Molecular Radiobiology in Non-Small Cell Lung Cancer: Prognostic and Predictive Response Factors

Simple Summary

The identification of prognostic and predictive gene signatures of response to cancer treatment (radiotherapy) could help in making therapeutic decisions in patients affected by NSCLC. There are multiple proposals for gene signatures that attempt to predict survival or predict response to treatment (not radiotherapy), but they mainly focus on early stages or metastasis at diagnosis. In contrast, there have been few studies that raise these predictive and/or prognostic elements in nonmetastatic locally advanced stages, where treatment with ionizing radiation plays an important role. In this work, we review in depth previous works discovering the prognostic and predictive response factors in non-small cell lung cancer, specially focused on non-deeply studied radiation-based therapy.

Abstract

Non-small-cell lung cancer (NSCLC) is the leading cause of cancer-related death worldwide, generating huge economic and social impacts that have not slowed in recent years. Oncological treatment for this neoplasm usually includes surgery, chemotherapy, treatments on molecular targets and ionizing radiation. The prognosis in terms of overall survival (OS) and the different therapeutic responses between patients can be explained, to a large extent, by the existence of widely heterogeneous molecular profiles. The identification of prognostic and predictive gene signatures of response to cancer treatment, could help in making therapeutic decisions in patients affected by NSCLC. Given the published scientific evidence, we believe that the search for prognostic and/or predictive gene signatures of response to radiotherapy treatment can significantly help clinical decision-making. These signatures may condition the fractions, the total dose to be administered and/or the combination of systemic treatments in conjunction with radiation. The ultimate goal is to achieve better clinical results, minimizing the adverse effects associated with current cancer therapies.

Prognostic Impact of EGFR Amplification and Visceral Pleural Invasion in Early Stage Pulmonary Squamous Cell Carcinomas Patients after Surgical Resection of Primary Tumor

Over the last few decades, an increasing amount of information has been accumulated on biomarkers in non-small cell lung cancer (NSCLC). Despite these advances, most biomarkers have been identified in the adenocarcinoma histological subtype (AC). However, the application of molecular-targeted therapies in the prognosis and treatment of SCC in the clinical setting is very limited, becoming one of the main focus areas in research. Here, we prospectively analyzed the frequency of numerical/structural abnormalities of chromosomes 5, 7, 8, 9, 13 and 22 with FISH in 48 pulmonary SCC patients. From a total of 12 probes, only abnormalities of the 7p12 and 22q12 chromosomal regions were identified as unique genetic variables associated with the prognosis of the disease. The study for these two chromosomal regions was extended to 108 patients with SCC. Overall, chromosome losses were observed more frequently than chromosome gains, i.e., 61% versus 19% of all the chromosome abnormalities detected. The highest levels of genetic amplification were detected for the 5p15.2, 7p12, 8q24 and 22q11 chromosome bands, of which several genes are potentially involved in the pathogenesis of SCC, among others, include the EGFR gene at chromosome 7p12. Patients who displayed EGFR amplification (n = 13; 12%) were mostly older than 65 years (p = 0.07) and exclusively patients in early T-primary tumor stage (pT1−pT2; p = 0.03) with a significantly shortened overall survival (OS) (p ≤ 0.001). Regarding prognosis, the clinical, biological, and histopathologic characteristics of the disease that displayed a significant adverse influence on OS in the univariate analysis included patients older than 65 years (p = 0.02), the presence of lymph node involvement (p = 0.005), metastasis (p = 0.01) and, visceral pleural invasion (VPI) at diagnosis (p = 0.04). EGFR amplification also conferred an adverse impact on patient OS in the whole series (p = 0.02) and especially in patients in early stages (pT1−pT2; p = 0.01). A multivariate analysis of the prognostic factors for OS showed that the most informative combination of independent variables to predict an adverse outcome was the presence of VPI and/or EGFR amplification (p < 0.001). Based on these two variables, a scoring system was built to stratify patients into low- (no adverse features: score 0; n = 69), intermediate- (one adverse feature: score 1; n = 29) and high-risk (two adverse features: score 2; n = 5) groups, with significantly different (p = 0.001) OS rates at 50 months, which were as following: 32%, 28% and 0%, respectively. In the present study, we show that the presence of a high level of 7p12 (EGFR) amplification, exclusively detected in early stage SCC (pT1−pT2), is an independent adverse prognostic factor for OS. The identification of the EGFR gene copy number using FISH techniques may provide a more accurate diagnosis of high-risk populations after the complete resection of the primary tumor. When combined with VPI, three groups of pulmonary SCC were clearly identified that show the extent of the disease. This is of such importance that further prospective studies are necessary in larger series of SCC patients to be classified at the time of diagnosis. This could be achieved with the combined assessment of 7p12 amplification and VPI in primary tumor samples.

A Six-Gene Prognostic and Predictive Radiotherapy-Based Signature for Early and Locally Advanced Stages in Non-Small-Cell Lung Cancer

Simple Summary

The search for prognostic and/or predictive gene signatures of the response to radiotherapy treatment can significantly aid clinical decision making. These signatures can condition the fractionation, the total dose to be administered, and/or the combination of systemic treatments and radiation. The ultimate goal is to achieve better clinical results, as well as to minimize the adverse effects associated with current cancer therapies. To this end, we analyzed the intrinsic radiosensitivity of 15 NSCLC lines and found the differences in gene expression levels between radiosensitive and radioresistant lines, resulting in a potentially applicable six-gene signature in NSCLC patients. The six-gene signature had the ability to predict overall survival and progression-free survival (PFS), which could translate into a prediction of the response to the cancer treatment received.

Abstract

Non-small-cell lung cancer (NSCLC) is the leading cause of cancer death worldwide, generating an enormous economic and social impact that has not stopped growing in recent years. Cancer treatment for this neoplasm usually includes surgery, chemotherapy, molecular targeted treatments, and ionizing radiation. The prognosis in terms of overall survival (OS) and the disparate therapeutic responses among patients can be explained, to a great extent, by the existence of widely heterogeneous molecular profiles. The main objective of this study was to identify prognostic and predictive gene signatures of response to cancer treatment involving radiotherapy, which could help in making therapeutic decisions in patients with NSCLC. To achieve this, we took as a reference the differential gene expression pattern among commercial cell lines, differentiated by their response profile to ionizing radiation (radiosensitive versus radioresistant lines), and extrapolated these results to a cohort of 107 patients with NSCLC who had received radiotherapy (among other therapies). We obtained a six-gene signature (APOBEC3B, GOLM1, FAM117A, KCNQ1OT1, PCDHB2, and USP43) with the ability to predict overall survival and progression-free survival (PFS), which could translate into a prediction of the response to the cancer treatment received. Patients who had an unfavorable prognostic signature had a median OS of 24.13 months versus 71.47 months for those with a favorable signature, and the median PFS was 12.65 months versus 47.11 months, respectively. We also carried out a univariate analysis of multiple clinical and pathological variables and a bivariate analysis by Cox regression without any factors that substantially modified the HR value of the proposed gene signature.

Bax/Bcl-2 Cascade Is Regulated by the EGFR Pathway: Therapeutic Targeting of Non-Small Cell Lung Cancer

Non-small cell lung carcinoma (NSCLC) comprises 80%-85% of lung cancer cases. EGFR is involved in several cancer developments, including NSCLC. The EGFR pathway regulates the Bax/Bcl-2 cascade in NSCLC. Increasing understanding of the molecular mechanisms of fundamental tumor progression has guided the development of numerous antitumor drugs. The development and improvement of rationally planned inhibitors and agents targeting particular cellular and biological pathways in cancer have been signified as a most important paradigm shift in the strategy to treat and manage lung cancer. Newer approaches and novel chemotherapeutic agents are required to accompany present cancer therapies for improving efficiency. Using natural products as a drug with an effective delivery system may benefit therapeutics. Naturally originated compounds such as phytochemicals provide crucial sources for novel agents/drugs and resources for tumor therapy. Applying the small-molecule inhibitors (SMIs)/phytochemicals has led to potent preclinical discoveries in various human tumor preclinical models, including lung cancer. In this review, we summarize recent information on the molecular mechanisms of the Bax/Bcl-2 cascade and EGFR pathway in NSCLC and target them for therapeutic implications. We further described the therapeutic potential of Bax/Bcl-2/EGFR SMIs, mainly those with more potent and selectivity, including gefitinib, EGCG, ABT-737, thymoquinone, quercetin, and venetoclax. In addition, we explained the targeting EGFR pathway and ongoing in vitro and in vivo and clinical investigations in NSCLC. Exploration of such inhibitors facilitates the future treatment and management of NSCLC.

Predictive Markers for Immune Checkpoint Inhibitors in Non-Small Cell Lung Cancer

Immune checkpoint inhibitors (ICIs) have dramatically improved the outcomes of non-small cell lung cancer patients and have increased the possibility of long-term survival. However, few patients benefit from ICIs, and no predictive biomarkers other than tumor programmed cell death ligand 1 (PD-L1) expression have been established. Hence, the identification of biomarkers is an urgent issue. This review outlines the current understanding of predictive markers for the efficacy of ICIs, including PD-L1, tumor mutation burden, DNA mismatch repair deficiency, microsatellite instability, CD8⁺ tumor-infiltrating lymphocytes, human leukocyte antigen class I, tumor/specific genotype, and blood biomarkers such as peripheral T-cell phenotype, neutrophil-to-lymphocyte ratio, interferon-gamma, and interleukin-8. A tremendous number of biomarkers are in development, but individual biomarkers are insufficient. Tissue biomarkers have issues in reproducibility and accuracy because of intratumoral heterogeneity and biopsy invasiveness. Furthermore, blood biomarkers have difficulty in reflecting the tumor microenvironment and therefore tend to be less predictive for the efficacy of ICIs than tissue samples. In addition to individual biomarkers, the development of composite markers, including novel technologies such as machine learning and high-throughput analysis, may make it easier to comprehensively analyze multiple biomarkers.

Current Landscape of Non-Small Cell Lung Cancer: Epidemiology, Histological Classification, Targeted Therapies, and Immunotherapy

Non-small cell lung cancer (NSCLC) is a subtype of the most frequently diagnosed cancer in the world. Its epidemiology depends not only on tobacco exposition but also air quality. While the global trends in NSCLC incidence have started to decline, we can observe region-dependent differences related to the education and the economic level of the patients. Due to an increasing understanding of NSCLC biology, new diagnostic and therapeutic strategies have been developed, such as the reorganization of histopathological classification or tumor genotyping. Precision medicine is focused on the recognition of a genetic mutation in lung cancer cells called "driver mutation" to provide a variety of specific inhibitors of improperly functioning proteins. A rapidly growing group of approved drugs for targeted therapy in NSCLC currently allows the following mutated proteins to be treated: EGFR family (ERBB-1, ERBB-2), ALK, ROS1, MET, RET, NTRK, and RAF. Nevertheless, one of the most frequent NSCLC molecular sub-types remains without successful treatment: the K-Ras protein. In this review, we discuss the current NSCLC landscape treatment focusing on targeted therapy and immunotherapy, including first- and second-line monotherapies, immune checkpoint inhibitors with chemotherapy treatment, and approved predictive biomarkers.

Reflex ROS1 IHC Screening with FISH Confirmation for Advanced Non-Small Cell Lung Cancer-A Cost-Efficient Strategy in a Public Healthcare System

ROS1 rearrangements are identified in 1-2% of lung adenocarcinoma cases, and reflex testing is guideline-recommended. We developed a decision model for population-based ROS1 testing from a Canadian public healthcare perspective to determine the strategy that optimized detection of true-positive (TP) cases while minimizing costs and turnaround time (TAT). Eight diagnostic strategies were compared, including reflex single gene testing via immunohistochemistry (IHC) screening, fluorescence in-situ hybridization (FISH), next-generation sequencing (NGS), and biomarker-informed (EGFR/ALK/KRAS wildtype) testing initiated by pathologists and clinician-initiated strategies. Reflex IHC screening with FISH confirmation of positive cases yielded the best results for TAT, TP detection rate, and cost. IHC screening saved CAD 1,000,000 versus reflex FISH testing. NGS was the costliest reflex strategy. Biomarker-informed testing was cost-efficient but delayed TAT. Clinician-initiated testing was the least costly but resulted in long TAT and missed TP cases, highlighting the importance of reflex testing. Thus, reflex IHC screening for ROS1 with FISH confirmation provides a cost-efficient strategy with short TAT and maximizes the number of TP cases detected.

Treatment sequencing for the care of patients with advanced or metastatic non-small cell lung cancer in the United States

OBJECTIVES

Therapeutic advances for the treatment of patients with advanced/metastatic non-small cell lung cancer (NSCLC) have led to additional options for care. This observational study was designed to describe emerging treatment patterns and survival outcomes.

MATERIALS AND METHODS

Flatiron Health's oncology electronic health records database was to identify eligible patients who were age 18+ who initiated second-line therapy for NSCLC Survival analyses were conducted using Kaplan Meier methods and Cox proportional hazard model using SAS 9.4. both unadjusted and adjusted, using generalized propensity score, to account for imbalances between groups.

RESULTS

The 10,060 eligible patients from Dec 2014 to Feb 2019 were 52.6% male; mean age 67.1 years; 70.3% white; 26.0% squamous/70.0% non-squamous (4.1% not specified); and 92.7% were treated at community practices. Immune checkpoint inhibitors (ICIs) were used by 79.9% of the cohort during any line of therapy; 12.1% and 53.7% used ICIs during first- and second-line therapy, respectively. There was heterogeneity in treatment sequencing, as the three most common first→second line sequences accounted for 7.7% (carboplatin + paclitaxel→nivolumab), 5.0% (carboplatin + pemetrexed→nivolumab), and 3.8% (carboplatin + nab-paclitaxel→nivolumab) of the total population, respectively. Unadjusted median overall survival was 21.1 months (95% confidence interval, CI: 20.5-21.6) from metastatic diagnosis. Median survival was 23.0 months (95% CI, 22.3-23.6) for non-squamous and 18.1 months (95% CI, 17.3-18.8) for squamous disease.

CONCLUSION

There is heterogeneity in sequencing strategies that limit the ability to conduct robust comparative effectiveness research of treatment sequences. Since few patients follow a similar treatment trajectory, comparative effectiveness research will be challenged to identify treatment sequences with sufficient sample size.

Detection of the EGFR G719S Mutation in Non-small Cell Lung Cancer Using Droplet Digital PCR

Objectives: The main objectives of the study were (1) to set-up a droplet digital PCR (ddPCR) assay for the non-invasive detection of G719S EGFR mutation in NSCLC patients; (2) to determine the limits of detection of the ddPCR assay for G719S mutation and (3) to compare COBAS® and ddPCR System for G719S quantification in plasma.

Materials and Methods: Blood samples were collected from 22 patients diagnosed with advanced NSCLC. Then, plasma ctDNA was extracted with the Qiagen Circulating Nucleic Acids kit and quantified by QuantiFluor® dsDNA System. The mutational study of EGFR was carried out by digital droplet PCR (ddPCR) with the QX200 Droplet Digital PCR System with specific probes and primers.

Results: We observed the lowest percentage of G719S mutant allele could be detected in a wildtype background was 0.058%. In the specificity analysis, low levels of G719S mutation were detected in healthy volunteers with a peak of 21.65 mutant copies per milliliter of plasma and 6.35 MAFs. In those patients whose tissue biopsy was positive for G719S mutation, mutant alleles could also be detected in plasma using both ddPCR and COBAS® System. Finally, when mutational status was studied using both genotyping techniques, higher mutant copies/ml and higher mutant allele fraction (MAF) correlated with higher Semiquantitative Index obtained by COBAS®.

Conclusions: Although tissue biopsies cannot be replaced due to the large amount of information they provide regarding tumor type and structure, liquid biopsy and ddPCR represents a new promising strategy for genetic analysis of tumors from plasma samples. In the present study, G719S mutation was detected in a highly sensitive manner, allowing its monitorization with a non-invasive technique.

Polyisoprenylated Cysteinyl Amide Inhibitors Deplete K-Ras and Induce Caspase-dependent Apoptosis in Lung Cancer Cells

BACKGROUND

Non-small cell lung cancers (NSCLC) harboring mutation-induced dysregulation of Ras signaling present some of the most difficult-to-manage cases, since directly targeting the constitutively active mutant Ras proteins has not resulted in clinically useful drugs. Therefore, modulating Ras activity for targeted treatment of cancer remains an urgent healthcare need.

OBJECTIVE

In the current study, we investigated a novel class of compounds, the polyisoprenylated cysteinyl amide inhibitors (PCAIs), for their anticancer molecular mechanisms using the NSCLC cell panel with K-Ras and/or other mutant genes.

METHODS

The effect of the PCAIs on intracellular K-Ras levels, cell viability, apoptosis, spheroid and colony formation were determined.

RESULTS

Treatment of the lung cancer cells with the PCAIs, NSL-RD-035, NSL-BA-036, NSL-BA- 040 and NSL-BA-055 resulted in concentration-dependent cell death in both K-Ras mutant (A549, NCI-H460, and NCI-H1573), N-Ras mutant (NCI-H1299) and other (NCI-H661, NCI-H1975, NCIH1563) NSCLC cells. The PCAIs at 1.0 -10 μM induced the degeneration of 3D spheroid cultures, inhibited clonogenic cell growth and induced marked apoptosis via the extrinsic pathway. The most potent of the PCAIs, NSL-BA-055, at 5 μM induced a seven-fold increase in the activity of caspase- 3/7 and a 75% selective depletion of K-Ras protein levels relative to GAPDH in A549 cells that correlated with PCAIs-induced apoptosis. NSL-BA-040 and NSL-BA-055 also induced the phosphorylation of MAP kinase (ERK 1/2).

CONCLUSION

Taken together, PCAIs may be potentially useful as targeted therapies that suppress NSCLC progression through disruption of Ras-mediated growth signaling.

The prognostic value of Kirsten rat sarcoma viral oncogene homolog mutations in resected lung adenocarcinoma differs according to clinical features

BACKGROUND

The ninth edition of lung cancer staging system recommends that specific driver mutations should be considered as prognostic factors in survival models. This study comprehensively investigated the prognostic value of Kirsten rat sarcoma viral oncogene homolog (KRAS) mutation in patients with resected lung adenocarcinomas according to different clinicopathologic and radiologic characteristics.

METHODS

In total, 1464 patients with completely resected primary lung adenocarcinomas were examined for KRAS mutations from November 2008 to March 2015. Age, sex, smoking status, performance status, tumor-node-metastasis stage, radiologic features, and histologic subtypes were collected. Competing risk model was used to estimate the cumulative incidence rate of recurrence. Cox regression multivariable analyses on recurrence-free survival (RFS) and overall survival (OS) were performed.

RESULTS

KRAS mutations were more frequent in male subjects (P < .001), current/former smokers (P < .001), invasive mucinous adenocarcinoma (P < .001), and solid tumors (P < .001). In general, KRAS-mutated patients had greater cumulative recurrence rate (hazard ratio [HR], 1.95; 95% confidence interval [CI], 1.23-3.08; P < .001) and worse overall survival (OS; HR, 1.88; 95% CI, 1.23-2.87; P < .001) than KRAS wild-type patients. The OS (P < .001) of patients harboring KRAS-G12C/V mutations was shorter than that of other KRAS-mutated patients. Cox multivariable analyses demonstrated that KRAS mutations were independently associated with worse RFS (HR, 5.34; 95% CI, 2.53-11.89; P = .001) and OS (HR, 2.63; 95% CI, 1.03-6.76; P = .044) in part-solid lung adenocarcinomas. For stage I patients, Cox multivariable analyses revealed that KRAS mutation was an independent risk factor for RFS (HR, 2.05; 95% CI, 1.19-3.56; P = .010) and OS (HR, 2.38; 95% CI, 1.29-4.40; P = .005).

CONCLUSIONS

In this study, we revealed that KRAS mutations was an independent prognostic factor in part-solid tumors and in stage I lung adenocarcinomas. These findings may contribute to the ninth edition of lung cancer staging project.

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.

Rationale for Lung Adenocarcinoma Prevention and Drug Development Based on Molecular Biology During Carcinogenesis

Lung adenocarcinoma (LUAD) is the most common and aggressive subtype of lung cancer with the greatest heterogeneity and aggression. Inspite of recent years’ achievements in understanding the pathogenesis of this disease, as well as the development of new therapeutic approaches, our knowledge on crucial early molecular events during its development is still rudimentary. Recent classification and grading of LUAD has postulated that LUAD does not arise spontaneously, but through a stepwise process from lung adenomatous premalignancy atypical adenomatous hyperplasia to adenocarcinoma in situ, minimally invasive adenocarcinoma, and eventually frankly invasive predominant adenocarcinoma. In this review, we discuss the molecular processes that drive the evolutionary process that results in the formation of LUAD. We also describe how to handle lung premalignancy in clinical settings based on the most recent advances in genomic biology and our own understanding of lung cancer prevention.

Incidence of ROS1-Rearranged Non-Small-Cell Lung Carcinoma in India and Efficacy of Crizotinib in Lung Adenocarcinoma Patients

BACKGROUND

The ROS1 gene is a member of the "sevenless" subfamily of tyrosine-kinase insulin-receptor genes. ROS1-fusion rearrangement causes constitutive downstream signal transduction, with an oncogenic role in non-small-cell lung carcinoma (NSCLC). Fortunately, crizotinib, an ALK1 tyrosine-kinase inhibitor, provides long-term disease control. The objective of this molecular epidemiological study was to estimate the frequency of ROS1 rearrangements and evaluate treatment outcomes with crizotinib therapy.

METHODS

Patients with stage IV NSCLC adenocarcinoma histology were considered for this study. The study was conducted according to the ethical principles stated in the latest version of the Declaration of Helsinki and the applicable guidelines for good clinical practice. Clinical characteristics and treatment details were collected from patients' medical records.

RESULTS

A total of 709 stage IV NSCLC adenocarcinoma patients were included in the study. There were 457 (64.46%) men and 252 (35.54%) women, with a median age of 60 years. ROS1-gene rearrangement was positive in 20 (2.82%) cases, 13 using Fluorescent In-Situ Hybridization (FISH), and two and five cases, respectively, using immunohistochemistry (IHC) and next-generation sequencing (NGS), followed by confirmation with FISH. Fourteen of the 20 patients with ROS1-gene rearrangement received crizotinib therapy, with an objective response rate of 64.28%. At a median follow-up of 6 months, the study had not achieved the end points of median progression free survival and overall survival.

CONCLUSION

ROS1-gene rearrangement was present at a relatively higher frequency of 2.8% in north Indian patients with lung adenocarcinoma and was successfully targeted by crizotinib therapy. Although the only US Food and Drug Administration and Conformité Européenne approved method for testing ROS1 rearrangement is NGS, FISH alone or IHC with D4D6 antibody as initial screen with subsequent confirmation of IHC-positive cases by FISH are cost-effective methods in institutions lacking NGS facilities.

Drug Combinatorial Therapies for the Treatment of KRAS Mutated Lung Cancers

KRAS is the most common oncogene to be mutated in lung cancer, and therapeutics directly targeting KRAS have proven to be challenging. The mutations of KRAS are associated with poor prognosis, and resistance to both adjuvant therapy and targeted EGFR TKI. EGFR TKIs provide significant clinical benefit for patients whose tumors bear EGFR mutations. However, tumors with KRAS mutations rarely respond to the EGFR TKI therapy. Thus, combination therapy is essential for the treatment of lung cancers with KRAS mutations. EGFR TKI combined with inhibitors of MAPKs, PI3K/mTOR, HDAC, Wee1, PARP, CDK and Hsp90, even miRNAs and immunotherapy, were reviewed. Although the effects of the combination vary, the combined therapeutics are one of the best options at present to treat KRAS mutant lung cancer.

Non-Small Cell Lung Cancer Patients Harboring HER2 Mutations: Clinical Characteristics and Management in a Real-Life Setting. Cohort HER2 EXPLORE GFPC 02-14

Background

Mutation of human receptor tyrosine kinase epidermal growth factor receptor-2 (HER2) is a rare event, found in approximately 1% non-small cell lung cancers (NSCLC). The objective was to investigate the clinical characteristics and management of HER2-mutated NSCLCs in a real-life setting.

Methods

This multicenter study described NSCLCs harboring HER2 mutations diagnosed between January 2012 and December 2014, according their clinical characteristics, management, and outcomes: response rate (RR), progression-free survival (PFS), and overall survival (OS).

Results

Thirty patients were included: 66.7% women; median age 65.2 ± 12 years; never or former smokers 73.3%. Of the stage IV patients (n = 23), 86% received first-line platin doublet chemotherapy: RR 61.5% and PFS 6.7 (95% CI 5.9–9.5) months; 52.1% received a second-line therapy: RR 18.2% and PFS 4.9 (95% CI 2.5–11.9) months. Median OS of stage IV was 10.7 months and 2-year OS was 27.2% (95% CI 11.7–63.2). All patients with stage I–III NSCLCs were alive at 2 years.

Conclusion

The rarity of HER2-mutated NSCLCs requires specific studies.

Restoration of mutant K-Ras repressed miR-199b inhibits K-Ras mutant non-small cell lung cancer progression

BACKGROUND

miRNAs play crucial role in the progression of K-Ras-mutated nonsmall cell lung cancer (NSCLC). However, most studies have focused on miRNAs that target K-Ras. Here, we investigated miRNAs regulated by mutant K-Ras and their functions.

METHODS

miRNAs regulated by mutant K-Ras were screened using miRNA arrays. miR-199b expression levels were measured by qRT-PCR. The protein expression levels were measured using Western blot and immunohistochemistry. The effects of miR-199b on NSCLC were examined both in vitro and in vivo by overexpressing or inhibiting miR-199b. DNA methylation was measured by bisulfite sequencing.

RESULTS

An inverse correlation was observed between K-Ras mutation status and miR-199b levels in NSCLC specimens and cell lines. The inhibition of miR-199b stimulated NSCLC growth and metastasis, while restoration of miR-199b suppressed K-Ras mutation-driven lung tumorigenesis as well as K-Ras-mutated NSCLC growth and metastasis. miR-199b inactivated ERK and Akt pathways by targeting K-Ras, KSR2, PIK3R1, Akt1, and Rheb1. Furthermore, we determined that mutant K-Ras inhibits miR-199b expression by increasing miR-199b promoter methylation.

CONCLUSION

Our findings suggest that mutant K-Ras plays an oncogenic role through downregulating miR-199b in NSCLC and that overexpression of miR-199b is a novel strategy for the treatment of K-Ras-mutated NSCLC.

Managing Resistance to EFGR- and ALK-Targeted Therapies

Targeted therapies have transformed the management of non-small cell lung cancer (NSCLC) and placed an increased emphasis on stratifying patients on the basis of genetic alterations in oncogenic drivers. To date, the best characterized molecular targets in NSCLC are the epidermal growth factor receptor (EGFR) and anaplastic lymphoma kinase (ALK). Despite steady advances in targeted therapies within these molecular subsets, however, acquired resistance to therapy is near universal. Recent preclinical models and translational efforts have provided critical insights into the molecular mechanisms of resistance to EGFR and ALK inhibitors. In this review, we present a framework for understanding resistance to targeted therapies. We also provide overviews of the molecular mechanisms of resistance and strategies to overcome resistance among EGFR-mutant and ALK-rearranged lung cancers. To date, these strategies have centered on the development of novel next-generation inhibitors, rationale combinations, and use of local ablative therapies, such as radiotherapy.

Recurrent and pathological gene fusions in breast cancer: current advances in genomic discovery and clinical implications

Gene fusions have long been considered principally as the oncogenic events of hematologic malignancies, but have recently gained wide attention in solid tumors due to several milestone discoveries and the advancement of deep sequencing technologies. With the progress in deep sequencing studies of breast cancer transcriptomes and genomes, the discovery of recurrent and pathological gene fusions in breast cancer is on the focus. Recently, driven by new deep sequencing studies, several recurrent or pathological gene fusions have been identified in breast cancer, including ESR1-CCDC170, SEC16A-NOTCH1, SEC22B-NOTCH2, and ESR1-YAP1 etc. More important, most of these gene fusions are preferentially identified in the more aggressive breast cancers, such as luminal B, basal-like, or endocrine-resistant breast cancer, suggesting recurrent gene fusions as additional key driver events in these tumors other than the known drivers such as the estrogen receptor. In this paper, we have comprehensively summarized the newly identified recurrent or pathological gene fusion events in breast cancer, reviewed the contributions of new genomic and deep sequencing technologies to new fusion discovery and the integrative bioinformatics tools to analyze these data, highlighted the biological relevance and clinical implications of these fusion discoveries, and discussed future directions of gene fusion research in breast cancer.

The Difference of Clinical Characteristics Between Patients With Exon 19 Deletion and Those With L858R Mutation in Nonsmall Cell Lung Cancer

Recent studies have demonstrated that exon 19 deletion (19 Del) and exon 21 L858R mutation (L858R) are 2 different types of sensitive epidermal growth factor receptor (EGFR) mutations in nonsmall cell lung cancer (NSCLC). However, whether there are some differences between those 2 groups in baseline clinical characteristics is still unclear.We enrolled consecutive 1271 NSCLC patients detected with either 19 Del or L858R and collected their baseline clinical characteristics including age, sex, comorbidity, smoking and drinking status, body mass index (BMI), TNM stage, histologic type, differentiation, tumor maximum diameter (TMD), and CEA level. χ test and multivariate logistic regression analysis were used to compare the difference.We found a higher percentage of 19 Del in younger patients group (< = 50 yr) than L858R (P < 0.001) through χ test. Besides, patients with 19 Del have higher risk of lymph node metastasis (P < 0.001). However, there were no significant differences in other items of clinical characteristics between 19 Del and L858R. Multivariate analysis showed similar significant results. Subgroup analysis in different age groups (10 yr as an interval) and N stages (stratified by N0, N1, N2, and N3) also indicated above-mentioned trends.NSCLC patients with 19 Del are more likely to be young and have lymphatic metastasis than those with L858R. Age and N stage might be considered in predicting EGFR mutation type in NSCLC.

Epidermal growth factor receptor gene mutations in patients with lung adenocarcinoma differ by frequency and type between Uighur and Han ethnic groups in Xinjiang Autonomous Region

Background

This study was designed to investigate epidermal growth factor receptor (EGFR) mutation types affecting lung cancer treatment in patients in Xinjiang, China. We detected and analyzed differences in the EGFR mutation points of Uighur and Han patients with lung adenocarcinoma. We examined 181 specimens of lung adenocarcinoma tissue embedded with paraffin (76 Uighur and 105 Han patients) for mutations in the EGFR gene in exon 18-21 by the amplification refractory mutation system (ARMS) method. We used the chi-square statistical method to analyze the relationship between mutations and patients’ clinical parameters.

Results

EGFR somatic mutations were detected in 59 of 181 cases (32.6%). The mutation rate was higher in Han patients (45.7%) than in Uighur patients (15.8%) (P < 0.001). The main mutation types were the exon 19 deletion and the L858R point mutation in exon 21. In Han patients we found 21 (44.7%) cases of exon 19 deletion, 24 (51.1%) cases of L858R in exon 21, 1 case (2.1%) with mutations in both exon 19 and exon 21, and 1 case (2.1%) with T790 mutation in exon 20. In Uighur patients we found 8 (66.7%) cases of exon 19 deletion and 4 (33.3%) cases of L858R in exon 21.

Conclusions

In comparing these groups, the exon 19 deletion was more common than L858R in exon 21 in Uighur patients. In Han patients, EGFR-sensitive mutations occurred in female, never-smoking patients with well-differentiated tumors; but for Uighur patients only smoking history showed an obvious correlation.

Tyrosine kinase gene rearrangements in epithelial malignancies

Chromosomal rearrangements that lead to oncogenic kinase activation are observed in many epithelial cancers. These cancers express activated fusion kinases that drive the initiation and progression of malignancy, and often have a considerable response to small-molecule kinase inhibitors, which validates these fusion kinases as 'druggable' targets. In this Review, we examine the aetiologic, pathogenic and clinical features that are associated with cancers harbouring oncogenic fusion kinases, including anaplastic lymphoma kinase (ALK), ROS1 and RET. We discuss the clinical outcomes with targeted therapies and explore strategies to discover additional kinases that are activated by chromosomal rearrangements in solid tumours.

Emerging options for the management of non-small cell lung cancer

Lung cancer is one of the leading causes of death in industrialized and developing countries. Approximately 80% of patients are diagnosed with non-small cell histology. Although a multidisciplinary approach is necessary for the treatment of patients at early or locally-advanced stages of the disease, further successes in the treatment of patients with advanced disease will largely rely on improved systemic tumor control. Although therapies directed against the epidermal growth factor receptor (EGFR) have been incorporated into daily clinical practice, the value of other treatments remains to be elucidated. The current review highlights the most important driver mutations in non-small cell lung cancer (NSCLC) and describes recent study results and the status of EGFR-directed therapy, anaplastic lymphoma kinase (ALK)-directed agents, antiangiogenic therapy, and mesenchymal-epithelial transition factor (MET) inhibitors. However, many other agents with different modes of action are being examined in clinical research.

Second-Line Therapy for Advanced NSCLC

Most patients with lung cancer have non-small cell lung cancer (NSCLC) subtype and have advanced disease at the time of diagnosis. Improvements in both first-line and subsequent therapies are allowing longer survival and enhanced quality of life for these patients. The median overall survival observed in many second-line trials is approximately 9 months, and many patients receive further therapy after second-line therapy. The cytotoxic agents pemetrexed and docetaxel and the epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) erlotinib and gefitinib are standard second-line therapies. For patients with EGFR mutation, a TKI is the favored second-line therapy if not already used in first-line therapy. For patients without the EGFR mutation, TKIs are an option, but many oncologists favor cytotoxic therapy. The inhibitor of the EML4/ALK fusion protein, crizotinib, has recently become a standard second-line treatment for patients with the gene rearrangement and has promise for patients with the ROS1 rearrangement.

From targets to targeted therapies and molecular profiling in non-small cell lung carcinoma

Although tumor molecular-profile-directed therapy appears promising in early clinical studies, there are many practical challenges to its successful clinical application in non-small-cell lung cancer (NSCLC). These challenges may be broadly classified as those relating to tumor (heterogeneity), tissue (acquisition and processing), testing (assays for molecular profiling) and trials (clinical evaluation of molecular markers and drugs). Strategies to overcome these challenges include (i) understanding the biological basis of tumor heterogeneity and of carcinogenesis in the large subset of patients with no currently evident driver events; (ii) technological advances in minimally invasive acquisition of tumor and next-generation sequencing (NGS) which would enable single-platform analysis of molecular alterations in limited tissue at a reasonable turnaround time (TAT); (iii) deliberation in early stages of drug development as well as clinical trial design to identify, validate and assess the clinical utility of biomarkers in conjunction with drugs and (iv) collaboration to improve understanding of and accrual to trials enrolling patients with rare molecular alterations.

The role of MET receptor tyrosine kinase in non-small cell lung cancer and clinical development of targeted anti-MET agents

A better understanding of the pathophysiology and evolution of non-small cell lung cancer (NSCLC) has identified a number of molecular targets and spurred development of novel targeted therapeutic agents. The MET receptor tyrosine kinase and its ligand hepatocyte growth factor (HGF) are implicated in tumor cell proliferation, migration, invasion, and angiogenesis in a broad spectrum of human cancers, including NSCLC. Amplification of MET has been reported in approximately 5%-22% of lung tumors with acquired resistance to small-molecule inhibitors of the epidermal growth factor receptor (EGFR). Resistance to EGFR inhibitors is likely mediated through downstream activation of the phosphoinositide 3-kinase /AKT pathway. Simultaneous treatment of resistant tumors with a MET inhibitor plus an EGFR inhibitor can abrogate activation of downstream effectors of cell growth, proliferation, and survival, thereby overcoming acquired resistance to EGFR inhibitors. Development and preclinical testing of multiple agents targeting the HGF-MET pathway, including monoclonal antibodies targeting HGF or the MET receptor and small-molecule inhibitors of the MET tyrosine kinase, have confirmed the crucial role of this pathway in NSCLC. Several agents are now in phase III clinical development for the treatment of NSCLC. This review summarizes the role of MET in the pathophysiology of NSCLC and in acquired resistance to EGFR inhibitors and provides an update on progress in the clinical development of inhibitors of MET for treatment of NSCLC.

Impact of genetic markers on treatment of non-small cell lung cancer

Non-small cell lung cancer represents a group of heterogeneous diseases. The last decade witnessed significant progress in improving our understanding of the biology of non-small cell lung cancer, which led to the identification of several genetic targets. Those genetic targets were utilized to explain clinical phenomena, such as the occurrence of non-small cell lung cancer in never-smokers, to predict response to conventional chemotherapy and biological agents, and to explain and predict resistance to therapy. The progress in the treatment of non-small cell lung cancer in the last few years was based on a new generation of population-enriched clinical trials that utilized genetic targets such as somatic EGFR mutations and ALK-EML4 mutations. In this review we will discuss the available information about the key genetic markers of non-small cell lung cancer and the pivotal clinical trials that validate the use of those genetic markers in non-small cell lung cancer patients.

Crizotinib for the treatment of ALK-rearranged non-small cell lung cancer: a success story to usher in the second decade of molecular targeted therapy in oncology

Crizotinib, an ALK/MET/ROS1 inhibitor, was approved by the U.S. Food and Drug Administration for the treatment of anaplastic lymphoma kinase (ALK)-rearranged non-small cell lung cancer (NSCLC) in August 2011, merely 4 years after the first publication of ALK-rearranged NSCLC. The crizotinib approval was accompanied by the simultaneous approval of an ALK companion diagnostic fluorescent in situ hybridization assay for the detection of ALK-rearranged NSCLC. Crizotinib continued to be developed as an ALK and MET inhibitor in other tumor types driven by alteration in ALK and MET. Crizotinib has recently been shown to be an effective ROS1 inhibitor in ROS1-rearranged NSCLC, with potential future clinical applications in ROS1-rearranged tumors. Here we summarize the heterogeneity within the ALK- and ROS1-rearranged molecular subtypes of NSCLC. We review the past and future clinical development of crizotinib for ALK-rearranged NSCLC and the diagnostic assays to detect ALK-rearranged NSCLC. We highlight how the success of crizotinib has changed the paradigm of future drug development for targeted therapies by targeting a molecular-defined subtype of NSCLC despite its rarity and affected the practice of personalized medicine in oncology, emphasizing close collaboration between clinical oncologists, pathologists, and translational scientists.

Oncogenic KRAS-induced epiregulin overexpression contributes to aggressive phenotype and is a promising therapeutic target in non-small-cell lung cancer

KRAS mutations are one of the most common driver mutations in non-small-cell lung cancer (NSCLC) and finding druggable target molecules to inhibit oncogenic KRAS signaling is a significant challenge in NSCLC therapy. We recently identified epiregulin (EREG) as one of several putative transcriptional targets of oncogenic KRAS signaling in both KRAS-mutant NSCLC cells and immortalized bronchial epithelial cells expressing ectopic mutant KRAS. In the current study, we found that EREG is overexpressed in NSCLCs harboring KRAS, BRAF or EGFR mutations compared with NSCLCs with wild-type KRAS/BRAF/EGFR. Small interfering RNAs (siRNAs) targeting mutant KRAS, but not an siRNA targeting wild-type KRAS, significantly reduced EREG expression in KRAS-mutant and EREG-overexpressing NSCLC cell lines. In these cell lines, EREG expression was downregulated by MEK and ERK inhibitors. Importantly, EREG expression significantly correlated with KRAS expression or KRAS copy number in KRAS-mutant NSCLC cell lines. Further expression analysis using 89 NSCLC specimens showed that EREG was predominantly expressed in NSCLCs with pleural involvement, lymphatic permeation or vascular invasion and in KRAS-mutant adenocarcinomas. In addition, multivariate analysis revealed that EREG expression is an independent prognostic marker and EREG overexpression in combination with KRAS mutations was associated with an unfavorable prognosis for lung adenocarcinoma patients. In KRAS-mutant and EREG overexpressing NSCLC cells, siRNA-mediated EREG silencing inhibited anchorage-dependent and -independent growth and induced apoptosis. Our findings suggest that oncogenic KRAS-induced EREG overexpression contributes to an aggressive phenotype and could be a promising therapeutic target in oncogenic KRAS-driven NSCLC.

Molecular pathology of non-small cell lung cancer: a practical guide

The traditional distinction between small cell lung cancer and non-small cell lung cancer (NSCLC) is no longer sufficient for treatment planning. It is advised to handle small diagnostic specimens prudently because they are often the only specimen available for molecular analysis. Pathologists are experiencing pressure to subclassify lung carcinoma based on extremely small tumor samples, because NSCLC tumor subtyping is now essential to determine molecular testing strategies. Evaluation for EGFR mutations and ALK rearrangements are now considered to be the standard of care in advanced-stage pulmonary adenocarcinomas. Immunohistochemical stains can aid in subclassifying NSCLC, but performing these ancillary studies can significantly reduce the quantity of tissue available for molecular tests, requiring careful balancing of these 2 needs. The pathologist plays a pivotal role in facilitating clear and timely communication between the clinical oncology care team and the molecular laboratory to ensure that the appropriate tests are ordered and optimal material is submitted for testing.

Treating ALK-positive lung cancer--early successes and future challenges

Rearrangements of the anaplastic lymphoma kinase (ALK) gene occur infrequently in non-small-cell lung cancer (NSCLC), but provide an important paradigm for oncogene-directed therapy in this disease. Crizotinib, an orally bioavailable inhibitor of ALK, provides significant benefit for patients with ALK-positive (ALK+) NSCLC in association with characteristic, mostly mild, toxic effects, and this drug has been approved by the FDA for clinical use in this molecularly defined subgroup of lung cancer. Many new ALK inhibitors are being developed and understanding the challenges of determining and addressing the adverse effects that are likely to be ALK specific, while maximizing the time of benefit on targeted agents, and understanding the mechanisms that underlie drug resistance will be critical in the future for informing the optimal therapy of ALK+ NSCLC.

The cost-effectiveness of screening lung cancer patients for targeted drug sensitivity markers

BACKGROUND

New oncology drugs are being developed in conjunction with companion diagnostics with approval restricting their use to certain biomarker-positive subgroups. We examined the impact of different predictive biomarker screening techniques and population enrichment criteria on the cost-effectiveness of targeted drugs in lung cancer, using ALK and crizotinib to build the initial model.

METHODS

Health economic modeling of cost per Quality Adjusted Life Year was based on literature review and expert opinion. The modeled population represented advanced non-small cell lung cancer (NSCLC), eligible for predictive biomarker screening with prescribing restricted to biomarker-positive patients.

RESULTS

For assays costing $1400 per person, cost per quality-adjusted life year (QALY) gained for ALK screening all advanced NSCLC, excluding treatment cost, is $106,707. This falls to $4756 when only a highly enriched population is screened (increasing biomarker frequency from 1.6 to 35.9%). However, the same enrichment involves missing 56% patients who segregate within the unscreened group. Cheaper screening tests that miss some true positives can be more cost-effective if proportional reductions in cost exceed proportion of subjects missed. Generic modeling of idealised screening assays, including treatment cost, reveals a dominant effect of screening cost per person at low biomarker frequencies. Cost-effectiveness of <$100,000 per QALY gained is not achievable at biomarker frequencies <5% (with drug costs $1-5000 per month and screening costs $600-1400 per person).

INTERPRETATION

Cost-effectiveness of oncology drugs whose prescribing is restricted to biomarker-positive subgroups should address the cost of detecting marker-positive patients. The cost of screening dominates at low frequencies and strategies to improve cost-effectiveness based on the assay cost, drug cost and the group screened should be considered in these scenarios.