Mutation testing for directing upfront targeted therapy and post-progression combination therapy strategies in lung adenocarcinoma

Acquired resistance to KRAS G12C small-molecule inhibitors via genetic/nongenetic mechanisms in lung cancer

Inherent or acquired resistance to sotorasib poses a substantialt challenge for NSCLC treatment. Here, we demonstrate that acquired resistance to sotorasib in isogenic cells correlated with increased expression of integrin β4 (ITGB4), a component of the focal adhesion complex. Silencing ITGB4 in tolerant cells improved sotorasib sensitivity, while overexpressing ITGB4 enhanced tolerance to sotorasib by supporting AKT-mTOR bypass signaling. Chronic treatment with sotorasib induced WNT expression and activated the WNT/β-catenin signaling pathway. Thus, silencing both ITGB4 and β-catenin significantly improved sotorasib sensitivity in tolerant, acquired, and inherently resistant cells. In addition, the proteasome inhibitor carfilzomib (CFZ) exhibited synergism with sotorasib by down-regulating ITGB4 and β-catenin expression. Furthermore, adagrasib phenocopies the combination effect of sotorasib and CFZ by suppressing KRAS activity and inhibiting cell cycle progression in inherently resistant cells. Overall, our findings unveil previously unrecognized nongenetic mechanisms underlying resistance to sotorasib and propose a promising treatment strategy to overcome resistance.

Nanotechnology - a robust tool for fighting the challenges of drug resistance in non-small cell lung cancer

Genomic and proteomic mutation analysis is the standard of care for selecting candidates for therapies with tyrosine kinase inhibitors against the human epidermal growth factor receptor (EGFR TKI therapies) and further monitoring cancer treatment efficacy and cancer development. Acquired resistance due to various genetic aberrations is an unavoidable problem during EGFR TKI therapy, leading to the rapid exhaustion of standard molecularly targeted therapeutic options against mutant variants. Attacking multiple molecular targets within one or several signaling pathways by co-delivery of multiple agents is a viable strategy for overcoming and preventing resistance to EGFR TKIs. However, because of the difference in pharmacokinetics among agents, combined therapies may not effectively reach their targets. The obstacles regarding the simultaneous co-delivery of therapeutic agents at the site of action can be overcome using nanomedicine as a platform and nanotools as delivery agents. Precision oncology research to identify targetable biomarkers and optimize tumor homing agents, hand in hand with designing multifunctional and multistage nanocarriers that respond to the inherent heterogeneity of the tumors, may resolve the challenges of inadequate tumor localization, improve intracellular internalization, and bring advantages over conventional nanocarriers.

A Systems Biology Approach for Addressing Cisplatin Resistance in Non-Small Cell Lung Cancer

Translational research in medicine, defined as the transfer of knowledge and discovery from the basic sciences to the clinic, is typically achieved through interactions between members across scientific disciplines to overcome the traditional silos within the community. Thus, translational medicine underscores 'Team Medicine', the partnership between basic science researchers and clinicians focused on addressing a specific goal in medicine. Here, we highlight this concept from a City of Hope perspective. Using cisplatin resistance in non-small cell lung cancer (NSCLC) as a paradigm, we describe how basic research scientists, clinical research scientists, and medical oncologists, in true 'Team Science' spirit, addressed cisplatin resistance in NSCLC and identified a previously approved compound that is able to alleviate cisplatin resistance in NSCLC. Furthermore, we discuss how a 'Team Medicine' approach can help to elucidate the mechanisms of innate and acquired resistance in NSCLC and develop alternative strategies to overcome drug resistance.

Clinical and Economic Impact of Upfront Next-Generation Sequencing for Metastatic NSCLC in East Asia

Introduction

Upfront next-generation sequencing (NGS) in patients with metastatic NSCLC has been associated with cost savings and shorter time-to-test results in the United States. Nevertheless, this may not apply in jurisdictions where the prevalence of patients with actionable mutations, cost of health care, and reimbursement models differ.

Methods

A decision analytical model was built to compare sequential, panel, exclusionary, and upfront NGS testing in patients with metastatic NSCLC in Hong Kong. In sequential and panel testing, patients were tested for genomic alterations (GAs) with treatment followed by sequential or NGS. In exclusionary testing, EGFR and ALK were tested first, followed by NGS. For each modality, the mutation identified, time to receive testing results, and costs (2020 U.S. dollars) were estimated.

Results

Exclusionary testing required the shortest time-to-results (1.6 wk) and was most cost saving. In the scenario where all patients used exclusionary testing, a cost saving of $4.6 million was expected relative to current practice, with 90.7% of actionable and 46.5% of nonactionable GAs detected; when all patients used NGS, it would be $2.9 million more expensive with a 100% GA detection rate. Results were sensitive to testing costs and the proportion of patients that continued testing.

Conclusions

Exclusionary testing is the best option in terms of cost and time-to-results in Hong Kong. This finding may be applicable for other Asian countries; however, exclusionary testing does not capture all possible GAs. As more GAs become actionable and the cost of NGS declines, NGS may become a cost-saving option.

Budget Impact Analysis of Comprehensive Genomic Profiling in Patients With Advanced Non-Small-Cell Lung Cancer

PURPOSE

This study assessed the economic impact of increased use of comprehensive genomic profiling (CGP) versus conventional testing strategies among patients with advanced non-small-cell lung cancer (aNSCLC) from a US commercial health plan perspective.

METHODS

A decision analytic model was developed to estimate the incremental benefits and costs across testing methodologies (CGP v non-CGP), as well as across sample types (tissue-based and liquid-based), for patients with newly diagnosed aNSCLC. Model outcomes included total direct costs, testing costs, and per member per month budget impact. Secondary model outcomes included the number of patients needed to test with CGP to add 1 life-year, and the number of patients needed to test with CGP to treat one individual with a biomarker-matched therapy.

RESULTS

In a hypothetical 2,000,000-member health plan, 790 members were estimated to have incident aNSCLC; 609 underwent molecular diagnostic testing with 122 (20%) tested with CGP (109 tissue-based and 13 liquid) in the base-case. An increase in CGP from 20% to 30% (an additional 61 patients tested with CGP) was associated with 3.11 additional life-years gained and a $0.01 in US dollars per member per month budget impact. Approximately 19.6 patients would need to be tested with CGP versus non-CGP to add one life-year and 5.9 patients would need to be tested with CGP to treat at least one patient with a biomarker-matched therapy.

CONCLUSION

An increase in CGP from 20% to 30% among patients with aNSCLC undergoing molecular diagnostic testing was associated with modest budget impact, most of which was attributable to prolonged survival associated with increased use of more effective treatments.

A Non-genetic Mechanism Involving the Integrin β4/Paxillin Axis Contributes to Chemoresistance in Lung Cancer

Tumor heterogeneity and cisplatin resistance are major causes of tumor relapse and poor survival. Here, we show that in lung cancer, interaction between paxillin (PXN) and integrin β4 (ITGB4), components of the focal adhesion (FA) complex, contributes to cisplatin resistance. Knocking down PXN and ITGB4 attenuated cell growth and improved cisplatin sensitivity, both in 2D and 3D cultures. PXN and ITGB4 independently regulated expression of several genes. In addition, they also regulated expression of common genes including USP1 and VDAC1, which are required for maintaining genomic stability and mitochondrial function, respectively. Mathematical modeling suggested that bistability could lead to stochastic phenotypic switching between cisplatin-sensitive and resistant states in these cells. Consistently, purified subpopulations of sensitive and resistant cells re-created the mixed parental population when cultured separately. Altogether, these data point to an unexpected role of the FA complex in cisplatin resistance and highlight a novel non-genetic mechanism.

Complex Oncological Decision-Making Utilizing Fast-and-Frugal Trees in a Community Setting-Role of Academic and Hybrid Modeling

Non-small cell lung cancer is a devastating disease and with the advent of targeted therapies and molecular testing, the decision-making process has become complex. While established guidelines and pathways offer some guidance, they are difficult to utilize in a busy community practice and are not always implemented in the community. The rationale of the study was to identify a cohort of patients with lung adenocarcinoma at a City of Hope community site (n = 11) and utilize their case studies to develop a decision-making framework utilizing fast-and-frugal tree (FFT) heuristics. Most patients had stage IV (N = 9, 81.8%) disease at the time of the first consultation. The most common symptoms at initial presentation were cough (N = 5, 45.5%), shortness of breath (N = 3, 27.2%), and weight loss (N = 3, 27.2%). The Eastern Cooperative Oncology Group (ECOG) performance status ranged from 0-1 in all patients in this study. Distribution of molecular drivers among the patients were as follows: EGFR (N = 5, 45.5%), KRAS (N = 2, 18.2%), ALK (N = 2, 18.2%), MET (N = 2, 18.2%), and RET (N = 1, 9.1%). Seven initial FFTs were developed for the various case scenarios, but ultimately the decisions were condensed into one FFT, a molecular stage IV FFT, that arrived at accurate decisions without sacrificing initial information. While these FFT decision trees may seem arbitrary to an experienced oncologist at an academic site, the simplicity of their utility is essential for community practice where patients often do not get molecular testing and are not assigned proper therapy.

Non-Small Cell Lung Cancer from Genomics to Therapeutics: A Framework for Community Practice Integration to Arrive at Personalized Therapy Strategies

Non-small cell lung cancer (NSCLC) is a heterogeneous disease, and therapeutic management has advanced with the identification of various key oncogenic mutations that promote lung cancer tumorigenesis. Subsequent studies have developed targeted therapies against these oncogenes in the hope of personalizing therapy based on the molecular genomics of the tumor. This review presents approved treatments against actionable mutations in NSCLC as well as promising targets and therapies. We also discuss the current status of molecular testing practices in community oncology sites that would help to direct oncologists in lung cancer decision-making. We propose a collaborative framework between community practice and academic sites that can help improve the utilization of personalized strategies in the community, through incorporation of increased testing rates, virtual molecular tumor boards, vendor-based oncology clinical pathways, and an academic-type singular electronic health record system.

Economic Impact of Next-Generation Sequencing Versus Single-Gene Testing to Detect Genomic Alterations in Metastatic Non–Small-Cell Lung Cancer Using a Decision Analytic Model

PURPOSE

The aim of the current study was to assess the economic impact of using next-generation sequencing (NGS) versus single-gene testing strategies among patients with metastatic non–small-cell lung cancer (mNSCLC) from the perspective of the Centers for Medicare & Medicaid Services (CMS) and US commercial payers.

METHODS

A decision analytic model considered patients who were newly diagnosed with mNSCLC who received programmed death ligand 1 and genomic alteration tests— EGFR, ALK, ROS1, BRAF, MET, HER2, RET, and NTRK1—using upfront NGS (all alterations tested simultaneously plus KRAS), sequential testing (sequence of single-gene tests), exclusionary testing ( KRAS plus sequential testing), and hotspot panels ( EGFR, ALK, ROS1, and BRAF tested simultaneously plus single-gene tests or NGS for MET, HER2, RET, and NTRK1). Model outcomes for each strategy were time-to-test results, the proportion of patients identified harboring alterations with or without US Food and Drug Administration–approved therapies, and total testing costs. A budget impact analysis assessed the economic effects of increasing the proportion of NGS-tested patients.

RESULTS

In a hypothetical 1,000,000-member health plan, 2,066 Medicare-insured patients and 156 commercially insured patients were estimated to have mNSCLC and to be eligible for testing. Time-to-test results were 2.0 weeks for NGS and the hotspot panel, faster than exclusionary and sequential testing by 2.7 and 2.8 weeks, respectively. NGS was associated with cost savings for both CMS ($1,393,678; $1,530,869; and $2,140,795 less than exclusionary, sequential testing, and hotspot panels, respectively) and commercial payers ($3,809; $127,402; and $250,842 less than exclusionary, sequential testing, and hotspot panels, respectively). Increasing the proportion of NGS-tested patients translated into substantial cost savings for both CMS and commercial payers.

CONCLUSION

Use of upfront NGS testing in patients with mNSCLC was associated with substantial cost savings and shorter time-to-test results for both CMS and commercial payers.

Kinesin Family Member 18A (KIF18A) Contributes to the Proliferation, Migration, and Invasion of Lung Adenocarcinoma Cells In Vitro and In Vivo

Objective

To determine the expression levels of KIF18A in lung adenocarcinoma and its relationship with the clinicopathologic features of patients undergoing radical colectomy and explore the potential role in the progression of lung adenocarcinoma.

Methods

Immunohistochemical assays were performed to explore the expression levels of KIF18A in 82 samples of lung adenocarcinoma and corresponding normal tissues. According to the levels of KIF18A expression in lung adenocarcinoma tissue samples, patients were classified into the KIF18A high expression group and low expression group. Clinical data related to the perioperative clinical features (age, gender, smoking, tumor size, differentiation, clinical stage, and lymph node metastasis), the potential correlation between KIF18A expression levels, and clinical features were analyzed, and the effects of KIF18A on lung adenocarcinoma cell proliferation, migration, and invasion were measured by colony formation assay, MTT assay, wound healing assay, and transwell assays. The possible effects of KIF18A on tumor growth and metastasis were measured in mice through tumor growth and tumor metastasis assays in vivo.

Results

KIF18A in lung adenocarcinoma tissues. Further, KIF18A was significantly associated to clinical characteristic features including the tumor size (P = 0.033) and clinical stage (P = 0.041) of patients with lung adenocarcinoma. Our data also investigated that KIF18A depletion dramatically impairs the proliferation, migration, and invasion capacity of lung adenocarcinoma cells in vitro and inhibits tumor growth and metastasis in mice.

Conclusions

Our study reveals the involvement of KIF18A in the progression and metastasis of lung adenocarcinoma and provides a novel therapeutic target for the treatment of lung adenocarcinoma.

Acquired Resistance to Tyrosine Kinase Inhibitors in Non-Small Cell Lung Cancers: The Role of Next-Generation Sequencing on Endobronchial Ultrasound-Guided Transbronchial Needle Aspiration Samples

CONTEXT

- Molecular testing is essential for the diagnostic workup of patients with advanced non-small cell lung cancers. Cytology specimens from minimally invasive procedures, such as endobronchial ultrasound-guided transbronchial needle aspiration, are often the only available samples for these patients. The implementation of molecular diagnostic testing, and in particular next-generation sequencing-based testing, on these cytologic specimens is currently an evolving field for lung cytopathology. The application of these molecular analyses on tyrosine kinase inhibitor-resistant non-small cell lung cancers raises unique technical, biologic, and clinical challenges.

OBJECTIVE

- To provide an overview of the implementation of next-generation sequencing analysis on endobronchial ultrasound-guided transbronchial needle aspiration samples to detect the molecular aberrations underneath the phenomenon of acquired resistance in patients with non-small cell lung cancers progressing while on the EGFR/ALK tyrosine kinase inhibitor treatment.

DATA SOURCES

- Peer-reviewed original articles, review articles, and published guidelines and expert opinion reports were reviewed, together with our single-center experience.

CONCLUSIONS

- Next-generation sequencing analyses and the endobronchial ultrasound-guided transbronchial needle aspiration procedure may represent a valuable strategy to address the unique requirements of molecular testing on tyrosine kinase inhibitor-resistant non-small cell lung cancers.

Economic analysis of BRAF gene mutation testing in real world practice using claims data: costs of single gene versus panel tests in patients with lung cancer

AIMS

To assess the time to BRAF testing, compare the characteristics of tested vs not-tested patients, and describe the costs for sequential vs next-generation sequencing (NGS) BRAF testing.

METHODS

Patients diagnosed with lung cancer after December 1, 2013 were identified from two US claims databases; their characteristics were assessed during the 12 months before diagnosis (index date). Testing modalities were analyzed from the index date to end of continuous health plan enrollment or data availability (December 2015), based on combinations of Current Procedural Terminology (CPT) procedure codes. Time to BRAF testing was assessed using Kaplan-Meier analysis. Costs were analyzed from a payer's perspective.

RESULTS

A total of 28,011 patients newly-diagnosed with lung cancer were identified. Of them, 1,260 (4.5%) were tested for BRAF: 3.2% and 4.2% were tested at 6 and 12 months, respectively, after the index date. Compared to non-tested patients, tested patients were younger (58.3 vs 65.3 years; p < .001), had a lower Charlson Comorbidity Index (2.8 vs 2.9; p = .005), and a higher proportion had metastases (70.9% vs 43.4%; p < .001). In 76.0% of cases, BRAF was tested along with KRAS. BRAF was tested using NGS in 6.6% of cases. The average reimbursed amounts for the 10 most common CPT code combinations were $207-$2,074. Using the average costs of individual mutation tests, the total cost of sequential testing comprising KRAS, EGFR, ALK, ROS1, and BRAF tests was $3,763 ($464, $696, $1,070, $1,127, and $406, respectively), that of NGS was $2,860.

LIMITATIONS

Claims data did not include BRAF test results.

CONCLUSIONS

Among patients newly-diagnosed with lung cancer, 4.5% were tested for BRAF. Tested patients were younger and had a lower comorbidity burden, but more advanced disease. While reimbursed amounts varied greatly based on combinations of testing procedures, NGS testing was associated with cost savings compared to sequential testing of individual mutations.

Cost-effectiveness of ceritinib in previously untreated anaplastic lymphoma kinase-positive metastatic non-small cell lung cancer in the United States

AIMS

To assess the cost-effectiveness of first-line ceritinib vs crizotinib and platinum doublet chemotherapy for anaplastic lymphoma kinase (ALK)-positive metastatic non-small cell lung cancer (NSCLC) from a US third-party payer's perspective.

MATERIALS AND METHODS

A partitioned survival model with three health states (stable disease, progressive disease, death) was developed over a 20-year time horizon. Ceritinib's efficacy inputs (progression-free and overall survival) were estimated from ASCEND-4; parametric survival models extrapolated data beyond the trial period. The relative efficacy of ceritinib vs chemotherapy was obtained from ASCEND-4, the relative efficacy of ceritinib vs crizotinib was estimated using a matching-adjusted indirect comparison based on ASCEND-4 and PROFILE 1014. Drug acquisition, treatment administration, adverse event management, and medical costs were obtained from publicly available databases and the literature, and inflated to 2016 US dollars. Treatment-specific stable-state utilities were derived from trials and progressive-state utility from the literature. Incremental costs per quality-adjusted life year (QALY) were estimated for ceritinib vs each comparator. Cost-effectiveness was assessed based on US willingness-to-pay thresholds. Deterministic and probabilistic sensitivity analyses were performed to test model robustness.

RESULTS

In the base case, first-line ceritinib was associated with total direct costs of $299,777 and 3.28 QALYs (from 4.61 life years gained [LYG]) over 20 years. First-line crizotinib and chemotherapy were associated with 2.73 and 2.41 QALYs, 3.92 and 3.53 LYG, and $263,172 and $228,184 total direct costs, respectively. The incremental cost per QALY gained was $66,064 for ceritinib vs crizotinib and $81,645 for ceritinib vs chemotherapy. In the first 2 years following treatment initiation, ceritinib dominated crizotinib by conferring greater health benefits at reduced total costs. Results were robust to deterministic and probabilistic sensitivity analyses.

LIMITATIONS

In the absence of head-to-head trials, an indirect comparison method was used.

CONCLUSIONS

Ceritinib is cost-effective compared to crizotinib and chemotherapy in the treatment of previously untreated ALK-positive metastatic NCSLC in the US.

Isoform specific gene expression analysis of KRAS in the prognosis of lung adenocarcinoma patients

Background

Aberrant mutations in KRAS play a critical role in tumor initiation and progression, and are a negative prognosis factor in lung adenocarcinoma (LUAD).

Results

Using genomic analysis for K-Ras isoforms (K-Ras4A and K-Ras4B) and large-scale multi-omics data, we inspected the overall survival (OS) and disease-free survival (DFS) of LUAD patients based on the abundance of transcript variants by analyzing RNA expression and somatic mutation data from The Cancer Genome Atlas (n = 516). The expression of the minor transcript K-Ras4A and its proportion were positively correlated with the presence of KRAS mutations in LUAD. We found that both K-Ras4A abundance measures (expression and proportion) have a strong association with poor OS (p = 0.0149 and p = 3.18E-3, respectively) and DFS (p = 3.03E-4 and p = 0.0237, respectively), but only in patients harboring KRAS mutations. A Cox regression analysis showed significant results in groups with low expression (hazard ratio (HR) = 2.533, 95% confidence interval (CI) = 1.380−4.651, p = 2.72E-3) and low proportion (HR = 2.549, 95% CI = 1.387−4.684, p = 2.58E-3) of K-Ras4A.

Conclusions

Based on the above results, we report the possible use of abundance measures for K-Ras4A for predicting the survival of LUAD patients with KRAS mutations.

Electronic supplementary material

The online version of this article (10.1186/s12859-018-2011-y) contains supplementary material, which is available to authorized users.

The Genetic/Non-genetic Duality of Drug 'Resistance' in Cancer

Drug resistance is a serious impediment to the treatment of cancer. However, the mechanisms involved remain poorly understood. While it is widely held that the phenomenon is genetic in nature, emerging evidence suggests that non-genetic mechanisms may also be important. Furthermore, at least in some cases, refractoriness to treatment can be reversed by epigenetic reprogramming, and combination and intermittent therapies, as opposed to sustained monotherapy, appear more effective in attenuating it. Here we iterate the confusion in understanding the phenomenon by which cancer cells evade drug response and underscore the need to recognize the genetic/non-genetic duality of drug resistance in cancer. We discuss how ecological and evolutionary principles may help to reconcile the duality and may even offer new treatment strategies.

S100A16, a promising candidate as a prognostic marker for platinum-based adjuvant chemotherapy in resected lung adenocarcinoma

Purpose

Although cisplatin-based adjuvant chemotherapy improves the survival of patients with resected non-small-cell lung cancer, not all patients show a survival benefit, and some patients experience severe toxicity. Therefore, identifying biomarkers is important for selecting subgroups of patients who may show improved survival with platinum-based adjuvant chemotherapy. S100A16 is thought to play key roles during different steps of tumor progression. The aim of this study was to evaluate the use of S100A16 expression as a prognostic marker in patients with completely resected lung adenocarcinoma receiving platinum-based adjuvant chemotherapy.

Methods

S100A16 expression was immunohistochemically studied in 65 consecutive lung adenocarcinoma patients who underwent complete resection and received platinum-based adjuvant chemotherapy. Kaplan–Meier survival analysis and Cox proportional hazards models were used to estimate the effect of S100A16 expression on disease-free survival (DFS) and overall survival (OS).

Results

S100A16 expression was detected in 26 of the 65 (40.0%) lung adenocarcinoma patients. Although S100A16 expression was not correlated with DFS (P=0.062), it was significantly correlated with OS (P=0.009). In addition, multivariable analysis revealed that S100A16 expression independently predicted a poorer survival (HR =4.79; 95% CI =1.87–12.23; P=0.001).

Conclusion

The present study revealed that S100A16 is a promising candidate as a prognostic marker for platinum-based adjuvant chemotherapy in resected lung adenocarcinoma. A further large-scale study is needed to confirm the present results.

Circulating Tumor DNA in Non–Small-Cell Lung Cancer: A Primer for the Clinician

Circulating tumor DNA (ctDNA) consists of short, double-stranded DNA fragments that are released into the circulation by tumor cells. With the advent of newer molecular platforms, ctDNA can be detected with high sensitivity and specificity in plasma. The assay’s noninvasive nature, ability to reflect intratumoral heterogeneity, short turnaround time, and ability to obtain serial samples make it an attractive option compared with traditional tissue biopsy tumor sequencing. Currently, this technology is mostly being used for the detection of EGFR mutations in patients with advanced non–small-cell lung cancer where tissue is inadequate to detect EGFR mutations that drive acquired resistance, most notably EGFR T790M. Emerging uses include the incorporation of ctDNA testing into primary diagnosis, treatment monitoring, detection of minimal residual disease, and detection of early-stage disease in screening populations. This review summarizes both validated and evolving uses of ctDNA testing in non–small-cell lung cancer in the context of oncologists’ daily practice and some of its potential challenges in the era of targeted therapy and immunotherapy.

Recent advances in subtyping tumors of the central nervous system using molecular data

INTRODUCTION

Primary brain tumors account for substantial morbidity and mortality. They often infiltrate the brain diffusely, continue growing, and cause adverse events, such as headaches, seizures, and neurological deficits. The classification of primary brain tumors, based for decades on histology, has been fundamentally changed by the World Health Organization in 2016 by incorporation of molecular data. Areas covered: Literature from glioblastomas, high- and low-grade astrocytic, oligodendroglial, glioneuronal and ependymal tumors from the last five years were reviewed. Results from comprehensive molecular profiling of neoplasms and impact of recent molecular subtyping on neuropathological diagnosis are presented. Expert commentary: The identification of frequent acquired mutations shows that adult and pediatric glioblastomas have divergent biology with differing prognoses. Astrocytoma and oligodendroglioma are more closely related than previously thought. Molecular profiling now enables the precise classification of most diffuse gliomas into three clinically and therapeutically different subtypes according to the presence or absence of IDH mutation and 1p/19q codeletion. New subgroups with different clinical outcomes and anatomic locations have emerged in ependymomas and pediatric embryonal tumors.

Non-Invasive Methods to Monitor Mechanisms of Resistance to Tyrosine Kinase Inhibitors in Non-Small-Cell Lung Cancer: Where Do We Stand?

The induction of resistance mechanisms represents an important problem for the targeted therapy of patients with non-small-cell lung cancer (NSCLC). The best-known resistance mechanism induced during treatment with epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitors (TKIs) is EGFR T790M mutation for which specific drugs are have been developed. However, other molecular alterations have also been reported as induced resistance mechanisms to EGFR-TKIs. Similarly, there is growing evidence of acquired resistance mechanisms to anaplastic lymphoma kinase (ALK)-TKI treatment. A better understanding of these acquired resistance mechanisms is essential in clinical practice as patients could be treated with specific drugs that are active against the induced alterations. The use of free circulating tumor nucleic acids or circulating tumor cells (CTCs) enables resistance mechanisms to be characterized in a non-invasive manner and reduces the need for tumor re-biopsy. This review discusses the main resistance mechanisms to TKIs and provides a comprehensive overview of innovative strategies to evaluate known resistance mechanisms in free circulating nucleic acids or CTCs and potential future orientations for these non-invasive approaches.