L858R EGFR mutation status correlated with clinico-pathological features of Japanese lung cancer

Somatic mutations of the epidermal growth factor receptor (EGFR) gene were found in about 25-40% of Japanese lung cancer patients. These mutations are associated with clinical and radiographic responses to EGFR tyrosine kinase inhibitors. Most common mutation are arginine for leucine substitution at amino acid 858 (L858R) and exon 19 deletions, especially deletion type 1 mutation. We investigated these EGFR mutation statuses in 575 surgically treated non-small cell lung cancer (NSCLC) cases. Three-hundred and sixty-two adenocarcinoma cases were included. The presence or absence of EGFR mutations of kinase domains was analyzed by genotyping analysis (TaqMan assay; n=386, and LightCycler assay; n=98) and sequences (n=91). EGFR mutations (CTG; CGG; L858R) were found from 63 of 575 lung cancer patients. We also detected the deletion 1a type mutations (2235-2249 del GGAATTAAGAGAAGC) from 39 patients and deletion 1b type mutations (2236-2250 del GAATTAAGAGAAGCA) from 15 patients in exon 19. These mutation statuses were significantly correlated with gender, smoking status (never smoker versus smoker), and pathological subtypes (adenocarcinoma versus non-adenocarcinoma). L858R mutation (p<0.0001), but not deletion 1 type mutation (p=0.0665), was correlated with differentiation status (well versus moderately or poorly) of lung cancers. L858R mutation ratio was significantly higher in non-smoker (p=0.0496) and adenocaicinoma (p=0.0136) when compared to deletion 1 type mutations. The EGFR mutation status, especially L858R mutation might be correlated with the clinico-pathological features related to good response to gefitinib, such as gender, smoking history, and pathological subtypes of Japanese lung cancers.     

Mutations within the tyrosine kinase domain of EGFR gene specifically occur in lung adenocarcinoma patients with a low exposure of tobacco smoking

Somatically acquired mutations in the epidermal growth factor receptor (EGFR) gene in lung cancer are associated with significant clinical responses to gefitinib, a tyrosine kinase inhibitor that targets EGFR. We screened the EGFR in 469 resected tumours of patients with lung cancer, which included 322 adenocarcinomas, 102 squamous cell carcinomas, 27 large cell carcinomas, 13 small cell carcinomas, and five other cell types. PCR with a specific condition was performed to identify any deletion in exon 19, while mutant-allele-specific amplification was performed to identify a mutation in codon 858 of exon 21. EGFR mutations were found in 136 cases (42.2%) with adenocarcinoma, in one case with large cell carcinoma, and in one case with pleomorphic carcinoma. An in-frame deletion in exon 19 was found in 62 cases while an L858R mutation was found in 77 cases. In the 322 cases with adenocarcinoma, these mutations were more frequently found in women than in men (P=0.0004), in well differentiated tumours than in poorly differentiated tumours (P=0.0014), and in patients who were never smokers than in patients who were current/former smokers (P<0.0001). The mutation was more frequently observed in patients who smoked 相似文献   

EGFR Mutation status in Japanese lung cancer patients: genotyping analysis using LightCycler.

PURPOSE: Recently, somatic mutations of the epidermal growth factor receptor (EGFR) gene were found in approximately 25% of Japanese lung cancer patients. These EGFR mutations are reported to be correlated with clinical response to gefitinib therapy. However, DNA sequencing using the PCR methods described to date is time-consuming and requires significant quantities of DNA; thus, this existing approach is not suitable for a routine pretherapeutic screening program. EXPERIMENTAL DESIGN: We have genotyped EGFR mutation status in Japanese lung cancer patients, including 102 surgically treated lung cancer cases from Nagoya City University Hospital and 16 gefitinib-treated lung cancer cases from Kinki-chuo Chest Medical Center. The presence or absence of three common EGFR mutations were analyzed by real-time quantitative PCR with mutation-specific sensor and anchor probes. RESULTS: In exon 21, EGFR mutations (CTG --> CGG; L858R) were found from 8 of 102 patients from Nagoya and 1 of 16 from Kinki. We also detected the deletion mutations in exon 19 from 7 of 102 patients from Nagoya (all were deletion type 1a) and 4 of 16 patients from Kinki (one was type 1a and three were type 1b). In exon 18, one example of G719S mutation was found from both Nagoya and Kinki. The L858R mutation was significantly correlated with gender (women versus men, P < 0.0001), Brinkman index (600 < or = versus 600, P = 0.001), pathologic subtypes (adenocarcinoma versus nonadenocarcinoma, P = 0.007), and differentiation status of the lung cancers (well versus moderately or poorly, P = 0.0439), whereas the deletion mutants were not. EGFR gene status, including the type of EGFR somatic mutation, was correlated with sensitivity to gefitinib therapy. For example, some of our gefitinib-responsive patients had L858R or deletion type 1a mutations. On the other hand, one of our gefitinib-resistant patients had a G719S mutation. CONCLUSIONS: Using the LightCycler PCR assay, the EGFR L858R mutation status might correlate with gender, pathologic subtypes, and gefitinib sensitivity of lung cancers. However, further genotyping studies are needed to confirm the mechanisms of EGFR mutations for the sensitivity or resistance of gefitinib therapy for the lung cancer.     

176例非小细胞肺癌的EGFR基因突变分析

目的 分析非小细胞肺癌（NSCLC）中上皮生长因子受体（EGFR）基因突变的发生率和突变类型。方法 收集123例正常肺组织和176例肺癌组织,采用PCR扩增和基因测序方法,对组织DNA中EGFR外显子19～21基因突变进行分析。结果 正常肺组织中EGFR基因均为野生型,肺癌组织中EGFR基因突变检测率为32．4％（57／176例）,其中,外显子19和21突变分别占突变总数的64．9％（37／57例）和31．6％（18／57例）,外显子20突变少见,仅占3．5％（2／57例）。外显子19突变发生在第746～753位密码子,均为碱基缺失突变,有7种不同类型。外显子20突变发生在第789—793位密码子,为碱基替换突变。外显子21突变全部是第858位密码子碱基替换突变。EGFR基因突变多见于女性,肺腺癌和腺鳞癌。结论 EGFR基因突变是一种肿瘤特异性的体细胞遗传改变,突变发生率约占肺癌总数的1／3,其中以外显子19和21为主。女性、肺腺癌和腺鳞癌中突变多见。     

Double mutation and gene copy number of EGFR in gefitinib refractory non-small-cell lung cancer

Mutations of the epidermal growth factor receptor (EGFR) gene have been reported in non-small-cell lung cancer (NSCLC), especially in patients with adenocarcinoma and never smokers. Some common somatic mutations in EGFR, including deletion mutations in exon 19 and leucine-to-arginine substitution at amino acid position 858 (L858R) in exon 21, have been examined for their ability to predict sensitivity to gefitinib or erlotinib, which are selective EGFR tyrosine kinase inhibitors (EGFR-TKIs). On the other hand, reports have shown that the threonine-to-methionine substitution at amino acid position 790 (T790M) in exon 20 is related to gefitinib resistance. Some studies have indicated that high copy numbers of the EGFR gene may be a more effective molecular predictor to responsiveness and prolonged survival in patients treated with EGFR-TKIs. Here, we describe two NSCLC patients with the L858R mutation who did not respond to gefitinib. Case 1 harbored both the T790M and L858R mutations, and fluorescence in situ hybridization showed EGFR gene amplification. Case 2 harbored both the L858R and aspartic acid-to-tyrosine substitution at amino acid position 761 in exon 19 of EGFR mutations and had a high polysomy status for EGFR. In these two cases, tumors showed resistance to gefitinib treatment despite the presence of EGFR L858R mutation and increased copy number. Our findings encourage further molecular analysis to elucidate the relationship between the EGFR status, including mutations and amplifications, and the responsiveness of NSCLC to gefitinib.     

Exon 19 deletion mutations of epidermal growth factor receptor are associated with prolonged survival in non-small cell lung cancer patients treated with gefitinib or erlotinib.

PURPOSE: Somatic mutations in the epidermal growth factor receptor (EGFR) have been detected in patients with non-small cell lung cancer (NSCLC) and are associated with sensitivity to treatment with gefitinib or erlotinib. Our study explored the relationship between the two most common types of somatic EGFR mutations, exon 19 deletions and the L858R point mutation, and outcomes of patients following treatment with gefitinib or erlotinib. EXPERIMENTAL DESIGN: Tumor specimens obtained before treatment with gefitinib or erlotinib were analyzed for EGFR mutations. Patients with exon 19 deletion or L858R mutations were identified. The response rate, time to progression, and overall survival were determined for the two groups. RESULTS: We identified 36 patients with NSCLC and an EGFR mutation who were treated with gefitinib or erlotinib. Patients with an exon 19 deletion had a significantly longer overall survival compared with patients with an L858R mutation (38 versus 17 months; P = 0.04). There were also trends toward higher response rate (73% versus 50%) and improved time to progression (24 versus 10 months) for the patients with an exon 19 deletion, although these were not independently significant in a multivariate analysis. A difference in response rate for patients treated with gefitinib compared with erlotinib was also noted [18 of 23 (78%) versus 3 of 9 (33%); P = 0.04]. No obvious difference in time to progression or overall survival was noted between gefitinib- and erlotinib-treated patients. CONCLUSIONS: Patients with NSCLC and EGFR exon 19 deletions have a longer survival following treatment with gefitinib or erlotinib compared with those with the L858R mutation. Pooling of greater numbers of patients and completion of prospective trials are needed to further define the predictive and prognostic roles of different EGFR mutations with respect to treatment with gefitinib, erlotinib, and other EGFR inhibitors.     

EGFR-TKI一线治疗EGFR基因突变的晚期非小细胞肺癌临床观察

背景与目的研究表明,一线表皮生长因子受体酪氨酸激酶抑制剂(epidermal growth factor receptortyrosine kinase inhibitor,EGFR-TKI)治疗晚期非小细胞肺癌(non-small cell lung cancer,NSCLC)的客观缓解率及无进展生存期明显优于铂二联的化疗,且耐受性更好。本研究旨在分析EGFR-TKI一线治疗晚期EGFR突变阳性的NSCLC患者的疗效与耐受性。方法 54例晚期NSCLC患者肿瘤标本采用直接测序法证实EGFR活化突变(外显子19缺失或外显子21点突变),一线给予EGFR-TKI口服治疗直至疾病进展,观察疗效及不良反应,并进行生存随访。结果 54例患者外显子19缺失33例(61%),外显子21点突变21例(39%)。均一线接受EGFR-TKI治疗,总体缓解率为90%,中位无进展生存期(progression free survival,PFS)为8.3个月,中位生存期为19.5个月;外显子19缺失患者的中位PFS(9.0个月)较21点突变(7.0个月)时间长(P=0.002)。外显子19缺失患者的中位总生存期(overall survival,OS)(25.0个月)较21点突变(16.0个月)时间长(P=0.001);吉非替尼与厄洛替尼疗效相当,但吉非替尼组安全性更好;最常见的不良事件为皮疹和腹泻,有2例患者(4%)出现了3度皮肤毒性反应,2例患者(4%)出现了3度的转氨酶升高,1例患者(1%)出现了3度口腔炎。结论存在EGFR基因突变的晚期NSCLC患者一线接受EGFR-TKI治疗安全有效,且外显子19缺失比L858R突变疗效更优。     

A Novel Insertion Mutation on Exon 20 of Epidermal Growth Factor Receptor,Conferring Resistance to Erlotinib

The epidermal growth factor receptor (EGFR) is a transmembrane glycoprotein tyrosine kinase receptor. The small-molecule tyrosine kinase receptor inhibitors (TKIs) are in clinical use to treat non-small cell lung cancer with EGFR mutations. Variable tumor responses to erlotinib and gefitinib have been observed. The response to these TKIs varies by the type of EGFR mutations found in the tumor. The deletion on exon 19 and the L858R substitution on exon 21 constitute the most frequent mutations and are known to show good response to TKIs. However, mutations on exon 20 are less common and seem to respond poorly to TKIs. In clinical settings, the reported response of exon 20 mutations to reversible TKIs (both gefitinib and erlotinib) remains inconstant. The type of coexisting mutation seems to affect the response of these insertions to TKIs. We herein present a case of disease progression despite the use of erlotinib in a female patient who had a novel insertion mutation on exon 20. Our patient was a never-smoker and was identified to have a Pro772_His773insGlnCysPro mutation on exon 20. She had previously been treated with cisplatin and gemcitabine and then with carboplatin and pemetrexed. She was treated with erlotinib upon intolerance to second-line chemotherapy and did not respond. Our patient had a novel insertion mutation on exon 20, which was found to be resistant to erlotinib.Key words: Epidermal growth factor receptor, Tyrosine kinase receptor inhibitors, Mutations, Exon 20, Non-small cell lung cancer, Erlotinib     

The relationship between epidermal growth factor receptor mutations and clinicopathologic features in non-small cell lung cancers.

PURPOSE: Recent studies reported that clinical responsiveness to gefitinib was associated with somatic mutation of epidermal growth factor receptor (EGFR) gene in non-small cell lung cancers (NSCLC). Here, we investigated the relationship between EGFR mutation and clinicopathologic features. EXPERIMENTAL DESIGN: EGFR mutational status of 120 NSCLCs was determined mainly in EGFR exons 18 to 21 by direct sequence and correlated with clinicopathologic parameters. RESULTS: EGFR mutations were present in 38 cases (32%) and the majority of mutations were in-frame deletions of exon 19 (19 cases) and a missense mutation in exon 21 (18 cases). EGFR mutations were frequently associated with adenocarcinoma (P < 0.0001), never smoker (P < 0.0001), and female gender (P = 0.0001). Of interest, increasing smoke exposure was inversely related to the rate of EGFR mutation (P < 0.0001). Multivariate analysis showed that smoking and histology were independent variables. Furthermore, gender difference was observed for the mutational location (P = 0.01) dominance of exon 19 for males and exon 21 for females. Twenty-one cases were treated with gefitinib and found that EGFR mutation was significantly related to gefitinib responsiveness (P = 0.002). In addition, median survival times of patients with and without EGFR mutations treated with gefitinib were 25.1 and 14.0 months, respectively. Patients with EGFR mutations had approximately 2-fold survival advantage; however, the difference was not significant. CONCLUSIONS: We show that EGFR mutations were significantly related to histology and smoke exposure and were a strong predictive factor for gefitinib responsiveness in NSCLC.     

High frequency of epidermal growth factor receptor mutations with complex patterns in non-small cell lung cancers related to gefitinib responsiveness in Taiwan.

PURPOSE: Epidermal growth factor receptor (EGFR) mutations related to gefitinib responsiveness in non-small cell lung cancer have been found recently. Detection of EGFR mutations has become an important issue for therapeutic decision-making in non-small cell lung cancer. EXPERIMENTAL DESIGN: Mutational analysis of the kinase domain of EGFR coding sequence was done on 101 fresh frozen tumor tissues from patients without prior gefitinib treatment and 16 paraffin-embedded tumor tissues from patients treated with gefitinib. Detection of phosphorylated EGFR by immunoblot was also done on frozen tumor tissues. RESULTS: The 101 non-small cell lung cancer tumor specimens include 69 adenocarcinomas, 24 squamous cell carcinomas, and 8 other types of non-small cell lung cancers. Mutation(s) in the kinase domain (exon 18 to exon 21) of the EGFR gene were identified in 39 patients. All of the mutations occurred in adenocarcinoma, except one that was in an adenosquamous carcinoma. The mutation rate in adenocarcinoma was 55% (38 of 69). For the 16 patients treated with gefitinib, 7 of the 9 responders had EGFR mutations, and only 1 of the 7 nonresponders had mutations, which included a nonsense mutation. The mutations seem to be complex in that altogether 23 different mutations were observed, and 9 tumors carried 2 mutations. CONCLUSIONS: Data from our study would predict a higher gefitinib response rate in lung adenocarcinoma patients in Chinese and, possibly, other East Asian populations. The tight association with adenocarcinoma and the high frequency of mutations raise the possibility that EGFR mutations play an important role in the tumorigenesis of adenocarcinoma of lung, especially in East Asians.     

Lung cancer with epidermal growth factor receptor exon 20 mutations is associated with poor gefitinib treatment response

PURPOSE: Clinical reports about responsiveness to gefitinib treatment in patients of non-small cell lung cancer (NSCLC) with mutations in exon 20 of epidermal growth factor receptor (EGFR) are limited. To increase understanding of the influence of exon 20 mutations on NSCLC treatment with gefitinib, we investigated the clinical features of lung cancer in patients with exon 20 mutations and analyzed the gefitinib treatment response. EXPERIMENTAL DESIGN: We surveyed the clinical data and mutational studies of NSCLC patients with EGFR exon 20 mutations in the National Taiwan University Hospital and reviewed the literature reports about EGFR exon 20 mutations and the gefitinib treatment response. RESULTS: Twenty-three patients with mutations in exon 20 were identified. Nine (39%) had coexisting mutations in EGFR exons other than exon 20. Sixteen patients received gefitinib treatment, and a response was noted in 4 patients. The gefitinib response rate of NSCLC with exon 20 mutations was 25%, far lower than those with deletions in exon 19 and L858R mutations. Interestingly, different exon 20 mutations and coexisting mutations seemed to have a different influence on gefitinib response. CONCLUSIONS: EGFR exon 20 mutations of NSCLC patients result in poorer responsiveness to gefitinib treatment, but variability exists between different individuals.     

Relationship between epidermal growth factor receptor gene mutations and the severity of adverse events by gefitinib in patients with advanced non-small cell lung cancer

PURPOSE: Recent reports have demonstrated that mutation of epidermal growth factor receptor (EGFR) gene is predictive factor for tumor responsiveness to gefitinib suggesting the importance of EGFR status for the treatment of the patients with non-small cell lung cancer (NSCLC). However, the relationship between EGFR mutation and adverse events of gefitinib is still unknown. The aim of this study was to evaluate its correlation. PATIENTS AND METHODS: Twenty-six tumor samples from Japanese NSCLC patients who received gefitinib in Okayama University Hospital between November 2000 and October 2004 were examined exons 18-21 of EGFR using direct sequence method. We retrospectively reviewed the clinical records and compared EGFR mutation status with adverse events during gefitinib treatment. RESULTS: Of all 26 patients, EGFR mutation (exon 19 in-frame deletion, 6; exon 21 L858R, 5), were detected in 11 patients (42.3%). The principal adverse event was skin rash (89%), diarrhea (39%), and liver injury (39%). Grade 3 or more adverse events were not common. EGFR mutation status was correlated with neither its frequency nor severity of adverse events during gefitinib treatment including skin rash, diarrhea, liver injury, and interstitial lung disease. As expected, objective response rate of those with EGFR mutations was significantly higher than those without EGFR mutations (78% versus 21%, P<0.001). CONCLUSION: Our study did not demonstrate the presence of close relationships between EGFR mutation status and adverse events during gefitinib treatment.     

非小细胞肺癌中EGFR和K-ras基因突变检测

目的:探讨不同类型非小细胞肺癌的EGFR和K-ras基因突变情况及其与肺癌相关临床病理特征的关系。方法:用厦门艾德ADxARMS试剂盒进行98例非小细胞肺癌患者肿瘤组织中EGFR（18,19,20,21外显子）基因和K-ras（12,13,61密码子）基因突变的检测。所有患者均未接受过吉非替尼的治疗。结果:98例样本中31例发生了EGFR基因突变,突变率为31.6%（31/98）,其中15例为19外显子缺失,13例为21 L858R外显子点突变,3例为20外显子突变,1例为18外显子突变。其中1例既有19外显子缺失突变,又有20外显子突变。腺癌中EGFR基因突变率较鳞癌、腺鳞癌、大细胞癌高。女性患者EGFR基因突变率较男性高。不吸烟患者EGFR基因突变率较吸烟患者高。低分化腺癌患者EGFR基因突变率较中、高分化患者高。21例发生了K-ras基因突变（21.4%）,其中12、13、61密码子均发现突变。突变率腺癌较鳞癌、腺鳞癌、大细胞癌高,与是否吸烟、患者性别、分化程度均无相关性。结论:非小细胞肺癌患者EGFR基因突变检出率较高,K-ras基因突变率较低,且两者不存在同时突变,EGFR基因突变与肺癌组织学类型、分化程度、性别等相关。K-ras基因突变与组织学类型相关。     

Differences in Epidermal Growth Factor Receptor Gene Mutations and Relationship with Clinicopathological Features in NSCLC Between Uygur and Han Ethnic Groups

Objective: To investigate differences in mutations of epidermal growth factor receptor (EGFR) gene andrelationships with clinicopathological features in patients with non-small cell lung cancer (NSCLC) betweenUygur and Han ethnic groups. Methods: The Scorpions amplification refractory mutation system (ScorpionsARMS) was used to measure mutations in exons 18, 19, 20 and 21 of the EGFR gene in paraffin-embedded tumortissue from NSCLC cases, and statistical analysis was performed to investigate links with clinicopathologicalfeatures in different histological types of NSCLC. Results: Results from ARMS testing showed EGFR mutationsin tumor tissues from six (6) of 50 NSCLC patients of Uygur ethnic group, with a positive rate of 12.0%; four ofthem (4) had exon 19 deletion in EGFR, and two (2) had L858R point mutation in exon 21 of EGFR. Statisticallysignificant difference was noted in EGFR genetic mutation between adenocarcinoma and non-adenocarcinoma(P < 0.05), but no differences with gender, age group, smoking status, or stage (P > 0.05). EGFR mutations weredetected in tumor tissues from 27 of 49 NSCLC patients of Han ethnic group , with a positive rate of 55.1%;19 of them had exon 19 deletions, seven (7) had L858R point mutations in exon 21 of EGFR and one (1) hadmutations in both exon 18 G719X and exon 20 T790M of EGFR. Statistically significant differences were notedin EGFR genetic mutations between genders and between adenocarcinoma and non-adenocarcinoma (P<0.05),but not with age group, smoking status, or stage (P > 0.05). Conclusion: Statistically significant differences werenoted in the positive rates of EGFR genetic mutations in NSCLC patients between Uygur and Han ethnic groups,with lower positive rates for the Uygur cases.     

Better survival with EGFR exon 19 than exon 21 mutations in gefitinib-treated non-small cell lung cancer patients is due to differential inhibition of downstream signals

Somatic mutations in the epidermal growth factor receptor (EGFR) kinase domain are associated with sensitivity to tyrosine kinase inhibitors (TKIs) in patients with non-small cell lung cancer (NSCLC). Our clinical data showed NSCLC patients with exon 19 deletions survived longer following gefitinib treatment than those with exon 21 point mutations. We aimed to investigate whether these two mutations produced differences in phosphorylation of EGFR and downstream signals. Two stable cell lines expressing these mutations were obtained by transfection. Inhibition of phosphorylation of EGFR, Akt, and Erk by gefitinib was detected using Western blotting, and cell inhibition tests were conducted to evaluate the bio-behavior. Gefitinib inhibited the phosphorylation of EGFR, Akt, and Erk to a greater degree in exon 19 deletion cells than in L858R cells. Gefitinib produced G1 arrest in more of the cells with exon 19 deletion than with L858R. This might be attributable to patient selection in TKIs therapy.     

表皮生长因子受体基因20号外显子插入突变型非小细胞肺癌的治疗现状与展望

自表皮生长因子受体(EGFR)基因突变被发现以来,酪氨酸激酶抑制剂(TKI)的应用拉开了EGFR阳性非小细胞肺癌精准靶向治疗的序幕。携带EGFR基因常见的两类经典代表性突变,即第19号外显子框内缺失突变和第21号外显子L858R点突变(约占所有EGFR突变的90%)的非小细胞肺癌患者,接受TKI靶向治疗的临床获益远远优于传统化疗。EGFR基因第20号外显子插入突变却与众不同,在剩余10%EGFR少见基因突变中为最常见的类型,且这类突变中的绝大多数对目前临床应用的第一、二、三代TKI原发耐药,临床预后差。目前,国际上亦缺乏针对此突变的深入研究和临床治疗指南。文章介绍了EGFR基因20号外显子插入突变型非小细胞肺癌的发病机制、氨基酸序列亚型和治疗现状,探讨了此突变在目前肺癌治疗领域所面临的挑战与展望。     

Sustained response to standard dose osimertinib in a patient with plasma T790M‐positive leptomeningeal metastases from primary lung adenocarcinoma

A 44‐year‐old male, never smoker, suffers from stage IV adenocarcinoma of the right lung with epidermal growth factor receptor (EGFR) exon‐21 L858R point mutation on initial presentation. After 23 months of treatment with gefitinib, intercalated with multiple courses of radiotherapy, leptomeningeal metastases (LMs) developed. Acquired T790M mutation was confirmed by the droplet digital polymerase chain reaction plasma EGFR test. After switching to osimertinib at the standard dose, his neurocognitive function improved clinically, coupled with sustained radiological improvement. As this clinical entity is underrepresented in clinical trials, the practicability of plasma EGFR testing and the optimal dose–response relationship of osimertinib in T790M‐positive lung cancer complicated with LM deserves further exploration.     

The Frequency of EGFR Mutation in Lung Adenocarcinoma and the Efficacy of Tyrosine Kinase Inhibitor Therapy in a Hungarian Cohort of Patients

In the last decades new therapeutic drugs have been developed for the treatment of non-small cell lung cancer (NSCLC) patients. Tyrosine kinase inhibitors (TKIs) significantly increase the progression free survival (PFS) of patients with NSCLC carrying epidermal growth factor receptor (EGFR) mutations. This type of lung cancer occurs mainly among non-smoking women and Asian origin. However, the new ESMO guideline recommends EGFR mutation analysis in every patient with NSCLC, because in patients with activating EGFR mutation, TKIs should be considered as first line therapy. In our recent work, we analyzed data of patients with EGFR-mutant adenocarcinoma from January 2009. The number of patients investigated was 446, among them 44 cases were positive for EGFR mutation. The ratio of positive cases was 9.86 % that is lower than the average mutation rate in Europe and much lower than that found in Asia. The exon 19 deletion was detected in 61.4 % of the patients, while L858R point mutation in exon 21 was observed in 34.1 % of them. In one subject, both exon 19 and 21 mutations were present simultaneously. A rare mutation located in exon 21 was found in another patient. TKI therapy was conducted in 38 patients. The disease control rate by TKI therapy was 85.7 %; primary resistance was documented in five subjects. Non-smoking patients with EGFR mutant adenocarcinoma had the highest benefit from TKI treatment. Our data support the recommendation that EGFR mutation status should be defined in all cases of locally advanced or metastatic lung adenocarcinoma.     

辽宁沈阳地区非小细胞肺癌EGFR基因突变分析

目的:探讨辽宁沈阳地区非小细胞肺癌（NSCLC）患者表皮生长因子受体（EGFR）基因突变情况及其与临床病理特征的关系。方法:采用扩增耐突变系统（Amplification Refractory Mutation System,ARMS）检测辽宁沈阳地区471例NSCLC患者EGFR基因第18,19,20及21外显子突变情况。结果:471例NSCLC患者共检出EGFR突变253例（53.7%）,其中19缺失和L858R突变占总突变数的42.3%,51.8%。女性患者突变率67.9%明显高于男性（37.4%）,两者之间差异有统计学意义（P=0.000）。腺癌患者突变率57.2%明显高于非腺癌患者（18.6%）,差异有统计学意义（P=0.000）。结论:辽宁沈阳地区NSCLC患者EGFR突变多见于女性,腺癌患者,突变类型以19缺失和21外显子的L858R突变为主。