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.     

Epidermal growth factor receptor gene copy number and protein level are not associated with outcome of non-small-cell lung cancer patients treated with chemotherapy.

BACKGROUND: Survival benefit of non-small-cell lung cancer (NSCLC) patients treated with epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors is predicted by high EGFR gene copy number and by strong EGFR protein expression. Clinical relevance of these features in patients treated with chemotherapy has not been reported. PATIENTS AND METHODS: This study included 82 NSCLC patients treated with chemotherapy. There were 45% of females, 6% of never smokers and 45% of patients diagnosed with adenocarcinoma. EGFR gene copy number was evaluated by fluorescence in situ hybridization and EGFR protein level by immunohistochemistry. RESULTS: High EGFR gene copy number and protein level were found in 33% and 71% of patients, respectively. Both markers were significantly associated (P = 0.01). For objective response and disease control, there was no difference between patients defined as negative or positive for both EGFR gene copy number (P = 0.39 and P = 1.00, respectively) and for EGFR protein (P = 1.00 and P = 0.80, respectively). There were no differences in progression-free and overall survival according to EGFR gene copy number (P = 0.76 and P = 0.82, respectively) and protein level (P = 0.67 and P = 0.62, respectively). CONCLUSION: In chemotherapy-treated NSCLC patients, EGFR gene copy number was positively associated with protein level but none of the features were predictive for either treatment response or survival.     

MET increased gene copy number and primary resistance to gefitinib therapy in non-small-cell lung cancer patients

Background: MET amplification has been detected in 20% of non-small-celllung cancer patients (NSCLC) with epidermal growth factor receptor(EGFR) mutations progressing after an initial response to tyrosinekinase inhibitor (TKI) therapy. Patients and methods: We analyzed MET gene copy number usingFISH in two related NSCLC cell lines, one sensitive (HCC827)and one resistant (HCC827 GR6) to gefitinib therapy and in twodifferent NSCLC patient populations: 24 never smokers or EGFRFISH-positive patients treated with gefitinib (ONCOBELL cohort)and 182 surgically resected NSCLC not exposed to anti-EGFR agents. Results: HCC827 GR6-resistant cell line displayed MET amplification,with a mean MET copy number >12, while sensitive HCC827 cellline had a mean MET copy number of 4. In the ONCOBELL cohort,no patient had gene amplification and MET gene copy number wasnot associated with outcome to gefitinib therapy. Among thesurgically resected patients, MET was amplified in 12 cases(7.3%) and only four (2.4%) had a higher MET copy number thanthe resistant HCC827 GR6 cell line. Conclusions: MET gene amplification is a rare event in patientswith advanced NSCLC. The development of anti-MET therapeuticstrategies should be focused on patients with acquired EGFR-TKIresistance. Key words: EGFR, gefitinib, MET, non-small cell lung cancer, tyrosine kinase inhibitor Received for publication March 30, 2008. Revision received August 4, 2008. Accepted for publication August 18, 2008.     

The EGFR mutation and its correlation with response of gefitinib in previously treated Chinese patients with advanced non-small-cell lung cancer.

BACKGROUND: The aim of the study was to evaluate the efficacy of gefitinib and the epidermal growth factor receptor (EGFR) mutation to gefitinib response in a series of Chinese patients with pretreated advanced non-small-cell lung cancer (NSCLC). METHODS: A total of 98 patients who had failed at least one platinum-based regimen received gefitinib 250 mg once daily. The mutation analysis of the EGFR kinase domain was performed for 30 patients using paraffin-embedded tumor tissue. RESULTS: The response rate was 31.6% and the disease control rate was 67.3%. Objective response was correlated with adenocarcinoma, female gender and non-smokers. Median progress free survival (PFS) was 7.0 months, median overall survival (OS) was 12.0 months and 1-year survival was 53.1%. The median PFS and OS were improved among patients with adenocarcinoma, gefitinib responders and non-smokers. Active gene mutation was detected in 12 patients. Mutation rates were higher among gefitinib responders, non-smokers, patients with adenocarcinoma and female patients. OS was longer for patients with gene mutation than for patients without mutation. CONCLUSION: Gefitinib demonstrated significant antitumor activity with a favorable toxicity profile for pretreated Chinese patients with advanced NSCLC. The active mutation of the EGFR kinase domain was strongly associated with response to gefitinib and prolonged overall survival.     

EGFR基因CA—SSR多态与晚期非小细胞肺癌吉非替尼临床疗效的关系

目的 研究EGFR基因第1内含子区CA-SSR多态性与晚期非小细胞肺癌患者吉非替尼临床疗效的相关性.方法 对80例接受过吉非替尼治疗的晚期非小细胞肺癌患者进行了分析.采用PCR扩增和直接序列测定的方法确定这80例肺癌患者外周血DNA样本中CA-SSR多态的基因型,统计学分析CA-SSR多态性与患者临床疗效的相关性.结果 80例患者中共检测到11种不同CA-SSR等位基因型,包含的cA重复序列数为10-24.携带短CA重复序列的患者(至少一条等位基因CA重复数≤16)吉非替尼治疗后的临床获益率为88.0%,而在长CA重复序列的患者(两条等位基因CA重复数均＞16)为50.9%,CA-SSR多态性与近期疗效具有显著的相关性(P=0.005),但两组患者的无进展生存和总生存差异均无显著性.结论 EGFR基因第1内含子区CA-SSR多态性可以应用于临床预测晚期非小细胞肺癌患者吉非替尼的近期疗效.     

Practical management of patients with non-small-cell lung cancer treated with gefitinib.

PURPOSE: The use of gefitinib, the first drug approved to inhibit the epidermal growth factor receptor tyrosine kinase, is indicated in patients with non-small-cell lung cancer with tumors progressive after chemotherapy. The unique mechanism of action of this agent leads to distinctive patterns of response and toxicity in persons with lung cancer. Many of the principles of management relevant to gefitinib are distinct from those with conventional cytotoxic drugs. To meet this need, we present practical guidelines on the use of gefitinib in patients with non-small-cell lung cancer. METHODS: This article reviews gefitinib's indications, dosing, response phenomena, and patterns of relapse in individuals with radiographic response. RESULTS: We present our recommendations for the management of rash and diarrhea caused by this agent. CONCLUSION: This information can guide practitioners and help them inform their patients about what to expect when they receive gefitinib.     

VCP gene variation predicts outcome of advanced non-small-cell lung cancer platinum-based chemotherapy

Valosin-containing protein (VCP), or p97, is a member of the ATP-binding protein family, and is involved in numerous cellular events, such as, protein degradation, membrane fusion, and chaperone activity. VCP has been demonstrated playing a critical role in non-small-cell lung cancer (NSCLC) pathogenesis and progression recently. We investigated the association between VCP polymorphisms and clinical outcome in advanced NSCLC patients undergoing platinum-based chemotherapy. We recruited 663 Chinese advanced NSCLC patients who were treated with platinum-based regimens, and using their clinical data, we assessed the efficacy and side effects of their treatment. Three tag-single nucleotide polymorphisms (SNPs) of VCP were genotyped. SNP rs2074549 showed a significant association with severe neutropenia. Its G/G genotype increased the risk of grade 3 or 4 neutropenia compared with wild-type homozygotes A/A (P?=?.001, odds ratio?=?2.975). Haplotype association analysis revealed that CGA was associated with the increased incidence of severe neutropenia (P?=?.041, odds ratio?=?1.439). However, no significant relationship was found between the presence of VCP polymorphisms and treatment efficacy when objective response, progression-free survival, and overall survival (OS) were evaluated. Our study is the first to provide evidence that VCP polymorphisms are associated with a severe chemotherapy-related adverse outcome in platinum-treated advanced NSCLC patients.     

Increased HER2 gene copy number is associated with response to gefitinib therapy in epidermal growth factor receptor-positive non-small-cell lung cancer patients.

PURPOSE: In non-small-cell lung cancer (NSCLC), response to tyrosine kinase inhibitors (TKIs) is significantly associated with the presence of increased copy number and/or activating mutations of the epidermal growth factor receptor gene (EGFR). Preclinical data indicate that HER2, a member of the EGFR family, could enhance TKI sensitivity. PATIENTS AND METHODS: HER2 gene copy numbers per cell were evaluated by fluorescent in situ hybridization (FISH) in 102 NSCLC patients treated with gefitinib, and previously evaluated for EGFR status by FISH, immunohistochemistry, and presence of mutations. RESULTS: Patients with HER2 high copy number (high polysomy and gene amplification [HER2 FISH positive]) represented 22.8% of patients, and compared with patients with no or low gain (HER2 FISH negative), had significantly better objective response (OR, 34.8% v 6.4%; P = .001), disease control rate (DCR, 56.5% v 33.3%; P = .04), time to progression (TTP, 9.05 v 2.7 months; P = .02), and a trend toward longer overall survival (OS, 20.8 v 8.4 months; P = .056). HER2 protein expression investigated by immunohistochemistry was positive in only five of 72 (7%) patients analyzed and all 89 patients tested by DNA sequencing were negative for mutations in HER2 exon 20. Patients with HER2 FISH-positive tumors displaying increased expression of EGFR protein, gene gain, or mutations (EGFR positive) had a significantly better OR, DCR, TTP, and OS than patients negative for both receptors. CONCLUSION: Increased copy number of the HER2 gene is associated with gefitinib sensitivity in EGFR-positive patients, supporting use of HER2 FISH analysis for selection of patients for TKI therapy.     

EGFR gene copy number assessment from areas with highest EGFR expression predicts response to anti-EGFR therapy in colorectal cancer

Background:

Only 40–70% of metastatic colorectal cancers (mCRCs) with wild-type (WT) KRAS oncogene respond to anti-epidermal growth factor receptor (anti-EGFR) antibody treatment. EGFR amplification has been suggested as an additional marker to predict the response. However, improved methods for bringing the EGFR analysis into routine laboratory are needed.

Methods:

The material consisted of 80 patients with mCRC, 54 of them receiving anti-EGFR therapy. EGFR gene copy number (GCN) was analysed by automated silver in situ hybridisation (SISH). Immunohistochemical EGFR protein analysis was used to guide SISH assessment.

Results:

Clinical benefit was seen in 73% of high (⩾4.0) EGFR GCN patients, in comparison with 59% of KRAS WT patients. Only 20% of low EGFR GCN patients responded to therapy. A high EGFR GCN number associated with longer progression-free survival (P<0.0001) and overall survival (P=0.004). Together with KRAS analysis, EGFR GCN identified the responsive patients to anti-EGFR therapy more accurately than either test alone. The clinical benefit rate of KRAS WT/high EGFR GCN tumours was 82%.

Conclusion:

Our results show that automated EGFR SISH, in combination with KRAS mutation analysis, can be a useful and easily applicable technique in routine diagnostic practise for selecting patients for anti-EGFR therapy.     

Prognostic role of EGFR gene copy number and KRAS mutation in patients with locally advanced rectal cancer treated with preoperative chemoradiotherapy

Background:

Epidermal growth factor receptor (EGFR), evaluated by immunohistochemistry, has been shown to have prognostic significance in patients with colorectal cancer. Gene copy number (GCN) of EGFR and KRAS status predict response and outcome in patients treated with anti-EGFR therapy, but their prognostic significance in colorectal cancer patients is still unclear.

Methods:

We have retrospectively reviewed the baseline EGFR GCN, KRAS status and clinical outcome of 146 locally advanced rectal cancer (LARC) patients treated with preoperative chemoradiotherapy. Pathological response evaluated by Dworak''s tumour regression grade (TRG), disease-free survival (DFS) and overall survival (OS) were analysed.

Results:

Tumour regression grade 4 and TRG3–4 were achieved in 14.4 and 30.8% of the patients respectively. Twenty-nine (19.9%) and 33 patients (19.2%) had an EGFR/nuclei ratio >2.9 and CEP7 polisomy >50% respectively; 28 patients (19.2%) had a KRAS mutation. Neither EGFR GCN nor KRAS status was statistically correlated to TRG. 5-year DFS and OS were 63.3 and 71.5%, respectively, and no significant relation with EGFR GCN or KRAS status was found.

Conclusion:

Our data show that EGFR GCN and KRAS status are not prognostic factors in LARC treated with preoperative chemoradiation.     

First-line single agent treatment with gefitinib in patients with advanced non-small-cell lung cancer

Background

Lung cancer is a malignant carcinoma which has the highest morbidity and mortality in Chinese population. Gefitinib, a tyrosine kinase (TK) inhibitor of epidermal growth factor receptor (EGFR), displays anti-tumor activity. The present data regarding first-line treatment with single agent gefitinib against non-small-cell lung cancer (NSCLC) in Chinese population are not sufficient.

Purpose

To assess the efficacy and toxicity of gefitinib in Chinese patients with advanced non-small-cell lung cancer (NSCLC), a study of single agent treatment with gefitinib in Chinese patients was conducted.

Methods

45 patients with advanced NSCLC were treated with gefitinib (250 mg daily) until the disease progression or intolerable toxicity.

Results

Among the 45 patients, 15 patients achieved partial response (PR), 17 patients experienced stable disease (SD), and 13 patients developed progression disease (PD). None of the patients achieved complete response (CR). The tumor response rate and disease control rate was 33% and 71.1%, respectively. Symptom remission rate was 72.5%, and median remission time was 8 days. Median overall survival and median progression-free survival was 15.3 months and 6.0 months, respectively. The main induced toxicities by gefitinib were skin rash and diarrhea (53.3% and 33.3%, respectively). The minor induced toxicities included dehydration and pruritus of skin (26.7% and 22.2%, respectively). In addition, hepatic toxicity and oral ulceration occurred in few patients (6.7% and 4.4%2, respectively).

Conclusions

Single agent treatment with gefitinib is effective and well tolerated in Chinese patients with advanced NSCLC.

     

CT findings in non-small-cell lung cancer patients treated with gefitinib or erlotinib

Purpose: We performed this study to explore the association of computed tomography (CT) findings with outcomes of patients with non-small-cell lung cancer (NSCLC) treated with tyrosin kinase inhibitor (TKI) such as gefitinib or erlotinib. Materials and Methods: We analyzed outcomes for 240 patients according to primary tumor (T), regional nodal (N) staging and diffuse small pulmonary metastases (DSPM) at the initial presentation. Tests for epidermal growth factor receptor (EGFR) mutation were performed in 92 patients. Results: On multivariate analysis for tumor response, the N3 stage was predictive of a poor response (P < 0.001), whereas DSPM was a favorable factor (P = 0.007). Multivariate analysis for progression-free survival showed that the T3-4 stage (hazard ratio [HR]: 2.5, P < 0.001), in addition to the N3 stage (HR: 2.1, P < 0.001), was predictive of a poor outcome, whereas DSPM (HR: 0.6, P = 0.006) was a favorable factor. Notably, the multivariate model that included the EGFR mutational status revealed that the T3-4 stage predicted poor progression-free survival (HR: 2.2, P = 0.017) and poor overall survival (HR: 4.1, P < 0.001). Conclusion: Our data suggest that, in addition to EGFR mutational status, T-stage based on CT is predictive of outcomes of TKI-treated NSCLC patients.     

Positive expression of ERCC1 predicts a poorer platinum-based treatment outcome in Chinese patients with advanced non-small-cell lung cancer

The goal of this study is to determine role of excision repair cross-complementing group 1 gene (ERCC1) and ribonucleotide reductase subunit M1 (RRM1) expression in predicting response and survival in Chinese patients with advanced stage non-small cell lung cancer (NSCLC) treated with platinum-based chemotherapy. Formalin-fixed, paraffin-embedded biopsy tissues were retrospectively obtained from 124 advanced NSCLC patients. Protein expression levels of ERCC1 and RRM1 were determined by immunohistochemistry (IHC). Associations between expression of ERCC1 and RRM1 and clinic-pathologic parameters were analyzed. The study shows that ERCC1 and RRM1 expression was detected in 43 (35%) and 50 (40%) of the 124 tumor samples, respectively. Expression of ERCC1 and RRM1 was negatively associated with tumor response. Fifty-four percent patients whose tumors did not express ERCC1 had partial response (PR) compared to 33% whose tumors expressed the protein (P = 0.022). Similarly, 54% patients whose tumor did not express RRM1 had PR compared to 36% whose tumors expression the protein (P = 0.042). Further, patients whose tumors lacked of ERCC1 but not RRM1 expression had a longer median survival time than those tumors expressed ERCC1 (13.4 months versus 9.1 months; P = 0.006), which is independent of other prognostic factors (P = 0.0066). In conclusion, tumor ERCC1 expression is associated with tumor response and patients’ survival in Chinese advanced NSCLC patients treated with platinum-based regimen and may serve as a biomarker in predicting tumor response and clinical outcome in the patient population.     

A Phase 1 study of gefitinib combined with durvalumab in EGFR TKI-naive patients with EGFR mutation-positive locally advanced/metastatic non-small-cell lung cancer

Background EGFR tyrosine kinase inhibitors (TKIs) induce cytolysis and release of tumour proteins, which can stimulate antigen-specific T cells. The safety and efficacy of durvalumab and gefitinib in combination for TKI-naive patients with advanced EGFRm NSCLC was evaluated.Methods This Phase 1 open-label, multicentre trial ({"type":"clinical-trial","attrs":{"text":"NCT02088112","term_id":"NCT02088112"}}NCT02088112) was conducted in 56 patients with NSCLC. Dose expansion permitted TKI-naive patients, primarily with activating L858R or Ex19del EGFRm. Arms 1 + 1a received concurrent therapy; Arm 2 received 4 weeks of gefitinib induction followed by concurrent therapy.Results From dose escalation, the recommended dose of durvalumab was 10 mg/kg Q2W with 250 mg QD gefitinib. Pharmacokinetics were as expected, consistent with inhibition of soluble PD-L1 and no treatment-emergent immunogenicity. In dose expansion, 35% of patients had elevated liver enzymes leading to drug discontinuation. In Arms 1 + 1a, objective response rate was 63.3% (95% CI: 43.9–80.1), median progression-free survival (PFS) was 10.1 months (95% CI: 5.5–15.2) and median response duration was 9.2 months (95% CI: 3.7–14.0).Conclusions Durvalumab and gefitinib in combination had higher toxicity than either agent alone. No significant increase in PFS was detected compared with historical controls. Therefore, concurrent PD-L1 inhibitors with gefitinib should be generally avoided in TKI-naive patients with EGFRm NSCLC.Subject terms: Tumour biomarkers, Cancer immunotherapy, Non-small-cell lung cancer, Targeted therapies     

Role of cMET expression in non-small-cell lung cancer patients treated with EGFR tyrosine kinase inhibitors

BackgroundApproximately 10% of unselected non-small-cell lung cancer (NSCLC) patients responded to the epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) treatment. However, resistance mechanisms are not well understood. We evaluated several potential biological markers of intrinsic EGFR-TKIs-resistance in NSCLC.Materials and methodspAKT, pERK, cSRC, E-cadherin, cMET[pY1003], cMET[pY1230/1234/1235], and cMET[pY1349] immunohistochemistry, cMET FISH analysis, and EGFR-, KRAS-, and cMET mutation analysis were carried out on tumor samples from 51 gefitinib-treated NSCLC patients. Biological parameters and survival end points were compared by univariate and multivariate analyses. cMET expression was also investigated in two additional series of patients. The in vitro antiproliferative activity of gefitinib alone or in combination with hepatocyte growth factor and the cMET antibody DN-30 was assessed in NSCLC cells.ResultsEGFR19 deletion and pAKT expression were significantly associated with response (P < 0.0001) and longer time to progression (TTP) (P = 0.007), respectively. Strong cMET[pY1003] membrane immunoreactivity was expressed in 6% of 149 tumors analyzed and was significantly associated with progressive disease (P = 0.019) and shorter TTP (P = 0.041). In vitro, the DN-30 combination synergistically (CI < 1) enhanced gefitinib-induced growth inhibition in all cMET[pY1003]-expressing cell lines studied.ConclusionsActivated cMET[pY1003] appears to be a marker of primary gefitinib resistance in NSCLC patients. cMET may be a target in treatment of NSCLC.     

Prolonged control of bone metastases in non-small-cell lung cancer patients treated with gefitinib

We describe two non-small-cell lung cancer (NSCLC) patients in which treatment with the epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKIs) gefitinib produced a prolonged control of bone disease. In the first patient, a 48-year-old male with adenocarcinoma (ADC) of the lung and multiple bone metastases, the bone scan became completely negative following treatment with gefitinib for 9 months. The patient remained alive and with no evidence of bone metastases for 20 months, despite two local recurrences that were surgically removed. Similarly, the bone scan of the second patient, a 49-year-old male with ADC of the lung and bone metastases, became negative after 6 months on gefitinib. The molecular mechanisms potentially involved in this phenomenon are discussed.     

Clinical outcome for EML4-ALK-positive patients with advanced non-small-cell lung cancer treated with first-line platinum-based chemotherapy

BackgroundThe EML4-ALK fusion oncogene represents a recently identified molecular target in a subset of patients with non-small-cell lung cancer (NSCLC). Limited data have been available, however, on the outcome of first-line platinum-based chemotherapy in patients with EML4-ALK-positive advanced NSCLC who have not been treated with an ALK kinase inhibitor.Patients and methodsThe efficacy of platinum-based chemotherapy was compared between patients with advanced nonsquamous NSCLC who harbor EML4-ALK and those who harbor EGFR mutations and those with neither molecular abnormality.ResultsAmong 200 patients with advanced nonsquamous NSCLC, 18 (9.0%) were positive for EML4-ALK, 31 (15.5%) harbored EGFR mutations, and 151 (75.5%) were wild type for both abnormalities. Platinum-based combination chemotherapy showed similar efficacies in the EML4-ALK, EGFR mutation, and wild-type cohorts in terms of response rate and progression-free survival, and overall survival in the EML4-ALK cohort closely resembled that in the wild-type cohort. Within the EML4-ALK cohort, patients with variants 1 or 3 of the fusion gene were predominant and did not appear to differ in their sensitivity to the platinum-based regimens.ConclusionPatients with EML4-ALK-positive advanced NSCLC manifest an aggressive clinical course similar to that of those with wild-type tumors if the effective targeted therapy is not instituted.     

Epidermal growth factor receptor gene mutations and increased copy numbers predict gefitinib sensitivity in patients with recurrent non-small-cell lung cancer.

PURPOSE: To evaluate epidermal growth factor receptor (EGFR) mutations and copy number as predictors of clinical outcome in patients with non-small-cell lung cancer (NSCLC) receiving gefitinib. PATIENTS AND METHODS: Sixty-six patients with NSCLC who experienced relapse after surgery and received gefitinib were included. Direct sequencing of exons 18 to 24 of EGFR and exons 18 to 24 of ERBB2 was performed using DNA extracted from surgical specimens. Pyrosequencing and quantitative real-time polymerase chain reaction were performed to analyze the allelic pattern and copy number of EGFR. RESULTS: Thirty-nine patients (59%) had EGFR mutations; 20 patients had deletional mutations in exon 19, 17 patients had missense mutations (L858R) in exon 21, and two patients had missense mutations (G719S or G719C) in exon 18. No mutations were identified in ERBB2. Response rate (82% [32 of 39 patients] v 11% [three of 27 patients]; P < .0001), time to progression (TTP; median, 12.6 v 1.7 months; P < .0001), and overall survival (median, 20.4 v 6.9 months; P = .0001) were significantly better in patients with EGFR mutations than in patients with wild-type EGFR. Increased EGFR copy numbers (> or = 3/cell) were observed in 29 patients (44%) and were significantly associated with a higher response rate (72% [21 of 29 patients] v 38% [14 of 37 patients]; P = .005) and a longer TTP (median, 9.4 v 2.6 months; P = .038). High EGFR copy numbers (> or = 6/cell) were caused by selective amplification of mutant alleles. CONCLUSION: EGFR mutations and increased copy numbers were significantly associated with better clinical outcome in gefitinib-treated NSCLC patients.