EGFR mutation status in pleural fluid predicts tumor responsiveness and resistance to gefitinib

It has been reported that the threonine-to-methionine substitution at amino acid position 790 (T790M) of the epidermal growth factor receptor (EGFR) gene is correlated with acquired resistance to gefitinib. We previously reported that there was some population that harbored the EGFR T790M mutation as a minor clone of tumor cells prior to drug treatment, may be causing resistance to gefitinib during treatment. This fact also suggests that the detection of the EGFR T790M mutation prior to treatment may predict the development of resistance. We also showed that pleural fluid is a useful specimen for detection of EGFR mutation using sensitive assays. In this study, we reported a female patient who was treated with gefitinib because an EGFR L858R mutation was found in her pleural fluid. Our patient showed partial response to gefitinib, but she had progressive disease only 4 months after the start of treatment. Furthermore, the EGFR T790M mutation was detected in the pleural fluid before gefitinib treatment by the mutant-enriched PCR assay. Our findings confirmed that the EGFR T790M mutation was occasionally present as a minor population in tumor cells before treatment and caused resistance after gefitinib administration. The detection of a small fraction of T790M-positive alleles may be useful to predict the clinical course of the gefitinib-treated non-small-cell lung cancer patients.     

Usefulness of EGFR mutation screening in pleural fluid to predict the clinical outcome of gefitinib treated patients with lung cancer

The importance of epidermal growth factor receptor (EGFR) gene mutation has been recognized in nonsmall cell lung cancer (NSCLC), requiring the standardization of mutation screening system including the kind of samples. Here, we examined the EGFR mutation status in 61 pleural fluid samples from NSCLC cases using direct sequencing, nonenriched PCR, mutant-enriched PCR and peptide nucleic acid-locked nucleic acid (PNA-LNA) PCR clamp assay. The mutant-enriched PCR assay detected 16 mutant cases. Among them, the nonenriched PCR assay failed to detect 3 mutant cases. Regarding the discrepancy between mutant-enriched PCR and PNA-LNA PCR clamp assays, 3 cases of exon19-deletions were detected only by mutant-enriched PCR assay and no difference at the L858R mutation. There was no difference in results between direct sequencing and nonenriched PCR assay. We also correlated the EGFR mutation with clinical outcome of gefitinib-treated 29 cases. EGFR mutations were present in 10 cases, revealing 7 partial response and 3 no change (NC). In EGFR wild-type cases, 10 revealed NC and 9 progressive disease. The responders were significantly more frequent among the EGFR mutant cases than among the wild-type (p < 0.0001). Overall survival (p = 0.0092) and progression-free survival (p = 0.018) were significantly longer among the EGFR mutant cases than among the wild-type. In summary, we evaluated the utility of EGFR mutation screening in pleural fluid using 4 assays that showed some discrepancies arising from the designs of the assays. As clinical importance, the EGFR mutation status in pleural fluid can be a biomarker for the favorable outcome of gefitinib-treated NSCLC cases.     

Aberrant promoter methylation in pleural fluid DNA for diagnosis of malignant pleural effusion

Accumulating evidence implicates epigenetic changes such as hypermethylation in carcinogenesis. We investigated whether DNA methylation of 5 tumor suppressor genes in pleural fluid samples could aid in diagnosis of malignant effusion. In samples from 47 patients with malignant pleural effusions and 34 with nonmalignant effusions, we used a methylation-specific polymerase chain reaction to detect aberrant hypermethylation of the promoters of the DNA repair gene O(6)-methylguanine-DNA methyltransferase (MGMT), p16(INK4a), ras association domain family 1A (RASSF1A), apoptosis-related genes, death-associated protein kinase (DAPK), and retinoic acid receptor beta (RARbeta). Promoter hypermethylation was associated with malignant effusion for MGMT (Odds ratio (OR) = infinity), p16(INK4a) (OR = infinity), RASSF1A (OR = 13.8; CI, 1.71-112), and RARbeta (OR = 3.17; CI, 1.10-9.11), but not for DAPK. Instead, DAPK methylation was associated with the length of smoking (p < 0.05). Patients with hypermethylation of MGMT, p16(INK4a), RASSF1A or RARbeta were 5.68 times more likely to have malignant effusions than patients without methylation (p = 0.008). Methylations per patient were more numerous for lung cancer than nonmalignant pulmonary disease (0.915 vs. 0.206, p < 0.001). Sensitivity, specificity, and positive predictive value of methylation in one or more genes for diagnosis of malignant effusion were 59.6%, 79.4%, and 80.0% respectively. In conclusion, aberrant promoter methylation of tumor suppressor genes in pleural fluid DNA could be a valuable diagnostic marker for malignant pleural effusion.     

Response to gefitinib in bronchioloalveolar carcinoma in the absence of EGFR mutation

Mutations in the tyrosine kinase (TK) domain of the epidermal growth factor receptor (EGFR) gene in non-small cell lung cancers are associated with increased sensitivity of these cancers to drugs that inhibit EGFR kinase activity such as gefitinib and erlotinib. Responses to TK inhibitors in the absence of EGFR gene mutation for BAC patients have not been reported. A case of a patient with BAC refractory to chemotherapy who responded to gefitinib in the absence of EGFR gene mutations is reported. Tyrosine kinase inhibitors may have a role in BAC in the absence of EGFR gene mutations. Additional studies on other molecular alterations of the EGFR family members are needed to better predict response to these agents.     

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.     

Detection of EGFR mutations in plasma DNA from lung cancer patients by mass spectrometry genotyping is predictive of tumor EGFR status and response to EGFR inhibitors

Aims

EGFR mutations now guide the clinical use of EGFR-targeted therapy in lung cancer. However, standard EGFR mutation analysis requires a minimum amount of tumor tissue, which may not be available in certain situations. In this study, we combined a mass spectrometry genotyping assay (Sequenom) with a mutant-enriched PCR (ME-PCR) to detect EGFR mutations in free plasma DNA from patients with lung cancer.

Method

DNAs were extracted from 31 plasma samples from 31 patients and analyzed by both methods for EGFR Exon 19 deletion and EGFR L858R mutation. Results in plasma DNA samples were compared with EGFR mutation status obtained in tumor DNA (18/31 EGFR mutant). The relationship of EGFR mutation status in tumor and/or plasma samples to overall survival was assessed.

Results

The EGFR mutation status in plasma DNA was identical to the primary tumor in 61% of patients (19/31). By mass spectrometry genotyping, the plasma samples contained mutant DNA corresponding to 5/14 EGFR Exon 19 deletions and 3/4 EGFR L858R mutations previously diagnosed in the matched tumors. Two samples were positive in plasma DNA but negative in primary tumor tissue. Results were similar for samples studied by ME-PCR. For patients treated with erlotinib, overall survival was correlated with the presence of EGFR mutation in plasma and/or tumor tissue (p = 0.002), with the two patients positive only in plasma DNA showing responses and favorable outcomes.

Conclusion

The detection of EGFR mutations in plasma DNA samples by mass spectrometry genotyping and ME-PCR is feasible. A positive EGFR result in plasma DNA has a high predictive value for tumor EGFR status and for favorable clinical course on EGFR-targeted therapy and could therefore be useful in guiding clinical decisions in patients with insufficient or unavailable tumor specimens.     

EGFR and KRAS mutations in lung carcinomas in the Dutch population: increased EGFR mutation frequency in malignant pleural effusion of lung adenocarcinoma

Background

Frequencies of EGFR and KRAS mutations in non-small cell lung cancer (NSCLC) have predominantly been determined in East Asian and North American populations, showing large differences between these populations. The aim of the present study was to determine the frequency of EGFR and KRAS mutations in NSCLC in the West European Dutch population in primary carcinomas and different metastatic locations.

Methods

EGFR (exons 19, 20 and 21) and KRAS (exons 2 and 3) mutation test results of NSCLC samples of patients in 13 hospitals were collected. The tests were performed on paraffin-embedded tissue or cytological material of primary and metastatic lung carcinomas.

Results

EGFR mutations were detected in 71/778 (9.1?%) tested patients; in 66/620 (10.6?%) adenocarcinomas. EGFR mutations were significantly more often detected in female than in male patients (13.4?% vs. 5.5?%, p?<?0.001). KRAS mutations were found in 277 out of 832 (33.3?%) tested patients; in 244/662 (36.9?%) adenocarcinomas. A significantly increased frequency of EGFR mutations was observed in patients with malignant pleural/pericardial effusions (26.5?%; odds ratio (OR) 2.80, 95?% confidence interval (CI) 1.22?C6.41), whereas the frequency of KRAS mutations was significantly decreased (18.8?%; OR 0.35, 95?% CI 0.14?C0.86).

Conclusions

In the investigated Dutch cohort, patients with malignant pleural/pericardial effusion of lung adenocarcinoma have an increased frequency of EGFR mutations. The overall frequency of EGFR mutations in lung adenocarcinomas in this West European population is within the frequency range of North American and South European populations, whereas KRAS mutation frequency is higher than in any population described to date.     

冀东满族肺腺癌患者胸液与相应肿瘤组织EGFR基因突变检测对比分析

目的:分析冀东满族肺腺癌患者胸液与相应肿瘤组织EGFR基因突变检测结果。方法:选取2010年9月至2014年9月间在我院胸外科治疗的74例有胸液的冀东满族肺腺癌患者为研究对象,采用变性高效液相色谱法(DHPLC)检测肺腺癌患者胸液及相应肿瘤组织样本中是否发生EGFR基因突变。结果:肿瘤组织EFGR基因突变检出率为50.00%,胸液样本EGFR基因突变检出率为52.70%,两者间无统计学差异(P＞0.05)。胸液上清、胸液沉淀、胸液上清与沉淀以及肿瘤组织EGFR基因检测结果一致性均良好。结论:肺腺癌患者胸液与相应肿瘤组织EGFR基因突变检测结果一致性良好,临床可通过胸液检测代替肿瘤组织检测,以期能够持续监测患者EGFR基因突变状态,以指导患者添加或者实施EGFR-TKIs治疗。     

Circulating miRNAs is a potential marker for gefitinib sensitivity and correlation with EGFR mutational status in human lung cancers

miRNA expression is deregulated in non-small cell lung cancer (NSCLC), and some miRNAs are associated with gefitinib sensitivity. Here, we investigated if circulating miRNAs could be a useful biomarker for the prediction of EGFR mutation and the patient’s prognosis. The differential miRNAs related to gefitinib sensitivity were screened and identified by microRNA array. Using Taqman-based real-time RT-PCR, we analyzed the expression of selected miRNAs in tumor tissues and plasma of 150 NSCLC patients. Kaplan-Meier survival analysis and Cox proportional hazards regression were used to determine the association between miRNAs expression and survival. Receiver operating characteristic curve analysis was also performed. Compared with PC9 cell line, 41 microRNAs detected by microarray were significantly differentially expressed in A549 and H1299 cells. The 5 selected hsa-miRNAs were all found differently expressed between wild and mutant EGFR carriers (all P<0.01). Down-regulation of 5 selected miRNAs were independently associated with lymphatic invasion (all P<0.01) and clinical stage (all P<0.01), respectively. Both down-regulation of has-miR-195 (P=0.012) and has-miR-21 (P=0.004) were associated with poor differentiation. All up-regulation of 5 has-miRNAs were associated with smoking (All P<0.05). 5 hsa-miRNAs were up-regulated both in plasma and tissue samples. A model including 4 hsa-miRNAs may predict EGFR mutational status and gefitinib-sensitivity (both AUC: 0.869). Plasma levels of has-miR-125b expression were associated with disease-free survival (P=0.033) and overall survival in the patients (P=0.028). In a word, Circulating 5 selected miRNAs may especially be useful in predicting EGFR mutation, and circulating hsa-miR-125b may have prognostic values in NSCLC patients.     

胸腔积液肺腺癌细胞中CXCR4、Ki67、MDM2、N-cadherin的表达及其与EGFR突变状态的关系

目的：研究胸腔积液肺腺癌细胞中趋化因子受体4(CXCR4)、增殖细胞核抗原Ki67、鼠双微体2(MDM2)和N-钙黏蛋白(Ncadherin)的表达与表皮生长因子受体(EGFR)突变状态的相关性。方法：收集46例晚期肺腺癌患者的胸腔积液,采用HE染色联合免疫细胞化学染色(ICC)法检测胸腔积液中是否含肿瘤细胞,突变扩增系统(ARMS)检测胸腔积液中癌细胞的EGFR基因突变状态,将癌细胞分为EGFR-TKI敏感突变组和EGFR野生型组。采用ICC法检测胸腔积液中肺腺癌细胞CXCR4、Ki67、MDM2和Ncadherin的表达,分析这些蛋白的表达阳性率和EGFR突变状态的相关性。结果：46例肺腺癌患者的恶性胸腔积液细胞中,31例(67.4%)存在EGFR-TKI敏感突变。CXCR4、Ki67、MDM2、N-cadherin表达阳性率与EGFR突变状态相关(r分别为0.452、0.428、0.417、0.524,均为P<0.05),且EGFR-TKI敏感突变组细胞CXCR4、Ki67、MDM2、N-cadherin表达的阳性率明显高于EGFR野生型组(P<0.05)。结论：EGFR突变状态与CXCR4、Ki67、MDM2和N-cadherin的表达相关,EGFR突变状态下,胸腔积液肺腺癌细胞的CXCR4、Ki67、MDM2和N-cadherin的表达阳性率高于非突变状态下的表达阳性率。     

microRNA-29a在结核性与恶性胸腔积液鉴别诊断和疗效预测中的价值

目的:研究microRNA-29a在鉴别结核性胸腔积液和恶性胸腔积液中的作用，探索microRNA-29a在预测结核性胸腔积液疗效中的价值。方法:2015年3月至2016年3月就诊于我院的48例结核性胸腔积液患者和40例恶性胸腔积液患者，用Trizol试剂提取胸水、血及痰中RNA，利用RT-PCR 技术检测 microRNA-29a的相对表达量，分析在结核性胸腔积液和恶性胸腔积液中表达的差异，对结核性胸腔积液患者进行胸腔穿刺抽液及2HRZE／10HRE方案抗结核治疗，动态检测microRNA-29a在血中表达的变化，分析其与患者疗效之间的关系。结果:microRNA-29a 在结核性胸腔积液患者外周血清和胸腔积液中的表达量显著高于恶性胸腔积液患者，差异有统计学意义(P＜0.05)；但在痰中的表达无明显差异，结核性胸腔积液患者给予穿刺抽液及抗结核治疗后，外周血中microRNA-29a的表达下调。结论:血及胸水中microRNA-29a的表达量有助于鉴别结核性胸腔积液和恶性胸腔积液，血中microRNA-29a的表达变化有助于预测结核性胸腔积液疗效。     

Ras mutational status is a biomarker for resistance to EGFR inhibitors in colorectal carcinoma

The epidermal growth factor receptor (EGFR) has been validated as a therapeutic target in several human tumours, including colorectal cancer (CRC). Although EGFR expression is used for patient selection, clinical experience shows that levels of EGFR expression (measured by immunohistochemistry) do not predict clinical benefit. Ras mutations in codons 12, 13 and 61 (found in 40-45% of CRC cases) result in inhibition of GTPase activity, thus leading to the constitutive activation of the ras proteins, which may render tumour cells independent of EGFR signalling and thereby, resistant to cetuximab, panitumumab and EGFR TKIs. Data from several recently published studies, as reviewed in this article, in patients with metastatic CRC (OPUS, CRYSTAL) clearly indicated that benefit from cetuximab, when added to chemotherapy, was only restricted to patients with wild-type K-ras tumours. These results showed that K-ras mutations predict the lack of clinical benefit from cetuximab and panitumumab therapies in CRC and indicate that K-ras status should be considered when selecting CRC patients as candidates for these antibodies. Moreover, the results from these studies should also trigger retrospective analyses of K-ras mutations from all available trials in CRC (as well as non-small cell lung cancer and pancreatic cancer). These studies may enable further establishment of the correlation between K-ras mutations and resistance to cetuximab and panitumumab in CRC patients.     

KRAS mutation status is predictive of response to cetuximab therapy in colorectal cancer

The anti-epidermal growth factor receptor (anti-EGFR) cetuximab has been proven to be efficient in metastatic colorectal cancer. The molecular mechanisms underlying the clinical response to this drug remain unknown. Genetic alterations of the intracellular effectors involved in EGFR-related signaling pathways may have an effect on response to this targeted therapy. In this study, tumors from 30 metastatic colorectal cancer patients treated by cetuximab were screened for KRAS, BRAF, and PIK3CA mutation by direct sequencing and for EGFR copy number by chromogenic in situ hybridization. Eleven of the 30 patients (37%) responded to cetuximab. A KRAS mutation was found in 13 tumors (43%) and was significantly associated with the absence of response to cetuximab (KRAS mutation in 0% of the 11 responder patients versus 68.4% of the 19 nonresponder patients; P = 0.0003). The overall survival of patients without KRAS mutation in their tumor was significantly higher compared with those patients with a mutated tumor (P = 0.016; median, 16.3 versus 6.9 months). An increased EGFR copy number was found in 3 patients (10%) and was significantly associated with an objective tumor response to cetuximab (P = 0.04). In conclusion, in this study, KRAS mutations are a predictor of resistance to cetuximab therapy and are associated with a worse prognosis. The EGFR amplification, which is not as frequent as initially reported, is also associated with response to this treatment.     

EGFR mutation status in plasma and tumor tissues in non-small cell lung cancer serves as a predictor of response to EGFR-TKI treatment

Objective: Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) can effectively control non-small cell lung cancer (NSCLC). Therefore, EGFR mutations should be detected before lung cancer patients undergo EGFR-TKI therapy. This study assessed the feasibility and predictive value of EGFR mutations in peripheral blood samples.Methods: EGFR mutations in exons 19 and 21 were analyzed in tumor tissue and plasma DNA samples from 121 NSCLC patients using amplification refractory mutation system (ARMS) and the integrated technique of mutant enriched PCR (me-PCR) and denaturing high performance liquid chromatography (DHPLC), respectively.Results: EGFR mutations were detected in 36.4% of tumor tissues and 34.7% of the plasma at a concordance rate of 85.1% (103/121). The sensitivity and specificity of plasma EGFR mutations were 77.3% and 89.6%, respectively. The gender and tumor histology of patients served as independent predictors of EGFR mutations in both tumor tissues and plasma, while CEA level was an independent predictor of EGFR mutations in the plasma. Furthermore, EGFR-TKI treatment showed a significantly higher objective response rate (ORR), median progression-free survival (mPFS), and overall survival (mOS) in patients harboring EGFR mutation than those that did not exhibit EGFR mutation (ORR: 69.4% versus 13.0% in tissues, P < 0.001; 64.5 % vs. 28.6% in the plasma, P = 0.006. mPFS: 10.4 months versus 4.1 months in tissues, P<0.001; 10.5 months vs. 5.2 months in the plasma, P=0.001. mOS: 25.7 months versus 8.3 months in tissues, P=0.005; 25.7 months vs. 13.5 months in the plasma, P=0.038).Conclusions: EGFR mutations can be detected in the plasma using the integrated technique of me-PCR and DHPLC, which enables us to predict patient response to EGFR-TKI therapy. High serum CEA levels served as an independent predictor for plasma EGFR mutations.