Clara Mayo

Screening for Epidermal Growth Factor Receptor Mutations in Lung Cancer

BACKGROUND Activating mutations in the epidermal growth factor receptor gene (EGFR) confer hypersensitivity to the tyrosine kinase inhibitors gefitinib and erlotinib in patients with advanced non-small-cell lung cancer. We evaluated the feasibility of large-scale screening for EGFR mutations in such patients and analyzed the association between the mutations and the outcome of erlotinib treatment. METHODS From April 2005 through November 2008, lung cancers from 2105 patients in 129 institutions in Spain were screened for EGFR mutations. The analysis was performed in a central laboratory. Patients with tumors carrying EGFR mutations were eligible for erlotinib treatment. RESULTS EGFR mutations were found in 350 of 2105 patients (16.6%). Mutations were more frequent in women (69.7%), in patients who had never smoked (66.6%), and in those with adenocarcinomas (80.9%) (P<0.001 for all comparisons). The mutations were deletions in exon 19 (62.2%) and L858R (37.8%). Median progression-free survival and overall survival for 217 patients who received erlotinib were 14 months and 27 months, respectively. The adjusted hazard ratios for the duration of progression-free survival were 2.94 for men (P<0.001); 1.92 for the presence of the L858R mutation, as compared with a deletion in exon 19 (P=0.02); and 1.68 for the presence of the L858R mutation in paired serum DNA, as compared with the absence of the mutation (P=0.02). The most common adverse events were mild rashes and diarrhea; grade 3 cutaneous toxic effects were recorded in 16 patients (7.4%) and grade 3 diarrhea in 8 patients (3.7%). CONCLUSIONS Large-scale screening of patients with lung cancer for EGFR mutations is feasible and can have a role in decisions about treatment.

Pretreatment EGFR T790M Mutation and BRCA1 mRNA Expression in Erlotinib-Treated Advanced Non–Small-Cell Lung Cancer Patients with EGFR Mutations

Purpose: Advanced non–small-cell lung cancer (NSCLC) patients harboring epidermal growth factor receptor (EGFR) mutations (deletion in exon 19 or L858R) show an impressive progression-free survival of 14 months when treated with erlotinib. However, the presence of EGFR mutations can only imperfectly predict outcome. We hypothesized that progression-free survival could be influenced both by the pretreatment EGFR T790M mutation and by components of DNA repair pathways. Experimental Design: We assessed the T790M mutation in pretreatment diagnostic specimens from 129 erlotinib-treated advanced NSCLC patients with EGFR mutations. The expression of eight genes and two proteins involved in DNA repair and four receptor tyrosine kinases was also examined. Results: The EGFR T790M mutation was observed in 45 of 129 patients (35%). Progression-free survival was 12 months in patients with and 18 months in patients without the T790M mutation (P = 0.05). Progression-free survival was 27 months in patients with low BRCA1 mRNA levels, 18 months in those with intermediate levels, and 10 months in those with high levels (P = 0.02). In the multivariate analysis, the presence of the T790M mutation (HR, 4.35; P = 0.001), intermediate BRCA1 levels (HR, 8.19; P < 0.0001), and high BRCA1 levels (HR, 8.46; P < 0.0001) emerged as markers of shorter progression-free survival. Conclusions: Low BRCA1 levels neutralized the negative effect of the T790M mutation and were associated with longer progression-free survival to erlotinib. We advocate baseline assessment of the T790M mutation and BRCA1 expression to predict outcome and provide alternative individualized treatment to patients based on T790M mutations and BRCA1 expression. Clin Cancer Res; 17(5); 1–9. ©2011 AACR.

Brain metastases from lung cancer responding to erlotinib: the importance of EGFR mutation

Median survival of patients with brain metastases from nonsmall cell lung cancer (NSCLC) is poor and more effective treatments are urgently needed. We have evaluated the efficacy of erlotinib in this setting and its association with activating mutations in the epidermal growth factor receptor (EGFR) gene. We retrospectively identified patients with NSCLC and brain metastases treated with erlotinib. EGFR mutations in exons 19 and 21 were analysed by direct sequencing. Efficacy and tolerability were compared according to EGFR mutational status. 69 NSCLC patients with brain metastases were identified, 17 of whom harboured EGFR mutations. Objective response rate in patients with EGFR mutations was 82.4%; no responses were observed in unselected patients (p<0.001). Median (95% CI) time to progression within the brain for patients harbouring EGFR mutations was 11.7 (7.9–15.5) months, compared to 5.8 (5.2–6.4) months for control patients whose EGFR mutational status had not been assessed (p<0.05). Overall survival was 12.9 (6.2–19.7) months and 3.1 (2.5–3.9) months (p<0.001), respectively. The toxicity of erlotinib was as expected and no differences between cohorts were observed. Erlotinib is active in brain metastases from NSCLC; this clinical benefit is related to the presence of activating mutations in exons 19 or 21 of the EGFR gene.

A Sensitive Method for Detecting EGFR Mutations in Non-small Cell Lung Cancer Samples with Few Tumor Cells

Background: Detection of epidermal growth factor receptor (EGFR) mutations in advanced non-small cell lung cancer (NSCLC) patients has relied on DNA purification from biopsies, amplification, and sequencing. However, the number of tumor cells in a sample is often insufficient for EGFR assessment. Methods: We prospectively screened 1380 NSCLC patients for EGFR mutations but found that 268 were not evaluable because of insufficient tumor tissue. We therefore developed and validated a method of detecting EGFR mutations in these samples. Tumor cells were microdissected into polymerase chain reaction buffer and amplified. EGFR mutations were detected by length analysis of fluorescently labeled polymerase chain reaction products and TaqMan assay. Results: We determined EGFR status in 217 (81%) of the 268 primary NSCLC samples not evaluable in our original study—fresh and paraffin-embedded with less than 150 cells. Exon 19 deletions were detected in 11.5% of patients and exon 21 L858R mutations in 5.5%. In addition, the exon 20 T790M mutation was detected in 6 of 15 (40%) patients at the time of progression to erlotinib. The primary, sensitive mutation was present in all tumor cells, whereas the T790M mutation was absent in some groups. Conclusions: The method presented here eliminates the need for DNA purification and allows for detection of EGFR mutations in samples containing as few as eight cancer cells.

Detection of EGFR mutations with mutation-specific antibodies in stage IV non-small-cell lung cancer.

BackgroundImmunohistochemistry (IHC) with mutation-specific antibodies may be an ancillary method of detecting EGFR mutations in lung cancer patients.MethodsEGFR mutation status was analyzed by DNA assays, and compared with IHC results in five non-small-cell lung cancer (NSCLC) cell lines and tumor samples from 78 stage IV NSCLC patients.ResultsIHC correctly identified del 19 in the H1650 and PC9 cell lines, L858R in H1975, and wild-type EGFR in H460 and A549, as well as wild-type EGFR in tumor samples from 22 patients. IHC with the mAb against EGFR with del 19 was highly positive for the protein in all 17 patients with a 15-bp (ELREA) deletion in exon 19, whereas in patients with other deletions, IHC was weakly positive in 3 cases and negative in 9 cases. IHC with the mAb against the L858R mutation showed high positivity for the protein in 25/27 (93%) patients with exon 21 EGFR mutations (all with L858R) but did not identify the L861Q mutation in the remaining two patients.ConclusionsIHC with mutation-specific mAbs against EGFR is a promising method for detecting EGFR mutations in NSCLC patients. However these mAbs should be validated with additional studies to clarify their possible role in routine clinical practice for screening EGFR mutations in NSCLC patients.

Pharmacogenetics of EGFR in lung cancer: perspectives and clinical applications

Lung cancer is a lethal disease, and most cases have already disseminated at the time of diagnosis. Driver mutations in the EGFR tyrosine kinase domain (mainly deletions in exon 19 and L858R mutation in exon 21) have been identified in lung adenocarcinomas, mostly in never smokers, at frequencies of 20-60%. The EGFR tyrosine kinase inhibitors (TKIs) gefitinib or erlotinib attain a response rate of 70% and progression-free survival of 9-13 months, although there are subgroups of patients with long-lasting remissions. No significant correlation between EGFR overexpression and response to treatment has been found, while controversial results have been reported regarding EGFR gene amplification. The pretreatment presence of the T790M mutation, initially identified as an acquired resistance mutation to treatment with EGFR TKIs, has also been reported and may indicate a genetically distinct disease. Finally, other genetic factors, such as mRNA expression of BRCA1 and components of the NF-κB pathway, can modulate response to EGFR TKIs in EGFR-mutated patients.

mRNA expression levels and genetic status of genes involved in the EGFR and NF-κB pathways in metastatic non-small-cell lung cancer patients

BackgroundMetastatic non-small-cell lung cancer (NSCLC) has a dismal prognosis. EGFR is overexpressed or mutated in a large proportion of cases. Downstream components of the EGFR pathway and crosstalk with the NF-κB pathway have not been examined at the clinical level. We explored the prognostic significance of the mRNA expression of nine genes in the EGFR and NF-κB pathways and of BRCA1 and RAP80 in patients in whom EGFR and K-ras gene status had previously been determined. In addition, NFKBIA and DUSP22 gene status was also determined.MethodsmRNA expression of the eleven genes was determined by QPCR in 60 metastatic NSCLC patients and in nine lung cancer cell lines. Exon 3 of NFKBIA and exon 6 of DUSP22 were analyzed by direct sequencing. Results were correlated with outcome to platinum-based chemotherapy in patients with wild-type EGFR and to erlotinib in those with EGFR mutations.ResultsBRCA1 mRNA expression was correlated with EZH2, AEG-1, Musashi-2, CYLD and TRAF6 expression. In patients with low levels of both BRCA1 and AEG-1, PFS was 13.02 months, compared to 5.4 months in those with high levels of both genes and 7.7 months for those with other combinations (P = 0.025). The multivariate analysis for PFS confirmed the prognostic role of high BRCA1/AEG-1 expression (HR, 3.1; P = 0.01). Neither NFKBIA nor DUSP22 mutations were found in any of the tumour samples or cell lines.ConclusionsThe present study provides a better understanding of the behaviour of metastatic NSCLC and identifies the combination of BRCA1 and AEG-1 expression as a potential prognostic model.

Clinical validation of a PCR assay for the detection of EGFR mutations in non-small-cell lung cancer: retrospective testing of specimens from the EURTAC trial.

The EURTAC trial demonstrated that the tyrosine kinase inhibitor (TKI) erlotinib was superior to chemotherapy as first-line therapy for advanced non-small cell lung cancers (NSCLC) that harbor EGFR activating mutations in a predominantly Caucasian population. Based on EURTAC and several Asian trials, anti-EGFR TKIs are standard of care for EGFR mutation-positive NSCLC. We sought to validate a rapid multiplex EGFR mutation assay as a companion diagnostic assay to select patients for this therapy. Samples from the EURTAC trial were prospectively screened for EGFR mutations using a combination of laboratory-developed tests (LDTs), and tested retrospectively with the cobas EGFR mutation test (EGFR PCR test). The EGFR PCR test results were compared to the original LDT results and to Sanger sequencing, using a subset of specimens from patients screened for the trial. Residual tissue was available from 487 (47%) of the 1044 patients screened for the trial. The EGFR PCR test showed high concordance with LDT results with a 96.3% overall agreement. The clinical outcome of patients who were EGFR-mutation detected by the EGFR PCR test was very similar to the entire EURTAC cohort. The concordance between the EGFR PCR test and Sanger sequencing was 90.6%. In 78.9% of the discordant samples, the EGFR PCR test result was confirmed by a sensitive deep sequencing assay. This retrospective study demonstrates the clinical utility of the EGFR PCR test in the accurate selection of patients for anti-EGFR TKI therapy. The EGFR PCR test demonstrated improved performance relative to Sanger sequencing.

EGFR mutation analysis in sputum of lung cancer patients: A multitechnique study

OBJECTIVES Epidermal growth factor receptor (EGFR) mutations have been identified in lung adenocarcinomas and are associated with high response chance to EGFR tyrosine kinase inhibitors. EGFR mutations can be detected in tumour tissue, cytology specimens and blood from lung cancer patients. Thus far, EGFR mutation analysis has not been systematically demonstrated for sputum samples. The aim of the present study was to determine whether EGFR mutation analysis is attainable on sputum samples, employing different assays in a multicenter study. MATERIALS AND METHODS Sputum DNA from 10 lung cancer patients with confirmed EGFR mutation in their tumour tissue, 10 lung cancer patients without evidence of an EGFR mutation, and 10 patients with chronic obstructive pulmonary disease (COPD) was used for mutation analysis by Cycleave PCR, COLD-PCR, PangaeaBiotech SL Technology (PST), and High Resolution Melting, respectively. Targeted resequencing (TruSeq Amplicon Cancer Panel) and droplet digital PCR were additionally performed on the 10 samples with EGFR mutation. RESULTS Dependent on the assay, EGFR mutations could be detected in 30-50% of the sputum samples of patients with EGFR mutations. The different techniques revealed consistent results, with slightly higher sensitivity for PST. Neither the lung cancer patients without EGFR mutation nor the COPD controls tested positive for EGFR mutations in their sputum samples, indicating high clinical specificity of all assays. CONCLUSION EGFR mutations can be detected in sputum samples from patients with EGFR-mutated non-small cell lung cancer, which may replace biopsy procedure for some patients.

BRCA1, LMO4, and CtIP mRNA Expression in Erlotinib-Treated Non–Small-Cell Lung Cancer Patients with EGFR Mutations

Introduction: Lung adenocarcinoma patients harboring EGFR activating mutations attain improved progression-free survival (PFS) with treatment with epidermal growth factor receptor tyrosine kinase inhibitors. However, patients ultimately relapse, indicating that other genetic factors could influence outcome in such patients. We hypothesized that PFS could be influenced by the expression of genes in DNA repair pathways. Methods: We examined the mRNA expression of C terminus-binding protein–interacting protein and Lin11, Isl-1, and Mec-3 domain only 4 (LMO4) in pretreatment tumor samples from 91 erlotinib-treated advanced non–small-cell lung cancer patients with EGFR mutations in whom breast cancer gene 1 (BRCA1) expression and the concomitant presence of the EGFR T790M mutation had previously been assessed. Gene expression was analyzed by polymerase chain reaction, using &bgr;-actin as endogenous gene. Results were correlated with PFS and overall survival. Results: In patients with low LMO4 levels, PFS was 13 months, whereas it was not reached for those with high LMO4 levels (p = 0.03). In patients with low levels of both BRCA1 and LMO4, PFS was 19 months whereas it was not reached in those with low BRCA1 and high LMO4 mRNA levels (p = 0.04). In patients with high BRCA1 and low LMO4 levels, PFS was 8 months, whereas it was 18 months in those with high levels of both genes (p = 0.03). Conclusions: Low BRCA1 and high LMO4 levels were associated with longer PFS to erlotinib. Baseline assessment of BRCA1 and LMO4 mRNA expression can help predict outcome to erlotinib.