the target gene and along its cascade(s). Finally, we provide our viewpoints on the future of personalized medicine in lung cancer, including target-based drug combination, mutation-guided drug design and the necessity for data of population genetics, to provide rough guidance on treating patients who are unable to get genetic testing.

Role of long non-coding RNA in drug resistance in non-small cell lung cancer

Lung cancer is the leading cause of cancer-associated death, and non-small cell lung cancer (NSCLC) accounts for 85% of all lung cancer cases. Many drugs have been used to treat NSCLC in order to improve patient prognosis. Platinum-based chemotherapy is the first-line treatment for locally advanced or metastatic patients. For patients with activating EGFR mutations, tyrosine kinase inhibitors are the best treatment choice. NSCLC initially exhibits an excellent response to treatment; however, acquired resistance has been observed in many patients, leading to ineffective treatment. Clinical resistance is an impediment in the treatment of patients with advanced NSCLC. Many sequencing technologies have shown that long non-coding RNA (lncRNA) is expressed differently between drug-resistant and drug-sensitive lung cancer cells. We review the literature on lncRNA in drug resistance of NSCLC. The aim of this review is to gain insight into the molecular mechanisms of drug resistance, mainly focusing on the role of lncRNA in NSCLC.

Medullary Thyroid Cancer: Clinical Characteristics and New Insights into Therapeutic Strategies Targeting Tyrosine Kinases

Medullary thyroid carcinoma (MTC) is a hyperplasia of thyroid C-cells, accounting for 5-10% of all thyroid cancers. MTCs may appear as sporadic or hereditary forms, and several molecules and signaling pathways have been found to function defectively in MTC cells. Tyrosine kinases are the most well-studied molecules that have abnormal function in these tumor cells. Due to their limited response, chemotherapeutic agents and radiation therapy are not effective in treating patients with advanced metastatic MTC. In the past decade, significant attention has been given to the utilization of multikinase inhibitors as targeted therapeutic agents for treating MTC patients, with the most promising results arising from the study of tyrosine kinase inhibitors, which generally bind to the ATP binding sites of these kinases. Two drugs-vandetanib and cabozantinib-are approved for the treatment of aggressive advanced MTC; however, the potential for toxicities and adverse effects of these agents on patient quality of life need to be considered against any therapeutic gain. According to recent data, it appears that inhibition of only one receptor or molecule in a pathway is not as effective as simultaneous inhibition of different pathways, indicating the need to use combination therapy. The main purpose of this review is to describe the clinical characteristics, molecular mechanisms, and current molecular and targeted therapeutic strategies active in clinical trials for advanced MTC treatment.

Human Organ Chip Models Recapitulate Orthotopic Lung Cancer Growth, Therapeutic Responses, and Tumor Dormancy In Vitro

Here, we show that microfluidic organ-on-a-chip (organ chip) cell culture technology can be used to create in vitro human orthotopic models of non-small-cell lung cancer (NSCLC) that recapitulate organ microenvironment-specific cancer growth, tumor dormancy, and responses to tyrosine kinase inhibitor (TKI) therapy observed in human patients in vivo. Use of the mechanical actuation functionalities of this technology revealed a previously unknown sensitivity of lung cancer cell growth, invasion, and TKI therapeutic responses to physical cues associated with breathing motions, which appear to be mediated by changes in signaling through epidermal growth factor receptor (EGFR) and MET protein kinase. These findings might help to explain the high level of resistance to therapy in cancer patients with minimal residual disease in regions of the lung that remain functionally aerated and mobile, in addition to providing an experimental model to study cancer persister cells and mechanisms of tumor dormancy in vitro.

Response to HER2 Inhibition in a Patient With Brain Metastasis With EGFR TKI Acquired Resistance and an HER2 Amplification

A 62-year-old man was referred to our university hospital for treatment of advanced adenocarcinoma of the lung after disease progression on two lines of EGFR TKI and one line of chemotherapy. Fluorescent in situ hybridization analysis upon progression showed an HER2 amplification. At our weekly Molecular Tumor Board (MTB), a decision was made to treat this patient with afatinib, which resulted in a partial response. However, progression was observed with a facial nerve paresis due to a metastasis in the skull. A biopsy of a location in the thorax revealed the presence of an EGFR-T790M mutation associated with acquired resistance, after which treatment with osimertinib was started. After 6 months, disease progression was observed, and a new biopsy was taken from the pelvic bone, which revealed the original amplification of HER2 together with the EGFR-L858R mutation, the EGFR-T790M mutation was not detected. The MTB decided to treat the patient with trastuzumab/paclitaxel. A partial response was observed in different bone lesions, while the skull metastasis with ingrowth in the brain remained stable for 6 months. Because of progression of the bone metastases after 6 months, a biopsy of a lesion in the thorax wall was taken. In this lesion, the EGFR-T790M mutation could be detected again. The MTB advised to start treatment with a combination of osimertinib and afatinib. This resulted in an impressive clinical improvement and a partial response of the bone metastases on the most recent 18-fluorodeoxyglucose positron emission tomography and computer tomography-scan. In conclusion, adjusting treatment to the mutational make-up of the tumor is a great challenge. For optimal treatment response multiple biopsies and re-biopsy upon progression are imperative. As more genes are investigated, treatment decision becomes increasingly difficult, therefore, expert opinions from an MTB is essential.

Epidermal growth factor receptor (EGFR) T790M mutation identified in plasma indicates failure sites and predicts clinical prognosis in non-small cell lung cancer progression during first-generation tyrosine kinase inhibitor therapy: a prospective observational study

Introduction

Plasma circulating tumor DNA (ctDNA) is an ideal approach to detecting the epidermal growth factor receptor (EGFR) T790M mutation, which is a major mechanism of resistance to first-generation EGFR-tyrosine kinase inhibitor (TKI) therapy. The present study aimed to explore the association of ctDNA-identified T790M mutation with disease failure sites and clinical prognosis in non-small cell lung cancer (NSCLC) patients.

Methods

Patients who progressed on first-generation TKIs were categorized into failure site groups of chest limited (CF), brain limited (BF) and other (OF). Amplification refractory mutation system (ARMS) and droplet digital PCR (ddPCR) were used to identify the T790M mutation in ctDNA. Prognosis was analyzed with Kaplan–Meier methods.

Results

Overall concordance between the two methods was 78.3%. According to both ARMS and ddPCR, patients in the OF group had a significantly higher rate of T790M mutation than did patients in the BF and CF groups (P < 0.001), and a significantly higher T790M mutation rate was also observed in OF-group patients than in those in the CF and BF groups (P < 0.001). AZD9291 was found to be an excellent treatment option and yielded the longest survival for T790M+ patients in all groups who had progressed on EGFR-TKIs; for other treatments, the prognosis of T790M− patient subgroups varied.

Conclusions

The present study demonstrates that T790M mutation in ctDNA is associated with failure sites for NSCLC patients after EGFR-TKI therapy and indicates that both failure site and T790M mutational status greatly influence treatment selection and prognosis.

Electronic supplementary material

The online version of this article (10.1186/s40880-018-0303-2) contains supplementary material, which is available to authorized users.

Knockdown of annexin A5 restores gefitinib sensitivity by promoting G2/M cell cycle arrest

Background

Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors, including gefitinib, are first-line drugs against advanced non-small cell lung cancer with activating EGFR mutations. However, the development of resistance to such drugs is a major clinical challenge.

Methods

The role of annexin A5 in resistance to EGFR tyrosine kinase inhibitors was investigated by qPCR and western blot of relevant molecules, by CCK8 and EdU assay of cell proliferation and viability, by annexin V/propidium iodide assay of apoptosis and cell cycle distribution, by JC-1 assay of mitochondrial integrity, and by xenograft assay of tumorigenicity.

Results

We found that annexin A5 is upregulated in gefitinib-resistant cell lines, as well as in clinical specimens resistant to EGFR tyrosine kinase inhibitors. Accordingly, knockdown of the gene from gefitinib-resistant cells restores gefitinib sensitivity in vitro and in vivo by downregulating polo-like kinase 1 signal pathway, thereby inducing mitochondrial damage, caspase activation, cell cycle arrest at G2/M, and, finally, apoptosis.

Conclusions

The data indicate that annexin A5 confers gefitinib resistance in lung cancer by inhibiting apoptosis and G2/M cell cycle arrest, and is thus a potential therapeutic target in non-small cell lung cancers resistant to EGFR tyrosine kinase inhibitors.

MicroRNA-7 facilitates the degradation of alpha-synuclein and its aggregates by promoting autophagy

Alpha-Synuclein (α-Syn) is an important protein in the pathogenesis of Parkinson disease (PD) as it accumulates as fibrillar inclusions in affected brain regions including dopaminergic neurons in the substantia nigra. Elevated levels of α-Syn seem to be crucial in mediating its toxicity. Thus, detailed information regarding the regulatory mechanism of α-Syn expression in several layers such as transcription, post-transcription and post-translation is needed in order to devise therapeutic interventions for PD. Previously, we reported that expression of α-Syn is repressed by microRNA-7 (miR-7) through its effect on the 3'-untranslated region (UTR) of α-Syn mRNA. Here, we show that miR-7 also accelerates the clearance of α-Syn and its aggregates by promoting autophagy in differentiated ReNcell VM cells. Further, miR-7 facilitates the degradation of pre-formed fibrils of α-Syn transported from outside the cells. This additional mechanism for reducing α-Syn levels show miR-7 to be an important molecular target for PD and other alpha-synucleinopathies.

Functional cooperation between HIF-1α and c-Jun in mediating primary and acquired resistance to gefitinib in NSCLC cells with activating mutation of EGFR

OBJECTIVE

Hypoxia-inducible factor 1 (HIF-1) and activator protein 1 (AP-1) are important transcription factors regulating expression of genes involved in cell survival. HIF-1α and c-Jun are key components of HIF-1 and AP-1, respectively, and are regulated by epidermal growth factor receptor (EGFR)-mediated cell signaling and tumor microenvironmental cues. The roles of HIF-1α and c-Jun in development of resistance to EGFR tyrosine kinase inhibitor (TKI) in non-small cell lung cancer (NSCLC) with activating mutation of EGFR have not been explored. In this study, we investigated the roles of HIF-1α and c-Jun in mediating primary and acquired resistance to gefitinib in NSCLC cells with activating mutation of EGFR.

MATERIALS AND METHODS

Changes in HIF-1α protein and in total and phosphorylated c-Jun levels in relation to changes in total and phosphorylated EGFR levels before and after gefitinib treatment were measured using Western blot analysis in NSCLC cells sensitive or resistant to gefitinib. The impact of overexpression of a constitutively expressed HIF-1α (HIF-1α/ΔODD) or a constitutively active c-Jun upstream regulator (SEK1 S220E/T224D mutant) on cell response to gefitinib was also examined. The effect of pharmacological inhibition of SEK1-JNK-c-Jun pathway on cell response to gefitinib was evaluated.

RESULTS

Downregulation of HIF-1α and total and phosphorylated c-Jun levels correlated with cell inhibitory response to gefitinib better than decrease in phosphorylated EGFR did in NSCLC cells with intrinsic or acquired resistance to gefitinib. Overexpression of HIF-1α/ΔODD or SEK1 S220E/T224D mutant conferred resistance to gefitinib. There exists a positive feed-forward regulation loop between HIF-1 and c-Jun. The JNK inhibitor SP600125 sensitized gefitinib-resistant NSCLC cells to gefitinib.

CONCLUSIONS

HIF-1α and c-Jun functionally cooperate in development of resistance to gefitinib in NSCLC cells. The translational value of inhibiting HIF-1α/c-Jun cooperation in overcoming resistance to EGFR TKI treatment of NSCLC cells with activating mutation of EGFR deserves further investigation.

PI3K/AKT inhibition induces compensatory activation of the MET/STAT3 pathway in non-small cell lung cancer

Constitutive activation of the phosphoinositide 3-kinase (PI3K)/AKT signaling pathway is evident in a diverse array of human cancer types, and targeting the pathway is an attractive therapeutic approach. However, pre-clinical and clinical studies have demonstrated that the antitumor efficacy of a number of inhibitors of the PI3K/AKT pathway is poor, and the underlying mechanisms are not completely clear. In the present study, activation of MET proto-oncogene (MET)/signal transducer and activator of transcription 3 (STAT3) signaling was demonstrated during PI3K/AKT inhibition. Western blotting showed that the pharmacological or genetic inhibition of PI3K/AKT signaling triggered compensatory activation of STAT3 and upregulation of the expression of its downstream genes. The results from RTK array analysis and western blotting demonstrated that the hyperactivated STAT3 signaling was demonstrated to be mediated by the activation of MET. In addition, PI3K/AKT inhibition suppressed tumor growth more effectively when combined with inhibitors targeting MET/STAT3 signaling by detecting apoptosis and colony formation. These results were further confirmed in a nude mouse model. Thus, our results highlight a compensatory survival mechanism via the MET/STAT3 signaling pathway after PI3K/AKT signaling inhibition in non-small cell lung cancer.

Characterizing Cancer Drug Response and Biological Correlates: A Geometric Network Approach

In the present work, we apply a geometric network approach to study common biological features of anticancer drug response. We use for this purpose the panel of 60 human cell lines (NCI-60) provided by the National Cancer Institute. Our study suggests that mathematical tools for network-based analysis can provide novel insights into drug response and cancer biology. We adopted a discrete notion of Ricci curvature to measure, via a link between Ricci curvature and network robustness established by the theory of optimal mass transport, the robustness of biological networks constructed with a pre-treatment gene expression dataset and coupled the results with the GI50 response of the cell lines to the drugs. Based on the resulting drug response ranking, we assessed the impact of genes that are likely associated with individual drug response. For genes identified as important, we performed a gene ontology enrichment analysis using a curated bioinformatics database which resulted in biological processes associated with drug response across cell lines and tissue types which are plausible from the point of view of the biological literature. These results demonstrate the potential of using the mathematical network analysis in assessing drug response and in identifying relevant genomic biomarkers and biological processes for precision medicine.

Activation of signal transducer and activator of transcription 3 (STAT3) signaling in EGFR mutant non-small-cell lung cancer (NSCLC)

Gefitinib, erlotinib or afatinib are the current treatment for non-small-cell lung cancer (NSCLC) harboring an activating mutation of the epidermal growth factor receptor (EGFR), but less than 5% of patients achieve a complete response and the median progression-free survival is no longer than 12 months. Early adaptive resistance can occur as soon as two hours after starting treatment by activating signal transducer and activation of transcription 3 (STAT3) signaling. We investigated the activation of STAT3 in a panel of gefitinib-sensitive EGFR mutant cell lines, and gefitinib-resistant PC9 cell lines developed in our laboratory. Afatinib has great activity in gefitinib-sensitive as well as in gefitinib-resistant EGFR mutant NSCLC cell lines. However, afatinib therapy causes phosphorylation of STAT3 tyrosine 705 (pSTAT3_Tyr705) and elevation of STAT3 and RANTES mRNA levels. The combination of afatinib with TPCA-1 (a STAT3 inhibitor) ablated pSTAT3_Tyr705 and down-regulated STAT3 and RANTES mRNA levels with significant growth inhibitory effect in both gefitinib-sensitive and gefitinib-resistant EGFR mutant NSCLC cell lines. Aldehyde dehydrogenase positive (ALDH⁺) cells were still observed with the combination at the time that Hairy and Enhancer of Split 1 (HES1) mRNA expression was elevated following therapy. Although the combination of afatinib with STAT3 inhibition cannot eliminate the potential problem of a remnant cancer stem cell population, it represents a substantial advantage and opportunity to further prolong progression free survival and probably could increase the response rate in comparison to the current standard of single therapy.

Combined caveolin-1 and epidermal growth factor receptor expression as a prognostic marker for breast cancer

Previous studies have indicated that caveolin-1 (Cav-1) is able to bind the signal transduction factor epidermal growth factor receptor (EGFR) to regulate its tyrosine kinase activity. The aim of the present study was to evaluate the clinical significance of Cav-1 gene expression in association with the expression of EGFR in patients with breast cancer. Primary breast cancer samples from 306 patients were analyzed for Cav-1 and EGFR expression using immunohistochemistry, and clinical significance was assessed using multivariate Cox regression analysis, Kaplan-Meier estimator curves and the log-rank test. Stromal Cav-1 was downregulated in 38.56% (118/306) of tumor tissues, whereas cytoplasmic EGFR and Cav-1 were overexpressed in 53.92% (165/306) and 44.12% (135/306) of breast cancer tissues, respectively. EGFR expression was positively associated with cytoplasmic Cav-1 and not associated with stromal Cav-1 expression in breast cancer samples; however, low expression of stromal Cav-1 was negatively associated with cytoplasmic Cav-1 expression in total tumor tissues, and analogous results were identified in the chemotherapy group. Multivariate Cox's proportional hazards model analysis revealed that, for patients in the estrogen receptor (ER)(+) group, the expression of stromal Cav-1 alone was a significant prognostic marker of breast cancer. However, in the chemotherapy, human epidermal growth factor receptor 2 (HER-2)(-), HER-2(+) and ER(-) groups, the use of combined markers was more effective prognostic marker. Stromal Cav-1 has a tumor suppressor function, and the combined marker stromal Cav-1/EGFR expression was identified as an improved prognostic marker in the diagnosis of breast cancer. Parenchymal expression of Cav-1 is able to promote EGFR signaling in breast cancer, potentially being required for EGFR-mediated initiation of mitosis.

An EGFR ligand promotes EGFR-mutant but not KRAS-mutant lung cancer in vivo

EGFR ligands (e.g., EGF and TGFA) have been shown to be clinically associated with poor survival in lung cancer. Since TGFA itself initiates autochthonous tumors in liver, breast, and pancreas but not in the lung in transgenic mice in vivo, it would appear that an EGFR ligand may not initiate but rather promote lung cancer. However, it has not been proven in vivo whether lung cancer is promoted by an EGFR ligand. Using transgenic mouse models conditionally expressing EGFR^L858R or Kras^G12D with TGFA (an EGFR ligand) in lung epithelium, we determined that TGFA promoted the growth of EGFR^L858R-lung tumors in airway regions but not that of Kras^G12D-lung tumors. Analysis of TCGA datasets identified ΔNp63 and AGR2 as potential key tumor-promoting regulators, which were highly induced in the TGFA-induced EGFR^L858R-lung tumors. The expression of AGR2 was positively correlated with the expression of TGFA in human EGFR-mutant lung adenocarcinomas. The expression of TGFA in human EGFR-mutant lung adenocarcinomas but not in the EGFR wild-type lung adenocarcinoma was associated with poor survival. These results suggest that targeting EGFR ligands may benefit patients who carry EGFR-mutant lung tumors but will not benefit patients with KRAS-mutant lung tumors.

Cigarette smoke enhances oncogene addiction to c-MET and desensitizes EGFR-expressing non-small cell lung cancer to EGFR TKIs

Cigarette smoking is one of the leading risks for lung cancer and is associated with the insensitivity of non‐small cell lung cancer (NSCLC) to epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs). However, it remains undetermined whether and how cigarette smoke affects the therapeutic efficacy of EGFR TKIs. In this study, our data showed that chronic exposure to cigarette smoke extract (CSE) or tobacco smoke‐derived carcinogen benzo[α]pyrene, B[α]P, but not nicotine‐derived nitrosamine ketone (NNK), reduced the sensitivity of wild‐type EGFR‐expressing NSCLC cells to EGFR TKIs. Treatment with TKIs almost abolished EGFR tyrosine kinase activity but did not show an inhibitory effect on downstream Akt and ERK pathways in B[α]P‐treated NSCLC cells. CSE and B[α]P transcriptionally upregulate c‐MET and activate its downstream Akt pathway, which is not inhibited by EGFR TKIs. Silencing of c‐MET reduces B[α]P‐induced Akt activation. The CSE‐treated NSCLC cells are sensitive to the c‐MET inhibitor crizotinib. These findings suggest that cigarette smoke augments oncogene addiction to c‐MET in NSCLC cells and that MET inhibitors may show clinical benefits for lung cancer patients with a smoking history.

Non-invasive tumor genotyping using radiogenomic biomarkers, a systematic review and oncology-wide pathway analysis

With targeted treatments playing an increasing role in oncology, the need arises for fast non-invasive genotyping in clinical practice. Radiogenomics is a rapidly evolving field of research aimed at identifying imaging biomarkers useful for non-invasive genotyping. Radiogenomic genotyping has the advantage that it can capture tumor heterogeneity, can be performed repeatedly for treatment monitoring, and can be performed in malignancies for which biopsy is not available. In this systematic review of 187 included articles, we compiled a database of radiogenomic associations and unraveled networks of imaging groups and gene pathways oncology-wide. Results indicated that ill-defined tumor margins and tumor heterogeneity can potentially be used as imaging biomarkers for 1p/19q codeletion in glioma, relevant for prognosis and disease profiling. In non-small cell lung cancer, FDG-PET uptake and CT-ground-glass-opacity features were associated with treatment-informing traits including EGFR-mutations and ALK-rearrangements. Oncology-wide gene pathway analysis revealed an association between contrast enhancement (imaging) and the targetable VEGF-signalling pathway. Although the need of independent validation remains a concern, radiogenomic biomarkers showed potential for prognosis prediction and targeted treatment selection. Quantitative imaging enhanced the potential of multiparametric radiogenomic models. A wealth of data has been compiled for guiding future research towards robust non-invasive genomic profiling.

Mutation abundance affects the therapeutic efficacy of EGFR-TKI in patients with advanced lung adenocarcinoma: A retrospective analysis

PURPOSE

To investigate the influence of mutation abundance and sites of epidermal growth factor receptor (EGFR) on therapeutic efficacies of EGFR-tyrosine kinase inhibitor (EGFR-TKIs) treatments of patients with advanced non-small cell lung carcinoma (NSCLC).

METHODS

EGFR mutational sites and mutation abundance were analyzed by amplification refractory mutation system (ARMS) in paraffin-embedded tissue sections taken from primary or metastatic tumors of 194 NSCLC patients.

RESULTS

The median progression-free survival (PFS) time of the enrolled patients was 9.3 months (95% CI, 8.2-10.8 months). The PFS was significantly different with EGFR gene mutation abundance after EGFR-TKI therapy (P = 0.014). The median PFS was significantly longer when the cut-off value of EGFR mutation abundance of exon 19 or exon 21, and solely exon 19 was > 26.7% and 61.8%, respectively. For patients who received EGFR-TKI as first-line treatment, the median PFS was significantly longer in the high mutation abundance group than in the low mutation abundance group (12.7 vs 8.7 months, P = 0.002).

CONCLUSION

The PFS benefits were greater in patients with a higher abundance of exon 19 deletion mutations in the EGFR gene after EGFR-TKI treatment and first line EGFR-TKI treatment led to improved PFS in high mutation abundance patients.

The value of radial endobronchial ultrasound-guided bronchial brushing in peripheral non-squamous non-small cell lung cancer

Radial endobronchial ultrasound (R-EBUS) is one important diagnostic approach in non-small cell lung cancers (NSCLC). However, the small samples obtained from R-EBUS-guided transbronchial biopsies are sometimes insufficient for pathological and molecular diagnosis. Herein, we investigated the suitability of R-EBUS-guided bronchial brushing specimens for NSCLC diagnosis and EGFR genotyping. We enrolled 941 consecutive patients with peripheral pulmonary lesions who underwent R-EBUS. Cytology-positive brushing specimens from non-squamous NSCLC patients were tested for EGFR mutations. Non-squamous NSCLC was diagnosed in 624 patients (66.3%). Positive cytology was documented in the brushing samples of 376 patients (60.3%). Higher diagnostic yields were obtained in patients exhibiting bronchus signs on chest tomography, and those with R-EBUS probe located within the lesion. EGFR genotyping was successfully performed in 363 samples (96.5% of cytology-positive brushing samples). EGFR genotyping concordance between brushing specimens and matched tissue samples was 88.7% (kappa = 0.745, P < 0.001). Furthermore, 144 non-squamous NSCLC patients (23.1%) with failed pathological diagnosis or EGER sequencing by R-EBUS-guided transbronchial biopsy required repeat biopsies. However, it was achieved successfully from the brushing specimens of 57 patients (39.6%). In conclusion, for patients with peripheral lung cancer, R-EBUS-guided bronchial brushing could provide an additional sampling method for diagnosis and EGFR genotyping.

The role of metabolic tumor volume (MTV) measured by [18F] FDG PET/CT in predicting EGFR gene mutation status in non-small cell lung cancer

Many noninvasive methods have been explored to determine the mutation status of the epidermal growth factor receptor (EGFR) gene, which is important for individualized treatment of non-small cell lung cancer (NSCLC). We evaluated whether metabolic tumor volume (MTV), a parameter measured by [18F] fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) might help predict EGFR mutation status in NSCLC. Overall, 87 patients who underwent EGFR genotyping and pretreatment PET/CT between January 2013 and September 2016 were reviewed. Clinicopathologic characteristics and metabolic parameters including MTV were evaluated. Univariate and multivariate analyses were used to assess the independent variables that predict mutation status to create prediction models. Forty-one patients (41/87) were identified as having EGFR mutations. The multivariate analysis showed that patients with lower MTV (MTV≤11.0 cm3, p=0.001) who were non-smokers (p=0.037) and had a peripheral tumor location (p=0.033) were more likely to have EGFR mutations. Prediction models using these criteria for EGFR mutation yielded a high AUC (0.805, 95% CI 0.712–0.899), which suggests that the analysis had good discrimination. In conclusion, NSCLC patients with EGFR mutations showed significantly lower MTV than patients with wild-type EGFR. Prediction models based on MTV and clinicopathologic characteristics could provide more information for the identification of EGFR mutations.