High sensitivity detection of epidermal growth factor receptor mutations in the pleural effusion of non-small cell lung cancer patients

Cytology–Based Specimen Triage for Epidermal Growth Factor Receptor Mutation Testing of Malignant Pleural Effusions in Non–Small Cell Lung Cancer

Introduction

Malignant pleural effusions are common in non–small cell lung cancer (NSCLC). Molecular testing is among the most critical steps in the management of patients with advanced NSCLC. However, the optimal approach for epidermal growth factor receptor (EGFR) mutation testing in such effusion samples remains unclear.

Methods

We prospectively collected effusion samples from patients with EGFR–mutant NSCLC. Following sample centrifugation, genomic DNA and cell–free DNA were respectively extracted from the sediment and supernatants. EGFR mutation was detected through a real–time PCR assay.

Results

A total of 108 effusions from 78 patients were examined, with 12 and 96 obtained before and after EGFR tyrosine kinase inhibitor treatment, respectively. Carcinoma cells or atypical cells were identified in 73 effusions (67.6%). EGFR mutations were detected in 86 (79.6%) sediment and 84 (77.8%) supernatant samples. Among the effusions with positive cytological findings, the EGFR mutation detection rates were 95.9% (70/73) and 86.3% (63/73) in the sediment and supernatants, respectively. Among the effusions with negative cytological findings, the corresponding detection rates were 45.7% (16/35) and 60% (21/35), respectively. Current clinical practice is to arrange EGFR mutation testing only for sediment from cytologically positive effusions. Through the proposed cytology–based specimen triage, wherein sediment and supernatants with positive and negative cytological findings, respectively, are tested, the detection rate was increased from 64.8% (70/108) to 84.3% (91/108). At half of the cost, this strategy provided a detection rate only slightly lower than the rate in a combined test of all the sediment and supernatants (87.0%, 94/108).

Conclusions

The separate extraction of DNA from sediment and supernatants obtained from centrifuged effusion samples can improve the overall EGFR mutation detection rate. The present cytology–based specimen triage is an efficient strategy for EGFR mutation testing in patients with EGFR–mutant NSCLC.

Cancer Epigenetic Biomarkers in Liquid Biopsy for High Incidence Malignancies

Early alterations in cancer include the deregulation of epigenetic events such as changes in DNA methylation and abnormal levels of non-coding (nc)RNAs. Although these changes can be identified in tumors, alternative sources of samples may offer advantages over tissue biopsies. Because tumors shed DNA, RNA, and proteins, biological fluids containing these molecules can accurately reflect alterations found in cancer cells, not only coming from the primary tumor, but also from metastasis and from the tumor microenvironment (TME). Depending on the type of cancer, biological fluids encompass blood, urine, cerebrospinal fluid, and saliva, among others. Such samples are named with the general term "liquid biopsy" (LB). With the advent of ultrasensitive technologies during the last decade, the identification of actionable genetic alterations (i.e., mutations) in LB is a common practice to decide whether or not targeted therapy should be applied. Likewise, the analysis of global or specific epigenetic alterations may also be important as biomarkers for diagnosis, prognosis, and even for cancer drug response. Several commercial kits that assess the DNA promoter methylation of single genes or gene sets are available, with some of them being tested as biomarkers for diagnosis in clinical trials. From the tumors with highest incidence, we can stress the relevance of DNA methylation changes in the following genes found in LB: SHOX2 (for lung cancer); RASSF1A, RARB2, and GSTP1 (for lung, breast, genitourinary and colon cancers); and SEPT9 (for colon cancer). Moreover, multi-cancer high-throughput methylation-based tests are now commercially available. Increased levels of the microRNA miR21 and several miRNA- and long ncRNA-signatures can also be indicative biomarkers in LB. Therefore, epigenetic biomarkers are attractive and may have a clinical value in cancer. Nonetheless, validation, standardization, and demonstration of an added value over the common clinical practice are issues needed to be addressed in the transfer of this knowledge from "bench to bedside".

Case Report: A Chronological Combination Treatment of Icotinib, Osimertinib, and Crizotinib on Lung Adenocarcinoma Guided by Serial Genetic Tests of Circulating Tumor DNA and Sediment Cell Genomic DNA From Pleural Effusion

Precision medicine has been getting more attention in lung cancer treatment. Here, we report an unusual case of a 71-year-old Chinese male patient with poorly differentiated lung adenocarcinoma with lymph node metastasis. A 5 years' treatment history of this patient is reported. By serial genetic tests of circulating tumor DNA (ctDNA) from peripheral blood and sediment cell genomic DNA (PE-sDNA) from pleural effusion, a novel chronological combination treatment of icotinib, osimertinib, and crizotinib was adopted for the present genetic mutations, including EGFR exon 19 deletion, EGFR p.T790M, and MET amplification.

Molecular Mechanisms and Targeted Therapies Including Immunotherapy for Non-Small Cell Lung Cancer

Lung cancer is the leading cause of cancer death worldwide. Molecular targeted therapy has greatly advanced the field of treatment for non-small cell lung cancer (NSCLC), which accounts for the majority of lung cancers. Indeed, gefitinib, which was the first molecular targeted therapeutic agent, has actually doubled the survival time of NSCLC patients. Vigorous efforts of clinicians and researchers have revealed that lung cancer develops through the activating mutations of many driver genes including the epidermal growth factor receptor (EGFR), anaplastic lymphoma kinase (ALK), c-ros oncogene 1 (ROS1), v-Raf murine sarcoma viral oncogene homolog B (BRAF), and rearranged during transfection (RET) genes. Although ALK, ROS1, and RET are rare genetic abnormalities, corresponding tyrosine kinase inhibitors (TKIs) can exert dramatic therapeutic effects. In addition to anticancer drugs targeting driver genes, bevacizumab specifically binds to human vascular endothelial growth factor (VEGF) and blocks the VEGF signaling pathway. The VEGF signal blockade suppresses angiogenesis in tumor tissues and inhibits tumor growth. In this review, we also explore immunotherapy, which is a promising new NSCLC treatment approach. In general, antitumor immune responses are suppressed in cancer patients, and cancer cells escape from the immune surveillance mechanism. Immune checkpoint inhibitors (ICIs) are antibodies that target the primary escape mechanisms, immune checkpoints. Patients who respond to ICIs are reported to experience longlasting therapeutic effects. A wide range of clinical approaches, including combination therapy involving chemotherapy or radiation plus adjuvant therapy, are being developed.

A multicenter real-world study of tumor-derived DNA from pleural effusion supernatant in genomic profiling of advanced lung cancer

Background

Pleural effusion (PE) is commonly observed in advanced lung cancer. Research has suggested that molecular profiling of PE could be used to detect tumor driver mutations, thus informing clinical decision-making. However, the performance of PE samples in a real-world setting has yet to be examined.

Methods

A total of 678 metastatic lung cancer patients with pleural effusion were enrolled in this study. Cohort 1 included 22 patients whose PE and matched plasma samples were simultaneously collected as a pilot study. Cohort 2 comprised 656 patients, from whom 734 samples were collected in a real world setting. These samples were subjected to targeted next-generation sequencing (NGS) of 1,021 cancer-related genes.

Results

PE supernatant was the preferred choice for genetic profiling. While the maximal somatic allele frequency (MSAF) of plasma in patients with M1a stage was significantly lower than that in patients with M1b/c stages (4.4%±9.6% vs. 9.0%±14.1%, P<0.01), the MSAF of PE supernatant was similar between M1a and M1b/c stages. PE supernatant demonstrated higher sensitivity than plasma in detecting actionable mutations in cohort 1 (81.8% vs. 45.5%, P=0.01) as well as in M1a disease (84.7% vs. 42.1%, P<0.01), but not in M1b/c disease, in cohort 2. Known resistant mutations were identified in 72 of the 117 patients who were resistant to first- or second-generation EGFR-TKIs, 22 of the 42 patients who were resistant to osimertinib, and 9 of the 13 patients who were resistant to crizotinib. Remarkably, PE supernatant outperformed plasma in identifying mutations that confer resistance to first- and second-generation EGFR-TKIs (75.4% vs. 29.8%, P<0.001).

Conclusions

This real-world large cohort study verified that PE supernatant had higher sensitivity than plasma for identifying actionable mutations, including resistance mutations. PE supernatant would be preferred by physicians for assessing tumor genomics in advanced lung cancer when tumor tissue is not available.

Usefulness of rapid on-site evaluation specimens from endoscopic ultrasound-guided fine-needle aspiration for cancer gene panel testing: A retrospective study

Pancreatic cancer (PC) is a highly lethal malignancy, with a 5-year survival rate of 6%. Cancer gene panel testing is expected to allow selection of suitable therapeutic drugs in individual patients with PC and improve their prognosis. Although somatic mutations can be identified in formalin-fixed, paraffin-embedded samples derived from surgical specimen, the rate of surgical indication among patients with PC is only 20%. To acquire genome information with a less invasive method, we used rapid on-site evaluation (ROSE) specimens from endoscopic ultrasound-guided fine-needle aspiration. The present study aimed to retrospectively evaluate the utility of comprehensive cancer gene panel testing with ROSE specimens. DNA was extracted from preserved ROSE specimens of 26 patients diagnosed with PC between 2011 and 2017. DNA sequences of oncogenes and cancer-related genes were determined using the Ion AmpliSeq Comprehensive Caner Panel. We compared KRAS mutations between cancer gene panel testing by next-generation sequencing (NGS) and KRAS mutation analysis by polymerase chain reaction. The mean yield of DNA per extraction from ROSE specimens was 171 ng (range, 34-478 ng). On cancer gene panel testing, we noted KRAS mutations (92%), TP53 mutations (50%), CDKN2A mutations (15%), and SMAD4 mutations (31%). The concordance rate of KRAS mutations between cancer gene panel testing by NGS using ROSE specimens and KRAS mutation analysis by the companion diagnostics using residual materials was 81%. Among five cases of KRAS discordance, three showed KRAS mutations in cancer gene panel testing but not in KRAS mutation analysis. Cancer gene panel testing with ROSE specimens can help stratify unresectable PC patients without additional invasive approaches, and it can be used for therapeutic drug selection.

Cytological-negative pleural effusion can be an alternative liquid biopsy media for detection of EGFR mutation in NSCLC patients

OBJECTIVE

Though the possibility of using malignant pleural effusions (MPEs) as alternatives for tumor tissues in epidermal growth factor receptor (EGFR) mutation test has been examined, the diagnosis of MPE is often clinically challenging, especially if the cytology is negative for malignancy. The aim of this study was to examine whether cytological-negative PE (CNPE) is useful in detecting EGFR mutation and evaluated its feasibility for predicting clinical outcomes.

METHOD

In this study, we performed capture-based targeted sequencing using a panel consisting of 520 lung cancer-related genes to detect EGFR mutation status in 121 MPEs and 40 CNPE samples from 161 advanced lung adenocarcinoma patients. Patients underwent TKI treatment with gefitinib, icotinib or erlotinib if EGFR sensitizing mutations were detected at their tumor biopsies or pleural effusion sediment.

RESULTS

We revealed a mutation detection rate of 99.2% and 100% for MPE and CNPE, respectively (p = 1). The maximum allelic fraction (maxAF) of MPE and CNPE were 57.4% and 56.8%, respectively (p = 0.77). CNPE supernatant is comparable to MPE in reflecting the mutational profile of lung adenocarcinoma. EGFR activating mutations were detected in 47.5% (19/40) of CNPE supernatant sample and 32.5% (13/40) of matched tumor biopsies. CNPE sample is superior to tumor tissues in identifying EFGR mutation. Among the 72 EGFR-TKI treated patients, 51 were cytology positive and the remaining 21 were cytology negative. Our data showed that MPE patients exhibited comparable PFS (p = 0.41) and OS (p = 0.26) with CNPE patients treated with EGFR-TKI. Among the 21 CNPE patients received TKI treatment, patients harboring either L858R or exon 19 deletion had longer PFS than patients without a detectable mutation (p = 0.036).

CONCLUSION

Collectively, we demonstrated that CNPE supernatant provided a comprehensive profile of NSCLC, and can serve as a reliable lipid biopsy media for EGFR mutational detection.

Tumor-derived DNA from pleural effusion supernatant as a promising alternative to tumor tissue in genomic profiling of advanced lung cancer

Pleural effusion (PE) is commonly observed in advanced lung cancer and was suggested to contain both cell-free tumor DNA and tumor cells. Molecular profiling of PE represents a minimally invasive approach of detecting tumor driver mutations for clinical decision making, especially when tumor tissues are not available. The objective of this study is to investigate the efficacy and precision of detecting gene alterations in PE samples to address the feasibility in clinical use. Methods: Sixty-three metastatic lung cancer patients with (n=30, cohort 1) or without (n=33, cohort 2) matched tumor tissues were enrolled in this study. PE and plasma samples of each patient were collected simultaneously. Supernatant and cell precipitate of PE were processed separately to extract cfDNA (PE-cfDNA) and sediment DNA (sDNA). All samples were subjected to targeted next-generation sequencing (NGS) of 416 cancer-related genes. Results: PE supernatants contain more abundant tumor DNA than PE sediments and plasma samples, suggested by higher mutant allele frequencies (MAF) and elevated mutation detection rate in PE-cfDNA (98.4% vs. 90.5% in PE sDNA vs. 87% in plasma cfDNA). In Cohort 1 with matched tumor tissue, tumor mutational burden (TMB) of PE-cfDNA was similar as tumor tissues (6.4 vs. 5.6), but significantly higher than PE sDNA (median TMB: 3.3) and plasma cfDNA (median TMB: 3.4). Ninety-three percent (27 out of 29) of tissue-determined driver mutations were detected in PE-cfDNA, including alterations in ALK, BRAF, EGFR, ERBB2, KRAS, NF1, PIK3CA, and RET, while only 62% were captured in plasma cfDNA. PE-cfDNA also has the highest detection rate of EGFR driver mutations in the full cohort (71% vs. 68% in PE sDNA vs. 59% in plasma cfDNA). Mutation detection from cytological negative and hemorrhagic PE is challenging. Comparatively, PE-cfDNA demonstrated absolute superiority than PE sDNA in such a scenario, suggesting that it is an independent source of tumor DNA and therefore less influenced by the abundance of tumor cells. Conclusion: Genomic profiling of PE-cfDNA offers an alternative, and potentially more meticulous approach in assessing tumor genomics in advanced lung cancer when tumor tissue is not available. Our data further demonstrate that in hemorrhagic or cytologically negative PE samples, PE-cfDNA has higher mutation detection sensitivity than sDNA and plasma cfDNA, and therefore is a more reliable source for genetic testing.

Sensitive detection of low-abundance in-frame deletions in EGFR exon 19 using novel wild-type blockers in real-time PCR

Epidermal growth factor receptor (EGFR) mutations are associated with response of tyrosine kinase inhibitors (TKIs) for patients with advanced non-small cell lung cancer (NSCLC). However, the existing methods for detection of samples having rare mutations(i.e. ~0.01%) have limits in terms of specificity, time consumption or cost. In the current study, novel wild-type blocking (WTB) oligonucleotides modified with phosphorothioate or inverted dT at the 5'-termini were designed to precisely detect 11 common deletion mutations in exon 19 of EGFR gene (E19del) using a WTB-PCR assay. And internal competitive leptin amplifications were further applied to enhance the specificity of the WTB-PCR system. Our results showed that WTB-PCR could completely block amplification of wild-type EGFR when 200 ng of DNA was used as template. Furthermore, the current WTB-PCR assay facilitated the detection of E19del mutations with a selectivity of 0.01% and sensitivity as low as a single copy. And, the results showed that the current WTB-PCR system exceeded detection limits afforded by the ARMS-PCR assay. In conclusion, the current WTB-PCR strategy represents a simple and cost-effective method to precisely detect various low-abundance deletion mutations.

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.

A review of existing and new methods of bronchoscopic diagnosis of lung cancer

Bronchoscopy is one of the main techniques used for sampling lung tumor biopsies. In recent years, a large number of tumor specimens have been required to determine the best chemotherapy regimen for each patient; this personalized approach is known as precision medicine. In this review, radial endobronchial ultrasound; bronchoscopic navigation systems, including virtual bronchoscopic navigation and electromagnetic navigation; ultrathin bronchoscope,; and endobronchial ultrasound-guided transbronchial needle aspiration are highlighted as techniques used to increase the diagnostic yield. Personalized therapy includes tests for analysis of epidermal growth factor mutations, anaplastic lymphoma kinase or ROS proto-oncogene 1 fusion gene, and programmed death ligand 1 expression. In cryobiopsy, a relatively large amount of tissue is collected from endobronchial lung cancer and peripheral pulmonary lesions, and it is a promising technique for analyzing these tissues using molecular tests.

EGFR-TKI-sensitive mutations in lung carcinomas: are they related to clinical features and CT findings?

Background

Epidermal growth factor receptor (EGFR) mutation testing is restricted to several limitations. In this study, we examined the relationship between EGFR mutation status and clinicoradiological characteristics in a Chinese cohort of patients.

Materials and methods

The data of patients who were diagnosed with lung carcinoma and underwent both EGFR testing and chest computed tomography (CT) at our hospital between January 1, 2011, and November 31, 2015, were retrospectively analyzed. The age, sex, and smoking index of the patients, the size, margin, and density of the tumor, and the presence of specific signs visible on the CT images were assessed.

Results

The results showed a higher rate of EGFR-tyrosine kinase inhibitor (TKI)-sensitive group than nonsensitive group in female patients and patients with a low smoking index (P<0.001, both). In logistic regression analyses, tumor size (P<0.001), smooth margins (P=0.015), and angular margins (P<0.001) were independent negative predictors of EGFR-TKI-sensitive group. Pleural indentation (P<0.001) and air bronchogram (P=0.025) were independent positive predictors of EGFR-TKI-sensitive group. Patients with squamous cell carcinoma had fewer sensitive mutations than those with either adenocarcinoma (P<0.001) or adenosquamous carcinoma (P<0.001).

Conclusion

Clinical and CT characteristics differed significantly between EGFR-TKI-sensitive and nonsensitive groups. Our findings may be useful in deciding therapeutic strategies for patients in whom EGFR testing is not possible.

Mutation abundance affects the therapeutic efficacy of EGFR-TKI in patients with advanced lung adenocarcinoma: A retrospective analysis

PURPOSE

To investigate the influence of mutation abundance and sites of epidermal growth factor receptor (EGFR) on therapeutic efficacies of EGFR-tyrosine kinase inhibitor (EGFR-TKIs) treatments of patients with advanced non-small cell lung carcinoma (NSCLC).

METHODS

EGFR mutational sites and mutation abundance were analyzed by amplification refractory mutation system (ARMS) in paraffin-embedded tissue sections taken from primary or metastatic tumors of 194 NSCLC patients.

RESULTS

The median progression-free survival (PFS) time of the enrolled patients was 9.3 months (95% CI, 8.2-10.8 months). The PFS was significantly different with EGFR gene mutation abundance after EGFR-TKI therapy (P = 0.014). The median PFS was significantly longer when the cut-off value of EGFR mutation abundance of exon 19 or exon 21, and solely exon 19 was > 26.7% and 61.8%, respectively. For patients who received EGFR-TKI as first-line treatment, the median PFS was significantly longer in the high mutation abundance group than in the low mutation abundance group (12.7 vs 8.7 months, P = 0.002).

CONCLUSION

The PFS benefits were greater in patients with a higher abundance of exon 19 deletion mutations in the EGFR gene after EGFR-TKI treatment and first line EGFR-TKI treatment led to improved PFS in high mutation abundance patients.

Predicting outcomes of EGFR-targeted therapy in non-small cell lung cancer patients using pleural effusions samples and peptide nucleic acid probe assay

BACKGROUND

Mutation of epidermal growth factor receptor (EGFR) is a prediction marker of the response to tyrosine kinase inhibitor (TKI) drugs in non-small cell lung cancer (NSCLC) patients. As late stage lung cancer patients rarely undergo surgery, samples for EGFR mutation identification usually come from computed tomography (CT)-guided or endoscopic biopsies, which is invasive and costly. Pleural effusion may serve as a less invasive sample for EGFR mutation detection.

METHODS

We designed a fluorophore-labeled peptide nucleic acid (PNA) probe assay for three types of EGFR mutations, including exon 19 deletions, L858R point mutations and T790M point mutations. The assay was applied in 39 pleural effusion samples from NSCLC patients. The correlation between detected EGFR status and clinical outcome were analyzed.

RESULTS

In 15 paired samples, PNA probe assay in pleural effusion samples could detect all the mutations that were identified by conventional PCR plus Sanger sequencing in tissue biopsies. In addition, PNA probe assay detected three more T790M mutations. In all 39 pleural effusions, the PNA probe assay detected 27 having at least one of the three EGFR mutations. Among the patients before TKI treatment, those with a sensitizing mutation (either exon 19 deletion or L858R) but without T790M, had 94.1% response rate and longer progression-free survival (mean 10.8 months) than patients without detected mutation (mean 4.2 months) and patients with T790M (mean 1.7 months).

CONCLUSIONS

Mutations detected in pleural effusions using PNA probe assay are highly associated with clinical outcome. This method appears to be a reliable way for the prediction of the efficacy of EGFR-targeted therapy.

Utility of bronchial lavage fluids for epithelial growth factor receptor mutation assay in lung cancer patients: Comparison between cell pellets, cell blocks and matching tissue specimens

The detection of epidermal growth factor receptor (EGFR) mutations is necessary for the selection of suitable patients with non-small cell lung cancer (NSCLC) for treatment with EGFR tyrosine kinase inhibitors. Cytology specimens are known to be suitable for EGFR mutation detection, although tissue specimens should be prioritized; however, there are limited studies that examine the utility of bronchial lavage fluid (BLF) in mutation detection. The purpose of the present study was to investigate the utility of BLF specimens for the detection of EGFR mutations using a conventional quantitative EGFR polymerase chain reaction (PCR) assay. Initially, quantification cycle (Cq) values of cell pellets, cell-free supernatants and cell blocks obtained from three series of 1% EGFR mutation-positive lung cancer cell line samples were compared for mutation detection. In addition, PCR analysis of BLF specimens obtained from 77 consecutive NSCLC patients, detecting EGFR mutations was validated, and these results were compared with those for the corresponding formalin-fixed paraffin-embedded (FFPE) tissue specimens obtained by surgical resection or biopsy of 49 of these patients. The Cq values for mutation detection were significantly lower in the cell pellet group (average, 29.58) compared with the other groups, followed by those in cell-free supernatants (average, 34.15) and in cell blocks (average, 37.12) for all three series (P<0.05). Mutational status was successfully analyzed in 77 BLF specimens, and the results obtained were concordant with those of the 49 matching FFPE tissue specimens. Notably, EGFR mutations were even detected in 10 cytological specimens that contained insufficient tumor cells. EGFR mutation testing with BLF specimens is therefore a useful and reliable method, particularly when sufficient cancer cells are not obtained.

Accuracy of the cobas EGFR Mutation Assay in Non-small-cell Lung Cancer Compared With Three Laboratory-developed Tests

BACKGROUND

The reliability of the cobas EGFR assay to detect epidermal growth factor receptor (EGFR) mutations in non-small-cell lung cancer (NSCLC) as an in vitro diagnostic test was compared with 3 laboratory-developed tests (LDTs).

MATERIALS AND METHODS

After screening for EGFR mutations using formalin-fixed-paraffin-embedded NSCLC tissue sections using the cobas EGFR assay, 151 samples were further tested with 3 LDTs; the peptide nucleic acid-locked nucleic acid polymerase chain reaction (PCR) clamp, PCR invader, and Cycleave assays. The cobas EGFR assay performance was evaluated by determining the concordance rate and κ-coefficient between the assays. In samples exhibiting discrepancies in the EGFR mutation status in the 4 assays, next-generation sequencing was performed to confirm mutated sequences.

RESULTS

Concordance rates and κ-coefficients between the cobas EGFR assay and the other tests were 96.0% and 0.921 for the peptide nucleic acid-locked nucleic acid PCR clamp assay, 94.0% and 0.881 for the PCR invader assay, and 96.7% and 0.934 for the Cycleave assay, respectively. Data showed very good agreement with the other assays. Precise mutated sequences or exons in the EGFR gene matched in 137 samples (90.7%). Different results were obtained in 4 samples (2.6%), owing to systemic limitations of the assay. Next-generation sequencing of 10 (6.6%) samples with discordant results exhibited a concordance rate of 60% to 80% in each assay.

CONCLUSIONS

The cobas EGFR assay showed high concordance rates and κ-coefficients between the 3 compared LDTs and can be used to select patients who would benefit from EGFR-tyrosine kinase inhibitors.

Impact of metastatic status on the prognosis of EGFR mutation-positive non-small cell lung cancer patients treated with first-generation EGFR-tyrosine kinase inhibitors

The aim of the present study was to analyze the impact of metastatic status on the prognosis of epithelial growth factor receptor (EGFR) mutation-positive patients with non-small cell lung cancer (NSCLC) treated with first-generation EGFR-tyrosine kinase inhibitors (TKIs). A total of 178 EGFR mutation-positive patients with stage IIIB-IV and relapsed NSCLC who were treated with gefitinib or erlotinib as the first-line treatment were enrolled in the present study. Metastatic status, progression-free survival (PFS), overall survival (OS) and treatment-response rates were investigated. The association between the number of metastatic organ sites and patient prognosis was also investigated. The median age at the time of treatment was 72 (range, 39-91) years. A total of 168 patients had adenocarcinoma; 156 were treated with gefitinib. Patients with brain metastases, bone metastases, liver metastases and pleural effusion exhibited a significantly reduced PFS and OS time in the univariate analysis, compared with patients without each of these symptoms. In the multivariate analysis, bone metastasis was associated with a poorer PFS (hazard ratio, 2.11; 95% confidence interval, 1.44-3.09; P<0.001) and brain metastasis was associated with a poorer OS (hazard ratio, 2.41; 95% confidence interval, 1.46-3.95; P<0.001). No association was observed between metastatic status and treatment response rates. Higher numbers of different sites of organ metastases were associated with significantly poorer PFS and OS. Bone, brain metastasis and higher numbers of metastatic organ sites are negative prognostic factors for EGFR mutation-positive NSCLC patients treated with first-generation EGFR-TKIs.

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.

Guide to detecting epidermal growth factor receptor (EGFR) mutations in ctDNA of patients with advanced non-small-cell lung cancer

Cancer treatment is evolving towards therapies targeted at specific molecular abnormalities that drive tumor growth. Consequently, to determine which patients are eligible, accurate assessment of molecular aberrations within tumors is required. Obtaining sufficient tumor tissue for molecular testing can present challenges; therefore, circulating free tumor-derived DNA (ctDNA) found in blood plasma has been proposed as an alternative source of tumor DNA. The diagnostic utility of ctDNA for the detection of epidermal growth factor receptor (EGFR) mutations harbored in tumors of patients with advanced non-small-cell lung cancer (NSCLC) is supported by the results of several large studies/meta-analyses. However, recent real-world studies suggest that the performance of ctDNA testing varies between geographic regions/laboratories, demonstrating the need for standardized guidance. In this review, we outline recommendations for obtaining an accurate result using ctDNA, relating to pre-analytical plasma processing, ctDNA extraction, and appropriate EGFR mutation detection methods, based on clinical trial results. We conclude that there are several advantages associated with ctDNA, including the potential for repeated sampling - particularly following progression after first-line tyrosine kinase inhibitor (TKI) therapy, as TKIs targeting resistance mutations (eg T790M) are now approved for use in the USA/EU/Japan (at time of writing). However, evidence suggests that ctDNA does not allow detection of EGFR mutations in all patients with known mutation-positive NSCLC. Therefore, although tumor tissue should be the first sample choice for EGFR testing at diagnosis, ctDNA is a promising alternative diagnostic approach.

Diagnosis of anaplastic lymphoma kinase rearrangement in cytological samples through a fluorescence in situ hybridization-based assay: Cytological smears versus cell blocks

Anaplastic lymphoma kinase (ALK) status analysis of lung cytological specimens should be successfully encouraged in routine practice because biopsy specimens are not always available. To date, the US Food and Drug Administration has approved both fluorescence in situ hybridization (FISH) and immunohistochemistry (IHC) as diagnostic tests for identifying ALK-positive patients eligible for treatment with crizotinib. Although ALK IHC is an optimal diagnostic tool, FISH becomes mandatory in equivocal cases. ALK FISH of paraffin-embedded tissue material is still the gold standard, whereas the cytological specimen assay has not yet been completely standardized. Many controversial data have been reported on the adequacy of cytology cell blocks (CBs) versus conventional smears for FISH testing. This review discusses some critical issues related to ALK FISH of cytological samples, including the triaging of collected specimens to optimize the material, the use of CBs versus conventional smears, and alternative methods for an ALK rearrangement diagnosis. Conventional smears have the advantages of an immediate evaluation, no probe tissue-related artifactual loss, no fixation-related alterations, and usually sufficient material for an analytic preparation. On the other hand, CBs have several advantages, including the appropriate conservation of the tissue architecture, an absence of problems related to cell overlapping, and the ability to evaluate neoplastic cells in a dark field. Cancer Cytopathol 2017;125:303-312. © 2017 American Cancer Society.

A primer and probe set for detecting multiple types of EGFR exon 19 deletions

EGFR exon 19 deletion is an important indicator for tyrosine kinase inhibitor treatment in non-small cell lung cancer. However, detection of exon 19 deletions faces a challenge: there are more than 30 types of mutations reported at the hotspot. Moreover, considering the application in body fluid samples, assays with high sensitivity and specificity are necessary for the detection of rare mutant alleles. Here, we describe a single tube reaction which could detect at least 29 types of exon 19 deletions with only an unlabeled peptide nucleic acid (PNA) clamp and a pair of DNA probes. The PNA clamp was used to inhibit amplification of wild-type templates; and the DNA probes were used to generate melting peaks for multiple types of mutations. Under optimal condition, the assay was able to detect as low as 0.01% mutant DNA in wild-type background, and had a limit of detection of 10 pg genomic DNA. Feasibility of the assay was tested in body fluid samples from lung cancer patients. The assay detected 100% and 60% of deletions in pleural effusions and plasma, respectively. We believe the present assay can be used in the clinical laboratories and has potential to be adapted for a microfluidic device.

Epidermal Growth Factor Receptor Mutation and Anaplastic Lymphoma Kinase Gene Fusion: Detection in Malignant Pleural Effusion by RNA or PNA Analysis

Analyzing EGFR mutations and detecting ALK gene fusion are indispensable when planning to treat pulmonary adenocarcinoma. Malignant pleural effusion (MPE) is a devastating complication of lung cancer and sometimes the only source for mutation analysis. The percentage of tumor cells in the pleural effusion may be low; therefore, mutant enrichment is required for a successful analysis. The EGFR mutation status in MPE was determined using three methods: (1) PCR sequencing of genomic DNA (direct sequencing), (2) mutant-enriched PCR sequencing of genomic DNA using peptide nucleic acid (PNA-sequencing), and (3) PCR sequencing of cDNA after reverse transcription for cellular RNA (RNA-sequencing). RT-PCR was also used to test cases for ALK gene fusion.

PNA-sequencing and RNA-sequencing had similar analytical sensitivities (< 1%), which indicates similar enrichment capabilities. The clinical sensitivity in 133 cases when detecting the common EGFR exon 19 and exon 21 mutations was 56.4% (75/133) for direct sequencing, 63.2% (84/133) for PNA-sequencing, and 65.4% (87/133) for RNA-sequencing. RT-PCR and sequencing showed 5 cases (3.8%) with ALK gene fusion. All had wild-type EGFR. For EGFR analysis of MPE, RNA-sequencing is at least as sensitive as PNA-sequencing but not limited to specific mutations. Detecting ALK fusion can be incorporated in the same RNA workflow. Therefore, RNA is a better source for comprehensive molecular diagnoses in MPE.

Assessment of the clinical application of detecting EGFR, KRAS, PIK3CA and BRAF mutations in patients with non-small cell lung cancer using next-generation sequencing

BACKGROUND

Next-generation sequencing (NGS) has been widely applied in clinical research, while its application in routine clinical molecular testing requires careful validation. The aim of our study was to assess the clinical usefulness of the NextDaySeq Lung panel on Ion Torrent™ PGM in mutation detection of actionable genes in lung cancer.

METHODS

The NextDaySeq assay was evaluated by blinded comparisons to Quantitative Real-Time PCR (qPCR) assays with 188 consecutive samples from Chinese patients with non-small cell lung cancer (NSCLC) to detect mutations in EGFR, KRAS, PIK3CA and BRAF. Discordant variants were further validated by Sanger sequencing and independent qPCR and NGS assays.

RESULTS

Our results showed 93.3% concordance of reportable variants mutually covered in both NGS and qPCR assays, with a clinical sensitivity of 89.9%, specificity of 97.5%. Through the comparison, the NGS assays demonstrated its advantages in offering more clinical relevant information, such as detecting non-hotspot mutations and providing mutation allele frequencies (MAF) and accurate mutation sequences. The analytical sensitivity of NGS to detect mutations with low MAF needs further improvement.

CONCLUSIONS

The NextDaySeq Lung panel exhibited good clinical performance, strongly supporting the implementation of the NGS assay in routine clinical use to facilitate therapeutic decision-making for lung cancer patients.

A comparison of four methods for detecting KRAS mutations in formalin-fixed specimens from metastatic colorectal cancer patients

There is currently no standard method for the detection of Kirsten rat sarcoma viral oncogene homolog (KRAS) mutation status in colorectal tumors. In the present study, we compared the KRAS mutation detection ability of four methods: direct sequencing, Scorpion-ARMS assaying, pyrosequencing and multi-analyte profiling (Luminex xMAP). We evaluated 73 cases of metastatic colorectal cancer (mCRC) resistant to irinotecan, oxaliplatin and fluoropyrimidine that were enrolled in an all-case study of cetuximab. The KRAS mutation detection capacity of the four analytical methods was compared using DNA samples extracted from tumor tissue, and the detection success rate and concordance of the detection results were evaluated. KRAS mutations were detected by direct sequencing, Scorpion-ARMS assays, pyrosequencing and Luminex xMAP at success rates of 93.2%, 97.3%, 95.9% and 94.5%, respectively. The concordance rates of the detection results by Scorpion-ARMS, pyrosequencing and Luminex xMAP with those of direct sequencing were 0.897, 0.923 and 0.900 (κ statistics), respectively. The direct sequencing method could not determine KRAS mutation status in five DNA samples. Of these, Scorpion-ARMS, pyrosequencing and Luminex xMAP successfully detected three, two and one KRAS mutation statuses, respectively. Three cases demonstrated inconsistent results, whereby Luminex xMAP detected mutated KRAS in two samples while wild-type KRAS was detected by the other methods. In the remaining case, direct sequencing detected wild-type KRAS, which was identified as mutated KRAS by the other methods. In conclusion, we confirmed that Scorpion-ARMS, pyrosequencing and Luminex xMAP were equally reliable in detecting KRAS mutation status in mCRC. However, in rare cases, the KRAS status was differentially diagnosed using these methods.

Malignant pleural effusion cell blocks are substitutes for tissue in EML4-ALK rearrangement detection in patients with advanced non-small-cell lung cancer

OBJECTIVE

To evaluate the feasibility of malignant pleural effusions (MPE) as surrogate samples for the detection of echinoderm microtubule-associated protein-like4 (EML4)-anaplastic lymphoma kinase (ALK) and to investigate the prognostic and predictive value of EML4-ALK in MPE of non-small-cell lung cancer (NSCLC).

METHODS

One hundred and nine NSCLC patients were retrospectively analysed. EML4-ALK was identified using paraffin-embedded tumour cells in MPE samples by immunohistochemistry (IHC, Ventana) and confirmed by fluorescence using in situ hybridisation (FISH) and qRT-PCR. The EGFR mutation was determined by MPE, using denaturing high-performance liquid chromatography (DHPLC).

RESULTS

A total of 5 out of 109 (4.58%) patients were identified as EML4-ALK rearrangement in MPE by IHC.; In addition to two metachronous samples, the consistency of MPE and tissue for EML4-ALK detection was 100% (21/21), and the sensitivity and specificity were 100% (2/2) and 100% (19/19), respectively. EML4-ALK rearrangement cases were confirmed by FISH and qRT-PCR; the sensitivity were both 100% (2/2) when compared with tissue, and it was 60% (3/5) and 100% (5/5), respectively, when compared with MPE by IHC. The overall response rate (ORR) was 100% (2/2) for patients with EML4-ALK in MPE. Moreover, the PFS of these patients appeared to be prolonged in chemotherapy (9.27 versus 6.53 and versus 4.67 months, P = 0.122), compared with the EGFR mutation and the EGFR/ALK double negative group, respectively.

CONCLUSION

EML4-ALK rearrangement detection in malignant pleural effusions is a complementary method for EML4-ALK detection. VETANA and qRT-PCR are more appropriate for MPE detection. EML4-ALK rearrangement in pleural effusions has a predictive value for treatment.

Phase II trial of gefitinib in combination with bevacizumab as first-line therapy for advanced non-small cell lung cancer with activating EGFR gene mutations: the Okayama Lung Cancer Study Group Trial 1001

PURPOSE

Whether bevacizumab enhances the effect of the epidermal growth factor receptor (EGFR) inhibitor gefitinib on EGFR mutant non-small cell lung cancers (NSCLCs) remains unknown. We conducted a phase II trial to investigate the efficacy and safety of gefitinib when combined with bevacizumab as first-line therapy in patients with advanced NSCLC harboring EGFR gene mutations.

METHODS

In this trial, 42 patients with a performance status of 0 to 2 received gefitinib (250 mg/d) and bevacizumab (15 mg/kg, every 3 weeks). The primary end point of this study was the 1-year progression-free survival (PFS) rate. We assumed that a 1-year PFS rate of 55% would indicate potential usefulness and that a 1-year PFS rate of 40% would constitute the lower limit of interest.

RESULTS

Forty-two patients were enrolled in the study with a median age of 73 (range 42-86) years. Activating EGFR gene mutations included exon 19 deletion (57%) and L858R point mutations in exon 21 (38%). The objective response rate was 73.8% and included two complete responses. The 1-year PFS rate and median PFS time were 56.7% (95% confidence interval [CI] 39.9-70.5) and 14.4 months (95% CI 10.1-19.2), respectively. The median PFS differed significantly between EGFR exon 19 deletion and the L858R point mutation (18.0 versus 9.4 months, respectively; p = 0.006). The median overall survival had not yet been reached. Severe adverse events included grade 3 skin rash (15%), hypertension (17%), aspartate transaminase/alanine aminotransferase elevation (17%), proteinuria (7%), intracranial hemorrhage (2%), and grade 4 perforation of the digestive tract (2%). There were no treatment-related deaths.

CONCLUSION

Gefitinib in combination with bevacizumab as first-line therapy seems to be a favorable and well-tolerated treatment for patients with advanced NSCLC with activating EGFR gene mutations, especially those with EGFR exon 19 deletion mutations, although the primary end point was not met because the lower limit of the CI was less than 40%.

Detection of EGFR-TK domain-activating mutations in NSCLC with generic PCR-based methods

Somatic mutations in the epidermal growth factor receptor-tyrosine kinase (EGFR-TK) domain of non-small cell lung cancer (NSCLC) influence the responsiveness of these tumors to EGFR-TK inhibitors, indicating their usefulness as a predictive molecular marker. However, for mutation analysis, the amount of clinical material available from NSCLC patients is often very limited, suboptimally preserved, and composed of both normal and tumor cells. As a consequence, the total amount of recovered DNA is frequently very limited, with mutant alleles being often strongly underrepresented, and thus requiring highly sensitive methods for the detection of mutations. In the present study, EGFR mutation screening was performed on 210 NSCLC clinical samples by heminested polymerase chain reaction (PCR), followed by denaturing gradient gel electrophoresis (DGGE). Candidate mutations were further characterized by sequencing. Seventeen different types of pathogenic EGFR-TK domain mutations were detected in 55 of the 210 samples (26%). We reanalyzed 149 of the 155 samples in which no mutation was found by real-time PCR for the presence of recurrent exon 21 and exon 19 mutations using peptide nucleic acid probes in the PCR mix to increase sensitivity by mutant allele enrichment. Four additional samples with exon 19 mutations were detected. Thus, it is found that the relatively simple and inexpensive PCR-DGGE assay is already very sensitive for the detection of mutations in clinical samples, including samples with low tumor cellularity (10% or higher tumor cell content), although the sensitivity and speed of the assay can be further increased for a restricted panel of mutations by introducing peptide nucleic acid probes in the DGGE or real-time PCR-based assay.

Epidermal growth factor receptor mutation analysis in cytological specimens and responsiveness to gefitinib in advanced non-small cell lung cancer patients

BACKGROUND

Epidermal growth factor receptor (EGFR) mutation is the key predictor of EGFR tyrosine kinase inhibitors (TKIs) efficacy in non-small cell lung cancer (NSCLC). We conducted this study to verify the feasibility of EGFR mutation analysis in cytological specimens and investigate the responsiveness to gefitinib treatment in patients carrying EGFR mutations.

METHODS

A total of 210 cytological specimens were collected for EGFR mutation detection by both direct sequencing and amplification refractory mutation system (ARMS). We analyzed EGFR mutation status by both methods and evaluated the responsiveness to gefitinib treatment in patients harboring EGFR mutations by overall response rate (ORR), disease control rate (DCR) and progression free survival (PFS).

RESULTS

Of all patients, EGFR mutation rate was 28.6% (60/210) by direct sequencing and 45.2% (95/210) by ARMS (P<0.001) respectively. Among the EGFR wild type patients tested by direct sequencing, 26.7% of them were positive by ARMS. For the 72 EGFR mutation positive patients treated with gefitinib, the ORR, DCR and median PFS were 69.4%, 90.2% and 9.3 months respectively. The patients whose EGFR mutation status was negative by direct sequencing but positive by ARMS had lower ORR (48.0% vs. 80.9%, P=0.004) and shorter median PFS (7.4 vs. 10.5 months, P=0.009) as compared with that of EGFR mutation positive patients by both detection methods.

CONCLUSIONS

Our study verified the feasibility of EGFR analysis in cytological specimens in advanced NSCLC. ARMS is more sensitive than direct sequencing in EGFR mutation detection. EGFR Mutation status tested on cytological samples is applicable for predicting the response to gefitinib. Abundance of EGFR mutations might have an influence on TKIs efficacy.

[Progress in Tissue Specimens Alternative for the Driver Genes Testing of Non-small Cell Lung Cancer]

Target treatment based on driver genes in advanced non-small cell lung cancer is very important currently. Tumor tissues is the gold standard for driver genes testing. However, most of patients could not get the gene information for lack of enough tissues. To explore the tissue specimens alternatives is a hot spot in clinical work. This report reviews the tissue specimen alternatives of driver gene testing in non-small cell lung cancer.

Detection of epidermal growth factor receptor mutation in lung cancer by droplet digital polymerase chain reaction

Background

Two types of epidermal growth factor receptor (EGFR) mutations in exon 19 and exon 21 (ex19del and L858R) are prevalent in lung cancer patients and sensitive to targeted EGFR inhibition. A resistance mutation in exon 20 (T790M) has been found to accompany drug treatment when patients relapse. These three mutations are valuable companion diagnostic biomarkers for guiding personalized treatment. Quantitative polymerase chain reaction (qPCR)-based methods have been widely used in the clinic by physicians to guide treatment decisions. The aim of this study was to evaluate the technical and clinical sensitivity and specificity of the droplet digital polymerase chain reaction (ddPCR) method in detecting the three EGFR mutations in patients with lung cancer.

Methods

Genomic DNA from H1975 and PC-9 cells, as well as 92 normal human blood specimens, was used to determine the technical sensitivity and specificity of the ddPCR assays. Genomic DNA of formalin-fixed, paraffin-embedded specimens from 78 Chinese patients with lung adenocarcinoma were assayed using both qPCR and ddPCR.

Results

The three ddPCR assays had a limit of detection of 0.02% and a wide dynamic range from 1 to 20,000 copies measurement. The L858R and ex19del assays had a 0% background level in the technical and clinical settings. The T790M assay appeared to have a 0.03% technical background. The ddPCR assays were robust for correct determination of EGFR mutation status in patients, and the dynamic range appeared to be better than qPCR methods. The ddPCR assay for T790M could detect patient samples that the qPCR method failed to detect. About 49% of this patient cohort had EGFR mutations (L858R, 15.4%; ex19del, 29.5%; T790M, 6.4%). Two patients with the ex19del mutation also had a naïve T790M mutation.

Conclusion

These data suggest that the ddPCR method could be useful in the personalized treatment of patients with lung cancer.

Rapid and label-free amplification and detection assay for genotyping of cancer biomarker

As understanding of the molecular pathways that drive malignancy in human cancer improves, personalized genotype-based therapy in combination with the predictive biomarker for the efficacy of targeted therapy is becoming more popular in cancer management. Sanger sequencing, that has been the gold standard for mutation analysis in cancer since the 1970s, suffers from low sensitivity, complexity, and time-consuming and labor-intensive procedure. Although several PCR based molecular testing methods are being emerged, there is no universal assay available for genotyping of cancer biomarkers. Here we present a rapid, simple and sensitive assay for the detection of epidermal growth factor receptor (EGFR) mutation in non-small cell lung cancers (NSCLCs). The assay employs a novel double mis-matched primer (DMP) set to improve the detection ability of isothermal solid-phase amplification/detection (ISAD) based on silicon microring biosensor. We show that the EGFR-DMP can detect EGFR gene mutations within 20 min in a label-free and real-time manner. The EGFR-DMP was able to detect a mutation in a sample containing only 1% of the mutant cells in a mixture of wild-type cells. Furthermore, to validate the proposed assay for potential applications in clinical diagnostics, we examined paraffin-embedded tissue samples from 10 NSCLC patients for the presence of EGFR mutations by performing EGFR-DMP and direct sequencing. The EGFR-DMP assay was able to rapidly detect the mutation, with high sensitivity and specificity. The EGFR-DMP assay offers a robust and sensitive approach for the rapid identification of the EGFR mutation. The high sensitivity and specificity and rapidity of this approach may make it useful for predicting the clinical response to targeted EGFR TKIs as a companion diagnostic.

Current challenges for detection of circulating tumor cells and cell-free circulating nucleic acids, and their characterization in non-small cell lung carcinoma patients. What is the best blood substrate for personalized medicine?

The practice of "liquid biopsy" as a diagnostic, prognostic and theranostic tool in non-small cell lung cancer (NSCLC) patients is an appealing approach, at least in theory, since it is noninvasive and easily repeated. In particular, this approach allows patient monitoring during treatment, as well as the detection of different genomic alterations that are potentially accessible to targeted therapy or are associated with treatment resistance. However, clinical routine practice is slow to adopt the liquid biopsy. Several reasons may explain this: (I) the vast number of methods described for potential detection of circulating biomarkers, without a consensus on the ideal technical approach; (II) the multiplicity of potential biomarkers for evaluation, in particular, circulating tumor cells (CTCs) vs. circulating tumor DNA (ctDNA); (III) the difficulty in controlling the pre-analytical phase to obtain robust and reproducible results; (IV) the present cost of the currently available techniques, which limits accessibility to patients; (V) the turnaround time required to obtain results that are incompatible with the urgent need for delivery of treatment. The purpose of this review is to describe the main advances in the field of CTC and ctDNA detection in NSCLC patients and to compare the main advantages and disadvantages of these two approaches.

Epidermal growth factor receptor mutations in non- small cell lung cancers in a multiethnic malaysian patient population

BACKGROUND

Mutations in the tyrosine kinase domain of the epidermal growth factor receptor (EGFR) in non- small cell lung cancer (NSCLC) are predictive of response to EGFR-targeted therapy in advanced stages of disease. This study aimed to determine the frequency of EGFR mutations in NSCLCs and to correlate their presence with clinical characteristics in multiethnic Malaysian patients.

MATERIALS AND METHODS

In this prospective study, EGFR mutations in exons 18, 19, 20 and 21 in formalin-fixed paraffin-embedded biopsy specimens of consecutive NSCLC patients were asessed by real-time polymerase chain reaction.

RESULTS

EGFR mutations were detected in NSCLCs from 55 (36.4%) of a total of 151 patients, being significantly more common in females (62.5%) than in males (17.2%) [odds ratio (OR), 8.00; 95% confidence interval (CI), 3.77-16.98; p<0.001] and in never smokers (62.5%) than in ever smokers (12.7%) (OR, 11.50; 95%CI, 5.08-26.03; p<0.001). Mutations were more common in adenocarcinoma (39.4%) compared to non-adenocarcinoma NSCLCs (15.8%) (p=0.072). The mutation rates in patients of different ethnicities were not significantly different (p=0.08). Never smoking status was the only clinical feature that independently predicted the presence of EGFR mutations (adjusted OR, 5.94; 95%CI, 1.94- 18.17; p=0.002).

CONCLUSIONS

In Malaysian patients with NSCLC, the EGFR mutation rate was similar to that in other Asian populations. EGFR mutations were significantly more common in female patients and in never smokers. Never smoking status was the only independent predictor for the presence of EGFR mutations.

Comparison of PNA clamping and direct sequencing for detecting KRAS mutations in matched tumour tissue, cell block, pleural effusion and serum from patients with malignant pleural effusion

BACKGROUND AND OBJECTIVE

Peptide nucleic acid (PNA)-mediated real-time polymerase chain reaction clamping was recently developed to improve mutation detection sensitivity. Pleural effusion could be a good sample candidate for mutation analysis. To establish if PNA clamping could be used to detect KRAS mutation in particular in pleural effusion, we analysed its diagnostic performance.

METHODS

We studied 57 patients with malignant effusion. KRAS mutation was evaluated in samples of matched tumour tissue, cell block, pleural effusion and serum using PNA clamping and direct sequencing.

RESULTS

The detection rate of KRAS mutation using pleural effusion was 14% for PNA clamping and 10.5% for direct sequencing. The κ coefficient between the two methods was 0.76 (P value < 0.0001), 1.00 (P value < 0.0001) and 0.87 (P value < 0.0001) in pleural effusion, tissue and cell block, respectively. The diagnostic performance of KRAS mutation detection from pleural effusion compared with the results obtained for all samples combined showed that the sensitivity, specificity, positive predictive value and negative predictive value were as follows: 89, 100, 100 and 98%, respectively for PNA clamping; 67, 100, 100 and 94%, respectively for directing sequencing.

CONCLUSIONS

The current study suggests that PNA clamping had a good concordance with direct sequencing for the detection of KRAS mutation in patients with malignant effusion. Furthermore, the good diagnostic performance obtained from pleural effusion samples provides evidence that pleural effusion can be a useful source for detecting KRAS mutation in a clinical setting, in which the collection of tumour tissues is challenging.

[Immunohistochemical detections of EGFR mutations in NSCLC]

近些年来，人们越来越认识到，存在表皮生长因子受体（epidermal growth factor receptor, EGFR）突变的非小细胞肺癌（non-small cell lung cancer, NSCLC）患者对靶向药物EGFR酪氨酸激酶抑制剂（EGFR-tyrosine kinase inhibitor, EGFR-TKI）的治疗有良好反应。目前，检测EGFR突变应用最多且较为可靠的是以DNA分子为基础的检测（如DNA测序）方法，但此法操作繁琐，耗时长，花费高，对样本要求严格。相比之下，免疫组织化学法（immunohistochemistry, IHC）则充分弥补了上述缺陷，可作为EGFR突变筛查的辅助手段。但影响其结果的因素较多，如不同的免疫组化染色方法、不同抗原修复液的选择及不同的结果评判标准等，因此此法尚未广泛应用于临床，仅处于研究阶段。本文通过检索不同研究者应用免疫组化法对NSCLC患者进行EGFR突变检测的相关文献，进一步讨论如何合理应用免疫组化法检测EGFR突变可发挥其临床应用的最大价值。

Realizing the potential of plasma genotyping in an age of genotype-directed therapies

The identification of oncogenic driver mutations in cancer has led to the rapid rise of genotype-directed treatments such as EGFR and BRAF kinase inhibitors. Standard tumor biopsy remains a cumbersome and morbid procedure for patients, leading to a growing interest in noninvasive plasma genotyping approaches. Circulating tumor cells are of interest; however, the processing of specimens is complicated and time consuming. By comparison, cell-free DNA (cfDNA) genotyping has the potential to be convenient and relatively simple to process in a short time period. Several technologies are under development for cfDNA analysis, such as allele-specific polymerase chain reaction (PCR), coamplification at Lower Denaturation temperatures (COLD) PCR, emulsion PCR, and massively parallel sequencing. Broad clinical validity will need to be established for different assays, and clinical utility will need to be evaluated within prospective trials to determine which assays will best predict the efficacy of therapy and patient outcomes. In addition, assay standardization will be critical prior to widespread use in routine clinical practice. The Cell Free DNA Working Group, under the sponsorship of Transgenomic, was convened to evaluate the molecular assays in development and provide recommendations for application and interpretation of these tests in the context of future clinical research. The consensus commentary of the Cell Free DNA Working Group for the use of cfDNA plasma genotyping assays is presented here, including future steps in the development of these technologies.

New targeted molecular therapies for cancer: radiological response in intrathoracic malignancies and cardiopulmonary toxicity: what the radiologist needs to know

The emergence of new novel therapeutic agents which directly target molecules that are uniquely or abnormally expressed in cancer cells (molecular targeted therapy, MTT) has changed dramatically the treatment of cancer in recent years. The clinical benefit associated with these agents is typically limited to a subset of treated patients, who in many cases are defined by a specific genomic mutations and expression lesion within their tumor cells. All these new therapy modalities represent new challenges to radiologists as their mechanism of action and side effect profiles differ from conventional chemotherapy agents. In this article we will discuss radiological patterns of response to molecular targeted therapies MTT in lung cancer, typical and atypical radiological responses of targeted molecular therapy for other intra thoracic malignancies, cardiopulmonary toxicity and other side effects of molecular targeted therapy MTT in the thorax.

Phase II study of erlotinib for previously treated patients with EGFR wild-type non-small-cell lung cancer, following EGFR mutation status reevaluation with the Scorpion Amplified Refractory Mutation System

While assessing the efficacy of erlotinib in patients with epidermal growth factor receptor (EGFR) wild-type (WT) non-small-cell lung cancer (NSCLC), the sensitivity of the method used for the EGFR mutation analysis may affect the evaluation of the efficacy. We conducted a phase II study of erlotinib for previously treated patients with EGFR WT NSCLC screened by the peptide nucleic acid-locked nucleic acid (PNA-LNA) polymerase chain reaction (PCR) clamp method, which is known to be highly sensitive. The primary endpoint was the objective response rate (ORR). Preplanned reevaluation of the EGFR genotype as an exploratory endpoint was performed using the Scorpion Amplification Refractory Mutation System (S-ARMS) assay. Erlotinib was administered daily until disease progression or development of unacceptable toxicity. A total of 53 evaluable patients were enrolled. The histological subtypes were adenocarcinoma in 40 patients, squamous cell carcinoma in 9 patients and not otherwise specified NSCLC in 4 patients. Partial response (PR) was achieved in 6 patients (4 with adenocarcinoma and 2 with squamous cell carcinoma). The ORR was 11.3% [95% confidence interval (CI): 4.3-23.0]. The median progression-free survival (PFS) was 1.8 months (95% CI: 1.2-2.3). Samples from 26 of the 53 patients (49.0%) were available for EGFR mutation reanalysis with the S-ARMS assay. Of these 26 samples, only 1 sample of adenocarcinoma was found to be EGFR mutation-positive (exon 19 deletion) and the patient achieved a PR. The EGFR WT genotype was reconfirmed by the S-ARMS assay in the remaining 25 patients and 2 of these patients exhibited a PR. This study did not meet the primary endpoint, although erlotinib was found to be moderately effective in pretreated patients with EGFR WT NSCLC, even when the EGFR mutational status was confirmed by the highly sensitive PNA-LNA clamp PCR method.

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.

Malignant pleural effusion supernatants are substitutes for metastatic pleural tumor tissues in EGFR mutation test in patients with advanced lung adenocarcinoma

Background

Though the possibility of using malignant pleural effusions (MPEs) as alternatives for metastatic pleural tumor tissues (MPTTs) in epidermal growth factor receptor (EGFR) mutation test has been examined, due to the lack of studies comparing the results in matching MPEs and MPTTs, the clinical value of MPEs for advanced adenocarcinoma patients with pleural effusions is not confirmed.

Methods

EGFR mutation statuses in matching MPTTs, MPE supernatants and cell blocks, of 41 patients with advanced lung adenocarcinoma as diagnosed by thoracoscopy were analyzed using amplification refractory mutation system (ARMS).

Results

EGFR mutations were detected in 46.3% (19/41) of MPTTs, 43.9% (18/41) of MPE supernatants and 56.3% (18/32) of MPE cell blocks by ARMS analysis. Generally, the same EGFR statuses were identified in both MPTTs and matching MPE cell blocks of 81.3% patients (26/32), whereas MPTTs and matching MPE supernatants of 87.8% (36/41) patients shared the same EGFR status. Compared with EGFR mutation detection in MPTTs, the sensitivity of EGFR mutation detection in MPE-cell blocks was 87.5% (14/16), specificity was 75.0% (12/16), while the sensitivity of EGFR mutation detection in MPE-supernatants was 84.2% (16/19), specificity was 90.9% (20/22).

Conclusions

The high concordance of EGFR mutation statuses between MPEs and MPTTs in lung adenocarcinoma patients with pleural metastasis as determined by ARMS analysis suggests that MPEs, particularly MPE supernatants, may be substitutes for MPTTs in EGFR mutation test.