BRAF mutations in non-small cell lung cancer: has finally Janus opened the door?

Combined SERS Microfluidic Chip with Gold Nanocone Array for Effective Early Lung Cancer Prognosis in Mice Model

Introduction

As the most common malignant tumor in the world, the prognosis of patients with advanced lung cancer remains poor even after treatment. There are many prognostic marker assays available, but there is still more room for the development of high-throughput and sensitive detection of circulating tumor DNA (ctDNA). Surface-enhanced Raman spectroscopy (SERS), a spectroscopic detection method that has received wide attention in recent years, can achieve exponential amplification of Raman signals by using different metallic nanomaterials. Integrating SERS with signal amplification strategy into the microfluidic chip and applying it to ctDNA detection is expected to be an effective tool for the prognosis of lung cancer treatment effect in the future.

Methods

To construct a high-throughput SERS microfluidic chip integrated with enzyme-assisted signal amplification (EASA) and catalytic hairpin self-assembly (CHA) signal amplification strategies, using hpDNA-functionalized Au nanocone arrays (AuNCAs) as capture substrates and cisplatin-treated lung cancer mice to simulate the detection environment for sensitive detection of ctDNA in serum of lung cancer patients after treatment.

Results

The SERS microfluidic chip constructed by this scheme, with two reaction zones, can simultaneously and sensitively detect the concentrations of four prognostic ctDNAs in the serum of three lung cancer patients with a limit of detection (LOD) as low as the aM level. The results of the ELISA assay are consistent with this scheme, and its accuracy is guaranteed.

Conclusion

This high-throughput SERS microfluidic chip has high sensitivity and specificity in the detection of ctDNA. This could be a potential tool for prognostic assessment of lung cancer treatment efficacy in future clinical applications.

Non-small cell lung cancer in China

In China, lung cancer is a primary cancer type with high incidence and mortality. Risk factors for lung cancer include tobacco use, family history, radiation exposure, and the presence of chronic lung diseases. Most early-stage non-small cell lung cancer (NSCLC) patients miss the optimal timing for treatment due to the lack of clinical presentations. Population-based nationwide screening programs are of significant help in increasing the early detection and survival rates of NSCLC in China. The understanding of molecular carcinogenesis and the identification of oncogenic drivers dramatically facilitate the development of targeted therapy for NSCLC, thus prolonging survival in patients with positive drivers. In the exploration of immune escape mechanisms, programmed cell death protein 1 (PD-1)/programmed death-ligand 1 (PD-L1) inhibitor monotherapy and PD-1/PD-L1 inhibitor plus chemotherapy have become a standard of care for advanced NSCLC in China. In the Chinese Society of Clinical Oncology's guidelines for NSCLC, maintenance immunotherapy is recommended for locally advanced NSCLC after chemoradiotherapy. Adjuvant immunotherapy and neoadjuvant chemoimmunotherapy will be approved for resectable NSCLC. In this review, we summarized recent advances in NSCLC in China in terms of epidemiology, biology, molecular pathology, pathogenesis, screening, diagnosis, targeted therapy, and immunotherapy.

BRAF-Mutated Non-Small Cell Lung Cancer: Current Treatment Status and Future Perspective

V-Raf murine sarcoma viral oncogene homolog B (BRAF) kinase, which was encoded by BRAF gene, plays critical roles in cell signaling, growth, and survival. Mutations in BRAF gene will lead to cancer development and progression. In non-small cell lung cancer (NSCLC), BRAF mutations commonly occur in never-smokers, women, and aggressive histological types and accounts for 1%-2% of adenocarcinoma. Traditional chemotherapy presents limited efficacy in BRAF-mutated NSCLC patients. However, the advent of targeted therapy and immune checkpoint inhibitors (ICIs) have greatly altered the treatment pattern of NSCLC. However, ICI monotherapy presents limited activity in BRAF-mutated patients. Hence, the current standard treatment of choice for advanced NSCLC with BRAF mutations are BRAF-targeted therapy. However, intrinsic or extrinsic mechanisms of resistance to BRAF-directed tyrosine kinase inhibitors (TKIs) can emerge in patients. Hence, there are still some problems facing us regarding BRAF-mutated NSCLC. In this review, we summarized the BRAF mutation types, the diagnostic challenges that BRAF mutations present, the strategies to treatment for BRAF-mutated NSCLC, and resistance mechanisms of BRAF-targeted therapy.

Drug resistance to targeted therapeutic strategies in non-small cell lung cancer

Rapidly developing molecular biology techniques have been employed to identify cancer driver genes in specimens from patients with non-small cell lung cancer (NSCLC). Inhibitors and antibodies that specifically target driver gene-mediated signaling pathways to suppress tumor growth and progression are expected to extend the survival time and further improve the quality of life of patients. However, the health of patients with advanced and metastatic NSCLC presents significant challenges due to treatment resistance, mediated by cancer driver gene alteration, epigenetic alteration, and tumor heterogeneity. In this review, we discuss two different resistance mechanisms in NSCLC targeted therapies, namely changes in the targeted oncogenes (on-target resistance) and changes in other related signaling pathways (off-target resistance) in tumor cells. We highlight the conventional mechanisms of drug resistance elicited by the complex heterogeneous microenvironment of NSCLC during targeted therapy, including mutations in epidermal growth factor receptor (EGFR), anaplastic lymphoma kinase (ALK), the receptor tyrosine kinase ROS proto-oncogene 1 (ROS1), and the serine/threonine-protein kinase BRAF (v-Raf murine sarcoma viral oncogene homolog B). We also discuss the mechanism of action of less common oncoproteins, as in-depth understanding of these molecular mechanisms is important for optimizing treatment strategies.

Role of miRNAs in lung cancer

Lung cancer (LC) is the leading cause of cancer-related deaths all over the world, among both men and women, with an incidence of over 200,000 new cases per year coupled with a very high mortality rate. LC comprises of two major clinicopathological categories: small-cell (SCLC) and nonsmall-cell lung carcinoma (NSCLC). The microRNAs (miRNAs) are small noncoding RNAs, usually 18-25 nucleotides long, which repress protein translation through binding to complementary target mRNAs. The miRNAs regulate many biological processes including cell cycle regulation, cellular growth, proliferation, differentiation, apoptosis, metabolism, neuronal patterning, and aging. This review summarizes the role of miRNAs expression in LC. It also provides information about the miRNAs as biomarker and therapeutic target for lung cancer. Understanding the role of miRNAs in LC may provide insights into the diagnosis and treatment strategy for LC.

Immune Checkpoint Inhibitors in Advanced-Stage Non-small Cell Lung Cancer

More than half of non-small cell lung cancer (NSCLC) patients are at an advanced stage at the time of diagnosis, and they have a poor prognosis. Systemic treatment is the basic treatment approach for advanced-stage NSCLC, and chemotherapy and targeted treatments are commonly used based on the molecular characteristics. Although targeted therapies have led to a significant level of improvement in terms of survival, the results are still unsatisfactory. However, considerable attention has been focused to the immunotherapy with recent positive results reported by studies on this field. In this context, a certain portion of clinical studies have shown dramatic results, and these have involved inhibitors developed particularly against the immune checkpoint protein programmed death receptor-1 and its ligand (programmed death ligand-1). This review aims to present the significance of immune checkpoint inhibitors in NSCLC and to summarize the findings of relevant contemporary clinical studies.

Driver genes in non-small cell lung cancer: Characteristics, detection methods, and targeted therapies

Lung cancer is one of the most common causes of cancer-related death in the world. The large number of lung cancer cases is non-small cell lung cancer (NSCLC), which approximately accounting for 75% of lung cancer. Over the past years, our comprehensive knowledge about the molecular biology of NSCLC has been rapidly enriching, which has promoted the discovery of driver genes in NSCLC and directed FDA-approved targeted therapies. Of course, the targeted therapies based on driver genes provide a more exact option for advanced non-small cell lung cancer, improving the survival rate of patients. Now, we will review the landscape of driver genes in NSCLC including the characteristics, detection methods, the application of target therapy and challenges.

Investigational therapies for squamous cell lung cancer: from animal studies to phase II trials

INTRODUCTION

It remains challenging to treat squamous cell lung cancer (SCC) with limited therapeutic options. However, recent breakthroughs in targeted therapies and immunotherapies have shed some light on the management of this deadly disease. Areas covered: The article first reviews the current treatment options for advanced SCC, especially recent FDA approved molecular agents (afatinib, ramucirumab and necitumumab) and immunotherapies (nivolumab, pembrolizumab and atezolimumab). We then provide an overview on investigational therapies with data ranging from preclinical to phase II studies, focusing on new cytotoxic agents, emerging molecularly targeted agents (including a PARP inhibitor for Homologous Recombinant Deficiency positive SCC) and novel immunotherapeutic strategies. Expert opinion summary: Identification of potential therapeutic targets, development of novel clinical trials and the rapid approvals of immune checkpoint inhibitors have shifted the management paradigm for squamous cell lung cancer. On the other hand, continued efforts are needed to identify the predictive biomarkers and to investigate novel mechanistically-driven mono- and combination therapies. We need to learn more about the biology behind immune checkpoint blockade and tumor genomics in SCC for better patient selection and future trial design.

Proteomic analysis of bronchoalveolar lavage fluid (BALF) from lung cancer patients using label-free mass spectrometry

BACKGROUND

Lung cancer is the leading cause of cancer-related mortality in both men and women throughout the world. The need to detect lung cancer at an early, potentially curable stage, is essential and may reduce mortality by 20%. The aim of this study was to identify distinct proteomic profiles in bronchoalveolar fluid (BALF) and plasma that are able to discriminate individuals with benign disease from those with non-small cell lung cancer (NSCLC).

METHODS

Using label-free mass spectrometry analysis of BALF during discovery-phase analysis, a significant number of proteins were found to have different abundance levels when comparing control to adenocarcinoma (AD) or squamous cell lung carcinoma (SqCC). Validation of candidate biomarkers identified in BALF was performed in a larger cohort of plasma samples by detection with enzyme-linked immunoassay.

RESULTS

Four proteins (Cystatin-C, TIMP-1, Lipocalin-2 and HSP70/HSPA1A) were selected as a representative group from discovery phase mass spectrometry BALF analysis. Plasma levels of TIMP-1, Lipocalin-2 and Cystatin-C were found to be significantly elevated in AD and SqCC compared to control.

CONCLUSION

The results presented in this study indicate that BALF is an important proximal biofluid for the discovery and identification of candidate lung cancer biomarkers.

GENERAL SIGNIFICANCE

There is good correlation between the trend of protein abundance levels in BALF and that of plasma which validates this approach to develop a blood biomarker to aid lung cancer diagnosis, particularly in the era of lung cancer screening. The protein signatures identified also provide insight into the molecular mechanisms associated with lung malignancy.

Clinicopathologic characteristics and outcomes of Chinese patients with non-small-cell lung cancer and BRAF mutation

BRAF mutation is one of the important driver oncogene in non‐small‐cell lung cancer (NSCLC). Data on Chinese patients with BRAF‐mutant NSCLC are inadequate. Hence, we conducted this study to investigate the clinicopathologic features and outcomes of Chinese patients with NSCLC and BRAF mutations. We identified patients with BRAF‐mutant NSCLC between January 2012 and April 2016. Patient characteristics and treatment outcomes were analyzed. In total, 1680 patients were included. Twenty‐eight (1.7%) patients harbored BRAF mutations. Compared to patients with non‐BRAF mutation, patients with BRAF mutations were associated with adenocarcinomas (89.3% vs. 70.6%, P = 0.048) and never smokers (78.6% vs. 56.7%, P = 0.019). There were no significant differences in the age, gender distribution, metastasis, or stage at first diagnosis between two groups. Response rates and progression‐free survival (PFS) were similar between patient with BRAF mutations and EGFR (5.6 vs. 5.8 months; P = 0.277) or KRAS (5.6 vs. 4.7 months; P = 0.741) mutations to first‐line chemotherapy. Compared to patients with non‐V600E mutations, patients with V600E‐mutated tumors had a shorter PFS to first‐line chemotherapy, although this did not reach statistical significance (5.2 vs. 6.4 months; P = 0.561). In multivariate analyses, only ECOG PS remained the independent predictor of overall survival (HR = 0.208; P = 0.004). In conclusion, BRAF mutation in Chinese patients with NSCLC was rare. BRAF mutation is more likely to be associated with adenocarcinoma and never smokers. BRAF mutations are not associated with enhanced chemosensitivity and novel and effective drugs inhibiting the BRAF pathway are in urgent need.

Application of Single-Molecule Amplification and Resequencing Technology for Broad Surveillance of Plasma Mutations in Patients with Advanced Lung Adenocarcinoma

Liquid biopsy to access the circulating tumor DNA is a promising surrogate for invasive tumor genotyping. We designed a multiplex assay based on circulating single-molecule amplification and resequencing technology (cSMART) to simultaneously detect and quantitate hot spot EGFR, KRAS, BRAF, ERBB2, and ALK plasma DNA variants in 103 patients with advanced lung adenocarcinoma. In validation studies using an analytical mutation standard, the sensitivity of the assay for EGFR mutation detection was at least 0.1% and specificity was 100%. The diagnostic detection sensitivity was one mutant molecule per 2 mL of plasma. The most frequently detected plasma mutations were EGFR variants L858R (21.4%), exon 19 deletions (19.4%), T790M (9.7%), and KRAS G12X variants (9.7%). Rarer were BRAF V600X (1.95%) and ERBB2 exon 20 (0.97%) variants. In single samples, four novel EGFR exon 19 deletions, one KIF5B-ALK, and two EML4-ALK variants were also detected. From comparisons of 103 matched plasma and tumor specimen genotypes, 75 (72.8%) were concordant, 9 (8.8%) were partially concordant, and 19 (18.4%) were discordant. Overall, the combined positive and negative concordance rate for detection of each oncogenic variant exceeded 90%. On the basis of these findings, we propose that cSMART displays the diagnostic hallmarks of a comprehensive plasma genotyping assay, with potential application for precisely monitoring changes in plasma mutation levels in response to targeted drug therapy.

The Droplet Digital PCR: A New Valid Molecular Approach for the Assessment of B-RAF V600E Mutation in Hairy Cell Leukemia

Hairy cell leukemia (HCL) is a chronic lymphoproliferative B-cell disorder where the B-RAF V600E mutation has been recently detected, as reported for solid neoplasias but not for other B-cell lymphomas. The digital droplet PCR (dd-PCR) is a molecular technique that, without standard references, is able to accurately quantitate DNA mutations. ddPCR could be an useful instrument for the detection of the B-RAF V600E mutation in HCL, where the minimal residual disease monitoring is fundamental for planning a patients-targeted treatment in the era of new anti-CD20 and anti-RAF compounds. This retrospective study enrolled 47 patients observed at the Hematology Unit of the University of Pisa, Italy, from January 2005 to January 2014: 27 patients were affected by “classic” HCL, two by the variant HCL (vHCL), and 18 by splenic marginal zone lymphoma (SMZL). The aim of the study was to compare dd-PCR to “classic” quantitative PCR (QT-PCR) in terms of sensitivity and specificity and to demonstrate its possible use in HCL. Results showed that: (1) the sensitivity of dd-PCR is about half a logarithm superior to QT-PCR (5 × 10^-5 vs. 2.5 × 10^-4), (2) the specificity of the dd-PCR is comparable to QT-PCR (no patient with marginal splenic lymphoma or HCL variant resulted mutated), (3) its high sensitivity would allow to use dd-PCR in the monitoring of MRD. At the end of treatment, among patients in complete remission, 33% were still MRD-positive by dd-PCR versus 28% by QT-PCR versus 11% by the evaluation of the B-cell clonality, after 12 months, dd-PCR was comparable to QT-PCR and both detected the B-RAF mutation in 15% of cases defined as MRD-negative by IgH rearrangement. Moreover, (4) the feasibility and the costs of dd-PCR are comparable to those of QT-PCR. In conclusion, our study supports the introduction of dd-PCR in the scenario of HCL, also during the follow-up.