Good response to gefitinib in a lung adenocarcinoma harboring a heterozygous complex mutation of L833V and H835L in epidermal growth factor receptor gene

Complete response to first-line osimertinib monotherapy in a complex epidermal growth factor receptor mutant ( L833V / H835L ) lung adenocarcinoma patient: a case report

Although uncommon epidermal growth factor receptor (EGFR) mutations account for 10-15% EGFR mutant non-small cell lung cancer (NSCLC) patients, clinical evidence for uncommon EGFR mutations, such as complex mutations remain limited. In this study, we reported a NSCLC patient harboring complex EGFR L833V / H835L mutation in exon 21, who had a complete response to first-line osimertinib monotherapy. The patient admitted to our hospital for space-occupying lesions of right lower lung during an annual health checkup, and was diagnosed as stage IIIA lung adenocarcinoma. Targeted next-generation sequencing (NGS) on tumor samples showed a complex EGFR mutation: L833V / H835L in exon 21. Therefore, she was treated with osimertinib monotherapy and complete remission achieved soon. During follow-up period, no metastasis was found and serum carcinoembryonic antigen returned to normal. In addition, NGS monitoring of mutations in circulating tumor DNA maintained negative. The patient remain benefitted for osimertinib monotherapy over 22 months with no disease progression. Our case firstly provided clinical evidences of first-line osimertinib therapy in lung cancer patients with rare L833V / H835L EGFR mutation.

Successful treatment of lung adenocarcinoma complicated with a rare compound EGFR mutation L833V/H835L using aumolertinib: a case report and literature review

Background: The deletion of exon 19 and the Leu858Arg mutation of exon 21 are the most frequently observed mutations in the epidermal growth factor receptor (EGFR) gene, and patients with these mutations have shown significant benefits from EGFR-tyrosine kinase inhibitors (TKIs). However, there exists a small subgroup of patients with uncommon/rare mutations of EGFR, including compound mutations, which display a high degree of heterogeneity in terms of clinical features and variable sensitivities to EGFR-TKIs. The understanding of these uncommon mutations and their response to targeted therapy is still unclear and requires further investigation. Case presentation: We presented a case of a never-smoking patient with lung adenocarcinoma and brain metastasis. Initially, she received chemotherapy plus immune checkpoint inhibitor as first-line therapy as no EGFR mutations were detected by amplification-refractory mutation system-polymerase chain reaction. However, disease progressed rapidly. Subsequently, next-generation sequencing was carried out and revealed a rare compound mutation, L833V/H835L, in exon 21 of EGFR. As a result, she was switched to second-line therapy with the third-generation TKI aumolertinib, which demonstrated good efficacy. The patient was evaluated for a remarkable progression-free survival of 18 months and an overall survival of 29 months. Conclusion: The present study supports that aumolertinib might be a good treatment option for advanced NSCLC patients with EGFR L833V/H835L mutation, particularly in patients with brain metastasis. Furthermore, conducting a comprehensive screening for gene mutations is crucial in effectively identifying potential oncogenic driver mutations and guiding mutation-targeted therapy decisions in clinical practice.

EGFR p.V774M/p.L833V compound mutations in lung adenocarcinoma responded well to almonertinib: a case report

Background

There are about 10-15% of uncommon EGFR mutations found in NSCLC patients, and their sensitivity to EGFR TKIs still lack sufficient clinical evidence, especially for rare compound mutations. Almonertinib is the third generation of EGFR-TKI that has demonstrated excellent efficacy in classical mutations, however, effects in rare mutations have also been rarely reported.

Case presentation

In this case report, we present a patient with advanced lung adenocarcinoma with a rare EGFR p.V774M/p.L833V compound mutations, who achieved long-lasting and stable disease control after first-line Almonertinib targeted therapy. This case report could provide more information for therapeutic strategy selecting of NSCLC patients harboring rare EGFR mutations.

Conclusion

We report for the first time the long-lasting and stable disease control with Almonertinib for EGFR p.V774M/p.L833V compound mutations treatment, hoping to provide more clinical case references for the treatment of rare compound mutations.

Effective treatment with icotinib in advanced lung adenocarcinoma harboring rare EGFR mutation G719A/L833V: A case report

RATIONALE

Mutations in epidermal growth factor receptor (EGFR) play critical roles in the pathogenesis of non-small cell lung cancer (NSCLC), and they are highly associated with sensitivity to tyrosine kinase inhibitors. Targeted therapies are approved for patients with "classical" mutations and a small number of other mutations. However, patients with rare, even double EGFR mutations have different responses to EGFR tyrosine kinase inhibitor, which brings uncertainty to clinical practice.

PATIENT CONCERNS

A 74-year-old woman, never-smoker, was presented with chest pain. Chest computed tomography scan showed a big lesion in the right upper lobe with mediastinal lymph nodes metastases. Fine-needle biopsy and pathology suggested lung adenocarcinoma. A rare G719A/L833V double mutation of EGFR was detected in both tissue and plasma samples by next-generation sequencing.Interventions and outcomes:Icotinib was used as first-line therapy and showed good efficacy. Partial response was achieved, and the progression-free survival was 8 months.

LESSONS

This is the first report of the icotinib treatment achieving long-lasting and stable disease control in an NSCLC patient with EGFR G719A/L833V mutation. Icotinib could be a first-line treatment option in NSCLC patients harboring EGFR G719A/L833V mutation.

Uncommon single and compound EGFR mutations: clinical outcomes of a heterogeneous subgroup of NSCLC

Molecular characterization of non-small-cell lung cancer (NSCLC) is essential to define the correct therapeutic algorithm in metastatic disease. Approximately 90% of epidermal growth factor receptor (EGFR) mutations are usually associated with sensitivity to EGFR tyrosine kinase inhibitors (TKIs). The remaining 10% defines a small, extremely heterogeneous subgroup of mutations, with a varied profile of sensitivity and response to target therapies.This retrospective observational study includes 47 patients affected by metastatic NSCLC harboring uncommon EGFR mutations (single or compound mutation). Patients were treated with EGFR-targeting TKIs or platinum-based chemotherapy as first-line treatment.Median OS resulted longer in the compound mutation group when compared to single rare mutations (33.6 vs 12 months; P = 0.473); a similar result was observed for PFS (16 vs 7.6 months; P = 0.281), although statistical significance was not reached. ORR, PFS and OS resulted similar for patients treated with first-line EGFR TKIs or chemotherapy. No difference in terms of PFS and OS was found according to the TKI administered.Compound mutations seem to be a good prognostic indicator for OS; they are also predictive of response to 1st and 2nd generation EGFR TKIs, as well as exon 19 insertions and mutations in codon 719 of exon 18. For mutations in exon 18 (not in codon 719) and exon 20 insertions, chemotherapy seems the most effective available option. The addition of immunotherapy to chemotherapy could change this approach in the next future.

Efficacy of afatinib for pulmonary adenocarcinoma with leptomeningeal metastases harboring an epidermal growth factor receptor complex mutation (exon 19del+K754E): A case report

RATIONALE

Liquid biopsy of cerebrospinal fluid (CSF) and sequencing of cell-free DNA has rarely been used to identify epidermal growth factor receptor (EGFR) mutations, which can guide the design of precise, personalized treatment for patients with leptomeningeal metastasis from lung adenocarcinoma.

PATIENT CONCERNS

A 42-year-old woman with lung adenocarcinoma and leptomeningeal metastasis was admitted to our hospital on March 31, 2019. She exhibited no response to treatment with gefitinib, osimertinib, or chemoradiotherapy and was in critical condition, with an expected survival of <4 weeks.

DIAGNOSIS

Next-generation sequencing of CSF and peripheral blood samples identified an EGFR complex mutation (exon19del+K754E).

INTERVENTIONS

On April 10, 2019, the patient started oral afatinib (40 mg po qd), but she developed a grade III oral mucosal reaction 1 week later. The afatinib dose was reduced to 30 mg po qd.

OUTCOMES

At the follow-up examination on May 15, 2019, the patient reported relief from headaches. Enhanced magnetic resonance imaging revealed a reduction in abnormal leptomeningeal enhancement, and the CSF pressure and carcinoembryonic antigen levels were also reduced. The patient continued to respond to afatinib treatment (30 mg once daily) with minimal adverse effects.

LESSONS

This is the first case report of clinical improvement after afatinib treatment in a patient with lung adenocarcinoma and leptomeningeal metastasis harboring an EGFR complex mutation (exon19del+K754E), and thus provides a clinical reference for treatment with afatinib of cancers harboring EGFR compound mutations.

Great Efficacy of Afatinib in a Patient with Lung Adenocarcinoma Harboring EGFR L833V/H835L Mutations: A Case Report

Uncommon mutations account for 10-15% of epidermal growth factor receptor (EGFR) mutations in patients with non-small-cell lung cancer (NSCLC). Most of them are proved to be sensitive or resistant to EGFR-tyrosine kinase inhibitors (TKIs). However, there is insufficient evidence for other less common types of EGFR mutations, such as complex mutations. Here, we present a 65-year-old never-smoking male who was diagnosed with stage IV lung adenocarcinoma. A rare L833V/H835L complex mutation in exon 21 of EGFR was detected in plasma and pleural effusion by next generation sequencing (NGS). Afatinib was used as first-line therapy and showed very good efficacy. To date, the patient is still benefited from afatinib treatment for a total of 10 months, with no signs of disease progression. Our case suggests that a comprehensive screening for EGFR mutations should be conducted before treatment in clinical practice, and afatinib could be a first-line treatment option in NSCLC patients harboring H833V/H835L mutations.

Four generations of EGFR TKIs associated with different pathogenic mutations in non-small cell lung carcinoma

Non-small cell lung carcinoma (NSCLC) is a malignant tumour with poor prognosis and high mortality. Platinum-based dual-agent chemotherapy is the main therapeutic regimen for this disease. In recent years, because of the introduction of molecular targeted therapy, various targeted therapeutic agents against epidermal growth factor receptor (EGFR) have been rapidly developed, which has become a research hotspot for NSCLC treatment. Here, we review the latest studies describing the features and types of EGFR pathogenic mutations, currently established EGFR-tyrosine kinase inhibitors from the first to fourth generation, including their action mechanisms, acquired resistance, and clinical applications, and potential challenges and perspectives that current researchers should address.

Detection of rare and novel EGFR mutations in NSCLC patients: Implications for treatment-decision

OBJECTIVES

Mutations in the gene that encodes epidermal growth factor receptor (EGFR) are biomarkers that predict how non-small cell lung cancer (NSCLC) patients respond to EGFR-targeted therapies collectively known as tyrosine kinase inhibitors (TKIs). Thus, EGFR genotyping provides crucial information for treatment decision. Both Sanger sequencing and real-time PCR methodologies are used for EGFR genotyping. However, methods based on real-time PCR have limitations, as they may not detect rare or novel mutations. The aim of this study was to determine the prevalence of rare mutations in the tyrosine kinase domain (exons 18-21) of the EGFR gene not targeted by the most frequently used real-time PCR approaches, i.e., the cobas® EGFR Mutation Test, and the Idylla™ EGFR Mutation Assay.

METHODS

A total of 1228 NSCLC patients were screened for mutations in exons 18-21 of the EGFR gene using Sanger sequencing.

RESULTS

We observed that 252 patients (∼20%) had at least one mutation in the EGFR gene, and 38 (∼3%) carried uncommon genetic alterations that would not be identified by the cobas® or the Idylla™ tests. We further found six new single mutations and seven previously unreported compound mutations. Clinical information and patient outcome are presented for these cases.

CONCLUSIONS

This study highlights the value of sequencing-based approaches to identify rare mutations. Our results add to the inventory of known EGFR mutations, thus contributing to improved lung cancer precision treatment.

Clinical Impact of Rare and Compound Mutations of Epidermal Growth Factor Receptor in Patients With Non-Small-Cell Lung Cancer

BACKGROUND

Standard therapy of advanced non-small-cell lung cancer harboring an activating mutation in the epidermal growth factor receptor (EGFR) gene is treatment with tyrosine kinase inhibitors (TKI). However, for rare and compound mutations of the EGFR gene, the clinical evidence of TKI therapy is still unclear.

PATIENTS AND METHODS

A total of 2906 lung cancer samples were analyzed for EGFR mutations during routine analysis between 2010 and 2017. The samples have been investigated by Sanger sequencing and since 2014 by next-generation sequencing.

RESULTS

We detected EGFR mutations in 408 specimens (14%). Among these, we found 41 samples with rare and 22 with compound mutations. In these 63 samples, 56 different rare EGFR mutations occurred. Information about the clinical outcome was available for 37. Among those with rare mutations, only one patient harboring the mutation p.G874D had disease that responded to first-generation TKI therapy. In contrast, the disease of all patients with compound mutations responded to first- or second-generation TKI therapy. Furthermore, we collected data on clinical relevance regarding TKI therapy from different databases and from an additional literature search, and only found data for 36 of the 56 detected rare mutations.

CONCLUSION

Information about the clinical outcome of patients with rare and compound EGFR mutations remains limited. At present, second- and third-generation TKIs are available, which may represent new treatment strategies for these patients. Therefore, it is becoming increasingly important to maintain databases concerning rare EGFR mutations.

The effectiveness of afatinib and osimertinib in a Chinese patient with advanced lung adenocarcinoma harboring a rare triple EGFR mutation (R670W/H835L/L833V): a case report and literature review

In patients without tissue availability at presentation, the analysis of cell-free DNA derived from liquid biopsy samples, in particular from plasma, represents an established alternative for providing epidermal growth factor receptor (EGFR) mutational testing for treatment decision-making. Compared with quantitative polymerase chain reaction and digital polymerase chain reaction-targeted methods, next-generation sequencing can provide more information about tumor molecular alterations, especially EGFR mutations. Here, we present a case of a patient with non-small cell lung cancer (NSCLC) harboring 3 uncommon mutations of EGFR-R670W in exon 17 and H833V, and H835L in exon 21, as shown by next-generation sequencing of plasma cell-free DNA. To the best of our knowledge, this is the first case report of a patient harboring the R670W mutation. The patient responded well to second-generation tyrosine kinase inhibitors (TKIs). T790M is an acquired resistant mutation in patients with R670W, H833V, and H835L. This is also the first case of a patient harboring the H833V/H835L/T790M triple mutation; the patient had a good response to the third-generation TKI osimertinib. In this work, we also performed a literature review on the clinical characteristics of NSCLC patients with the H833V/H835L double mutation, together with a descriptive analysis about their response to EGFR TKI monotherapy as a first-line treatment, according to data from previous case reports. The results showed that the cohort of NSCLC patients with H833V/H835L responded well to EGFR TKIs; thus, before treatment in clinical practice, screening for EGFR mutations should be conducted and EGFR TKIs should be preferred in NSCLC patients with H833V/H835L mutations.

First-generation EGFR tyrosine kinase inhibitor therapy in 106 patients with compound EGFR-mutated lung cancer: a single institution's clinical practice experience

Background

The antitumour efficacy of tyrosine kinase inhibitors (TKIs) in lung cancer patients with compound epidermal growth factor receptor (EGFR) mutations has not been resolved. Our study summarizes a single institutional experience of first-generation TKI therapy for lung cancers with compound EGFR mutations.

Methods

A total of 106 consecutive patients with tumours bearing compound EGFR mutations were identified between January 2012 and May 2016; all patients received first-generation TKI therapy. Deletions in exon 19 and the L858R point mutation in exon 21 were considered common mutations; T790M was considered separately because of its association with TKIs resistances. Any other mutation was defined as a rare mutation. Patients were divided as follows: double common mutations (group A); common plus T790M mutations (group B); common plus rare mutations (group C); double rare mutations (group D); and rare plus T790M mutations (group E). A separate group of 115 consecutive patients with a single common mutation was created for comparative analysis (group F).

Results

The frequency of patients with compound EGFR was 2.9% (114/3925) and their response rate to first-generation TKIs was 50.9%, which was not significantly different from group F (67.0%, P = 0.088). The progression-free survival (PFS) of the 106 patients receiving TKI therapy was worse than that of group F (median, 9.1 vs. 13.0 months, respectively; P < 0.001). The PFS of the compound mutation group was shorter than that of the single common mutation group (median, 10.1 months in group A, P = 0.240; 9.1 months in group B, P < 0.001; 9.6 months in group C, P = 0.010; 6.5 months in group D, P = 0.048; 5.4 months in group E, P = 0.017). Patients with a co-occurring mutation in exon 20 (excluding T790M) exhibited significantly worse PFS than the patients with other compound mutations or with a single common mutation (median, 6.5 vs. 9.1 vs. 13.0 months, respectively, P = 0.002).

Conclusions

There was significant heterogeneity among the compound EGFR mutations and their response to first-generation TKIs. Individualized treatment in clinical practice should be considered for each case.

The utilization of next-generation sequencing to detect somatic mutations and predict clinical prognosis of Chinese non-small cell lung cancer patients

Purpose

The development of next-generation sequencing (NGS) has revolutionized the understanding of oncogenesis of multiple types of cancer, including non-small cell lung cancer (NSCLC). However, there has been some debate over the utility of NGS for predicting patient prognosis and determining molecular targeted therapy. Therefore, we sought to demonstrate the numerous applications of NGS in the prognostic predictions and treatment of NSCLC patients.

Materials and methods

We performed NGS on either liquid or tissue tumor biopsies obtained from 53 NSCLC patients. The sequences were analyzed for oncogenic mutations, which were then correlated to clinical prognosis and smoking history.

Results

NGS of tumor biopsies detected both well-known driver mutations as well as rare or novel mutations. EGFR was the most frequently mutated gene, accounting for 32.4% (33/102) of the somatic mutations in this study. The EGFR mutations detected included rare variants such as EGFR exon 19 insertion (K745_E746insIPVAIK) and in cis H835L+L833V. Additionally, novel RET fusion mutations PCM1–RET and ADD3-RET were detected in two adenocarcinoma patients. To demonstrate the functional applications of NGS, we correlated mutations with patient characteristics, outcomes of matched targeted therapy, and outcomes based on allelic frequency of the EGFR-T790M mutation. Finally, we demonstrated that circulating tumor DNA can be used both to measure response to targeted therapy and as a predictor of clinical outcome, by presenting a case study of a single patient.

Conclusion

We demonstrated that NGS can be used in multiple applications to effectively identify potential oncogenic driver mutations, guide mutation-targeted therapy decisions, and predict clinical outcomes in Chinese NSCLC patients.

Clinical features and treatment outcome of non-small cell lung cancer (NSCLC) patients with uncommon or complex epidermal growth factor receptor (EGFR) mutations

Introduction

Tyrosine-kinase inhibitors (TKIs) represent the best treatment for advanced non-small cell lung cancer (NSCLC) with common exon 19 deletion or exon 21 epidermal growth factor receptor mutation (EGFRm). This is an observational study investigating epidemiology, clinical features and treatment outcome of NSCLC cases harbouring rare/complex EGFRm.

Results

Among 764 non-squamous NSCLC cases with known EGFRm status, 26(3.4%) harboured rare/complex EGFRm. Patients receiving first-line TKIs (N = 17) achieved median Progression Free Survival (PFS) and Overall Survival (OS) of 53 (IC 95%, 2–105) and 84 (CI 95%, 27–141) weeks respectively, without significant covariate impact. Response Rate and Disease Control Rate (DCR) were 47% and 65%, respectively. Uncommon exon 19 mutations achieved longer OS and PFS and higher DCR compared with exon 18 and 20 mutations. No additional gene mutation was discovered by MassARRAY analysis. TKIs were globally well tolerated.

Materials and methods

A retrospective review of advanced non-squamous NSCLC harbouring rare/complex EGFRm referred to our Center between 2010 and 2015 was performed. Additional molecular pathways disregulation was explored in selected cases, through MassARRAY analysis.

Conclusions

Peculiar clinical features and lower TKIs sensitivity of uncommon/complex compared with common EGFRm were shown. Exon 19 EGFRm achieved the best TKIs treatment outcome, while the optimal treatment of exon 18 and 20 mutations should be further clarified.

Routine genetic testing of lung cancer specimens derived from surgery, bronchoscopy and fluid aspiration by next generation sequencing

After the development of EGFR tyrosine kinase inhibitors (TKIs), genetic testing of EGFR became required for effective treatment of lung cancer. Initially, the testing was conducted separately for each mutated region. However, many EGFR mutations have since been identified that determine the efficacy of EGFR-TKIs. Therefore, genetic testing of EGFR by next generation sequencing (NGS) may be a suitable strategy for lung cancer. Here we examined the applicability of the NGS method in regard to sensitivity, time and cost. A total of 939 specimens were obtained from 686 lung cancer patients at our hospital. DNA and RNA were simultaneously extracted from specimens derived from surgery, bronchoscopy, and fluid aspiration. Specimens included cerebrospinal fluid, pleural effusion, abdominal fluid, and pericardial effusion. From RNA, target regions (EGFR, KRAS, ALK fusion and RET fusion) were enriched by RT-PCR and sequenced with MiSeq. From DNA, PCR or PCR-RFLP conventional methods were performed. NGS and conventional methods were carried out routinely per week. Among the total 939 specimens, 38 specimens could not be examined with NGS. Among these, 34 specimens were analyzed by conventional testing with simultaneously extracted DNA. The remaining four specimens could not be tested with either method. Compared with the conventional method, the concordance rate of mutations was 99% (892/901), excluding specimens with NGS failure. The time period required from processing of specimens to results was 4 days, and the cost per sample was sufficiently low. In conclusion, the genetic testing with NGS method was useful for lung cancer treatment. The cost, sensitivity and time were able to tolerate routine examinations.

[Effectiveness of Tyrosine Kinase Inhibitors on Uncommon Epidermal Growth Factor Receptor Mutations in Non-small Cell Lung Cancer]

背景与目的

表皮生长因子受体（epidermal growth factor receptor, EGFR）敏感性突变是EGFR酪氨酸激酶抑制剂（tyrosine kinase inhibitors, TKIs）的有效预测因子。85%-90%敏感性突变发生于19缺失突变及21外显子L858R突变。常见EGFR敏感性突变患者EGFR-TKIs治疗的客观缓解率（objective response rate, ORR）和无病进展生存时间（progression-free survival, PFS）显著延长，可分别达70%-80%和9个月-14个月。但EGFR-TKIs对于EGFR少见突变（uncommon mutations）的疗效尚不明确。本研究旨在探讨EGFR少见突变的临床病理特征及EGFR-TKIs治疗的远近期疗效。

方法

收集2010年4月-2015年4月北京大学肿瘤医院胸部肿瘤内科24例少见EGFR突变患者的临床资料，分析少见EGFR突变的临床病理特征及与TKIs疗效及PFS之间的关系。

结果

24例携带少见突变的患者中，单突变者15例，双突变者9例。15例单突变中，S768I、L861Q、20外显子插入突变、G719X分别为4例、4例、3例、2例。双突变中以S768I合并G719X最为常见（3/9）。在接受EGFR-TKIs治疗的13例患者中，ORR为46.1%（6/13），疾病控制率（disease control rate, DCR）为76.9%（10/13），中位PFS为7.4个月。

结论

作为特殊类型的EGFR突变，EGFR少见突变对于一代EGFR-TKIs的敏感性介于EGFR敏感性突变和EGFR野生型之间。相对于一代EGFR-TKIs而言，二代EGFR-TKIs可能更适用于EGFR少见突变的治疗。。

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.

Screening for EGFR and KRAS mutations in endobronchial ultrasound derived transbronchial needle aspirates in non-small cell lung cancer using COLD-PCR

EGFR mutations correlate with improved clinical outcome whereas KRAS mutations are associated with lack of response to tyrosine kinase inhibitors in patients with non-small cell lung cancer (NSCLC). Endobronchial ultrasound (EBUS)-transbronchial needle aspiration (TBNA) is being increasingly used in the management of NSCLC. Co-amplification at lower denaturation temperature (COLD)–polymerase chain reaction (PCR) (COLD-PCR) is a sensitive assay for the detection of genetic mutations in solid tumours. This study assessed the feasibility of using COLD-PCR to screen for EGFR and KRAS mutations in cytology samples obtained by EBUS-TBNA in routine clinical practice. Samples obtained from NSCLC patients undergoing EBUS-TBNA were evaluated according to our standard clinical protocols. DNA extracted from these samples was subjected to COLD-PCR to amplify exons 18–21 of EGFR and exons two and three of KRAS followed by direct sequencing. Mutation analysis was performed in 131 of 132 (99.3%) NSCLC patients (70F/62M) with confirmed lymph node metastases (94/132 (71.2%) adenocarcinoma; 17/132 (12.8%) squamous cell; 2/132 (0.15%) large cell neuroendocrine; 1/132 (0.07%) large cell carcinoma; 18/132 (13.6%) NSCL-not otherwise specified (NOS)). Molecular analysis of all EGFR and KRAS target sequences was achieved in 126 of 132 (95.5%) and 130 of 132 (98.4%) of cases respectively. EGFR mutations were identified in 13 (10.5%) of fully evaluated cases (11 in adenocarcinoma and two in NSCLC-NOS) including two novel mutations. KRAS mutations were identified in 23 (17.5%) of fully analysed patient samples (18 adenocarcinoma and five NSCLC-NOS). We conclude that EBUS-TBNA of lymph nodes infiltrated by NSCLC can provide sufficient tumour material for EGFR and KRAS mutation analysis in most patients, and that COLD-PCR and sequencing is a robust screening assay for EGFR and KRAS mutation analysis in this clinical context.