Molecular characteristics of bronchioloalveolar carcinoma and adenocarcinoma, bronchioloalveolar carcinoma subtype, predict response to erlotinib

GMILT: A Novel Transformer Network That Can Noninvasively Predict EGFR Mutation Status

Noninvasively and accurately predicting the epidermal growth factor receptor (EGFR) mutation status is a clinically vital problem. Moreover, further identifying the most suspicious area related to the EGFR mutation status can guide the biopsy to avoid false negatives. Deep learning methods based on computed tomography (CT) images may improve the noninvasive prediction of EGFR mutation status and potentially help clinicians guide biopsies by visual methods. Inspired by the potential inherent links between EGFR mutation status and invasiveness information, we hypothesized that the predictive performance of a deep learning network can be improved through extra utilization of the invasiveness information. Here, we created a novel explainable transformer network for EGFR classification named gated multiple instance learning transformer (GMILT) by integrating multi-instance learning and discriminative weakly supervised feature learning. Pathological invasiveness information was first introduced into the multitask model as embeddings. GMILT was trained and validated on a total of 512 patients with adenocarcinoma and tested on three datasets (the internal test dataset, the external test dataset, and The Cancer Imaging Archive (TCIA) public dataset). The performance (area under the curve (AUC) =0.772 on the internal test dataset) of GMILT exceeded that of previously published methods and radiomics-based methods (i.e., random forest and support vector machine) and attained a preferable generalization ability (AUC =0.856 in the TCIA test dataset and AUC =0.756 in the external dataset). A diameter-based subgroup analysis further verified the efficiency of our model (most of the AUCs exceeded 0.772) to noninvasively predict EGFR mutation status from computed tomography (CT) images. In addition, because our method also identified the "core area" of the most suspicious area related to the EGFR mutation status, it has the potential ability to guide biopsies.

Clinical practice guidelines for molecular tumor markers, 2nd edition review part 1

With advances in gene and protein analysis technologies, many target molecules that may be useful in cancer diagnosis have been reported. Therefore, the "Tumor Marker Study Group" was established in 1981 with the aim of "discovering clinically" useful molecules. Later, the name was changed to "Japanese Society for Molecular Tumor Marker Research" in 2000 in response to the remarkable progress in gene-related research. Currently, the world of cancer treatment is shifting from the era of representative tumor markers of each cancer type used for tumor diagnosis and treatment evaluation to the study of companion markers for molecular-targeted therapeutics that target cancer cells. Therefore, the first edition of the Molecular Tumor Marker Guidelines, which summarizes tumor markers and companion markers in each cancer type, was published in 2016. After publication of the first edition, the gene panel testing using next-generation sequencing became available in Japan in June 2019 for insured patients. In addition, immune checkpoint inhibitors have been indicated for a wide range of cancer types. Therefore, the 2nd edition of the Molecular Tumor Marker Guidelines was published in September 2021 to address the need to revise the guidelines. Here, we present an English version of the review (Part 1) of the Molecular Tumor Marker Guidelines, Second Edition.

First-in-Humans PET Imaging of KRASG12C Mutation Status in Non-Small Cell Lung and Colorectal Cancer Patients Using [18F]PFPMD

Kirsten rat sarcoma (KRAS) mutations are an important marker for tumor-targeted therapy. In this study, we sought to develop a KRASG12C oncoprotein-targeted PET tracer and to evaluate its translational potential for noninvasive imaging of the KRASG12C mutation in non-small cell lung cancer (NSCLC) and colorectal cancer (CRC) patients. Methods: [18F]PFPMD was synthesized on the basis of AMG510 (sotorasib) by attaching a polyethylene glycol chain to the quinazolinone structure. The binding selectivity and imaging potential of [18F]PFPMD were verified by cellular uptake, internalization, and blocking (H358: KRASG12C mutation; A549: non-KRASG12C mutation) studies, as well as by a small-animal PET/CT imaging study on tumor-bearing mice. Five healthy volunteers were enrolled to assess the safety, biodistribution, and dosimetry of [18F]PFPMD. Subsequently, 14 NSCLC or CRC patients with or without the KRASG12C mutation underwent [18F]PFPMD and [18F]FDG PET/CT imaging. The SUVmax of tumor uptake of [18F]PFPMD was measured and compared between patients with and without the KRASG12C mutation. Results: [18F]PFPMD was obtained with a high radiochemical yield, radiochemical purity, and stability. The protein-binding assay showed that [18F]PFPMD selectively binds to the KRASG12C protein. [18F]PFPMD uptake was significantly higher in H358 than in A549 and was decreased by pretreatment with AMG510 (H358 vs. A549: 3.22% ± 0.28% vs. 2.50% ± 0.25%, P < 0.05; block: 2.06% ± 0.13%, P < 0.01). Similar results were observed in tumor-bearing mice on PET imaging (H358 vs. A549: 3.93% ± 0.24% vs. 2.47% ± 0.26% injected dose/g, P < 0.01; block: 2.89% ± 0.29% injected dose/g; P < 0.05). [18F]PFPMD was safe in humans and was excreted primarily by the gallbladder and intestines. The whole-body effective dose was comparable to that of [18F]FDG. The accumulation of [18F]PFPMD in KRASG12C mutation tumors was significantly higher than that in non-KRASG12C mutation tumors (SUVmax: 3.73 ± 0.58 vs. 2.39 ± 0.22, P < 0.01) in NSCLC and CRC patients. Conclusion: [18F]PFPMD is a safe and promising PET tracer for noninvasive screening of the KRASG12C mutation status in NSCLC and CRC patients.

Optimizing the Treatment for Advanced Non-Small-Cell Lung Cancer with Mutated Epidermal Growth Factor Receptor in Low-Income Countries: A Review

Introduction

Osimertinib is the treatment of choice for epidermal growth factor receptor (EGFR)-mutated advanced non-small-cell lung cancer (NSCLC). Because of its high price, many low-income countries, such as Syria, cannot provide osimertinib, which makes it difficult to choose the appropriate treatment for these patients. This study aimed to review articles that assessed tyrosine kinase inhibitors (TKIs) for advanced NSCLC and developed an appropriate treatment plan for Syrian patients.

Methods

An electronic literature search was conducted of published phase II and III studies that assessed the efficacy of EGFR-TKIs for advanced NSCLC between January 2003 and May 2022.

Results

Seventeen articles were reviewed. The results were similar when erlotinib or icotinib was compared with gefitinib. Progression-free survival and overall survival for afatinib and dacomitinib were longer than for gefitinib, with small significant differences. Osimertinib was the only TKI that showed efficacy against the T790M mutation, which showed an improvement over the first- and second-generation TKIs. Osimertinib as a first-line therapy is not cost-effective compared with first- and second-generation TKIs.

Conclusion

Osimertinib is the preferred first-line treatment in patients with advanced EGFR-mutated NSCLC. First- and second-generation TKIs are still considered good options, especially in low-income countries that cannot cover the costs of osimertinib.

Deep learning analysis to predict EGFR mutation status in lung adenocarcinoma manifesting as pure ground-glass opacity nodules on CT

Background

Epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) showed potency as a non-invasive therapeutic approach in pure ground-glass opacity nodule (pGGN) lung adenocarcinoma. However, optimal methods of extracting information about EGFR mutation from pGGN lung adenocarcinoma images remain uncertain. We aimed to develop, validate, and evaluate the clinical utility of a deep learning model for predicting EGFR mutation status in lung adenocarcinoma manifesting as pGGN on computed tomography (CT).

Methods

We included 185 resected pGGN lung adenocarcinomas in the primary cohort. The patients were divided into training (n = 125), validation (n = 23), and test sets (n = 37). A preoperative CT-based deep learning model with clinical factors as well as clinical and radiomics models was constructed and applied to the test set. We evaluated the clinical utility of the deep learning model by applying it to 83 GGNs that received EGFR-TKI from an independent cohort (clinical validation set), and treatment response was regarded as the reference standard.

Results

The prediction efficiencies of each model were compared in terms of area under the curve (AUC). Among the 185 pGGN lung adenocarcinomas, 122 (65.9%) were EGFR-mutant and 63 (34.1%) were EGFR-wild type. The AUC of the clinical, radiomics, and deep learning with clinical models to predict EGFR mutations were 0.50, 0.64, and 0.85, respectively, for the test set. The AUC of deep learning with the clinical model in the validation set was 0.72.

Conclusions

Deep learning approach of CT images combined with clinical factors can predict EGFR mutations in patients with lung adenocarcinomas manifesting as pGGN, and its clinical utility was demonstrated in a real-world sample.

Non-Small Cell Lung Cancer, Version 3.2022, NCCN Clinical Practice Guidelines in Oncology

NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines) for Non-Small Cell Lung Cancer (NSCLC) provide recommended management for patients with NSCLC, including diagnosis, primary treatment, surveillance for relapse, and subsequent treatment. Patients with metastatic lung cancer who are eligible for targeted therapies or immunotherapies are now surviving longer. This selection from the NCCN Guidelines for NSCLC focuses on targeted therapies for patients with metastatic NSCLC and actionable mutations.

The emergence of new prognostic scores in lung cancer patients with spinal metastasis: A 12-year single-center retrospective study

Objective: Lung cancer patients exhibit spinal metastases from a specific population, and with this study, we aimed to develop a model that can predict this particular group's survival.

Methods: Data were retrospectively collected from 83 lung cancer patients who underwent spinal metastasis surgery at our center from 2009 to 2021. After the initial assessment of treatment and scoring effects, a nomogram for survival prediction was created by identifying and integrating critical prognostic factors, followed by a consistency index (C-index) to measure consistency, and finally, a subject working characteristic curve (ROC) to compare the predictive accuracy of the three existing models.

Results: The mean postoperative survival was 14.7 months. Surgical treatment significantly improved the VAS and Frankel scores in lung cancer patients with spinal metastases. The revised Tokuhashi score underestimated the life expectancy of these patients. Six independent prognostic factors, including age, extraspinal bone metastasis foci, visceral metastasis, Frankel score, targeted therapy, and radiotherapy, were identified and incorporated into the model. Calibration curves for 3-, 6-, and 12-month overall survival showed a good concordance between predicted and actual risk. The nomogram C-index for the cohort study was 0.800 (95% confidence interval [CI]: 0.757-0.843). Model comparisons showed that the nomogram's prediction accuracy was better than revised Tokuhashi and Bauer's scoring systems.

Conclusions: Spine surgery offered patients the possibility of regaining neurological function. Having identified shortcomings in existing scoring systems, we have recreated and validated a new nomogram that can be used to predict survival outcomes in patients with spinal metastases from lung cancer, thereby assisting spinal surgeons in making surgical decisions and personalizing treatment for these patients.

Clinical Value of EGFR Copy Number Gain Determined by Amplicon-Based Targeted Next Generation Sequencing in Patients with EGFR-Mutated NSCLC

BACKGROUND

The clinical relevance of epidermal growth factor receptor (EGFR) copy number gain in patients with EGFR mutated advanced non-small cell lung cancer on first-line tyrosine kinase inhibitor treatment has not been fully elucidated.

OBJECTIVE

We aimed to estimate EGFR copy number gain using amplicon-based next generation sequencing data and explored its prognostic value.

PATIENTS AND METHODS

Next generation sequencing data were obtained for 1566 patients with non-small cell lung cancer. EGFR copy number gain was defined based on an increase in EGFR read counts relative to internal reference amplicons and normal controls in combination with a modified z-score ≥ 3.5. Clinical follow-up data were available for 60 patients treated with first-line EGFR-tyrosine kinase inhibitors.

RESULTS

Specificity and sensitivity of next generation sequencing-based EGFR copy number estimations were above 90%. EGFR copy number gain was observed in 27.9% of EGFR mutant cases and in 7.4% of EGFR wild-type cases. EGFR gain was not associated with progression-free survival but showed a significant effect on overall survival with an adjusted hazard ratio of 3.14 (95% confidence interval 1.46-6.78, p = 0.003). Besides EGFR copy number gain, osimertinib in second or subsequent lines of treatment and the presence of T790M at relapse revealed significant effects in a multivariate analysis with adjusted hazard ratio of 0.43 (95% confidence interval 0.20-0.91, p = 0.028) and 0.24 (95% confidence interval 0.1-0.59, p = 0.001), respectively.

CONCLUSIONS

Pre-treatment EGFR copy number gain determined by amplicon-based next generation sequencing data predicts worse overall survival in EGFR-mutated patients treated with first-line EGFR-tyrosine kinase inhibitors. T790M at relapse and subsequent treatment with osimertinib predict longer overall survival.

18F-fluorodeoxyglucose positron emission tomography/computed tomography-based radiomic features for prediction of epidermal growth factor receptor mutation status and prognosis in patients with lung adenocarcinoma

Background

To investigate whether radiomic features from (¹⁸F)-fluorodeoxyglucose positron emission tomography/computed tomography [(¹⁸F)-FDG PET/CT] can predict epidermal growth factor receptor (EGFR) mutation status and prognosis in patients with lung adenocarcinoma.

Methods

One hundred and seventy-four consecutive patients with lung adenocarcinoma underwent (¹⁸F)-FDG PET/CT and EGFR gene testing were retrospectively analyzed. Radiomic features combined with clinicopathological factors to construct a random forest (RF) model to identify EGFR mutation status. The mutant/wild-type model was trained on a training group (n=139) and validated in an independent validation group (n=35). The second RF classifier predicting the 19/21 mutation site was also built and evaluated in an EGFR mutation subset (training group, n=80; validation group, n=25). Radiomic score and 5 clinicopathological factors were integrated into a multivariate Cox proportional hazard (CPH) model for predicting overall survival (OS). AUC (the area under the receiver characteristic curve) and C-index were calculated to evaluate the model’s performance.

Results

Of 174 patients, 109 (62.6%) harbored EGFR mutations, 21L858R was the most common mutation type [55.9% (61/109)]. The mutant/wild-type model was identified in the training (AUC, 0.77) and validation (AUC, 0.71) groups. The 19/21 mutation site model had an AUC of 0.82 and 0.73 in the training and validation groups, respectively. The C-index of the CPH model was 0.757. The survival time between targeted therapy and chemotherapy for patients with EGFR mutations was significantly different (P=0.03).

Conclusions

Radiomic features based on (¹⁸F)-FDG PET/CT combined with clinicopathological factors could reflect genetic differences and predict EGFR mutation type and prognosis.

Near-infrared/pH dual-responsive nanocomplexes for targeted imaging and chemo/gene/photothermal tri-therapies of non-small cell lung cancer

Combination therapy offers promising opportunities for treating advanced non-small cell lung cancer (NSCLC). Here, we established a chitosan-based nanocomplex CE7Q/CQ/S to deliver molecular-targeted drug erlotinib (Er), Survivin shRNA-expressing plasmid (SV), and photothermal agent heptamethine cyanine dye (Cy7) in one platform for simultaneous near-infrared (NIR) fluorescence imaging and triple-combination therapy of NSCLC bearing epidermal growth factor receptor (EGFR) mutations. The obtained CE7Q/CQ/S exhibited favorable photothermal effects, good DNA binding ability, and pH/NIR dual-responsive release behaviors. The conjugated Er could mediate specific delivery of Cy7 to EGFR-mutated NSCLC cells to enable targeted NIR fluorescence imaging and photothermal therapy (PTT). The in vitro and in vivo results showed that downregulation of Survivin expression and the photothermal effects could act synergistically with Er to induce satisfactory anticancer effects in either Er-sensitive or Er-resistant EGFR-mutated NSCLC cells. By integrating chemo/gene/photothermal therapies into one theranostic nanoplatform, CE7Q/CQ/S could significantly suppress EGFR-mutated NSCLC, indicating its potential use in treating NSCLC. STATEMENT OF SIGNIFICANCE: The development of epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) has improved overall survival in patients with NSCLC driven by EGFR mutations. Unfortunately, the emergence of acquired resistance of EGFR-TKIs is almost inevitable after treatment. Here, we constructed a NIR/pH dual-responsive nanocomplex CE7Q/CQ/S based on chitosan which could integrate targeted near-infrared fluorescence imaging and chemo/gene/phototheramal tri-therapies together. We found that CE7Q/CQ/S possessed a promising outcome in fighting against EGFR-mutated NSCLC. The inhibition of Survivin expression and the application of photothermal therapy could act synergistically with erlotinib and reverse erlotinib resistance. The results of this work suggested that this chitosan-based combination therapeutic nanoplatform could be a promising candidate for NSCLC treatment.

Competitive Endogenous RNA Network Construction and Comparison of Lung Squamous Cell Carcinoma in Smokers and Nonsmokers

Background

Lung squamous cell carcinoma (LUSC) is a subtype of highly malignant lung cancer with poor prognosis, for which smoking is the main risk factor. However, the underlying genetic and molecular mechanisms of smoking-related LUSC remain largely unknown.

Methods

We mined existing LUSC-related mRNA, miRNA, and lncRNA transcriptome data and corresponding clinical data from The Cancer Genome Atlas (TCGA) database and divided them into smoking and nonsmoking groups, followed by differential expression analysis. Functional enrichment analysis of the unique differentially expressed mRNAs of the two groups was performed using the DAVID database. Subsequently, the lncRNA-miRNA-mRNA competing endogenous RNA (ceRNA) network of LUSC in smoking and nonsmoking groups was constructed. Finally, survival analyses were performed to determine the effects of differentially expressed lncRNAs/mRNAs/miRNAs that were involved in the ceRNA network on overall survival and to discover the hub genes.

Results

A total of 1696 lncRNAs, 125 miRNAs, and 3246 mRNAs and 1784 lncRNAs, 96 miRNAs, and 3229 mRNAs with differentially expressed profiles were identified in the smoking and nonsmoking groups, respectively. The ceRNA network and survival analysis revealed four lncRNAs (LINC00466, DLX6-AS1, LINC00261, and AGBL1), one miRNA (hsa-mir-210), and two mRNAs (CITED2 and ENPP4), with the potential as biomarkers for smoking-related LUSC diagnosis and prognosis.

Conclusion

Taken together, our research has identified the differences in the ceRNA regulatory networks between smoking and nonsmoking LUSC, which could lay the foundation for future clinical research.

Positive PD-L1 expression is predictive for patients with advanced EGFR wild-type non-small cell lung cancer treated with gemcitabine and cisplatin

This retrospective study aimed to investigate the association between programmed death ligand-1 (PD-L1) expression and the clinicopathological characteristics of patients with advanced epidermal growth factor receptor (EGFR) wild-type non-small cell lung cancer (NSCLC). The predictive role and cut-off value of PD-L1 expression was subsequently investigated. A total of 172 patients with advanced EGFR wild-type NSCLC were enrolled. All patients received platinum-based doublet chemotherapy (gemcitabine plus cisplatin). PD-L1 expression in lung tissues was assessed using immunohistochemical methods. The χ² test was used to analyze the association between PD-L1 expression and clinicopathological characteristics. Survival time analysis was performed using the Kaplan-Meier method. The two groups, positive PD-L1 expression and negative PD-L1 expression, were compared using the log-rank test. Multivariate analysis using the Cox proportional hazard regression model was conducted to determine prognostic factors for overall survival (OS) and progression-free survival (PFS) times. Positive PD-L1 expression was observed in 48.3% (84/172), 40.7% (70/172), 21.5% (37/172) and 8.1% (14/172) of patients when using cut-off values of 1, 5, 10 and 50%, respectively. The χ² test revealed that elevated pretreatment C-reactive protein (CRP) level and cancer stage IV were significantly associated with positive PD-L1 expression. The OS and PFS of positive PD-L1 (1, 5, 10 and 50% cut-off) expression group were shorter compared with the negative PD-L1 (1, 5, 10 and 50% cut-off) expression group. Multivariate survival analysis revealed that PD-L1 expression ≥50% was significantly associated with decreased OS and PFS [OS time, P=0.001; hazard ratio (HR), 2.768; 95% confidence interval (CI), 1.551–4.940; PFS time, P=0.002; HR, 2.537; 95% CI, 1.423–4.524]. These results indicated that positive PD-L1 (50% cut-off) expression was an independent predictor of poor prognosis for patients with advanced NSCLC treated with gemcitabine plus cisplatin. PD-L1 expression was associated with CRP level and cancer stage. The results obtained in the present study suggest that positive PD-L1 expression serves a prognostic role in advanced NSCLC and that the optimal cut-off value may be 50%.

Discordance of epidermal growth factor receptor mutation between primary lung tumor and paired distant metastases in non-small cell lung cancer: A systematic review and meta-analysis

Purpose

To evaluate the rate of discordance of epidermal growth factor receptor (EGFR) mutation between primary lung tumor and paired distant metastases in non-small-cell lung cancer (NSCLC).

Methods

We performed a meta-analysis of 17 studies (518 cases) assessing discordance rates of EGFR mutation in primary tumors and paired distant metastases. We performed subgroup analyses based on EGFR mutation status in primary tumor (mutant or wildtype), site of distant metastasis (bone, central nervous system (CNS) or lung/ pleural), methods of testing (direct sequencing or allele-specific testing) and timing of metastasis (synchronous or metachronous).

Results

The overall discordance rate in EGFR mutation was low at 10.36% (95% CI = 4.23% to 18.79%) and varied widely between studies (I² = 83.18%). The EGFR discordance rate was statistically significantly higher in bone metastases (45.49%, 95% CI = 14.13 to 79.02) than CNS (17.26%, 95% CI = 7.64 to 29.74; P = 0.002) and lung/ pleural metastases (8.17%, 95% CI = 3.35 to 14.85; P < 0.001). Subgroup analyses did not demonstrate any significant effect modification on the discordance rates by the EGFR mutation status in primary lung tumor, methods of testing and timing of metastasis.

Conclusion

The overall discordance rate in EGFR mutation between primary lung tumor and paired distant metastases in NSCLC is low, although higher discordance rates were observed in bone metastases compared with CNS and lung/pleural metastases. Future studies assessing the impact of EGFR mutation discordance on treatment outcomes are required.

Toward automatic prediction of EGFR mutation status in pulmonary adenocarcinoma with 3D deep learning

To develop a deep learning system based on 3D convolutional neural networks (CNNs), and to automatically predict EGFR‐mutant pulmonary adenocarcinoma in CT images. A dataset of 579 nodules with EGFR mutation status labels of mutant (Mut) or wild‐type (WT) was retrospectively analyzed. A deep learning system, namely 3D DenseNets, was developed to process 3D patches of nodules from CT data, and learn strong representations with supervised end‐to‐end training. The 3D DenseNets were trained with a training subset of 348 nodules and tuned with a development subset of 116 nodules. A strong data augmentation technique, mixup, was used for better generalization. We evaluated our model on a holdout subset of 115 nodules. An independent public dataset of 37 nodules from the cancer imaging archive (TCIA) was also used to test the generalization of our method. Conventional radiomics analysis was also performed for comparison. Our method achieved promising performance on predicting EGFR mutation status, with AUCs of 75.8% and 75.0% for our holdout test set and public test set, respectively. Moreover, strong relations were found between deep learning feature and conventional radiomics, while deep learning worked through an enhanced radiomics manner, that is, deep learned radiomics (DLR), in terms of robustness, compactness and expressiveness. The proposed deep learning system predicts EGFR‐mutant of lung adenocarcinomas in CT images noninvasively and automatically, indicating its potential to help clinical decision‐making by identifying eligible patients of pulmonary adenocarcinoma for EGFR‐targeted therapy.

The Diagnostic Value of Quantitative CT Analysis of Ground-Glass Volume Percentage in Differentiating Epidermal Growth Factor Receptor Mutation and Subtypes in Lung Adenocarcinoma

Objective

To retrospectively investigate computed tomographic (CT) quantitative analysis of ground-glass opacity (GGO) volume percentage and morphologic features of resected lung adenocarcinomas according to epidermal growth factor receptor (EGFR) mutation status and subtypes.

Methods

Amplification refractory mutation system was used to detect mutations in the EGFR gene. Distribution of demographics and GGO volume percentage were performed according to EGFR mutation status and subtypes.

Results

EGFR mutations were significantly more frequent in women (55.2% vs. 37.0%, p=0.001) and in never-smokers (59.5% vs. 38.4%, p < 0.001) than those without EGFR mutation. GGO volume percentage was significantly higher in tumors with EGFR mutation than in tumors without EGFR mutation (52.8±25.7% vs. 29.0±20.7%, p < 0.001). The GGO volume percentages in tumors with exon 21 mutation and EGFR mutation showed a significant difference compared with those without EGFR mutation (p < 0.001, area under the curve=0.871, sensitivity=94.6%, specificity=73.8%, and p < 0.001, area under the curve=0.783, sensitivity=69.9%, specificity=75.4%, resp.), with cut-off values of 37.7% and 34.3% in receiver operating characteristic curve analysis.

Conclusion

GGO volume percentage in adenocarcinomas with EGFR mutation was significantly higher than that in tumors without EGFR mutation, and adenocarcinomas with exon 21 mutation showed significantly higher GGO volume percentage than in tumors with exon 19 mutation and those without EGFR mutation. Our results indicate that GGO volume percentage cut-off values of more than 37.7% and 34.3% were predictors of positive exon 21 mutation and EGFR mutation, respectively.

Development and Validation of a Novel Survival Prediction Model in Patients With Spinal Metastasis From Non-small Cell Lung Cancer

STUDY DESIGN

Retrospective study.

OBJECTIVE

The aim of this study was to develop a model for predicting survival of patients with non-small cell lung cancer (NSCLC) spinal metastasis and compare its accuracy with the existing scoring systems.

SUMMARY OF BACKGROUND DATA

Spinal metastasis is commonly seen in advanced NSCLC and usually associated with poor survival prognosis.

METHODS

A total of 376 patients with NSCLC spinal metastases admitted to our institution from January 2010 to October 2016 were enrolled. They were randomly assigned at a 3:1 ratio to a training cohort (n = 282) and a validation cohort (n = 94). A nomogram for survival prediction was established by identifying and integrating significant prognostic factors, and then subjected to bootstrap validation in both training and validation cohorts. The discrimination was measured by concordance index (C-index). Predictive accuracy was compared with three existing models by the receiver-operating characteristic curve (ROC) and area under ROC in both training and validation cohorts.

RESULTS

Six independent prognostic factors including sex (P = 0.008), the presence of visceral metastasis (P = 0.008), the number of metastases in the vertebral body (P = 0.011), Frankel score (P < 0.001), D-dimer (P = 0.002), and sensitive epidermal growth factor receptor mutation (p < 0.001) were identified and entered into the nomogram. The calibration curves for probability of 3-, 6-, 12- and, 24-month overall survival showed good agreement between the predictive risk and the actual risk. The C-index of the nomogram was 0.708 (95% confidence interval [CI], 0.674-0.742) in the training cohort and 0.683 (95% CI, 0.619-0.747) in the validation cohort. Model comparison showed that this nomogram had better predictive accuracy than the Tomita et al, Tokuhashi et al, and Schwab et al scoring systems (P < 0.05 in the training cohort).

CONCLUSION

We established and validated a novel nomogram that could be used to predict the survival outcome of patients with NSCLC spinal metastasis, thus helping clinicians in decision making and individualized care planning of such patients.

LEVEL OF EVIDENCE

4.

Chemotherapy for Lung Cancer in the Era of Personalized Medicine

Although recent advances in molecular targeted therapy and immuno-oncology have revolutionized the landscape of lung cancer therapeutics, cytotoxic chemotherapy remains an essential component of lung cancer treatment. Extensive evidence has demonstrated the clinical benefit of chemotherapy, either alone or in combination with other treatment modalities, on survival and quality of life of patients with early and advanced lung cancer. Combinational approaches with other classes of anti-neoplastic agents and new drug-delivery systems have revealed promising data and are areas of active investigation. Chemotherapy is recommended as a standard of care in patients that have progressed after tyrosine kinase inhibitors or immune checkpoint inhibitors. Chemotherapy remains the fundamental means of lung cancer management and keeps expanding its clinical implication. This review will discuss the current position and future role of chemotherapy, and specific consideration for its clinical application in the era of precision medicine.

Retrospective Assessment of a Serum Proteomic Test in a Phase III Study Comparing Erlotinib plus Placebo with Erlotinib plus Tivantinib (MARQUEE) in Previously Treated Patients with Advanced Non-Small Cell Lung Cancer

BACKGROUND

The VeriStrat test provides accurate predictions of outcomes in all lines of therapy for patients with non-small cell lung cancer (NSCLC). We investigated the predictive and prognostic role of VeriStrat in patients enrolled on the MARQUEE phase III trial of tivantinib plus erlotinib (T+E) versus placebo plus erlotinib (P+E) in previously treated patients with advanced NSCLC.

METHODS

Pretreatment plasma samples were available for 996 patients and were analyzed by matrix-assisted laser desorption/ionization-time of flight mass spectrometry to generate VeriStrat labels (good, VS-G, or poor, VS-P).

RESULTS

Overall, no significant benefit in overall survival (OS) and progression-free survival (PFS) were observed for the addition of tivantinib to erlotinib. Regardless of treatment arm, patients who were classified as VS-G had significantly longer PFS (3.8 mo for T+E arm, 2.0 mo for P+E arm) and OS (11.6 mo for T+E, 10.2 mo for P+E arm) than patients classified as VS-P (PFS: 1.9 mo for both arms, hazard ratio [HR], 0.584; 95% confidence interval [CI], 0.468-0.733; p < .0001 for T+E, HR, 0.686; 95% CI, 0.546-0.870; p = .0015 for P+E; OS: 4.0 mo for both arms, HR, 0.333; 95% CI, 0.264-0.422; p < .0001 for T+E; HR, 0.449; 95% CI, 0.353-0.576; p < .0001 for P+E). The VS-G population had higher OS than the VS-P population within Eastern Cooperative Oncology Group (ECOG) performance score (PS) categories. VS-G patients on the T+E arm had longer PFS, but not OS, than VS-G patients on the P+E arm (p = .0108). Among EGFR mutation-positive patients, those with VS-G status had a median OS more than twice that of any other group (OS: 31.6 mo for T+E and 22.8 mo for P+E), whereas VS-P patients had similar survival rates as VS-G, EGFR-wild type patients (OS: 13.7 mo for T+E and 6.5 mo for P+E).

CONCLUSION

In these analyses, VeriStrat showed a prognostic role within EGOC PS categories and regardless of treatment arm and EGFR status, suggesting that VeriStrat could be used to identify EGFR mutation-positive patients who will have a poor response to EGFR tyrosine kinase inhibitors.

IMPLICATIONS FOR PRACTICE

This study suggests that VeriStrat testing could enhance the prognostic role of performance status and smoking status and replicates findings from other trials that showed that the VeriStrat test identifies EGFR mutation-positive patients likely to have a poor response to EGFR tyrosine kinase inhibitors (TKIs). Although these findings should be confirmed in other populations, VeriStrat use could be considered in EGFR mutation-positive patients as an additional prognostic tool, and these results suggest that EGFR mutation-positive patients with VeriStrat "poor" classification could benefit from other therapeutic agents given in conjunction with TKI monotherapy.

Pneumonitis in advanced non-small-cell lung cancer patients treated with EGFR tyrosine kinase inhibitor: Meta-analysis of 153 cohorts with 15,713 patients: Meta-analysis of incidence and risk factors of EGFR-TKI pneumonitis in NSCLC

PURPOSE

Pneumonitis is a significant toxicity of EGFR tyrosine kinase inhibitors (EGFR-TKI) in non-small-cell lung cancer (NSCLC) patients. We studied the incidence of pneumonitis in clinical trials of EGFR-TKI published in 2003-2017, and performed subgroups analyses to identity predisposing factors.

METHODS

Ovid-MEDLINE and EMBASE search up to 4/17/17 using the keywords, "erlotinib", "gefitinib", "afatinib", "osimertinib", and "lung cancer", resulted in a total of 153 eligible trial cohorts with 15,713 advanced NSCLC patients treated with EGFR-TKI. The pooled incidence of all-grade, high-grade, and grade 5 pneumonitis was obtained. Subgroup analyses were performed with meta-regression using study-level covariates.

RESULTS

Among the patients without prior exposure to EGFR-TKI, the overall incidence was 1.12% (95% CI:0.79-1.58%) for all-grade, 0.61% (95% CI:0.40-0.93%) for high-grade, and 0.20% (95% CI:0.11-0.38%) for grade 5 pneumonitis. The incidence was significantly higher in Japanese studies compared to studies of non-Japan origin, for all-grade (4.77% vs. 0.55%, p < 0.001), high grade (2.49% vs. 0.37%, p < 0.001), and grade 5 pneumonitis (1.00% vs. 0.18%, p < 0.001). Multivariate analyses demonstrated higher odds of pneumonitis in Japanese studies for all-grade (odds ratio [OR]: 5.04; 95% CI:3.14-8.11, p < 0.001), high-grade (OR: 4.45; 95% CI:2.50-7.93, p < 0.001), and grade 5 pneumonitis (OR: 4.55; 95% CI:2.20-9.44, p < 0.001) compared to others, after adjusting for types of EGFR-TKI and lines of therapy. In patients with EGFR retreatment analyzed separately, the pooled incidence was 1.13% (95% CI:0.40-3.15%) for all-grade, 0.49% (95% CI:0.21-1.11%) for high-grade, and 0.16% (95% CI:0.04-0.65%) for grade 5 pneumonitis.

CONCLUSIONS

The overall incidence of EGFR-TKI pneumonitis was 1.12% in patients without prior exposure to EGFR-TKI, and 1.13% in EGFR-TKI retreatment group. The cohorts from Japan had significantly higher incidence of pneumonitis, providing insights for further mechanistic studies.

Favorable response to pemetrexed, cisplatin and bevacizumab in invasive mucinous adenocarcinoma: A case report and literature review

Invasive mucinous adenocarcinoma (IMA) was formerly referred to as mucinous bronchioloalveolar carcinoma. The lack of effective chemotherapy and comprehensive treatment for this type of tumor poses a great challenge in clinical practice. We herein report the case of a male patient with IMA who was treated with a combination of pemetrexed (500 mg/m²), cisplatin (75 mg/m²) and bevacizumab (15 mg/kg) as first-line chemotherapy. The patient achieved significant radiological improvement with 6 courses of this regimen. After the tumor progressed, the patient again achieved marked improvement with an additional 4 courses of the same regimen. The patient survived for a total of 30 months after the first chemotherapy. Therefore, bevacizumab in combination with pemetrexed/cisplatin may be an effective strategy for the treatment of IMA. The available literature on this chemotherapy regimen was also reviewed and discussed in the present study.

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

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

TASK-1 induces gefitinib resistance by promoting cancer initiating cell formation and epithelial-mesenchymal transition in lung cancer

Cancer initiating cell (CIC) formation and epithelial-mesenchymal transition (EMT) are pivotal events in lung cancer cell invasion and metastasis. They have been shown to occur in gefitinib resistance. Studying the molecular mechanisms of CICs, EMT and acquired gefitinib resistance will enhance the understanding of the pathogenesis and progression of the disease and offer novel targets for effective therapies. TWIK-related acid-sensitive K(+) (TASK-1) is expressed in a subset of non-small-cell lung cancer (NSCLC) cell lines, where it promotes cell proliferation while inhibiting apoptosis. In the present study, TASK-1 was demonstrated to induce gefitinib resistance in the A549 NSCLC cell line. Overexpression of TASK-1 promoted the acquisition of CIC-like traits by A549 cells. CD133, octamer-binding transcription factor 4 (OCT-4) and Nanog have been suggested to be markers of CICs in lung cancer. It was demonstrated that overexpression of TASK-1 promoted CD133, OCT-4 and Nanog protein expression in A549 cells. Increased formation of stem cell-like populations results in EMT of cancer cells. The present study found that overexpression of TASK-1 promoted EMT of A549 cells. Thus, downregulation of TASK-1 may represent a novel strategy for EMT reversal, decreasing CIC-like traits and increasing gefitinib sensitivity of NSCLCs.

Phase 1b Trial of Ficlatuzumab, a Humanized Hepatocyte Growth Factor Inhibitory Monoclonal Antibody, in Combination With Gefitinib in Asian Patients With NSCLC

Hepatocyte growth factor (HGF)/c-Met pathway dysregulation is a mechanism for epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs). Ficlatuzumab (AV-299; SCH 900105), a humanized IgG₁ κ HGF inhibitory monoclonal antibody, prevents HGF/c-Met pathway ligand-mediated activation. This phase 1b study assessed the safety/tolerability, pharmacokinetics/pharmacodynamics, and antitumor activity of ficlatuzumab plus gefitinib in Asian patients with previously treated advanced non-small cell lung cancer (NSCLC). Patients received intravenous ficlatuzumab either 10 mg/kg (cohort 1; n = 3) or 20 mg/kg (cohort 2; n = 12) every 2 weeks plus oral gefitinib 250 mg daily. Patients tolerated the drug combination well. Four treatment-related grade 3/4 adverse events were reported in 3 patients (cohort 2). Pharmacokinetic profiles for ficlatuzumab and gefitinib were consistent with prior single-agent trials. Partial responses were achieved in 5 patients (4 confirmed), all in cohort 2; objective response rate (ORR) was 33% (duration, 1.9-6.4 months). Responding patients had no prior EGFR TKI treatment, 2 without an EGFR mutation. Four additional patients had disease stabilization (cohort 2; duration, 2.7-9.1 months; 42% ORR). The recommended phase 2 dose for ficlatuzumab plus gefitinib 250 mg/day was 20 mg/kg every 2 weeks. This drug combination has shown preliminary dose-related antitumor activity in advanced NSCLC.

Histologic Grade Is Predictive of Incidence of Epidermal Growth Factor Receptor Mutations in Metastatic Lung Adenocarcinoma

Activating epidermal growth factor receptor (EGFR) mutations in metastatic non-small cell lung cancer (NSCLC) are associated with a high response rate to EGFR tyrosine kinase inhibitor (TKI). The current guidelines recommend routine EGFR mutational analysis prior to initiating first line systemic therapy. The clinical characteristics including smoking status, histologic type, sex and ethnicity are known to be associated with the incidence of EGFR mutations. We retrospectively analyzed 277 patients with metastatic NSCLC within Kaiser Permanente Northern California (KPNC); among these patients, 83 were positive for EGFR mutations. We performed both univariate and multivariable logistic regressions to identify predictors of EGFR mutations. We found that histologic grade was significantly associated with the incidence of EGFR mutation, regardless of ethnicity, sex and smoking status. In grade I (well differentiated) and II (moderately differentiated), histology was associated with significantly higher incidence of EGFR mutations compared to grade II–III (moderate-to-poorly differentiated) and III (poorly differentiated). Ever-smokers with grade III lung adenocarcinoma had 1.8% incidence of EGFR mutations. This study indicates that histologic grade is a predictive factor for the incidence of EGFR mutations and suggests that for patients with grade II–III or III lung adenocarcinoma, prompt initiation of first-line chemotherapy or immunotherapy is appropriate while awaiting results of EGFR mutational analysis, particularly for patients with history of smoking.

A study of therapy targeted EGFR/ALK mutations in Indian patients with lung adenocarcinoma: A clinical and epidemiological study

Background

Established predictive biomarkers for Non-Small Cell Lung Carcinoma (NSCLC) include sensitizing Epidermal Growth Factor Receptor (EGFR) mutations and Anaplastic Lymphoma Kinase (ALK) fusion oncogene. The primary aim of the study is to ascertain the prevalence of EGFR mutation and ALK gene rearrangement in patients of lung adenocarcinoma in Indian population and the second objective is to impress upon the importance of adequate processing of limited tissue samples.

Methods

Histopathologically confirmed cases of lung adenocarcinoma, whose tumour had been tested for both EGFR and ALK gene mutations, were included in this study. The EGFR mutations were analyzed using PCR and Gene Sequencing. ALK fusion oncogene was found by Fluorescence In Situ Hybridization (FISH) technique using kit of Vysis LSI ALK Dual colour Break Apart Rearrangement probe.

Results

A total of 152 cases of lung adenocarcinoma were included. Out of which, 92 (60.5%) were male and 60 (39.5%) were female. After exclusion of 17 cases due to unsatisfactory result, EGFR mutations were found positive in 35.5% cases (48/135). ALK gene rearrangement was found in 7.6% (10/131) after excluding 21 cases with unsatisfactory result.

Conclusion

EGFR mutations and ALK gene rearrangement was found to be mutually exclusive. Incidence of EGFR mutations (35.5%) is much higher in Indian population than in Caucasians (13%) and is close to the incidence in East Asian countries. The 7.6% incidence of ALK fusion oncogene in Indian patients establishes the importance of molecular studies to give maximum benefit of targeted therapy to the patients.

A pediatric trial of radiation/cetuximab followed by irinotecan/cetuximab in newly diagnosed diffuse pontine gliomas and high-grade astrocytomas: A Pediatric Oncology Experimental Therapeutics Investigators' Consortium study

BACKGROUND

Diffuse intrinsic pontine gliomas (DIPGs) and high-grade astrocytomas (HGA) continue to have dismal prognoses. The combination of cetuximab and irinotecan was demonstrated to be safe and tolerable in a previous pediatric phase 1 combination study. We developed this phase 2 trial to investigate the safety and efficacy of cetuximab given with radiation therapy followed by adjuvant cetuximab and irinotecan.

METHODS

Eligible patients of age 3-21 years had newly diagnosed DIPG or HGA. Patients received radiation therapy (5,940 cGy) with concurrent cetuximab. Following radiation, patients received cetuximab weekly and irinotecan daily for 5 days per week for 2 weeks every 21 days for 30 weeks. Correlative studies were performed. The regimen was considered to be promising if the number of patients with 1-year progression-free survival (PFS) for DIPG and HGA was at least six of 25 and 14 of 26, respectively.

RESULTS

Forty-five evaluable patients were enrolled (25 DIPG and 20 HGA). Six patients with DIPG and five with HGA were progression free at 1 year from the start of therapy with 1-year PFS of 29.6% and 18%, respectively. Fatigue, gastrointestinal complaints, electrolyte abnormalities, and rash were the most common adverse events and generally of grade 1 and 2. Increased epidermal growth factor receptor copy number but no K-ras mutations were identified in available samples.

CONCLUSIONS

The trial did not meet the predetermined endpoint to deem this regimen successful for HGA. While the trial met the predetermined endpoint for DIPG, overall survival was not markedly improved from historical controls, therefore does not merit further study in this population.

Spotlight on brigatinib and its potential in the treatment of patients with metastatic ALK-positive non-small cell lung cancer who are resistant or intolerant to crizotinib

In the last decade, there have been major therapeutic advances in the management of patients with anaplastic lymphoma kinase (ALK)-positive non-small cell lung cancer. Crizotinib was the first approved ALK inhibitor with significant benefits over chemotherapy. However, patients inevitably develop disease progression especially in central nervous system and acquire resistance to crizotinib. Several next-generation ALK inhibitors have been developed to overcome these resistance mechanisms and have demonstrated clinical benefits in crizotinib-refractory non-small cell lung cancer including in central nervous system. Brigatinib is a second-generation ALK inhibitor with high level of activity against ALK and several other targets. It is active in vitro against many ALK kinase domain mutations including L1196M, E1210K, and G1202R which may mediate acquired resistance to other ALK inhibitors. In Phase I/II and ALTA clinical studies, brigatinib has demonstrated substantial and durable responses and intracranial responses after progression on crizotinib. It has acceptable safety profile, but early pulmonary toxicity has been observed prompting to pursue daily dosing of 180 mg (with lead-in). Overall, 180 mg (with lead-in) has showed consistently better efficacy than 90 mg. In this review, we will discuss in detail these two pivotal trials that led to the accelerated approval for brigatinib and its future directions.

NANOG as an adverse predictive marker in advanced non-small cell lung cancer treated with platinum-based chemotherapy

Purpose

NANOG is a master transcription factor that regulates stem cell pluripotency and cellular reprograming. Increased NANOG expression has been associated with poor survival in several human malignancies. However, the clinical significance of NANOG overexpression in lung cancer has been scarcely evaluated. The aim of this study was to investigate whether NANOG levels are associated with clinical outcomes of patients with non–small cell lung cancer (NSCLC) who were treated with platinum-based chemotherapy.

Methods

NANOG levels were evaluated immunohistochemically using the histologic score (H-score) in tumor tissues from patients with advanced NSCLC who received platinum-based doublet treatment. We performed survival analyses according to the NANOG levels and evaluated the association between clinicopathological parameters and levels of NANOG.

Results

Multivariate analyses using 112 tumor specimens showed that high NANOG levels were independently associated with short progression-free survival (hazard ratio [HR] =3.09, 95% confidence interval [CI]: 2.01–4.76) and with short overall survival (HR =3.00, 95% CI: 1.98–4.54). Similar results were shown in the subgroup analyses for patients with adenocarcinoma and squamous cell carcinoma. NANOG expression was not associated with any clinicopathological parameter such as age, gender, smoking status, stage, differentiation, or histological subtypes.

Conclusion

NANOG overexpression was associated with poor response and short overall survival in patients with advanced NSCLC who were treated with platinum-based chemotherapy, suggesting that NANOG could be a potential adverse predictive marker in this setting.

Prioritizing molecular markers to test for in the initial workup of advanced non-small cell lung cancer: wants versus needs

The current standard of care for molecular marker testing in patients with advanced non-small cell lung cancer (NSCLC) has been evolving over several years and is a product of the quality of the evidence supporting a targeted therapy for a specific molecular marker, the pre-test probability of that marker in the population, and the magnitude of benefit seen with that treatment. Among the markers that have one or more matched targeted therapies, only a few are in the subset for which they should be considered as most clearly worthy of prioritizing to detect in the first line setting in order to have them supplant other first line alternatives, and in only a subset of patients, as defined currently by NSCLC histology. Specifically, this currently includes testing for an activating epidermal growth factor receptor (EGFR) mutation or an anaplastic lymphoma kinase (ALK) or ROS1 rearrangement. This article reviews the history and data supporting the prioritization of these markers in patients with non-squamous NSCLC, a histologically selected population in whom the probability of these markers combined with the anticipated efficacy of targeted therapies against them is high enough to favor these treatments in the first line setting. In reviewing the evidence supporting this very limited core subset of most valuable molecular markers to detect in the initial workup of such patients, we can also see the criteria by which other actionable markers need to reach in order to be widely recognized as reliably valuable enough to warrant prioritization to detect in the initial workup of advanced NSCLC as well.

The Role of Extent of Surgical Resection and Lymph Node Assessment for Clinical Stage I Pulmonary Lepidic Adenocarcinoma: An Analysis of 1991 Patients

BACKGROUND

This study examined the association of extent of lung resection, pathologic nodal evaluation, and survival for patients with clinical stage I (cT1-2N0M0) adenocarcinoma with lepidic histologic features in the National Cancer Data Base.

METHODS

The association between extent of surgical resection and long-term survival for patients in the National Cancer Data Base with clinical stage I lepidic adenocarcinoma who underwent lobectomy or sublobar resection was evaluated using Kaplan-Meier and Cox proportional hazards regression analyses.

RESULTS

Of the 1991 patients with cT1-2N0M0 lepidic adenocarcinoma who met the study criteria, 1544 underwent lobectomy and 447 underwent sublobar resection. Patients treated with sublobar resection were older, more likely to be female, and had higher Charlson/Deyo comorbidity scores, but they had smaller tumors and lower T status. Of the patients treated with lobectomy, 6% (n = 92) were upstaged because of positive nodal disease, with a median of seven lymph nodes sampled (interquartile range 4-10). In an analysis of the entire cohort, lobectomy was associated with a significant survival advantage over sublobar resection in univariate analysis (median survival 9.2 versus 7.5 years, p = 0.022, 5-year survival 70.5% versus 67.8%) and after multivariable adjustment (hazard ratio = 0.81, 95% confidence interval: 0.68-0.95, p = 0.011). However, lobectomy was no longer independently associated with improved survival when compared with sublobar resection (hazard ratio = 0.99, 95% confidence interval: 0.77-1.27, p = 0.905) in a multivariable analysis of a subset of patients in which only those patients who had undergone a sublobar resection including lymph node sampling were compared with patients treated with lobectomy.

CONCLUSIONS

Surgeons treating patients with stage I lung adenocarcinoma with lepidic features should cautiously utilize sublobar resection rather than lobectomy, and they must always perform adequate pathologic lymph node evaluation.

Expression level of CRKL and AXL combined with exon 19 deletion in EGFR and ALK status confer differential prognosis of lung adenocarcinoma subtypes

Non-small cell lung cancer (NSCLC) is a lethal cancer-related disease in population. Adenocarcinoma (AC) is subclassified into several subtypes based on the new classification by the International Association for the Study of Lung Cancer, American Thoracic Society and European Respiratory Society in 2011. Correlation between original expression of Crk-like (CRKL) and anaplastic lymphoma receptor tyrosine kinase in diverse histological components of AC and epidermal growth factor receptor (EGFR) or ALK status was evaluated by immunohistochemistry and sequencing in present study. A total of 106 cases, including 83 patients (78.3%) with mixed-type ACs, were assessed in the present study using eligible follow-up data. The ACs consisted of 32 acinar, 12 papillary, 5 mucinous, 11 micropapillary and 46 solid-predominant ACs. In total, 69.8% samples were composed of 2 or 3 histological components, with different expression levels of CRKL and AXL. ACs with EGFR mutation had a higher level of AXL expression compared with ACs without mutation (P=0.019). Multivariate survival analysis showed that AC subtypes and EGFR mutation subtypes were significantly associated with the progression-free survival (PFS) time. Acinar AC was the subtype with the most notable PFS time (30.6 months), which was significantly different from the PFS time of papillary, mucinous, micropapillary and solid-predominant ACs (hazard ratio, 0.4; 95% CI, 0.21-0.75; P=0.005). Among the ACs with exon 19 mutation, the median PFS time (28.8 months) of patients with a lower level of AXL protein expression was increased compared with the PFS time of patients with the L858R mutation and wild-type EGFR (9.1 months and 11 months, respectively; P=0.03), whereas no significant difference in ACs with an increased level of AXL expression. However, AC patients with higher level of CRKL expression had better PFS (28.8 months) than patients with the L858R mutation and wild-type EGFR (9.1 months and 11.3 months, respectively). Exon 19 deletion is an important status that is associated with an improved response to conventional chemotherapy. The identification of EGFR mutations combined with CRKL and AXL status may potentially alter the way that lung AC is treated.

Biopsy Procedures and Molecular Testing Utilization and Related Costs in Patients with Metastatic Lung Cancer

BACKGROUND

Epidermal growth factor receptor (EGFR) gene mutations and anaplastic lymphoma kinase (ALK) gene rearrangements are key therapeutic targets for biomarker-driven treatment with an EGFR or ALK tyrosine kinase inhibitor (TKI) in patients with metastatic non-small cell lung cancer (NSCLC). To appropriately guide treatment decisions, since 2011, the National Comprehensive Cancer Network and the American Society of Clinical Oncology therefore recommend EGFR and ALK analysis in tumor samples obtained at the time of diagnosis in patients with non-squamous NSCLC. Currently, there are limited data on utilization patterns and cost of biopsy procedures and biomarker tests in patients with metastatic NSCLC who receive an EGFR or ALK TKI.

OBJECTIVES

To (a) describe utilization patterns and costs associated with biopsy procedures and biomarker testing in patients with NSCLC who received erlotinib or crizotinib between 2009 and 2012 and (b) investigate the timing of these procedures relative to the erlotinib or crizotinib index date.

METHODS

Adult patients with metastatic lung cancer were identified by ICD-9-CM diagnostic codes within the Truven Health Analytic MarketScan database. Patients were included in the analysis if they had an index erlotinib or crizotinib claim between January 1, 2009, and September 30, 2012 (index period) and were continuously enrolled for ≥ 12 months before the index claim. Because there is no specific ICD-9-CM diagnostic code for NSCLC, patients with metastatic lung cancer who received erlotinib or crizotinib were considered to have metastatic NSCLC. Using CPT and ICD-9-CM codes, lung biopsy procedures performed during the 24 months before or 12 months after the index claim date were identified. For every patient, biomarker testing claims for EGFR and ALK were identified using the molecular pathology stacked CPT code during the 2 months before or 1 month after the index date. The frequency of claims for biopsy procedures and biomarker testing was analyzed descriptively. The overall summary measures for biomarker testing, especially frequency of EGFR testing in patients receiving erlotinib, was also described as before and after 2011, the year when biomarker testing became part of the guidelines. Per patient and overall costs for biopsy procedures and biomarker testing were calculated from payer and patient perspectives.

RESULTS

Of the 4,926 identified patients, 4,801 (97.5%) received erlotinib, and 125 (2.5%) received crizotinib. Biopsy procedure claims were identified for 3,579 (72.7%) patients, including 3,503 (73.0%) erlotinib recipients and 76 (60.8%) crizotinib recipients. Biomarker testing claims were identified for 675 (13.7%) patients, including 634 (13.2%) erlotinib recipients and 41 (32.8%) crizotinib recipients. Overall, most biomarker testing procedures (476 of 741) were identified in 435 (of 675) patients after year 2011. Also, among erlotinib recipients, percentage of patients receiving EGFR testing was increased over the index period. Per patient mean (SD) numbers of biopsy procedures and biomarker tests were 1.2 (1.1) and 0.2 (0.4), respectively. In the outpatient setting, per patient mean (SD) cost per biopsy procedure was $1,223 ($1,899) from the payer perspective and $60 ($147) from the patient perspective, whereas in the inpatient setting, it was $8,163 ($18,712) and $180 ($691), respectively. Among patients receiving at least 1 biomarker test, the per patient mean (SD) cost for the overall population was $891 ($1,062) and $43 ($229); for erlotinib recipients, it was $906 ($1,084) and $42 ($228); and for crizotinib recipients, it was $664 ($576) and $55 ($243) in payer and patient perspectives, respectively.

CONCLUSIONS

This study provides insight into the use and cost of biopsy and biomarker testing procedures in patients with metastatic NSCLC. The low frequency of biomarker testing highlights the need for more awareness of testing to guide treatment decisions in these patients. Costs associated with biopsy procedures and biomarker testing provide insight into the economic impact on metastatic NSCLC patients treated with targeted therapy.

DISCLOSURES

This study was sponsored by Merck & Co. Shinde is a study manager working for Merck under contract with AllSourcePPS, an Agile 1 company in Huntington Beach, California. Cao and Kothari are employees of Merck & Co., Kenilworth, New Jersey. Study concept and design were contributed primarily by Shinde and Kothari. Data analysis was performed by Cao. Data interpretation was performed by Shinde, Cao, and Kothari. Shinde wrote the manuscript with assistance from Cao and Kothari. The revision was completed primarily by Shinde and Kothari.

EGFR gene copy number as a predictive/biomarker for patients with non-small-cell lung cancer receiving tyrosine kinase inhibitor treatment: a systematic review and meta-analysis

Epidermal growth factor receptor (EGFR) gene copy number has been proposed as a candidate biomarker for predicting treatment response to EGFR tyrosine kinase inhibitors (EGFR-TKIs) in patients with advanced non-small-cell lung cancer (NSCLC). MEDLINE, PubMed, Cochrane, and Google Scholar databases were searched until October 21, 2015 using the following search terms: lung neoplasms/lung cancer/non-small cell lung cancer/NSCLC, EGFR, gene amplification, copy number, erlotinib, gefitinib, tyrosine-kinase inhibitor/TKI, predictor. 17 studies were included in the analysis with a total of 2047 patients. The overall analysis found that increased EGFR gene copy number was associated with higher overall response rate (ORR), overall survival (OS) and progression-free survival (PFS; p values ≤0.008) compared with patients without a high EGFR gene copy number. Subgroup analysis found that in a population of patients who were primarily Caucasian, a higher EGFR gene copy number was also associated with increased ORR, OS, and PFS (p values ≤0.018). The results were similar in a population of Asian patients, except that a higher EGFR gene copy number was not associated with improved OS (p=0.248). Sensitivity analysis indicated that no one study overly influenced the results and that the findings are robust. The result of the analysis found that EGFR gene copy number was associated with increased OS and PFS, supporting the idea that EGFR gene copy number is a biomarker for response to EGFR-TKI therapy in patients with advanced NSCLC.

Concordant and Discordant EGFR Mutations in Patients With Multifocal Adenocarcinomas: Implications for EGFR-Targeted Therapy

PURPOSE

Adenocarcinoma remains the most common subtype of lung cancer in the United States. Most patients present with tumors that are invasive and often metastatic, but in some patients, multiple precursor in situ or minimally invasive adenocarcinoma tumors develop that can be synchronous and metachronous. These precursor lesions harbor the same spectrum of genetic mutations found in purely invasive adenocarcinomas, such as EGFR, KRAS, and p53 mutations. It is less clear, however, whether separate lesions in patients who present with multifocal disease share common underlying genetic driver mutations.

METHODS

Here we review the relevant literature on molecular driver alterations in adenocarcinoma precursor lesions. We then report 4 patients with multifocal EGFR mutant adenocarcinomas in whom we performed molecular testing on 2 separate lesions.

FINDINGS

In 2 of these patients, the mutations are concordant, and in 2 patients, the mutations are discordant. A review of the literature demonstrates increasing evidence that lesions with discordant mutations may confer a more favorable prognosis because they are unlikely to represent metastases.

IMPLICATIONS

Our findings suggest that the emergence of the dominant EGFR driver alteration is often independent between lesions in patients with multifocal adenocarcinomas, and thus the same targeted therapy may not be effective for all lesions. However, genetic testing of multiple lesions can help to distinguish separate primary tumors from metastatic disease.

Reactive Oxygen Species Modulator 1 (Romo1) Predicts Poor Outcomes in Advanced Non-small Cell Lung Cancer Patients Treated with Platinum-Based Chemotherapy

Purpose

Reactive oxygen species modulator 1 (Romo1) is a key mediator of intracellular reactive oxygen species production. However, examination of the clinical usefulness of Romo1 in cancers has been limited. We evaluated the association of Romo1 expression with clinical outcomes in advanced non-small cell lung cancer (NSCLC) patients treated with platinum-based chemotherapy.

Materials and Methods

Romo1 expression in tumor tissue was examined by immunohistochemistry and evaluated by histological score. Survival analyses were performed according to Romo1 expression and the association between Romo1 expression and clinical parameters was evaluated.

Results

A total of 88 tumor specimens were analyzed. Significantly shorter median progression-free survival (PFS) was observed in the high Romo1 group compared with the low Romo1 group (4.5 months vs. 9.8 months, p < 0.001), and the median overall survival (OS) of the high Romo1 group was also significantly shorter than that of the low Romo1 group (8.4 months vs. 15.5 months, p < 0.001). Results of multivariate analyses showed significant association of high Romo1 expression with both poor PFS (hazard ratio [HR], 2.75; 95% confidence interval [CI], 1.71 to 4.44) and poor OS (HR, 3.99; 95% CI, 2.36 to 6.74). Results of the subgroup analysis showed a similar association regardless of tumor histology. Romo1 expression showed no association with any clinical parameter including age, sex, smoking status, stage, differentiation, or tumor histology.

Conclusion

Romo1 overexpression was associated with poor response to treatment and shorter survival in advanced NSCLC patients treated with platinum-based chemotherapy. Romo1 could be a potential adverse predictive marker in this setting.

The role of epithelial to mesenchymal transition in resistance to epidermal growth factor receptor tyrosine kinase inhibitors in non-small cell lung cancer

Inhibition of the epidermal growth factor receptor (EGFR) is an important strategy when treating non-small cell lung cancer (NSCLC) patients. However, intrinsic resistance or development of resistance during the course of treatment constitutes a major challenge. The knowledge on EGFR-directed tyrosine kinase inhibitors (TKIs) and their biological effect keeps increasing. Within the group of patients with EGFR mutations some benefit to a much higher degree than others, and for patients lacking EGFR mutations a subset experience an effect. Up to 70% of patients with EGFR mutations and 10-20% of patients without EGFR mutations initially respond to the EGFR-TKI erlotinib, but there is a severe absence of good prognostic markers. Despite initial effect, all patients acquire resistance to EGFR-TKIs. Multiple mechanisms have implications in resistance development, but much is still to be explored. Epithelial to mesenchymal transition (EMT) is a transcriptionally regulated phenotypic shift rendering cells more invasive and migratory. Within the EMT process lays a need for external or internal stimuli to give rise to changes in central signaling pathways. Expression of mesenchymal markers correlates to a bad prognosis and an inferior response to EGFR-TKIs in NSCLC due to the contribution to a resistant phenotype. A deeper understanding of the role of EMT in NSCLC and especially in EGFR-TKI resistance-development constitute one opportunity to improve the benefit of TKI treatment for the individual patient. Many scientific studies have linked the EMT process to EGFR-TKI resistance in NSCLC and our aim is to review the role of EMT in both intrinsic and acquired resistance to EGFR-TKIs.

Strategies to overcome acquired resistances conferred by mutations in the kinase domain of EGFR

Deregulation of EGFR is involved in the development of many cancers. The inhibition of EGFR kinase activity has been clinically validated as a promising approach for the treatment of non-small-cell lung cancer (NSCLC). However, all NSCLC patients who initially benefited from first-generation EGFR inhibitors eventually develop drug resistance. A point mutation at the gatekeeper position, T790M in EGFR kinase domain accounts for more than 50% of acquired resistance. Therefore, second- and third-generation EGFR inhibitors have been developed to overcome the resistance conferred by the gatekeeper mutation. This review has highlighted recent advances in overcoming acquired resistance for the development of each generation of EGFR inhibitors along with their potential issues, and urgent quest for the development of new generation of EGFR inhibitors.

Advances in EGFR as a Predictive Marker in Lung Adenocarcinoma

BACKGROUND

Worldwide, lung cancer is the most common cause of mortality. Toxins from tobacco smoke are known to increase the risk of lung cancer; however, up to 15% of lung cancer-related deaths in men and up to 50% of lung cancer-related deaths in women occur in people who do not smoke. Despite the fact that chemotherapy generally provides a survival benefit for non-small-cell lung cancer, not every patient will respond to therapy and many experience therapy-related adverse events. Thus, predictive markers are used to determine which patients are more likely to respond to a given regimen.

METHODS

We reviewed the current medical literature in English relating to predictive markers that may be positive, such as the presence of an activating EGFR mutation.

RESULTS

The advances in using EGFR as a molecular predictive marker were summarized. This biomarker influences therapeutic response in patients with lung adenocarcinoma. Clinical evidence supporting its value is also reviewed.

CONCLUSIONS

The use of EGFR as a predictive factor in lung adenocarcinoma may help target therapy to individual tumors to achieve the best likelihood for long-term survival and to avoid adverse events from medications unlikely to be effective.

The prevalence and prognostic significance of KRAS mutation subtypes in lung adenocarcinomas from Chinese populations

BACKGROUND

We performed this retrospective study to identify the prevalence of KRAS mutation in Chinese populations and make a comprehensive investigation of the clinicopathological features of KRAS mutation in these patients.

PATIENTS AND METHODS

Patients from 2007 to 2013 diagnosed with primary lung adeno-carcinoma who received a radical resection were examined for KRAS, EGFR, HER2, BRAF mutations, and ALK, RET, and ROS1 fusions. Clinicopathological features, including sex, age, tumor-lymph node-metastasis stage, tumor differentiation, smoking status, histological subtypes, and survival information were analyzed.

RESULT

KRAS mutation was detected in 113 of 1,368 patients. Nine different subtypes of KRAS mutation were identified in codon 12, codon 13, and codon 61. KRAS mutation was more frequently found in male patients and former/current smoker patients. Tumors with KRAS mutation had poorer differentiation. Invasive mucinous adenocarcinoma predominant and solid predominant subtypes were more frequent in KRAS mutant patients. No statistical significance was found in relapse-free survival or overall survival between patients with KRAS mutation and patients with other mutations.

CONCLUSION

In Chinese populations, we identified KRAS mutation in 8.3% (113/1,368) of the patients with lung adenocarcinoma. KRAS mutation defines a molecular subset of lung adenocarcinoma with unique clinicopathological features.

Risk of brain metastasis reduced after erlotinib treatment in advanced pulmonary adenocarcinoma patients with sensitive EGFR mutation

Purpose

Brain metastasis (BM) is associated with impaired quality of life and increased mortality. The study aimed to compare BM risk after erlotinib administration and chemotherapy in stage IIIB/IV pulmonary adenocarcinoma patients harboring epidermal growth factor receptor (EGFR) mutation.

Patients and methods

Eligible patients underwent match pair process with matching factors, including age, sex, performance status score, first-line or second-line treatment, first-line chemotherapy regimen (for the second-line treatment subgroup), stage IIIB or IV, and genotypes of EGFR mutation. BM and mortality risk of both groups were recorded and compared.

Results

In total 129 matched pairs were included for analysis. During a median follow-up of 21.5 months, time to BM risk was longer and incidences of BM within 2 years were lower in patients who received erlotinib than chemotherapy in total population, as well as subgroups of first-line treatment, second-line treatment, stage IIIB, stage IV, exon 19 deletion mutation, and exon 21 L858R mutation. Similar overall survival time and 2-year survival rates were seen in two groups totally or in any subgroup. Multivariate analysis showed that BM was retarded in patients who received erlotinib administration (hazard ratio, 1.695; P=0.001) and in patients who were in stage IIIB (hazard ratio, 1.751; P=0.001).

Conclusion

Erlotinib administration decreases BM risk in advanced pulmonary adenocarcinoma patients harboring sensitive EGFR mutations.

Management of Lung Cancer in the Elderly

Lung cancer is the leading cause of cancer-associated mortality in the USA. The median age at diagnosis of lung cancer is 70 years, and thus, about one-half of patients with lung cancer fall into the elderly subgroup. There is dearth of high level of evidence regarding the management of lung cancer in the elderly in the three broad stages of the disease including early-stage, locally advanced, and metastatic disease. A major reason for the lack of evidence is the underrepresentation of elderly in prospective randomized clinical trials. Due to the typical decline in physical and physiologic function associated with aging, most elderly do not meet the stringent eligibility criteria set forth in age-unselected clinical trials. In addition to performance status, ideally, comorbidity, cognitive, and psychological function, polypharmacy, social support, and patient preferences should be taken into account before applying prevailing treatment paradigms often derived in younger, healthier patients to the care of the elderly patient with lung cancer. The purpose of this chapter was to review the existing evidence of management of early-stage, locally advanced disease, and metastatic lung cancer in the elderly.

Targeted Therapies for Lung Cancer

Targeted therapies have become standard therapies for patients with non-small cell lung cancer (NSCLC). A phase III trial of carboplatin and paclitaxel with and without bevacizumab in patients with advanced NSCLC with non-squamous histology demonstrated a statistically significant improvement in efficacy. In patients with NSCLC with an activating epidermal growth factor receptor (EGFR) mutation (defined as exon 19 deletion and exon 21 L858R point mutation), phase III trials of EGFR tyrosine kinase inhibitors (TKI) compared to platinum-based chemotherapy have demonstrated superior efficacy in the first-line setting. In patients with NSCLC with anaplastic lymphoma kinase (ALK) rearrangements, phase III trials of crizotinib have demonstrated superior efficacy compared to platinum-pemetrexed in the first-line setting and standard chemotherapy in the second-line setting. A second-generation ALK inhibitor, ceritinib, is available for patients who have progressed after or were intolerant of crizotinib. Crizotinib has also demonstrated activity on patients with ROS1 rearrangements, and BRAF inhibitors (dabrafenib, vemurafenib) have demonstrated activity in patients with NSCLC with BRAF V600E mutation. The oncogenic mutations that are susceptible to targeted therapy are mainly found in non-squamous NSCLC. The development of targeted therapy in patients with squamous NSCLC has been more challenging due to the genomic complexity observed in the squamous histology and the low prevalence of EGFR, ALK, and ROS1 molecular alterations. A phase III trial of cisplatin and gemcitabine with and without necitumumab in patients with advanced NSCLC with squamous histology demonstrated a statistically significant improvement in progression-free and overall survival.

Erlotinib versus carboplatin and paclitaxel in advanced lepidic adenocarcinoma: IFCT-0504

The IFCT-0504 phase II trial evaluated the efficacy of erlotinib versus carboplatin-paclitaxel (CP) as first-line treatment in 130 cases of advanced lepidic-predominant adenocarcinoma (ADC).The primary objective of the study was treatment efficacy, evaluated based on an end-point of disease control at 16 weeks.The primary objective was met, with a disease control in 35 (53%) out of 66 patients treated with CP and in 25 (39.1%) out of 64 patients treated with erlotinib. Median progression-free survival (PFS) for the total population was 3.6 months. The disease control rate did not differ between either the therapeutic arms or pathological subtypes, whereas there was a strong interaction between treatment arms and tumour pathological subtypes for PFS (p=0.009). Mucinous tumour patients treated with erlotinib exhibited an increased progression risk (hazard ratio 3.4, 95% CI 1.7-6.5; p≤0.001). The PFS for nonmucinous tumour patients was similar in both arms. Median overall survival was 20.1 months and did not differ between therapeutic arms. These findings were not further elucidated by molecular analyses and the toxicity profiles were as expected.Our study demonstrated the dominant role of CP alongside erlotinib in the management of advanced lepidic ADC. Based on these findings, erlotinib should not be administered in first-line therapy to patients with lepidic ADC in the absence of an epidermal growth factor receptor mutation.

Predictive value of K-ras and PIK3CA in non-small cell lung cancer patients treated with EGFR-TKIs: a systemic review and meta-analysis

Objective

A meta-analysis was performed to augment the insufficient data on the impact of mutative EGFR downstream phosphatidylinositol-3-kinase (PI3K) and mitogen-activated protein kinase (MAPK) pathways on the clinical efficiency of epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI) treatment of non-small cell lung cancer (NSCLC) patients.

Methods

Network databases were explored in April, 2015. Papers that investigated the clinical outcomes of NSCLC patients treated with EGFR-TKIs according to the status of K-ras and/or PIK3CA gene mutation were included. A quantitative meta-analysis was conducted using standard statistical methods. Odds ratios (ORs) for objective response rate (ORR) and hazard ratios (HRs) for progression-free survival (PFS) and overall survival (OS) were calculated.

Results

Mutation in K-ras significantly predicted poor ORR [OR =0.22; 95% confidence interval (CI), 0.13-0.35], shorter PFS (HR =1.56; 95% CI, 1.27-1.92), and shorter OS (HR =1.59; 95% CI, 1.33-1.91) in NSCLC patients treated with EGFR-TKIs. Mutant PIK3CA significantly predicted shorter OS (HR =1.83; 95% CI, 1.05-3.20), showed poor ORR (OR =0.70; 95% CI, 0.22-2.18), and shorter PFS (HR =1.79; 95% CI, 0.91-3.53) in NSCLC patients treated with EGFR-TKIs.

Conclusion

K-ras mutation adversely affected the clinical response and survival of NSCLC patients treated with EGFR-TKIs. PIK3CA mutation showed similar trends. In addition to EGFR, adding K-ras and PIK3CA as routine gene biomarkers in clinical genetic analysis is valuable to optimize the effectiveness of EGFR-TKI regimens and identify optimal patients who will benefit from EGFR-TKI treatment.

Concurrence of EGFR amplification and sensitizing mutations indicate a better survival benefit from EGFR-TKI therapy in lung adenocarcinoma patients

OBJECTIVES

Tumor heterogeneity, which causes different EGFR mutation abundance, is believed to be responsible for varied progression-free survival (PFS) in lung adenocarcinoma (ADC) patients receiving EGFR-TKI treatment. Frequent EGFR amplification and its common affection in EGFR mutant allele promote the hypothesis that EGFR mutant abundance might be determined by EGFR copy number variation and therefore examination of EGFR amplification status in EGFR mutant patients could predict the efficacy of EGFR-TKI treatment.

MATERIALS AND METHODS

In this study, 86 lung ADC patients, who harbored EGFR activating mutations and received EGFR-TKI treatment, were examined for EGFR amplification and expression by Dual-color Silver in situ Hybridization (DISH) and immunohistochemistry analysis, respectively.

RESULTS AND CONCLUSION

Forty-one of 86 (47.7%) samples with EGFR activating mutations were identified with EGFR amplification. Patients with EGFR gene amplification had a significantly longer PFS than those without (16.3 vs. 9.1 months, p=0.004). The EGFR expression was then examined by immunohistochemistry analysis. Thirty-nine of 86 (45%) tumors had EGFR overexpression, which was significantly correlated with EGFR amplification (p=0.000). However, patients with EGFR overexpression exhibited no difference in PFS (14.1 vs. 13.3 months, p=0.797). In conclusion, EGFR amplification occurs frequently in lung ADC patients harboring EGFR activating mutations, and could serve as an indicator for better response from EGFR-TKI treatment.