Detection of epidermal growth factor receptor mutation in transbronchial needle aspirates of non-small cell lung cancer

Guidelines for diagnostic flexible bronchoscopy in adults: Joint Indian Chest Society/National College of chest physicians (I)/Indian association for bronchology recommendations

Flexible bronchoscopy (FB) is commonly performed by respiratory physicians for diagnostic as well as therapeutic purposes. However, bronchoscopy practices vary widely across India and worldwide. The three major respiratory organizations of the country supported a national-level expert group that formulated a comprehensive guideline document for FB based on a detailed appraisal of available evidence. These guidelines are an attempt to provide the bronchoscopist with the most scientifically sound as well as practical approach of bronchoscopy. It involved framing appropriate questions, review and critical appraisal of the relevant literature and reaching a recommendation by the expert groups. The guidelines cover major areas in basic bronchoscopy including (but not limited to), indications for procedure, patient preparation, various sampling procedures, bronchoscopy in the ICU setting, equipment care, and training issues. The target audience is respiratory physicians working in India and well as other parts of the world. It is hoped that this document would serve as a complete reference guide for all pulmonary physicians performing or desiring to learn the technique of flexible bronchoscopy.

Conventional transbronchial needle aspiration is promising for identifying EGFR mutations in lung adenocarcinoma

Background

Conventional transbronchial needle aspiration (TBNA) is advantageous for the one‐step diagnosis and staging of lung adenocarcinoma under topical anesthesia and conscious sedation. We examined its efficacy for identifying EGFR mutations.

Methods

Forty‐seven patients with proven or suspected lung adenocarcinoma indicated for hilar‐mediastinal lymph node (LN) staging between June 2011 and December 2017 were enrolled. The cellblock was prepared using the plasma‐thrombin method. TaqMan PCR was used to detect mutations. Considering cost effectiveness, only the sample with the highest tumor cell fraction in the same patient was chosen for analysis.

Results

TBNA provided positive results of malignancy in 27 patients. Seventeen patients (63.0%) had cellblocks eligible for mutation testing. Bronchial biopsy (n = 6), neck LN fine needle aspiration (n = 1), and brushing (n = 1), provided higher tumor cell fractions for analysis in eight patients. TBNA was the exclusive method used in nine patients (19.1%). For patients with an inadequate TBNA cellblock, bronchial biopsy (n = 5), neck LN fine needle aspiration (n = 3), computed tomography‐guided transthoracic needle biopsy (n = 1), and brushing (n = 1) were used for analysis. Modification to specimen processing to prevent exhaustion by cytology after June 2016 improved the adequacy of cellblock samples (9/10, 90% vs. 8/17, 47.1%; P = 0.042).

Conclusions

These findings suggest the promising role of conventional TBNA and highlight the challenges of doing more with less in an era of precision medicine.

Somatic mutations and immune checkpoint biomarkers

The development of molecular testing for identifying somatic mutations and immune checkpoint biomarkers has directed treatment towards personalized medicine for patients with non-small cell lung cancer. The choice of molecular testing in a clinical setting is influenced by cost, expertise in the technology, instrumentation setup and sample type availability. The molecular techniques described in this review include immunohistochemistry (IHC), fluorescent in situ hybridization, direct sequencing, real-time polymerase chain reaction (PCR), denaturing high-performance liquid chromatography, matrix-assisted laser desorption/ionization time of flight mass spectrometry and next-generation sequencing (NGS). IHC is routinely used in clinical practice for the classification, differentiation, histology and identification of targetable alterations of epidermal growth factor receptor (EGFR), anaplastic lymphoma kinase (ALK) and programmed death ligand-1 (PD-L1). Recently, the PD-L1 pathway was identified as being exploited by tumour cells, allowing immune resistance and tumour evasion. The development of immune checkpoint inhibitors as treatment for tumours expressing checkpoints has highlighted the need for standardized IHC assays to inform treatment decisions for patients. Direct sequencing was historically the gold standard for mutation testing for EGFR, KRAS (Kirsten rat sarcoma viral oncogene homologue) and BRAF (v-Raf murine sarcoma viral oncogene homologue B1) requiring a high ratio of tumour to normal cells, but this has been superseded by more sensitive methods. NGS is a new emerging technique, which allows high-throughput coverage of frequently mutated genes, including less common BRAF and MET mutations and alterations in tumour suppressor genes. When an NGS platform is unavailable, PCR-based technologies offer an efficient and cost-effective single gene test to guide patient treatment. This article will review these techniques and discuss the future of molecular platforms underpinning clinical management decisions.

Efficacy of EGFR tyrosine kinase inhibitors in non-small cell lung cancer patients harboring different types of EGFR mutations: A retrospective analysis

With the development of molecular pathology, many types of epidermal growth factor receptor (EGFR) mutations have been identified. The efficacy of EGFR tyrosine kinase inhibitors (EGFR-TKIs) in non-small cell lung cancer (NSCLC) patients with different types of EGFR mutations, especially in patients with single rare mutations or complex mutations (co-occurrence of two or more different mutations), has not been fully understood. This study aimed to examine the efficacy of EGFR-TKIs in NSCLC patients with different types of EGFR mutations. Clinical data of 809 NSCLC patients who harbored different types of EGFR mutations and treated from January 2012 to October 2016 at Renmin Hospital and Zhongnan Hospital, Wuhan, were retrospectively reviewed. The clinical characteristics of these patients and the efficacy of EGFR-TKIs were analyzed. Among these patients, 377 patients had only the EGFR del-19 mutation, 362 patients the EGFR L858R mutation in exon 21, 33 patients single rare mutations and 37 patients complex mutations. Among these 809 patients, 239 patients were treated with EGFR-TKIs. In all the 239 patients, the disease control rate (DCR) was 93.7% with two patients (0.2%) achieving complete response (CR), the median progression free survival (PFS) was 13.0 months (95% confidence interval [CI], 11.6-14.4 months), and the median overall survival (OS) was 55.0 months (95% CI, 26.3-83.7 months). Subgroup analysis revealed that the DCR in patients harboring single rare or complex mutations of EGFR was significantly lower than in those with del-19 or L858R mutation (P<0.001). Patients with classic mutations (del-19 and/or L858R mutations) demonstrated longer PFS (P<0.001) and OS (P=0.017) than those with uncommon mutations (single rare and/or complex mutations). Furthermore, the patients with single rare mutations had shorter median OS than in those with other mutations. Multivariate Cox regression analysis identified that the type of EGFR mutations was an independent risk factor for PFS (hazard ratio [HR]=0.308, 95% CI, 0.191-0.494, P<0.001) and OS (HR=0.221, 95% CI, 0.101-0.480, P<0.001). The results suggest that the single rare or complex EGFR mutations confer inferior efficacy of EGFR-TKIs treatment to the classic mutations. The prognosis of the single rare EGFR mutations is depressing. EGFR-TKIs may be not a good choice for NSCLC patients with single rare mutations of EGFR. Further studies in these patients with uncommon mutations (especially for the patients with single rare mutations) are needed to determine a better precision treatment.

Comparison of direct sequencing and amplification refractory mutation system for detecting epidermal growth factor receptor mutation in non-small-cell lung cancer patients: a systematic review and meta-analysis

BACKGROUND

Direct sequencing and amplification refractory mutation system (ARMS) are commonly used to detect epidermal growth factor receptor (EGFR) mutation status in patients with non-small-cell lung cancer to inform the decision-making on tyrosine kinase inhibitors treatment. This study aimed to systematically compare the two methods in terms of the rate of detected mutations and the association of detected mutations with clinical outcomes.

MATERIAL AND METHODS

PubMed, EMBASE, China National Knowledge Infrastructure (in Chinese) and Wanfang database (in Chinese) were searched to identify relevant studies. Meta-analyses of EGFR mutation rates, rate differences, and the associations of EGFR mutations with clinical outcomes of tyrosine kinase inhibitors treatment were conducted.

RESULTS

Eight hundred and sixty-six records were retrieved and 26 studies with 3282 patients were included. The pooled rate of mutations detected by ARMS (41%, 95% confidence interval (CI) 35% to 47%) was significantly higher than that by direct sequencing (28%, 95%CI 22% to 34%), with a weighted rate difference of 11% (95%CI 8% to 13%). There was a consistent trend that the associations between ARMS-detected mutations and clinical outcomes were stronger than those between direct-sequencing-detected mutations and clinical outcomes (pooled risk ratio for objective response: 5.18 vs. 2.25; hazard ratio for progression-free survival: 0.30 vs. 0.42; hazard ratio for overall survival: 0.46 vs. 0.54).

CONCLUSIONS

More patients with EGFR mutations can be identified by ARMS than by direct sequencing, and those identified by ARMS seems to be able to benefit more from tyrosine kinase inhibitors than those identified by direct sequencing.

Detection of epidermal growth factor receptor gene T790M mutation in cytology samples using the cobas® EGFR mutation test

OBJECTIVE

Detection of epidermal growth factor receptor (EGFR) gene mutations is essential in deciding therapeutic strategy in non-small cell lung cancer (NSCLC) patients at initial diagnosis. Moreover, in EGFR mutation-positive (EGFRm) NSCLC patients, re-biopsy at disease progression to clarify resistance mechanisms is also important. However, collecting histology samples is often difficult because of inaccessibility and invasiveness. In some cases, only cytology samples can be collected, and studies have reported that cytology samples are appropriate for EGFR gene mutation testing. The cobas^® EGFR Mutation Test (Roche Molecular Systems Inc., Branchburg, New Jersey, USA) is approved as a companion diagnostic for osimertinib, a third-generation EGFR-tyrosine kinase inhibitor approved in Japan. However, it is not clear whether the EGFR T790M mutation can be detected in cytology samples using this test. The primary objective of this study was to assess concordance of EGFR T790M gene mutation detection between histology and matched cytology samples using the cobas^® EGFR Mutation Test.

MATERIALS AND METHODS

We conducted a multicenter, observational study in Japan. Overall, 41 EGFRm NSCLC patients who had both histology and cytology samples collected at the same time at re-biopsy and with the results of EGFR mutation test using histology samples were enrolled. The EGFR mutation status of both sample types was tested using the cobas^® EGFR Mutation Test and the concordance rates were calculated.

RESULTS

The EGFR T790M mutation detection rate in histology and cytology samples was 42.5% and 37.5%, respectively. The overall percent agreement between the histology and cytology samples was 91.7%.

CONCLUSIONS

These data demonstrate that the cobas^® EGFR Mutation Test can detect the EGFR T790M mutation in both cytology and histology samples.

Impact of epidermal growth factor receptor gene expression level on clinical outcomes in epidermal growth factor receptor mutant lung adenocarcinoma patients taking first-line epidermal growth factor receptor-tyrosine kinase inhibitors

Epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitors (TKIs) are first-choice treatments for advanced non-small-cell lung cancer patients harboring EGFR mutations. Although EGFR mutations are strongly predictive of patients' outcomes and their response to treatment with EGFR-TKIs, early failure of first-line therapy with EGFR-TKIs in patients with EGFR mutations is not rare. Besides several clinical factors influencing EGFR-TKI efficacies studied earlier such as the Eastern Cooperative Oncology Group performance status or uncommon mutation, we would like to see whether semi-quantify EGFR mutation gene expression calculated by 2^-ΔΔct was a prognostic factor in EGFR-mutant non-small cell lung cancer patients receiving first-line EGFR-TKIs. This retrospective study reviews 926 lung cancer patients diagnosed from January 2011 to October 2013 at the Kaohsiung Chang Gung Memorial Hospital in Taiwan. Of 224 EGFR-mutant adenocarcinoma patients, 148 patients who had 2^-ΔΔct data were included. The best cutoff values of 2^-ΔΔct for in-frame deletions in exon 19 (19 deletion) and a position 858 substituted from leucine (L) to an arginine (R) in exon 21 (L858R) were determined using receiver operating characteristic curves. Patients were divided into high and low 2^-ΔΔct expression based on the above cutoff level. The best cutoff point of 2^-ΔΔct value of 19 deletion and L858R was 31.1 and 104.7, respectively. In all, 92 (62.1%) patients showed high 2^-ΔΔct expression and 56 patients (37.9%) low 2^-ΔΔct expression. The mean age was 65.6 years. Progression-free survival of 19 deletion mutant patients with low versus high expression level was 17.07 versus 12.04 months (P = 0.004), respectively. Progression-free survival of L858 mutant patients was 13.75 and 7.96 months (P = 0.008), respectively. EGFR-mutant lung adenocarcinoma patients with lower EGFR gene expression had longer progression-free survival duration without interfering overall survival.

Association between GWAS-identified lung adenocarcinoma susceptibility loci and EGFR mutations in never-smoking Asian women, and comparison with findings from Western populations

To evaluate associations by EGFR mutation status for lung adenocarcinoma risk among never-smoking Asian women, we conducted a meta-analysis of 11 loci previously identified in genome-wide association studies (GWAS). Genotyping in an additional 10,780 never-smoking cases and 10,938 never-smoking controls from Asia confirmed associations with eight known single nucleotide polymorphisms (SNPs). Two new signals were observed at genome-wide significance (P < 5 × 10-8), namely, rs7216064 (17q24.3, BPTF), for overall lung adenocarcinoma risk, and rs3817963 (6p21.3, BTNL2) which is specific to cases with EGFR mutations. In further sub-analyses by EGFR status, rs9387478 (ROS1/DCBLD1) and rs2179920 (HLA-DPB1) showed stronger estimated associations in EGFR-positive compared to EGFR-negative cases. Comparison of the overall associations with published results in Western populations revealed that the majority of these findings were distinct, underscoring the importance of distinct contributing factors for smoking and non-smoking lung cancer. Our results extend the catalogue of regions associated with lung adenocarcinoma in non-smoking Asian women and highlight the importance of how the germline could inform risk for specific tumour mutation patterns, which could have important translational implications.

A Survival Scoring System for Non-Small Cell Lung Cancer Patients with De Novo Bone Metastases

In the pre-tyrosine kinase inhibitors (TKIs) era, non-small cell lung cancer (NSCLC) patients with de novo bone metastases had a worse prognosis than those without. However, whether epidermal growth factor receptor (EGFR)-TKIs affect the outcomes of EGFR mutant NSCLC patients with de novo bone metastases has not been well studied thus far. We retrospectively studied the effect of EGFR mutation status and first-line EGFR-TKIs on patient outcomes and created a survival scoring system for NSCLC patients with de novo bone metastases. This retrospective study evaluated 1510 NSCLC patients diagnosed between November 2010 and March 2014. Among these patients, 234 patients had de novo bone metastases. We found that 121 of these 234 patients (51.7%) had positive EGFR mutation tests, and a positive EGFR mutation test significantly affected overall survival (OS) (EGFR mutant: 15.2 months, EGFR wild type: 6.5 months; p < 0.001). Other prognostic factors significant in the multivariable analysis for NSCLC with de novo bone metastases included Eastern Cooperative Oncology Group performance status (PS) (OS; PS 0–2: 11.2 months, PS 3–4: 4.9 months; p = 0.002), presence of extraosseous metastases (OS; with extraosseous metastases: 8.8 months, without extraosseous metastases: 14.0 months; p = 0.008), blood lymphocyte-to-monocyte ratio (LMR) (OS; LMR > 3.1: 17.1months, LMR ≤ 3.1: 6.9months; p < 0.001). A positive EGFR mutation status reversed the poor outcomes of NSCLC patients with de novo bone metastases. A simple and useful survival scoring system including the above clinical parameters was thus created for NSCLC patients with de novo bone metastases.

Association of variations in HLA class II and other loci with susceptibility to EGFR-mutated lung adenocarcinoma

Lung adenocarcinoma driven by somatic EGFR mutations is more prevalent in East Asians (30–50%) than in European/Americans (10–20%). Here we investigate genetic factors underlying the risk of this disease by conducting a genome-wide association study, followed by two validation studies, in 3,173 Japanese patients with EGFR mutation-positive lung adenocarcinoma and 15,158 controls. Four loci, 5p15.33 (TERT), 6p21.3 (BTNL2), 3q28 (TP63) and 17q24.2 (BPTF), previously shown to be strongly associated with overall lung adenocarcinoma risk in East Asians, were re-discovered as loci associated with a higher susceptibility to EGFR mutation-positive lung adenocarcinoma. In addition, two additional loci, HLA class II at 6p21.32 (rs2179920; P =5.1 × 10⁻¹⁷, per-allele OR=1.36) and 6p21.1 (FOXP4) (rs2495239; P=3.9 × 10⁻⁹, per-allele OR=1.19) were newly identified as loci associated with EGFR mutation-positive lung adenocarcinoma. This study indicates that multiple genetic factors underlie the risk of lung adenocarcinomas with EGFR mutations.

EGFR mutations in lung adenocarcinoma are more frequent in East Asians compared to other populations. Here, the authors carry out a genome-wide association study in EGFR mutant cancers and identify loci that are associated with risk of developing this molecular subtype of cancer.

Antacid Use and De Novo Brain Metastases in Patients with Epidermal Growth Factor Receptor-Mutant Non-Small Cell Lung Cancer Who Were Treated Using First-Line First-Generation Epidermal Growth Factor Receptor Tyrosine Kinase Inhibitors

Background

Antacid treatments decrease the serum concentrations of first-generation epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitors (TKIs), although it is unknown whether antacids affect clinical outcomes. As cerebrospinal fluid concentrations of TKIs are much lower than serum concentrations, we hypothesized that this drug-drug interaction might affect the prognosis of patients with de novo brain metastases.

Materials and Methods

This retrospective study evaluated 269 patients with EGFR-mutant non-small cell lung cancer (NSCLC) who had been diagnosed between December 2010 and December 2013, and had been treated using first-line first-generation EGFR-TKIs. Among these patients, we identified patients who concurrently used H2 receptor antagonists (H2RAs) and proton pump inhibitors (PPIs) as antacids. Patients who exhibited >30% overlap between the use of TKIs and antacids were considered antacid users.

Results

Fifty-seven patients (57/269, 21.2%) were antacid users, and antacid use did not significantly affect progression-free survival (PFS; no antacids: 11.2 months, H2RAs: 9.4 months, PPIs: 6.7 months; p = 0.234). However, antacid use significantly reduced overall survival (OS; no antacids: 25.0 months, H2RAs: 15.5 months, PPIs: 11.3 months; p = 0.002). Antacid use did not affect PFS for various metastasis sites, although antacid users with de novo brain metastases exhibited significantly shorter OS, compared to non-users (11.8 vs. 16.3 months, respectively; p = 0.041). Antacid use did not significantly affect OS in patients with bone, liver, or pleural metastases.

Conclusion

Antacid use reduced OS among patients with EGFR-mutant NSCLC who were treated using first-line first-generation EGFR-TKIs, and especially among patients with de novo brain metastases.

Fine-needle aspiration of small pulmonary nodules yields material for reliable molecular analysis of adenocarcinomas

INTRODUCTION

Early molecular characterization with Kirsten rat sarcoma factor, epidermal growth factor, and anaplastic lymphoma kinase are critical to manage pulmonary adenocarcinoma. Fine-needle aspiration (FNA) of lesions <2 cm are routine in our institution and are used in molecular analysis. We report our experience.

MATERIALS AND METHODS

We searched our databank for primary pulmonary adenocarcinomas diagnosed by FNA between January 2009 and April 2013. Size of the lesion aspirated, molecular results, and sample source (FNA versus surgical specimen) were recorded. We compared the frequency of mutations identified by FNA versus surgical specimens and the frequency of mutations in lesions by size (<1 cm, 1-2 cm, >2 cm).

RESULTS

We identified 397 primary pulmonary adenocarcinomas. Molecular studies were requested by the clinician in 89 (22%) of primary adenocarcinomas. FNAs were used in 55 cases; 51 (93%) yielded sufficient material for molecular studies; surgical tissue were used in 34 cases; 33 (97%) yielded sufficient material for molecular studies. The insufficient specimens came from 2 FNAs of 0.6 cm nodules, an FNA of a 2 cm nodule, and a core biopsy.

CONCLUSIONS

FNA was adequate for molecular analysis of small nodules. In nodules greater than 0.6 cm, the adequacy is comparable to surgical tissue. There was no statistically significant change in mutation rate by size (53%-58%). Importantly, FNA of small lesions for cytological diagnosis and molecular analysis is encouraged by our data and experience in order to provide early treatment.

Baseline, Trend, and Normalization of Carcinoembryonic Antigen as Prognostic Factors in Epidermal Growth Factor Receptor-Mutant Nonsmall Cell Lung Cancer Patients Treated With First-Line Epidermal Growth Factor Receptor Tyrosine Kinase Inhibitors

Among epidermal growth factor receptor (EGFR) mutation status unknown nonsmall cell lung cancer (NSCLC) patients, those with higher carcinoembryonic antigen (CEA) level are more likely to response to EGFR-tyrosine kinase inhibitors (TKIs) because they tend to have mutant epidermal growth factor receptor (EGFR). However, patients with higher CEA also have more tumor burden. With the above paradoxical evidence, it is prudent to understand the prognostic significance of baseline CEA in patients with EGFR-mutant NSCLC treated with first-line EGFR-TKIs. The clinical significance of the trend in CEA after treatment and the impact of CEA normalization during EGFR-TKI therapy are also unknown and potentially important. A total of 241 patients who received first-line EGFR-TKIs were included. As to baseline CEA, patients were divided into normal, low, and high baseline CEA by cut point determined by receiver operating characteristic curves. As to CEA responses, patients were divided into 3 groups accordingly to their amount of CEA change after taking TKIs. In group A, 1-month follow-up CEA level decreased more than 35% with nadir CEA normalization; in group B, 1-month follow-up CEA level decreased more than 35% without nadir CEA normalization; and in group C, 1-month follow-up CEA level decreased less than 35% or increased. Patients with higher baseline CEA levels had shorter progression-free survival (PFS) and overall survival (OS) (CEA > 32 vs 5-32 vs <5  ng/mL, PFS = 8.8 vs 11.3 vs 14.4 months, respectively, P < 0.001; OS = 17.8 vs 22.0 vs 27.9 months, respectively, P = 0.01). For trend and CEA normalization in groups A, B, and C, PFS was 14.3, 10.6, and 7.1 months, respectively (P < 0.001); OS was 29.7, 20.0, and 16.2 months, respectively (P < 0.001). Baseline, trend, and normalization of CEA levels are potential prognostic markers for patients with EGFR-mutant advanced NSCLC treated with first line EGFR-TKIs.

Targeted therapies for patients with advanced NSCLC harboring wild-type EGFR: what's new and what's enough

Historically, non-small cell lung cancer (NSCLC) is divided into squamous and nonsquamous subtypes based on histologic features. With a growing number of oncogenic drivers being identified in squamous and nonsquamous NSCLC, this malignancy has been recently divided into several distinct subtypes according to the specific molecular alterations. This new paradigm has substantially highlighted the treatment of advanced NSCLC, shifting it from standard chemotherapy according to specific histologic subtypes to targeted therapy according to specific oncogenic drivers. The application of epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitors (TKIs) in NSCLC patients harboring activating EGFR mutations has been a representative model of precise medicine in the treatment of NSCLC. As the role of EGFR-TKIs in routine management of patients with advanced NSCLC has been well established, this review provides an overview of alternative targeted therapy in the treatment of NSCLC, including EGFR-TKIs for patients with wild-type EGFR NSCLC, as well as other targeted agents either clinical available or in early- to late-stage development.

Suitability of surgical tumor tissues, biopsy, or cytology samples for epidermal growth factor receptor mutation testing in non-small cell lung carcinoma based on chinese population

BACKGROUND

Epidermal growth factor receptor (EGFR) mutation status is crucial in treatment selection for non-small cell lung cancer (NSCLC) patients; however, the detection materials' availability remains challenging in clinical practice. In this study, we collected surgical resection tissues, lymph node biopsy, and cytological samples for EGFR mutation testing and investigated the associations between gene mutation and clinical characteristics.

METHODS

Two hundred and seventy-six NSCLC adenocarcinoma specimens were collected, and highly sensitive amplification refractory mutation system method was implemented for EGFR mutation detection, with clinicopathologic characteristics involved in the final analysis.

RESULTS

In the total of 276 samples, 96% (265/276) of tumors obtained evaluable EGFR mutation status, the frequency of mutation was 55.8% (148/265) in all specimens, and three different type samples shared a comparable successful testing rate: 97.4% (38/39) in surgical tumor tissues, 100% (108/108) in lymph node biopsy samples, and 92.2% (119/129) in cytological samples. EGFR mutation was significantly associated with sex, smoking history, lymph node metastasis status (N stage), primary tumor size, testing tissues origin, and sample type (P < .05). Multivariate analysis reconfirmed that smoking history and primary tumor size shared significant correlation with EGFR mutation after adjustment.

CONCLUSIONS

Both lymph node biopsy and cytological samples were suitable surrogates for EGFR mutation detection in NSCLC compared with tumor tissues, gene status should be detected widely considering the high EGFR mutation rate, and nonsmoking history together with smaller primary tumor size was an independent indicator of EGFR mutation status.

Targeted treatment of mutated EGFR-expressing non-small-cell lung cancer: focus on erlotinib with companion diagnostics

Deeper understanding of the pathobiology of non-small-cell lung cancer (NSCLC) has led to the development of small molecules that target genetic mutations known to play critical roles in the progression to metastatic disease. The discovery of epidermal growth factor receptor (EGFR) mutations in 15%–20% of lung adenocarcinomas and the associated response to EGFR tyrosine kinase inhibitors have provided a successful avenue of attack in late-stage adenocarcinomas. Use of the EGFR tyrosine kinase inhibitors gefitinib, erlotinib, and afatinib is limited to patients who have adenocarcinomas with known activating EGFR mutations. However, the EGFR mutation testing landscape is varied and includes many screening and targeted methods, each with its own benefits and limitations. These tests can simplify the drug discovery process, make clinical trials more efficient and informative, and individualize cancer therapy. In practice, the choice of method should be determined by the nature of the sample to be tested, the testing laboratory’s expertise and access to equipment, and whether the detection of only known activating EGFR mutations, or of all possible mutations, is required. Development of companion diagnostic tests for this identification is advancing; nevertheless, the use of such tests merits greater attention.

Guideline for the acquisition and preparation of conventional and endobronchial ultrasound-guided transbronchial needle aspiration specimens for the diagnosis and molecular testing of patients with known or suspected lung cancer

RATIONALE

Conventional transbronchial needle aspiration (TBNA) and endobronchial ultrasound (EBUS)-TBNA are widely accepted tools for the diagnosis and staging of lung cancer and the initial procedure of choice for staging. Obtaining adequate specimens is key to provide a specific histologic and molecular diagnosis of lung cancer.

OBJECTIVES

To develop practice guidelines on the acquisition and preparation of conventional TBNA and EBUS-TBNA specimens for the diagnosis and molecular testing of (suspected) lung cancer. We hope to improve the global unification of procedure standards, maximize the yield and identify areas for research.

METHODS

Systematic electronic database searches were conducted to identify relevant studies for inclusion in the guideline [PubMed and the Cochrane Library (including the Cochrane Database of Systematic Reviews)].

MAIN RESULTS

The number of needle aspirations with both conventional TBNA and EBUS-TBNA was found to impact the diagnostic yield, with at least 3 passes needed for optimal performance. Neither needle gauge nor the use of miniforceps, the use of suction or the type of sedation/anesthesia has been found to improve the diagnostic yield for lung cancer. The use of rapid on-site cytology examination does not increase the diagnostic yield. Molecular analysis (i.e. EGFR, KRAS and ALK) can be routinely performed on the majority of cytological samples obtained by EBUS-TBNA and conventional TBNA. There does not appear to be a superior method for specimen preparation (i.e. slide staining, cell blocks or core tissue). It is likely that optimal specimen preparation may vary between institutions depending on the expertise of pathology colleagues.

Predictive factors associated with gefitinib response in patients with advanced non-small-cell lung cancer (NSCLC)

PURPOSE

A number of different clinical characteristics have been reported to singly correlate with therapeutic activity of epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) in advanced non-small-cell lung cancer (NSCLC). This study aimed to identify predictive factors associated with prognostic benefits of gefitinib.

PATIENTS AND METHODS

EGFR gene typing in 33 advanced NSCLC patients received gefitinib (250 mg/day) were analyzed with mutant-enriched PCR assay. Gefitinib response was evaluated with potential predictive factors retrospectively.

RESULTS

The overall objective response rate (ORR) and median progression-free survival (PFS) in the 33 patients treated by gefitinib were 45.5% and 3.0 (2.0-4.0) months. The ORR and median PFS in EGFR gene mutation patients were significantly higher/longer than those in EGFR gene wild-type patients (P<0.01). Similarly, the ORR and median PFS in non-smoker patients were significantly higher/longer than those in smoker patients (P<0.05, P<0.01, respectively). However, no difference for ORR and median PFS occurred between male and female patients. Logistic multivariate analysis showed that only EGFR mutated gene was significantly associated with the ORR (P<0.01). Both EGFR mutated gene and non-smoker were the major factors that contributed to PFS (P<0.05).

CONCLUSIONS

EGFR mutated gene and non-smoker status are potential predictors for gefitinib response in NSCLC patients.

Impact of EGFR mutation detection methods on the efficacy of erlotinib in patients with advanced EGFR-wild type lung adenocarcinoma

INTRODUCTION

Methods used for epidermal growth factor receptor (EGFR) mutation testing vary widely. The impact of detection methods on the rates of response to EGFR-tyrosine kinase inhibitors (TKIs) in EGFR-wild type (wt) lung adenocarcinoma patients is unknown.

METHODS

We recruited the Group-I patients to evaluate the efficacy of erlotinib in patients with EGFR-wt lung adenocarcinoma by either direct sequencing (DS) or mutant type-specific sensitive (MtS) methods in six medical centers in Taiwan. Cross recheck of EGFR mutations was performed in patients who achieved objective response to erlotinib and had adequate specimens. The independent Group-II lung adenocarcinoma patients whose EGFR mutation status determined by DS were recruited to evaluate the potential limitations of three MtS methods.

RESULTS

In Group-I analysis, 38 of 261 EGFR-wt patients (14.6%) achieved partial response to erlotinib treatment. Nineteen patients (50.0%) had adequate specimens for cross recheck of EGFR mutations and 10 of them (52.6%) had changes in EGFR mutation status, 5 in 10 by DS and 5 in 9 by MtS methods originally. In Group-II analysis, 598 of 996 lung adenocarcinoma patients (60.0%) had detectable EGFR mutations. The accuracy rates of the three MtS methods, MALDI-TOF MS, Scorpions ARMS and Cobas, were 87.8%, 86.8% and 85.8%, respectively.

CONCLUSIONS

A significant portion of the erlotinib responses in EGFR-wt lung adenocarcinoma patients were related to the limitations of detection methods, not only DS but also MtS methods with similar percentages. Prospective studies are needed to define the proper strategy for EGFR mutation testing.

A comparison of epidermal growth factor receptor mutation testing methods in different tissue types in non-small cell lung cancer

The detection of somatic epidermal growth factor receptor (EGFR) mutations is valuable when an appropriate therapy, either EGFR-tyrosine kinase inhibitor (TKI) therapy or chemotherapy, for patients with advanced non-small cell lung cancer (NSCLC) needs to be selected. Although it is well‑understood that EGFR mutation detection is significant for the decision‑making regarding treatment, no consensus on the methodology that should be the most preferebale for detecting mutations in clinical practice has been reached. The presence of false positives due to the technique carried out for mutation analysis affects the accurate estimation of response EGFR-TKI therapy. Furthermore, false negatives directly exclude the potential application of an EGFR-TKI. In the present study, we present the results of detecting EGFR mutations in individual sample types using three different low- or high-sensitivity techniques. We suggest that the choice of the method used should be made based on the type of the sample. Our results revealed that EGFR mutations were less frequently detected in bronchoscopic biopsies, regardless of the method used. However, the amplification refractory mutation system (ARMS) was optimal owing to the small amount of DNA prepared for biopsy. The cytology sample was a valuable alternative to traditional samples, given that a sensitive method for detecting mutations was used. For surgical resections, the testing method may be selected based on the expertise of each laboratory, but direct sequencing is highly recommended. We also suggest that two methods should be used sequentially (the screening and targeted methods) in clinical practice due to the presence of non-neglected discordance between any method from its own benefits and drawbacks.

Molecular testing of NSCLC using a platform for rapid detection of multiple oncogenetic mutations

INTRODUCTION

Molecular testing has become the standard of care for treatment of non-small cell lung cancer. Cytologic samples are frequently the only diagnostic material obtained due to the reduced procedure-related morbidity of fine-needle aspiration. This is a report of our laboratory's experience using cytology specimens for molecular testing of lung tumors.

MATERIALS AND METHODS

All tumors were tested in the Molecular Diagnostics Laboratory at Vanderbilt University Medical Center using the ABI PRISM SNaPshot Multiplex Kit and a separate laboratory-developed test. The assay included testing for KRAS, BRAF, NRAS, PIK3CA, MEK1, AKT1, PTEN, and EGFR mutations. Specimens were tested using a paraffin-embedded cell block, and a percentage of tumor cells was determined to establish adequacy of the sample. Ten percent or more tumor cells was considered adequate. Eighty-five cytology specimens were referred for testing, and 12% were considered inadequate. Specimens tested included 55 adenocarcinomas, 6 squamous cell carcinomas, 5 large cell neuroendocrine carcinomas, 2 small cell carcinomas, and 7 categorized as non-small cell carcinoma, unable to further differentiate. Primary lung tumors as well as lung tumors metastatic to other tissues were tested. The samples ranged from 3 mm to 15 mm, and all but 1 sample had >10% tumor cells on initial and final hematoxylin and eosin slides.

RESULTS

Forty-eight mutations were identified in 42 tumors: 21 KRAS, 22 EGFR, 1 BRAF, 1 NRAS, 1 PIK3CA, 1 ERBB2, and 1 MEK1. Thirty-three tumors were negative for the mutations tested.

CONCLUSIONS

The DNA yield from cytology specimens is routinely adequate for molecular mutation analysis of lung cancer.

Highly sensitive EGFR mutation detection by specific amplification of mutant alleles

Mutations in the tyrosine kinase domain of the epidermal growth factor receptor (EGFR) gene predict benefit from tyrosine kinase inhibitors in patients suffering from non-small-cell lung cancer. In this study, we developed a fast, simple, cost-effective and highly sensitive assay for detection of five clinically important EGFR mutations in exon 19 (2235_2249del and 2236_2250del), exon 20 (C2369T) and exon 21 (T2573G and c.2573_2574 TG > GT). We designed EGFR mutation detection assays by combining allele-specific PCR amplification with the detection of SYBR Green I fluorescence, and optimized PCR conditions to specifically amplify mutant alleles. These one-step assays were able to detect the mutations at levels as low as 1.5 mutant copies in a DNA sample. Commercially available probe-based allele-specific PCR exhibited relatively poor performance when detecting very low copies of mutated DNA, especially in exon 19 and 20. Our assays offered dramatically less reagent cost than that of the commercial kit and generated results in less than 90 min after DNA extraction. These protocols can also be applied to conventional thermal cyclers followed by gel electrophoresis detection.

Determination of EGFR mutations in single cells microdissected from enriched lung tumor cells in peripheral blood

A minimally invasive and repeatable approach for real-time epidermal growth factor receptor (EGFR) mutation surveillance would be highly beneficial for individualized therapy of late stage lung cancer patients whose surgical specimens are often not available. We aim to develop a viable method to detect EGFR mutations in single circulating tumor cells (CTCs). Using a model CTC system of spiked tumor cells in whole blood, we evaluated EGFR mutation determination in single tumor cells enriched from blood. We used magnetic beads labeled with antibody against leukocyte surface antigens to deplete leukocytes and enrich native CTCs independent of epithelial marker expression level. We then used laser cell microdissection (LCM) to isolate individual CTCs, followed by whole-genome amplification of the DNA for exon 19 microdeletion, L858R and T790M mutation detection by PCR sequencing. EGFR mutations were successfully measured in individual spiked tumor cells enriched from 7.5 ml whole blood. Whole-genome amplification provided sufficient DNA for mutation determination at multiple sites. Ninety-five percent of the single CTCs microdissected by LCM (19/20) yielded PCR amplicons for at least one of the three mutation sites. The amplification success rates were 55 % (11/20) for exon 19 deletion, 45 % (9/20) for T790M, and 85 % (17/20) for L858R. Sequencing of the amplicons showed allele dropout in the amplification reactions, but mutations were correctly identified in 80 % of the amplicons. EGFR mutation determination from single captured tumor cells from blood is feasible with the approach described here. However, to overcome allele dropout and to obtain reliable information about the tumor's EGFR status, multiple individual tumor cells should be assayed.

Molecular testing guideline for selection of lung cancer patients for EGFR and ALK tyrosine kinase inhibitors: guideline from the College of American Pathologists, International Association for the Study of Lung Cancer, and Association for Molecular Pathology

OBJECTIVE

To establish evidence-based recommendations for the molecular analysis of lung cancers that are required to guide EGFR- and ALK-directed therapies, addressing which patients and samples should be tested, and when and how testing should be performed.

PARTICIPANTS

Three cochairs without conflicts of interest were selected, one from each of the 3 sponsoring professional societies: College of American Pathologists, International Association for the Study of Lung Cancer, and Association for Molecular Pathology. Writing and advisory panels were constituted from additional experts from these societies.

EVIDENCE

Three unbiased literature searches of electronic databases were performed to capture published articles from January 2004 through February 2012, yielding 1533 articles whose abstracts were screened to identify 521 pertinent articles that were then reviewed in detail for their relevance to the recommendations. EVIDENCE was formally graded for each recommendation.

CONSENSUS PROCESS

Initial recommendations were formulated by the cochairs and panel members at a public meeting. Each guideline section was assigned to at least 2 panelists. Drafts were circulated to the writing panel (version 1), advisory panel (version 2), and the public (version 3) before submission (version 4).

CONCLUSIONS

The 37 guideline items address 14 subjects, including 15 recommendations (evidence grade A/B). The major recommendations are to use testing for EGFR mutations and ALK fusions to guide patient selection for therapy with an epidermal growth factor receptor (EGFR) or anaplastic lymphoma kinase (ALK) inhibitor, respectively, in all patients with advanced-stage adenocarcinoma, regardless of sex, race, smoking history, or other clinical risk factors, and to prioritize EGFR and ALK testing over other molecular predictive tests. As scientific discoveries and clinical practice outpace the completion of randomized clinical trials, evidence-based guidelines developed by expert practitioners are vital for communicating emerging clinical standards. Already, new treatments targeting genetic alterations in other, less common driver oncogenes are being evaluated in lung cancer, and testing for these may be addressed in future versions of these guidelines.

Molecular testing guideline for selection of lung cancer patients for EGFR and ALK tyrosine kinase inhibitors: guideline from the College of American Pathologists, International Association for the Study of Lung Cancer, and Association for Molecular Pathology

OBJECTIVE

To establish evidence-based recommendations for the molecular analysis of lung cancers that are that are required to guide EGFR- and ALK-directed therapies, addressing which patients and samples should be tested, and when and how testing should be performed.

PARTICIPANTS

Three cochairs without conflicts of interest were selected, one from each of the 3 sponsoring professional societies: College of American Pathologists, International Association for the Study of Lung Cancer, and Association for Molecular Pathology. Writing and advisory panels were constituted from additional experts from these societies.

EVIDENCE

Three unbiased literature searches of electronic databases were performed to capture articles published published from January 2004 through February 2012, yielding 1533 articles whose abstracts were screened to identify 521 pertinent articles that were then reviewed in detail for their relevance to the recommendations. Evidence was formally graded for each recommendation.

CONSENSUS PROCESS

Initial recommendations were formulated by the cochairs and panel members at a public meeting. Each guideline section was assigned to at least 2 panelists. Drafts were circulated to the writing panel (version 1), advisory panel (version 2), and the public (version 3) before submission (version 4).

CONCLUSIONS

The 37 guideline items address 14 subjects, including 15 recommendations (evidence grade A/B). The major recommendations are to use testing for EGFR mutations and ALK fusions to guide patient selection for therapy with an epidermal growth factor receptor (EGFR) or anaplastic lymphoma kinase (ALK) inhibitor, respectively, in all patients with advanced-stage adenocarcinoma, regardless of sex, race, smoking history, or other clinical risk factors, and to prioritize EGFR and ALK testing over other molecular predictive tests. As scientific discoveries and clinical practice outpace the completion of randomized clinical trials, evidence-based guidelines developed by expert practitioners are vital for communicating emerging clinical standards. Already, new treatments targeting genetic alterations in other, less common driver oncogenes are being evaluated in lung cancer, and testing for these may be addressed in future versions of these guidelines.

Epidermal growth factor receptor tyrosine kinase inhibitors as initial therapy for non-small cell lung cancer: focus on epidermal growth factor receptor mutation testing and mutation-positive patients

Activation of the epidermal growth factor receptor (EGFR) pathway has been implicated in tumorigenesis in non-small cell lung cancer (NSCLC), the most common type of lung cancer. As a result, EGFR has become a key focus for the development of personalized therapy, with several molecular biomarkers having been investigated as potential predictors of response with EGFR tyrosine kinase inhibitors (TKIs) in NSCLC (e.g., EGFR expression, EGFR gene copy gain, and EGFR mutations). Of these, activating mutations in EGFR have thus far given the most consistent results based on the available evidence from preclinical studies and clinical trials. In an attempt to identify patients who are most likely to benefit from treatment with EGFR TKIs, EGFR mutation testing is being increasingly utilized in clinical practice. Currently in the United States, no EGFR TKI or accompanying mutational test is approved for the identification and first-line treatment of patients with advanced NSCLC. However, the first-generation EGFR TKIs, erlotinib and gefitinib, as well as investigational ErbB family TKIs and EGFR mutation testing methods are being evaluated in this setting. This review will discuss EGFR mutation testing as a biomarker of response to EGFR TKIs and the evolution of EGFR mutational analysis in NSCLC. Completed and ongoing clinical trials evaluating currently available or investigational EGFR TKIs as first-line therapy in molecularly and clinically selected patients with NSCLC, with a focus on trials in patients whose tumors have EGFR mutations, will also be reviewed.

Molecular testing guideline for selection of lung cancer patients for EGFR and ALK tyrosine kinase inhibitors: guideline from the College of American Pathologists, International Association for the Study of Lung Cancer, and Association for Molecular Pathology

OBJECTIVE

To establish evidence-based recommendations for the molecular analysis of lung cancers that are required to guide EGFR- and ALK-directed therapies, addressing which patients and samples should be tested, and when and how testing should be performed.

PARTICIPANTS

Three cochairs without conflicts of interest were selected, one from each of the 3 sponsoring professional societies: College of American Pathologists, International Association for the Study of Lung Cancer, and Association for Molecular Pathology. Writing and advisory panels were constituted from additional experts from these societies.

EVIDENCE

Three unbiased literature searches of electronic databases were performed to capture articles published from January 2004 through February 2012, yielding 1533 articles whose abstracts were screened to identify 521 pertinent articles that were then reviewed in detail for their relevance to the recommendations. Evidence was formally graded for each recommendation.

CONSENSUS PROCESS

Initial recommendations were formulated by the cochairs and panel members at a public meeting. Each guideline section was assigned to at least 2 panelists. Drafts were circulated to the writing panel (version 1), advisory panel (version 2), and the public (version 3) before submission (version 4).

CONCLUSIONS

The 37 guideline items address 14 subjects, including 15 recommendations (evidence grade A/B). The major recommendations are to use testing for EGFR mutations and ALK fusions to guide patient selection for therapy with an epidermal growth factor receptor (EGFR) or anaplastic lymphoma kinase (ALK) inhibitor, respectively, in all patients with advanced-stage adenocarcinoma, regardless of sex, race, smoking history, or other clinical risk factors, and to prioritize EGFR and ALK testing over other molecular predictive tests. As scientific discoveries and clinical practice outpace the completion of randomized clinical trials, evidence-based guidelines developed by expert practitioners are vital for communicating emerging clinical standards. Already, new treatments targeting genetic alterations in other, less common driver oncogenes are being evaluated in lung cancer, and testing for these may be addressed in future versions of these guidelines.

Detection of epidermal growth factor receptor mutations in formalin fixed paraffin embedded biopsies in Malaysian non-small cell lung cancer patients

Background

Somatic mutations of the epidermal growth factor receptor (EGFR) are reportedly associated with various responses in non-small cell lung cancer (NSCLC) patients receiving the anti-EGFR agents. Detection of the mutation therefore plays an important role in therapeutic decision making. The aim of this study was to detect EGFR mutations in formalin fixed paraffin embedded (FFPE) samples using both Scorpion ARMS and high resolution melt (HRM) assay, and to compare the sensitivity of these methods.

Results

All of the mutations were found in adenocarcinoma, except one that was in squamous cell carcinoma. The mutation rate was 45.7% (221/484). Complex mutations were also observed, wherein 8 tumours carried 2 mutations and 1 tumour carried 3 mutations.

Conclusions

Both methods detected EGFR mutations in FFPE samples. HRM assays gave more EGFR positive results compared to Scorpion ARMS.

Preparation of DNA from cytological material: effects of fixation, staining, and mounting medium on DNA yield and quality

BACKGROUND

Personalized oncology requires molecular analysis of tumor cells. Several studies have demonstrated that cytological material is suitable for DNA analysis, but to the authors' knowledge there are no systematic studies comparing how the yield and quality of extracted DNA is affected by the various techniques used for the preparation of cytological material.

METHODS

DNA yield and quality were compared using cultured human lung cancer cells subjected to different preparation techniques used in routine cytology, including fixation, mounting medium, and staining. The results were compared with the outcome of epidermal growth factor receptor (EGFR) genotyping of 66 clinical cytological samples using the same DNA preparation protocol.

RESULTS

All tested protocol combinations resulted in fragment lengths of at least 388 base pairs. The mounting agent EcoMount resulted in higher yields than traditional xylene-based medium. Spray and ethanol fixation resulted in both a higher yield and better DNA quality than air drying. In liquid-based cytology (LBC) methods, CytoLyt solution resulted in a 5-fold higher yield than CytoRich Red. Papanicolaou staining provided twice the yield of hematoxylin and eosin staining in both liquid-based preparations. Genotyping outcome and quality control values from the clinical EGFR genotyping demonstrated a sufficient amount and amplifiability of DNA in both spray-fixed and air-dried cytological samples.

CONCLUSIONS

Reliable clinical genotyping can be performed using all tested methods. However, in the cell line experiments, spray- or ethanol-fixed, Papanicolaou-stained slides provided the best results in terms of yield and fragment length. In LBC, the DNA recovery efficiency of the preserving medium may differ considerably, which should be taken into consideration when introducing LBC. Cancer (Cancer Cytopathol) 2013;121:344-353. © 2013 American Cancer Society.

Comparative study of epidermal growth factor receptor mutation analysis on cytology smears and surgical pathology specimens from primary and metastatic lung carcinomas

BACKGROUND

The detection of epidermal growth factor receptor (EGFR) mutations on small biopsy or fine-needle aspiration samples is required to guide therapy in nonsmall cell lung cancer (NSCLC). In this study, the authors compared results from EGFR mutation testing on both cytologic smears and surgical specimens and also compared the performance of platforms using 2 different technologies (pyrosequencing and real-time polymerase chain reaction) for both specimen types.

METHODS

Specimens from 114 patients were divided into 2 subsets. The first subset had 60 paired cytology smears and surgical specimens, including 37 paired specimens from the same site and 23 paired specimens from different sites. The second subset consisted of nonpaired cytology smears and formalin-fixed, paraffin-embedded (FFPE) tissues (including 8 cell blocks), which were compared on the pyrosequencing and real-time polymerase chain reaction platforms. Laser-capture microscopy was used to enrich tumor in the FFPE specimens before DNA extraction.

RESULTS

All cytology smears that were used in the study were adequate for analysis on both platforms. Comparison between smears and concurrent FFPE tissues from the same anatomic site had a concordance rate of 97%. The concordance rate between the pyrosequencing platform and the real-time polymerase chain reaction platform was 84% and 85% for FFPE tissues and cytology smears, respectively.

CONCLUSIONS

The current results indicated that direct extraction and analysis of EGFR mutations from cytology smears can be performed successfully on both a pyrosequencing platform and a real-time polymerase chain reaction platform with results comparable to those achieved in matched surgical specimens. In fine-needle aspiration/endobronchial ultrasound samples with limited tissue, cytology smears can be important for molecular analysis. Cancer (Cancer Cytopathol) 2013;121:361-369. © 2012 American Cancer Society.

Reliability of EGFR and KRAS mutation analysis on fine-needle aspiration washing in non-small cell lung cancer

INTRODUCTION

Molecular profiling of advanced non-small cell lung cancer (NSCLC) has become essential for predicting customized medical treatment decision. In light of recent advances in non-invasive diagnostic procedures in NSCLC, we aimed to demonstrate the reliability of assessing molecular tests for epidermal growth factor receptor (EGFR) and KRAS genes on cytological samples by comparing the molecular profile obtained on cells from scraped smears with that on paired needle washing in a series of NSCLC cases.

METHODS

Thirty-two cytological specimens obtained by fine-needle aspiration biopsy procedures from primary or metastatic lesions of NSCLCs were Giemsa stained for a rapid on-site evaluation and, in case of an adequate sampling, the cellular material obtained from needle washing was collected into a saline solution. Scraped smears and needle washings were tested for EGFR and KRAS by polymerase chain reaction followed by direct sequencing.

RESULTS

The concordance between EGFR and KRAS mutational status in 29 paired scraped smears and needle washing was 100%, with 7 paired samples showing the same EGFR mutation (4 L858R mutation, 2 E746_A750 deletion and 1 A767_V769 duplication) and 8 paired samples showing the same KRAS mutations (4 G12D, 1 G12A, 1 G12V and 2 G12C). Three scraped smears, uninformative for poor DNA quality, resulted EGFR mutated on paired needle washings.

CONCLUSIONS

Needle washing obtained in the course of NSCLC non-invasive fine needle diagnostic procedures allows reliable mutation testing and can be regarded as an additional important source of biological material for molecular profiling of advanced NSCLC.

Effective assessment of egfr mutation status in bronchoalveolar lavage and pleural fluids by next-generation sequencing

PURPOSE

The therapeutic choice for patients with lung adenocarcinoma depends on the presence of EGF receptor (EGFR) mutations. In many cases, only cytologic samples are available for molecular diagnosis. Bronchoalveolar lavage (BAL) and pleural fluid, which represent a considerable proportion of cytologic specimens, cannot always be used for molecular testing because of low rate of tumor cells.

EXPERIMENTAL DESIGN

We tested the feasibility of EGFR mutation analysis on BAL and pleural fluid samples by next-generation sequencing (NGS), an innovative and extremely sensitive platform. The study was devised to extend the EGFR test to those patients who could not get it due to the paucity of biologic material. A series of 830 lung cytology specimens was used to select 48 samples (BAL and pleural fluid) from patients with EGFR mutations in resected tumors. These samples included 36 cases with 0.3% to 9% of neoplastic cells (series A) and 12 cases without evidence of tumor (series B). All samples were analyzed by Sanger sequencing and NGS on 454 Roche platform. A mean of 21,130 ± 2,370 sequences per sample were obtained by NGS.

RESULTS

In series A, EGFR mutations were detected in 16% of cases by Sanger sequencing and in 81% of cases by NGS. Seventy-seven percent of cases found to be negative by Sanger sequencing showed mutations by NGS. In series B, all samples were negative for EGFR mutation by Sanger sequencing whereas 42% of them were positive by NGS.

CONCLUSIONS

The very sensitive EGFR-NGS assay may open up to the possibility of specific treatments for patients otherwise doomed to re-biopsies or nontargeted therapies.

Hotspot oncomutations: implications for personalized cancer treatment

Understanding the extent to which specific tumor mutations impact or mediate patient response to particular cancer therapies has become a rapidly increasing area of research. Recent research findings regarding four predominant mutational targets (KRAS, BRAF, EGFR and PIK3CA) show that these tumor mutations have predictive power for identifying which patients are likely to respond to particular therapies, and have prognostic significance irrespective of treatment. However, in this regard, the literature is frequently nuanced and sometimes contradictory. This lack of clarity may be due, at least in part, to the utilization of mutation detection methods with varying sensitivities across studies of different patient populations. Nevertheless, considerable evidence suggests minor tumor subpopulations may be contributing to inappropriate patient stratification, development of resistance to treatment, and the relapse that often follows treatment with molecularly targeted therapies. Consequently, mutant tumor subpopulations need to be considered in order to improve strategies for personalized cancer treatment.

EGFR mutation testing in lung cancer: a review of available methods and their use for analysis of tumour tissue and cytology samples

Aims

Activating mutations in the gene encoding epidermal growth factor receptor (EGFR) can confer sensitivity to EGFR tyrosine kinase inhibitors such as gefitinib in patients with advanced non-small-cell lung cancer. Testing for mutations in EGFR is therefore an important step in the treatment-decision pathway. We reviewed reported methods for EGFR mutation testing in patients with lung cancer, initially focusing on studies involving standard tumour tissue samples. We also evaluated data on the use of cytology samples in order to determine their suitability for EGFR mutation analysis.

Methods

We searched the MEDLINE database for studies reporting on EGFR mutation testing methods in patients with lung cancer.

Results

Various methods have been investigated as potential alternatives to the historical standard for EGFR mutation testing, direct DNA sequencing. Many of these are targeted methods that specifically detect the most common EGFR mutations. The development of targeted mutation testing methods and commercially available test kits has enabled sensitive, rapid and robust analysis of clinical samples. The use of screening methods, subsequent to sample micro dissection, has also ensured that identification of more rare, uncommon mutations is now feasible. Cytology samples including fine needle aspirate and pleural effusion can be used successfully to determine EGFR mutation status provided that sensitive testing methods are employed.

Conclusions

Several different testing methods offer a more sensitive alternative to direct sequencing for the detection of common EGFR mutations. Evidence published to date suggests cytology samples are viable alternatives for mutation testing when tumour tissue samples are not available.

An evaluation study of EGFR mutation tests utilized for non-small-cell lung cancer in the diagnostic setting

BACKGROUND

Epidermal growth factor receptor (EGFR) mutation is predictive for the efficacy of EGFR tyrosine kinase inhibitors in advanced non-small-cell lung cancer (NSCLC) treatment. We evaluated the performance, sensitivity, and concordance between five EGFR tests.

MATERIALS AND METHODS

DNA admixtures (n = 34; 1%-50% mutant plasmid DNA) and samples from NSCLC patients [116 formalin-fixed paraffin-embedded (FFPE) tissue, 29 matched bronchofiberscopic brushing (BB) cytology, and 20 additional pleural effusion (PE) cytology samples] were analyzed. EGFR mutation tests were PCR-Invader, peptide nucleic acid-locked nucleic acid PCR clamp, direct sequencing, Cycleave, and Scorpion Amplification Refractory Mutation System (ARMS). Analysis success, mutation status, and concordance rates were assessed.

RESULTS

All tests except direct sequencing detected four mutation types at ≥1% mutant DNA. Analysis success rates were 91.4%-100% (FFPE) and 100% (BB and PE cytology), respectively. Inter-assay concordance rates of successfully analyzed samples were 94.3%-100% (FFPE; kappa coefficients: 0.88-1.00), 93.1%-100% (BB cytology; 0.86-1.00), and 85.0%-100% (PE cytology; 0.70-1.00), and 93.1%-96.6% (0.86-0.93) between BB cytology and matched FFPE.

CONCLUSIONS

All EGFR assays carried out comparably in the analysis of FFPE and cytology samples. Cytology-derived DNA is a viable alternative to FFPE samples for analyzing EGFR mutations.

Comparison of epidermal growth factor receptor mutation analysis results between surgically resected primary lung cancer and metastatic lymph nodes obtained by endobronchial ultrasound-guided transbronchial needle aspiration

BACKGROUND

  Lung cancers with mutations in the epidermal growth factor receptor (EGFR) gene respond well to treatment with EGFR inhibitors. Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) is considered a useful modality to obtain samples from the mediastinal and hilar lymph nodes. However, the EGFR gene status of EBUS-TBNA samples may not always match that of primary tumors.

METHODS

  In 14 node-positive patients diagnosed by EBUS-TBNA, EGFR mutation analysis results were compared between EBUS-TBNA samples and surgically removed primary tumors. EGFR mutation was screened with peptide nucleic acid-locked nucleic acid polymerase chain reaction (PNA-LNA PCR) clamp followed by direct sequence analysis. For one controversial case, gene mutation analyses were performed for the multiple micro-fractions of a metastatic lymph node, which exhibited the heterogeneous immunohistochemical features.

RESULTS

  EBUS-TBNA diagnosed one case of exon 21 point mutations, one case of exon 19 deletion, and 12 cases of wild-type EGFR. Results were consistent with those of surgically removed primary tumors in 13 of 14 cases. One case of wild-type EGFR diagnosed by EBUS-TBNA exhibited exon 21 point mutation in the surgically removed primary tumor. The metastatic lymph node targeted by EBUS-TBNA mostly consisted of cancer cells with wild-type EGFR; however, a minor component positive for thyroid transcription factor-1 (TTF-1) and surfactant-associated protein A (PE-10) exhibited EGFR mutation.

CONCLUSION

  The combination of EBUS-TBNA and PNA-LNA clamp is useful for EGFR mutation analysis. However, EGFR mutation status in EBUS-TBNA samples may not be consistent with that of the primary tumor when the tumor contains few EGFR mutations.

The peptide nucleic acid-locked nucleic acid polymerase chain reaction clamp-based test for epidermal growth factor receptor mutations in bronchoscopic cytological specimens of non-small cell lung cancer

OBJECTIVES

Cytological examination of samples obtained by bronchoscopy is a useful method for establishing the diagnosis of non-small cell lung cancer (NSCLC). However, the utility of a highly sensitive method for the detection of epidermal growth factor receptor (EGFR) mutation in the cytological specimens has not been fully evaluated.

METHODS

We retrospectively examined the efficacy of the peptide nucleic acid-locked nucleic acid polymerase chain reaction (PNA-LNA PCR) clamp method for detecting EGFR mutations in 122 bronchoscopic cytological specimens from NSCLC patients.

RESULTS

Overall, 41 specimens (33.6%) were positive for EGFR mutation. Twenty-nine (39.7%) of 73 specimens obtained by using endobronchial ultrasonography with a guide sheath, 7 (33.3%) of 21 specimens obtained under direct vision by using a conventional bronchoscope, 4 (36.4%) of 11 specimens obtained by using an ultrathin bronchoscope, and 1 (5.9%) of 17 specimens obtained by endobronchial ultrasound-guided transbronchial needle aspiration were positive for EGFR mutation. Furthermore, among 22 resected NSCLC cases, the EGFR mutation status obtained from bronchoscopic materials was consistent with the status obtained from surgical samples, with the exception of 1 case.

CONCLUSION

The detection of EGFR mutation by subjecting bronchoscopic cytological specimens to a PNA-LNA PCR clamp assay proves useful.

Detection of EGFR mutation status in lung adenocarcinoma specimens with different proportions of tumor cells using two methods of differential sensitivity

INTRODUCTION

To evaluate epidermal growth factor receptor (EGFR) mutation status in lung adenocarcinoma specimens with different proportions of tumor cells using two methods with different sensitivities.

METHODS

EGFR mutation status was determined by peptide nucleic acid (PNA) clamping and direct sequencing. The samples consisted of 41 cell blocks of malignant pleural effusions with various proportions of tumor cells, as well as 23 lung biopsy specimens containing more than 20% tumor cells and the corresponding surgically resected tumors.

RESULTS

In the analysis of malignant pleural effusions, EGFR mutations were detected only by PNA clamping in four of nine patients who exhibited partial response to EGFR tyrosine kinase inhibitors; all the cell blocks of these four patients contained less than 20% tumor cells. Direct sequencing revealed wild-type EGFR, whereas PNA clamping revealed mutant EGFR, in one of five patients who exhibited progressive disease in response to EGFR tyrosine kinase inhibitor; the cell block of this patient contained a high proportion of tumor cells. A comparison of biopsy specimens containing sufficient tumor cells and the corresponding surgically resected tumors revealed discordance in the EGFR mutation status in four patients based on PNA clamping, whereas no discrepancies were observed by direct sequencing.

CONCLUSIONS

Highly sensitive methods, such as PNA clamping, may be superior to direct sequencing for the detection of EGFR mutations in diagnostic specimens with a low proportion of tumor cells. Direct sequencing may be more representative when diagnostic specimens with a high proportion of tumor cells are available.

Personalized medicine for non-small-cell lung cancer: implications of recent advances in tissue acquisition for molecular and histologic testing

In light of recent advances in individualized therapy for non-small-cell lung cancer (NSCLC), molecular and histologic profiling is essential for guiding therapeutic decisions. Results of these analyses may have implications for both response (eg, molecular testing for EGFR [epidermal growth factor receptor] mutations) and safety (eg, contraindications for squamous histology) in NSCLC. Most patients with NSCLC present with unresectable advanced disease; therefore, greater emphasis is being placed on minimally invasive tissue acquisition techniques, such as small biopsy and cytology specimens. Due to the need for increasing histologic and molecular information and increasingly smaller tissue sample sizes, efforts must be focused on optimizing tissue acquisition and the development of more sensitive molecular assays. Recent advances in tissue acquisition techniques and specimen preservation may help to address this challenge and lead to enhanced personalized treatment in NSCLC.

Retrospective study of erlotinib in patients with advanced squamous lung cancer

BACKGROUND

The effective targeted therapy for lung squamous cell carcinoma (SCC) is needed. The epidermal growth factor receptor (EGFR) mutation rate is low in lung SCC. The aim of this study was to evaluate the status of erlotinib treatment and EGFR mutation in lung SCC patients.

METHODS

We retrospectively enrolled lung cancer patients with SCC histology and history of erlotinib treatment. The primary objective was to assess overall response rate (ORR) and disease control rate (DCR) and the secondary objective was to assess progression-free survival (PFS) and overall survival (OS). EGFR mutations were assessed in parts of patients using both direct sequencing and protein nucleic acid-locked nucleic acid polymerase chain reaction (PNA-LNA PCR) clamp methods.

RESULTS

In total, 92 patients were analyzed (75 men and 17 women, median age 69 years, and 74 current or former smokers). Sixteen patients achieved partial response and 9 had stable disease. The ORR was 17.4% and the DCR was 27.2%. The PFS and OS were longer in patients with disease control than with progressive disease (PFS 7.8 versus 1.3 months and OS 20.7 versus 2.7 months, both p<0.0001). The 1-year survival rate was 21.7%. In 27 patients with adequate specimens for molecular analysis (including 4 PR and 4 SD), two (7.4%) had EGFR complex mutations. One patient experienced response to erlotinib and the other did not.

CONCLUSIONS

A significant proportion of lung SCC patients would derive a clinical benefit from erlotinib treatment. The relatively higher response rate than the EGFR mutation rate in present study needs further evaluation.

Subtyping of non-small cell lung carcinoma: a comparison of small biopsy and cytology specimens

BACKGROUND

There is growing evidence that lung adenocarcinoma and squamous cell carcinoma (SQCC) have distinct oncogenic mutations and divergent therapeutic responses, which is driving the heightened emphasis on accurate pathologic subtyping of non-small cell lung carcinoma (NSCLC). The relative feasibility and accuracy of NSCLC subtyping by small biopsy versus cytology is not well established, particularly in current practice where immunohistochemistry (IHC) is becoming routinely used to aid in this distinction.

METHODS

Concurrent biopsy and cytology specimens obtained during a single procedure and diagnosed as NSCLC during a 2-year period (n = 101) were reviewed. Concordance of diagnoses in the two methods was assessed. Accuracy was determined based on subsequent resection or autopsy diagnosis (n = 21) or IHC for thyroid transcription factor 1 and p63 on a subset of cases (n = 43).

RESULTS

The distribution of definitive versus favored versus unclassified categories (reflecting the degree of diagnostic certainty) was similar for biopsy (71% versus 23% versus 6%, respectively) and cytology (69% versus 19% versus 12%, respectively), p = 0.29. When results from paired specimens were combined, the rate of definitive diagnoses by at least one method was increased to 84% and the unclassified rate was decreased to 4%. NSCLC subtype concordance between biopsy and cytology was 93%. Kappa coefficient (95% confidence interval) for agreement between methods was 0.88 (0.60-0.89) for adenocarcinoma and 0.76 (0.63-0.89) for SQCC. In pairs with discordant diagnoses (n = 7) the correct tumor type was identified with a similar frequency by biopsy (n = 4) and cytology (n = 3). Factors contributing to mistyping were poor differentiation, necrosis, low cellularity, and lack of supporting IHC. All concordant diagnoses for which verification was available (n = 57) were correct. IHC was used more frequently to subtype NSCLC in biopsy than cytology (32% versus 6%; p = 0.0001).

CONCLUSIONS

Small biopsy and cytology achieve comparable rates of definitive and accurate NSCLC subtyping, and the optimal results are attained when the two modalities are considered jointly. The lower requirement for IHC in cytology highlights the strength of cytomorphology in NSCLC subtyping. Whenever clinically feasible, obtaining parallel biopsy and cytology specimens is encouraged.

The role of molecular analyses in the era of personalized therapy for advanced NSCLC

Platinum-based doublet chemotherapy is the traditional treatment of choice for advanced non-small cell lung cancer (NSCLC); however, the efficacy of these regimens has reached a plateau. Increasing evidence demonstrates that patients with sensitizing mutations in the epidermal growth factor receptor (EGFR) experience improved progression-free survival and response rates with first-line gefitinib or erlotinib therapy relative to traditional platinum-based chemotherapy, while patients with EGFR-mutation negative tumors gain greater benefit from platinum-based chemotherapy. These results highlight the importance of molecular testing prior to the initiation of first-line therapy for advanced NSCLC. Routine molecular testing of tumor samples represents an important paradigm shift in NSCLC therapy and would allow for individualized therapy in specific subsets of patients. As these and other advances in personalized treatment are integrated into everyday clinical practice, pulmonologists will play a vital role in ensuring that tumor samples of adequate quality and quantity are collected in order to perform appropriate molecular analyses to guide treatment decisions. This article provides an overview of clinical trial data supporting molecular analysis of NSCLC, describes specimen acquisition and testing methods currently in use, and discusses future directions of personalized therapy for patients with NSCLC.

The challenge of NSCLC diagnosis and predictive analysis on small samples. Practical approach of a working group

Until recently, the division of pulmonary carcinomas into small cell lung cancer (SCLC) and non-small cell lung cancer (NSCLC) was adequate for therapy selection. Due to the emergence of new treatment options subtyping of NSCLC and predictive testing have become mandatory. A practical approach to the new requirements involving interaction between pulmonologist, oncologist and molecular pathology to optimize patient care is described. The diagnosis of lung cancer involves (i) the identification and complete classification of malignancy, (ii) immunohistochemistry is used to predict the likely NSCLC subtype (squamous cell vs. adenocarcinoma), as in small diagnostic samples specific subtyping is frequently on morphological grounds alone not feasible (NSCLC-NOS), (iii) molecular testing. To allow the extended diagnostic and predictive examination (i) tissue sampling should be maximized whenever feasible and deemed clinically safe, reducing the need for re-biopsy for additional studies and (ii) tissue handling, processing and sectioning should be optimized. Complex diagnostic algorithms are emerging, which will require close dialogue and understanding between pulmonologists and others who are closely involved in tissue acquisition, pathologists and oncologists who will ultimately, with the patient, make treatment decisions. Personalized medicine not only means the choice of treatment tailored to the individual patient, but also reflects the need to consider how investigative and diagnostic strategies must also be planned according to individual tumour characteristics.

Evaluation of EGFR mutation status in cytology specimens: an institutional experience

Epidermal growth factor receptor (EGFR) mutation status has been shown to predict response to anti-EGFR tyrosine kinase inhibitors in non-small cell lung cancer (NSCLC). In patients with advanced-stage NSCLC, evaluation of mutational status is increasingly requested on biopsy or fine-needle aspiration specimens, which often have limited material. There are limited data on the suitability of cytology cell blocks (CB) for EGFR mutation testing. In this study, we report our institutional experience with cytology cell block material for EGFR mutation testing. We retrospectively reviewed EGFR mutation analyses performed on 234 surgical (SP) and cytology (CB) from October 2007 to May 2010. One hundred ninety-two SP specimens and 42 CB specimens were evaluated for EGFR mutation. CB specimens were evaluated for overall specimen size based on aggregate cellularity in comparison to small biopsy specimens, and percent tumor. Of the 192 SP and 42 CB specimens, 31 (16.1%) and 11 (26.2%) were positive for EGFR mutation, respectively; there does not appear to be an association between mutation detection rate and the source of the specimen (P = 0.124). Limited DNA was obtained from 70.0% (29/42), including 81.8% (9/11) of those which were mutation positive. Additionally, 45.4% (5/11) of mutation positive specimens had extremely low DNA yields. Although 16.6% (7/42) of CB specimens had <10% tumor, all 11 mutation positive CB cases had >10% tumor. These data indicate that CB specimens provide an alternative source for molecular evaluation of NSCLC, and that tumor percentage may be more important than specimen size and/or DNA yield in determining the suitability of these specimens for testing.

[Modified Restriction Enzyme-based Detection of EGFR Mutations in Lung Cancer]

背景与目的

表皮生长因子受体(epidermal growth factor receptor, EGFR)基因突变是肺癌靶向药物疗效的可靠预测指标，因此基因突变的检测具有非常重要的临床意义。本研究建立使用常规实验仪器、高灵敏度、简便的检测表皮生长因子受体突变的方法，以利于临床中快速的检测EGFR基因突变。

方法

采用改良的内切酶法富集法检测251例肺腺癌DNA标本中EGFR基因外显子19缺失突变和21(L858R)点突变，并与直接测序进行比较。利用混合突变/野生型EGFR基因的细胞系测定改良方法的灵敏度。

结果

在251例腺癌标本DNA中使用测序法检测出EGFR外显子19突变46例、外显子21突变26例。采用改良的突变体富集法检另外测出外显子19突变78例、外显子21突变57例，总突变率53.8%。灵敏度检测显示对于外显子19和21，新方法的检测灵敏度达0.5%。

结论

本方法具有简便、经济、灵敏度高等特点，便于临床快速筛查非小细胞肺癌病理组织中的EGFR基因突变。