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.     

ADx-ARMS方法检测晚期非小细胞肺癌患者胸水标本癌细胞基因突变的临床意义

目的:探讨应用ADx-ARMS方法检测非小细胞肺癌患者胸水标本癌细胞基因突变应用于指导小分子EGFR酪氨酸激酶抑制剂（EGFR-TKIs）治疗的可行性与临床意义。方法:ADx-ARMS检测24例非小细胞肺癌患者胸水标本EGFR基因第19、20和21外显子突变与KRAS基因第2外显子突变。统计分析胸水标本与前期检测过的非小细胞肺癌组织中的EGFR、KRAS突变率差异。结果:24例胸水标本中,EGFR突变与KRAS突变分别为14例（58.3%）和1例（4.2%）。前期检测过的非小细胞肺癌组织EGFR和KRAS突变率分别为47.6%和4.5%。EGFR和KRAS突变率在胸水标本与前期肺癌组织中差异无统计学意义（P>0.05）。结论:对失去手术机会而难以获得组织标本的晚期非小细胞肺癌患者,可应用ADx-ARMS方法选择胸水标本筛查EGFR、KRAS基因突变,从而指导EGFR-TKIs的临床应用。     

Comparison of the Amplification Refractory Mutation System,Super Amplification Refractory Mutation System,and Droplet Digital PCR for T790 M Mutation Detection in Non-small Cell Lung Cancer after Failure of Tyrosine Kinase Inhibitor Treatment

Plasma mutation detection has the advantages of non-invasiveness and accessibility. Here, we evaluated three methods, the amplification refractory mutation system (ARMS), second-generation ARMS (SuperARMS), and droplet digital PCR (ddPCR), to assess their concordance and feasibility for the detection of mutations in plasma samples. Non-small lung cancer patients with stage IIIB/IV that were resistant to epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKI) treatment were enrolled. Blood samples were collected within 14 days after TKI resistance. Each sample was simultaneously assessed by the three methods. In total, 169 patients were enrolled; 54.4% were female, 72.2% were diagnosed with stage IV disease; and 97.6% had adenocarcinoma. T790 M mutations were detected in 42 (24.8%) of the 169 samples using ARMS, one of which carried the T790 M alone, 22 that also encoded exon 19 deletions, and 19 with L858R mutations. For the SuperARMS assay, 59 (34.9%) samples exhibited the T790 M mutation, and 110 (65.1%) showed no detectable T790 M mutation. ddPCR showed that 61 (36.1%) samples contained the T790 M mutation, whereas 108 (63.9%) were not positive. T790 M abundance ranged from 0.04% to 38.2%. The median T790 M abundance was 0.15% for total samples and 2.98% for T790 M mutation samples. The overall concordance was 78.7% (133/169) among ARMS, SuperARMS, and ddPCR. Compared with patients with stage III disease, patients with stage IV disease exhibited a higher T790 M mutation detection rate (28.7% vs. 14.9% by ARMS; 37.7% vs. 27.7% by SuperARMS; and 41.8% vs. 21.3% by ddPCR). Liquid biopsy showed promise and has the advantages of non-invasiveness and accessibility. T790 M detection based on circulating tumor DNA showed high concordance. Compared with non-digital platforms, ddPCR showed higher sensitivity and provided both frequency and abundance information, which might be important for treatment decisions.     

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

Epidermal growth factor receptor (EGFR) mutations are a strong determinant of tumor response to gefitinib in non-small cell lung cancer (NSCLC). We attempted to elucidate the feasibility of EGFR mutation detection in cells of pleural effusion fluid. We obtained 24 samples of pleural effusion fluid from NSCLC patients. The pleural effusion fluid was centrifuged, and the cellular components obtained were used for detection. EGFR mutation status was determined by a direct sequencing method (exons 18-21) and by the Scorpion Amplified Refractory Mutation System (ARMS) method. EGFR mutations were detected in eight cases. Three mutations were detected by both methods, and the other five mutations were detected by Scorpion ARMS alone. The mutations were detected by both methods in all four partial responders among the seven patients who received gefitinib therapy. Direct sequencing detected the mutations in only two of four cases with partial response. These results suggest that the DNA in pleural effusion fluid can be used to detect EGFR mutations. The Scorpion ARMS method appears to be more sensitive for detecting EGFR mutations than the direct sequencing method.     

BEAMing ddPCR与Super ARMS检测EGFR酪氨酸激酶抑制剂治疗后非小细胞肺癌患者循环肿瘤DNA EGFR基因突变的比较研究

背景与目的:BEAMing微滴数字PCR(droplet digital PCR,ddPCR)被认为是灵敏度极高的基因突变检测方法,探讨该方法和扩增阻碍突变系统(Super amplification refractory mutation system,Super ARMS)检测表皮生长因子受体(epidermal growth factor receptor,EGFR)酪氨酸激酶抑制剂(tyrosine kinase inhibitor,TKI)治疗非小细胞肺癌(non-small cell lung cancer,NSCLC)患者后循环肿瘤DNA(circulating tumor DNA,ctDNA)EGFR基因突变的灵敏度差异,进而为指导临床ctDNA检测方法的选择提供更多参考。方法:收集复旦大学附属肿瘤医院2017-2018年接受过EGFR TKI治疗的NSCLC患者血浆33例及国家病理质控评价中心(PathologyQualityControlCenter,PQCC)模拟血浆10例,采用凯杰血浆游离核酸纯化试剂盒进行循环游离DNA(circulating free DNA,cfDNA)提取,分别用ddPCR和Super ARMS方法进行EGFR基因19 del、T790M和L858R突变检测,两种结果进行对比和统计学分析。结果:33例临床样本应用两种方法检测19 del、T790M和L858R突变,阳性率分别为27.3%vs 27.3%(P=1.00)、42.4%vs 27.3%(P=0.23)和27.3%vs 27.3%(P=1.00)。10例PQCC样本结果与标准结果相比,ddPCR检测T790M符合率显著高于Super ARMS(P=0.01)。ddPCR和Super ARMS检测T790M的样本突变丰度范围分别为0.04%~7.66%和0.05%~7.66%。11例T790MddPCR(+)/Super ARMS(-)的平均突变丰度为0.19%(0.04%~0.76%),与10例Super ARMS(+)平均突变丰度[1.73%(0.05%~7.66%)]差异有统计学意义(P=0.03)。EGFR TKI耐药突变T790M突变丰度在0.01%~0.20%、0.20%~1.00%和>1.00%区间的分布分别为42.9%、14.2%和42.9%。结论:BEAMing ddPCR法较Super ARMS法具有更高的灵敏度,可检出更多T790M耐药患者,可能为更多患者选择最有效的靶向治疗方案提供参考。     

Monitoring of carcinoembryonic antigen levels is predictive of EGFR mutations and efficacy of EGFR-TKI in patients with lung adenocarcinoma

For the detection of epidermal growth factor receptor (EGFR) mutations, tumor tissues may not always be available. Not all the patients harboring EGFR mutation have a clinical response after the treatment of epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKI). EGFR mutations were detected in 70 cases of newly diagnosed non-smoking adenocarcinoma, and patients harboring EGFR mutations received EGFR-TKI treatment. The EGFR mutation status of these patients’ blood was analyzed by amplification refractory mutation system (ARMS). The patients’ carcinoembryonic antigen (CEA) levels were tested on the third, seventh, 15^th, and 30th days after EGFR-TKI treatment. Forty-four cases were found with EGFR mutations. EGFR mutation rate of CEA high-level group was significantly higher than low-level group (70.8 % vs. 40.9 %, P?=?0.017). Multivariate analysis showed that high-level CEA is independently associated with EGFR gene mutation (P?=?0.020, OR?=?3.508, 95 %CI, 1.223–10.059). The sensitivity of high CEA level and ARMS to predict EGFR mutation were 79.1 % and 51.2 %. We divided the patients who received EGFR-TKI treatment into three groups by the variation types of CEA. Univariate analysis showed that patients in descending type group have longer progression-free survival (P?=?0.001, HR 6.981, 95 %CI, 2.534–19.237). Multivariate Cox proportional hazards model analyses shows the same result (P?=?0.001, HR 9.82, 95 %CI, 3.322-26.031). In conditions of the current technique, using high CEA level to predict EGFR mutations seems to be more sensitive than using EGFR mutations in plasma. The variation types of CEA level could help us to predict the efficacy of EGFR-TKI in patients harboring EGFR mutation within only 1 month of tyrosine kinase inhibitor therapy.     

Evaluation of epidermal growth factor receptor mutation status in serum DNA as a predictor of response to gefitinib (IRESSA)

The aim of this study was to evaluate the usefulness of EGFR mutation status in serum DNA as a means of predicting a benefit from gefitinib (IRESSA) therapy in Japanese patients with non-small cell lung cancer (NSCLC). We obtained pairs of tumour and serum samples from 42 patients treated with gefitinib. EGFR mutation status was determined by a direct sequencing method and by Scorpion Amplification Refractory Mutation System (ARMS) technology. EGFR mutations were detected in the tumour samples of eight patients and in the serum samples of seven patients. EGFR mutation status in the tumours and serum samples was consistent in 39 (92.9%) of the 42 pairs. EGFR mutations were strong correlations between both EGFR mutation status in the tumour samples and serum samples and objective response to gefitinib (P<0.001). Median progression-free survival time was significantly longer in the patients with EGFR mutations than in the patients without EGFR mutations (194 vs 55 days, P=0.016, in tumour samples; 174 vs 58 days, P=0.044, in serum samples). The results suggest that it is feasible to use serum DNA to detect EGFR mutation, and that it's potential as a predictor of response to, and survival on gefitinib is worthy of further evaluation.     

非小细胞肺癌原发灶与淋巴结转移灶中KRAS和EGFR基因状态的比较及其临床意义

  目的  比较表皮生长因子受体(EGFR)基因和KRAS基因在非小细胞肺癌原发灶及其淋巴结转移灶之间突变状态的差异, 并分析其与吉非替尼治疗非小细胞肺癌(NSCLC)疗效之间的关系。   方法  收集天津医科大学附属肿瘤医院2010年5月至2010年11月间手术切除的80例NSCLC病例标本, 利用直接测序和实时荧光定量PCR的方法分别检测原发灶和相应淋巴结转移灶中EGFR基因第18、19、20、21外显子及KRAS基因第12、13密码子的突变情况; 其中5例在淋巴结转移灶中检出EGFR酪氨酸激酶抑制剂(EGFR-TKI)敏感型基因突变的患者接受了吉非替尼的新辅助靶向治疗。   结果  80例患者中, 检出原发灶携带KRAS和EGFR基因突变分别为1例和21例, 检出转移灶携带KRAS和EGFR基因突变分别为7例和26例; 分别有6例(7.50%)和7例(8.75%)患者其KRAS和EGFR基因状态在原发灶和转移灶之间不一致。直接测序法和实时荧光定量PCR法的检测结果一致。在5例接受吉非替尼治疗的患者中仅1例原发病灶中未检出EGFR-TKI敏感型基因突变, 并表现为疾病进展。   结论  部分NSCLC患者中KRAS和EGFR的基因状态在肿瘤转移过程中会发生改变, 在给予患者靶向治疗时不应忽视这一现象的存在。实时荧光定量PCR法比直接测序法更适用于临床的快速检测工作。      

EGFR mutation status and its impact on survival of Chinese non-small cell lung cancer patients with brain metastases

Brain metastasis (BM) is a leading cause of death in patients with non-small cell lung cancer (NSCLC). EGFR mutations in primary NSCLC lesions have been associated with sensitivity to EGFR tyrosine kinase inhibitor (TKI). Therefore, it has become important to understand EGFR mutation status in BM lesions of NSCLC, and its clinical implications. BM samples of 136 NSCLC patients from South China, in which 15 had paired primary lung tumors, were retrospectively analyzed for EGFR mutation by amplification mutation refractory system (ARMS). Effect of BM EGFR mutations on progression-free survival (PFS) and overall survival (OS) was evaluated by Kaplan–Meier curves and log-rank test. EGFR mutations were detected in 52.9 % (72 of 136) of the BM lesions, with preference in female and never-smokers. A concordance rate of 93.3 % (14 of 15) was found between the primary NSCLC and corresponding BM. Positive prediction value of testing primary NSCLCs for BM EGFR mutation is 100.0 %, and negative prediction value is 87.5 %. Median PFS of BM surgery was 12 and 10 months (P?=?0.594) in the wild-type and mutant group, respectively. Median OS of BM surgery was 24.5 and 15 months (P?=?0.248) in the wild-type and mutant group, respectively. In conclusion, EGFR mutation status is highly concordant between the primary NSCLC and corresponding BM. The primary NSCLC could be used as surrogate samples to predict EGFR mutation status in BM lesions or vice versa. Moreover, EGFR mutations showed no significant effect on PFS or OS of NSCLCs with BM.     

A comparison of ARMS and DNA sequencing for mutation analysis in clinical biopsy samples

Background

We have compared mutation analysis by DNA sequencing and Amplification Refractory Mutation System™ (ARMS™) for their ability to detect mutations in clinical biopsy specimens.

Methods

We have evaluated five real-time ARMS assays: BRAF 1799T>A, [this includes V600E and V600K] and NRAS 182A>G [Q61R] and 181C>A [Q61K] in melanoma, EGFR 2573T>G [L858R], 2235-2249del15 [E746-A750del] in non-small-cell lung cancer, and compared the results to DNA sequencing of the mutation ''hot-spots'' in these genes in formalin-fixed paraffin-embedded tumour (FF-PET) DNA.

Results

The ARMS assays maximised the number of samples that could be analysed when both the quality and quantity of DNA was low, and improved both the sensitivity and speed of analysis compared with sequencing. ARMS was more robust with fewer reaction failures compared with sequencing and was more sensitive as it was able to detect functional mutations that were not detected by DNA sequencing. DNA sequencing was able to detect a small number of lower frequency recurrent mutations across the exons screened that were not interrogated using the specific ARMS assays in these studies.

Conclusions

ARMS was more sensitive and robust at detecting defined somatic mutations than DNA sequencing on clinical samples where the predominant sample type was FF-PET.     

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

BackgroundEpidermal growth factor receptor (EGFR) mutation is predictive for the efficacy of EGFR tyrosine kinase inhibitors in advanced non-small-cell lung cancer (NSCLC) treatment. We evaluated the performance, sensitivity, and concordance between five EGFR tests.Materials and methodsDNA admixtures (n = 34; 1%–50% mutant plasmid DNA) and samples from NSCLC patients [116 formalin-fixed paraffin-embedded (FFPE) tissue, 29 matched bronchofiberscopic brushing (BB) cytology, and 20 additional pleural effusion (PE) cytology samples] were analyzed. EGFR mutation tests were PCR-Invader®, peptide nucleic acid-locked nucleic acid PCR clamp, direct sequencing, Cycleave™, and Scorpion Amplification Refractory Mutation System (ARMS)®. Analysis success, mutation status, and concordance rates were assessed.ResultsAll tests except direct sequencing detected four mutation types at ≥1% mutant DNA. Analysis success rates were 91.4%–100% (FFPE) and 100% (BB and PE cytology), respectively. Inter-assay concordance rates of successfully analyzed samples were 94.3%–100% (FFPE; kappa coefficients: 0.88–1.00), 93.1%–100% (BB cytology; 0.86–1.00), and 85.0%–100% (PE cytology; 0.70–1.00), and 93.1%–96.6% (0.86–0.93) between BB cytology and matched FFPE.ConclusionsAll EGFR assays carried out comparably in the analysis of FFPE and cytology samples. Cytology-derived DNA is a viable alternative to FFPE samples for analyzing EGFR mutations.     

Assessment of EGFR and K-ras mutations in fixed and fresh specimens from transesophageal ultrasound-guided fine needle aspiration in non-small cell lung cancer patients

In non-small cell lung cancer (NSCLC) patients, somatic EGFR and K-ras mutations predict therapeutic effectiveness and resistance, respectively, to EGFR tyrosine kinase inhibitors (TKIs). Transesophageal ultrasound-guided fine needle aspiration (EUS-FNA) is a validated technique for diagnosis and staging of NSCLC. In the present study, we compared the feasibility and reliability of EGFR and K-ras gene mutation analysis in fixed and fresh mediastinal lymph nodes and extra-lymph nodal samples obtained by EUS-FNA in patients suspicious for NSCLC. Thirty-six patients were enrolled into the study. For each patient, DNA was extracted from both fresh samples and fixed cytological smears. Exons 18-21 of EGFR and exon 2 of K-ras were amplified by PCR and mutation status was determined by direct sequencing and pyrosequencing. All cases were eligible for analysis. NSCLC was diagnosed in 32 patients (25 adenocarcinomas and 7 squamous cell carcinomas) and 4 patients were free of malignancy. Of the 25 patients with adenocarcinoma, EGFR mutations were detected in 2 (8%) fresh tumor samples and in 3 (12%) fixed cytological smears. K-ras mutations were detected in 8 (32%) fresh samples, and in 9 (36%) fixed cytological smears. Fixed and stained cytological samples seem to be more reliable than fresh material for molecular analysis.     

High Feasibility of Liquid-Based Cytological Samples for Detection of EGFR Mutations in Chinese Patients with NSCLC

Background: Activating mutations of epidermal growth factor receptor (EGFR) could predict response totyrosine kinase inhibitor (TKI) treatment in patients with non-small cell lung cancer (NSCLC). However, thedetection of EGFR mutation is frequently challenging in clinical practice for the lack of tumor tissue. The aim ofthis study was to investigate the feasibility of performing EGFR mutation testing on various types of liquid-basedcytology (LBC) samples. Materials and Methods: A total of 434 liquid-based cytology samples were collectedfrom March 2010 and November 2013. Among them, 101 with diagnosis of lung adenocarcinoma had pairedsurgically resected specimens. The ADx Amplification Refractory Mutation System (ADx-ARMS) was used todetermine EGFR mutation status both in LBC and resected samples. Results: All liquid-based cytology sampleswere adequate for EGFR mutation analysis. The mutation rate was 50.5% in the 434 NSCLC patients with LBCsamples and the incidence rates of EGFR mutation were consistent among different specimens. We also detectedEGFR positives in 52.5% (53/101) patients with paired histologic specimens. The concordance rate of EGFRmutation between LBC samples and paired histologic specimens was 92.1%. Conclusions: Our results suggestthat liquid-based cytology samples are highly reliable for EGFR mutation testing in patients with NSCLC.     

非小细胞肺癌胸腔积液与配对肿瘤组织中EGFR基因突变检测的比较

目的:探讨非小细胞肺癌胸腔积液与配对肿瘤组织标本中EGFR基因突变检测结果的一致性,评价胸腔积液标本检测EGFR基因突变的应用价值.方法:收集非小细胞肺癌患者胸腔积液与配对肿瘤组织样本72例,采用ARMS方法,检测样本中EGFR基因第18~21外显子突变情况.结果:细胞学样本和组织学样本中EGFR基因突变阳性率分别为48.61%和51.39%,两者差异无统计学意义(P>0.05),二者一致率为92.11%,不一致率为7.89%.结论:二者的一致率较高,恶性胸水可以作为无法获得肿瘤组织的晚期非小细胞肺癌EGFR基因检测的有效样本.     

肺癌细胞学及血液标本表皮生长因子受体基因突变对比研究

目的:研究肺癌患者渗出液细胞学及血液标本中表皮生长因子受体(EGFR)第18、19、21外显子基因突变频率和类型以及与肿瘤组织学标本的关系。方法:收集肺癌患者渗出液细胞学标本53例及血液标本24例,提取DNA,聚合酶链反应扩增EGFR外显子18、19、21序列,用直接测序法检测基因序列,分析EGFR基因突变频率和类型以及与肿瘤组织学标本的关系。结果:53例细胞学标本检测到15例EGFR基因突变（28.3%,15/53）,18外显子突变1例,19外显子突变5例,21外显子突变9例,细胞学标本与肺腺癌组织学标本突变率（32.2%）相比,差异没有显著性（P=0.624）。24例血液标本中检测到1例突变（4.2%,1/24）,位于21外显子,血液标本与肿瘤组织学标本突变率相比,差异有显著性(P=0.006)。结论:肺癌患者渗出液细胞学标本适用于直接测序法检测EGFR突变,血液标本不适于用直接测序法检测肿瘤EGFR基因突变状态。     

Barcode sequencing identifies resistant mechanisms to epidermal growth factor receptor inhibitors in circulating tumor DNA of lung cancer patients

Most patients with epidermal growth factor receptor (EGFR) mutation‐positive non‐small cell lung cancer (NSCLC) will inevitably develop acquired resistance induced by treatment with EGFR tyrosine kinase inhibitors (EGFR‐TKI). The mechanisms of resistance to EGFR‐TKI are multifactorial, and the detection of these mechanisms is critical for treatment choices in patients who have progressed after EGFR‐TKI therapy. We evaluated the feasibility of a molecular barcode method using next‐generation sequencing to detect multifactorial resistance mechanisms in circulating tumor DNA and compared the results with those obtained using other technologies. Plasma samples were collected from 25 EGFR mutation‐positive NSCLC patients after the development of EGFR‐TKI resistance. Somatic mutation profiles of these samples were assessed using two methods of next‐generation sequencing and droplet digital PCR (ddPCR). The positive rate for EGFR‐sensitizing mutations was 18/25 (72.0%) using ddPCR, 17/25 (68.0%) using amplicon sequencing, and 19/25 (76.0%) using molecular barcode sequencing. Rate of the EGFR T790M resistance mutation among patients with EGFR‐sensitizing mutations was shown to be 7/18 (38.9%) using ddPCR, 6/17 (35.3%) using amplicon sequencing, and 8/19 (42.1%) using molecular barcode sequencing. Copy number gain in the MET gene was detected in three cases using ddPCR. PIK3CA, KRAS and TP53 mutations were detected using amplicon sequencing. Molecular barcode sequencing detected PIK3CA, TP53, KRAS, and MAP2K1 mutations. Results of the three assays were comparable; however, in cell‐free DNA, molecular barcode sequencing detected mutations causing multifactorial resistance more sensitively than did the other assays.     

Direct serum and tissue assay for EGFR mutation in non-small cell lung cancer by high-resolution melting analysis

Biological therapy with epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) have noted promising outcomes for patients with non-small cell lung carcinoma (NSCLC), especially those with mutated EGFR. Tissue EGFR gene mutation testing can predict the benefit of taking a first-line EGFR-TKI, thus, allowing the physician to prescribe the most suitable therapy. Unfortunately, most lung cancer patients, especially NSCLC patients present with advanced disease that is surgically unresectable. The goal of this study was to develop high-resolution melting (HRM) assays to detect EGFR mutations in exons 18 to 21, compare their sensitivity and concordance to direct sequencing, and evaluate the feasibility and reliability of serum as a tissue alternate for routine EGFR mutation screening. EGFR mutations of 126 Formalin-Fixed Paraffin-Embedded (FFPE), 47 fresh frozen tissues and from 47 matched pre-operation serum specimens of NSCLC patients were screened by the HRM assays. EGFR mutations by HRM were confirmed through sequencing. We found 78 EGFR mutations in 70 FFPE tissues, 25 EGFR mutations in 24 fresh frozen tissues, with a mutation rate of 55.56% (70/126) and 51.06% (24/47), respectively. Most mutations were correctly identified by sequencing. EGFR mutations were detected in 22 serum samples from 24 tissue EGFR mutation-positive patients. The concordance rate between serum and tissue in EGFR mutation screening was 91.67%. We conclude that the HRM assay can provide convincing and valuable results both for serum and tissues samples, thus, it is suitable for routine serum EGFR mutation screening for NSCLC patients, especially those surgically unresectable.     

Clinicopathologic and Molecular Features of Epidermal Growth Factor Receptor T790M Mutation and c-MET Amplification in Tyrosine Kinase Inhibitor-resistant Chinese Non-small Cell Lung Cancer

To investigate the clinicopathologic and molecular features of the T790M mutation and c-MET amplification in a cohort of Chinese non-small cell lung cancer (NSCLC) patients resistant to epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs). EGFR TKI-resistant NSCLC patients (n?=?29) and corresponding tumor specimens, and 53 samples of postoperative TKI-naïve NSCLC patients were collected. EGFR exon 19, 20, and 21 mutations were analyzed. And c-MET gene copy number was determined. The EGFR T790M mutation in exon 20 was not detected in the population of 53 TKI-naïve patients, but found in 48.3% (14/29) of the enrolled TKI-resistant patients. c-MET was amplified in 3.8% (2/53) of the TKI-naïve NSCLC patients and highly amplified in 17.2% (5/29) of the cohort. Most of T790M mutations were frequently associated with non-smoker, adenocarcinoma and EGFR activating mutations. Three male patients with T790M mutation occurred with wild-type EGFR, and were resistant to the treatments following TKI resistance. Features of c-MET amplification in TKI-naïve patients were indistinguishable from TKI-resistant patients. In the group of wild-type EGFR, patients with T790M mutation had median progression free survival (PFS) and overall survival (OS) as 9.6 months and 12.6 months, respectively; whereas the median PFS and OS of c-MET amplified patients was 4.1 months and 8.0 months, respectively. These results suggest that EGFR T790M mutation and c-MET amplification can occur in TKI-resistant NSCLC with wild-type EGFR, and these genetic defects might be related to different survival outcome. c-MET amplification in TKI-naïve or -resistant patients might share similarities in clinicopathologic features.     

Use of SuperARMS EGFR Mutation Detection Kit to Detect EGFR in Plasma Cell-free DNA of Patients With Lung Adenocarcinoma

Background

The SuperARMS EGFR Mutation Detection Kit (SuperARMS) is highly selective and sensitive and able to detect 41 of the most common somatic mutations in exons 18 to 21 of the epidermal growth factor receptor gene (EGFR). It allows for the detection of 0.2% to 0.8% mutant DNA in a background of 99.8% to 99.2% normal DNA. The present study assessed the performance of SuperARMS in detecting EGFR mutations in cell-free DNA (cfDNA) samples derived from plasma in patients with advanced lung adenocarcinoma.

IDH1 mutation as a potential novel biomarker for distinguishing pseudoprogression from true progression in patients with glioblastoma treated with temozolomide and radiotherapy

The purpose of this study was to distinguish pseudoprogression (PP) from early true progression in patients with glioblastoma (GBM) based on the presence of a mutation in isocitrate dehydrogenase 1 (IDH1). We retrospectively surveyed 32 patients with GBM or GBM with oligodendroglioma component (GBMO) who underwent biopsy or maximal tumor resection followed by concurrent radiotherapy and temozolomide (TMZ). We then selected patients with early radiological progression in magnetic resonance imaging within 6 months after concurrent radiotherapy and TMZ treatment. DNA was extracted from their tumor blocks. The IDH1 mutation was analyzed in the genomic region by direct sequencing as a biomarker for PP. Twenty-eight patients were diagnosed with GBM and four with GBMO. Eleven patients were discovered to have early radiological progression. PP was detected in two patients (6.3 %) diagnosed with GBMO and one patient with GBM. Both of the GBMO patients with PP had the IDH1 mutation, the one GBM patient with PP and the other eight patients with early true progression with wild type. The sensitivity and specificity of the IDH1 mutation for detecting PP were 66.7 and 100 %, respectively. This study suggests the IDH1 mutation may become a novel molecular biomarker for PP. Analyzing the IDH1 mutation, in the case of recognizing early radiological progression, may enable distinction of PP from early true progression, and we could determine the need for second-look surgery.