Co-existence of positive MET FISH status with EGFR mutations signifies poor prognosis in lung adenocarcinoma patients

MET, a receptor tyrosine kinase for hepatocyte growth factor, is associated with tumor progression and acquired resistance to epidermal growth factor tyrosine kinase inhibitors (EGFR-TKI). Therefore, MET gene alterations could be both prognostic and predictive. Fluorescence in situ hybridization (FISH) is one method for assessing gene alteration, but the frequency of positive cases varies due to a lack of standardized criteria. We evaluated MET gene copy number in lung adenocarcinoma and its association with clinicopathological characteristics. FISH was applied to evaluate high MET gene copy number and true amplification in 138 lung adenocarcinoma patients using two criteria: the Cappuzzo scoring system and PathVysion. MET positive cases according to the Cappuzzo scoring system evidenced both aneuploidy and true amplification, whereas PathVysion revealed only amplification. Proportion of MET FISH positive cases was 15% and 4% determined by the Cappuzzo system and PathVysion, respectively. PathVysion demonstrated higher frequencies of MET FISH positives among men and smokers and evidenced no MET FISH positives in patients with bronchioloalveolar carcinoma. Prognosis was significantly associated with MET FISH positive only as defined by the PathVysion system (gene amplification), not by the Cappuzzo system. However, progression-free survival time of patients with both EGFR mutations and MET FISH positive defined by the Cappuzzo scoring system was significantly shorter than with EGFR mutations alone. These results suggest that MET FISH is a potential prognostic factor and coexistence of MET FISH with EGFR mutations signifies worse prognosis.     

Epidermal growth factor receptor mutation status in pulmonary adenocarcinoma: Multi-institutional data discussion at national conference of “Lung Cancer Management in Indian context”

The presence of activating mutations in the tyrosine kinase domain of the epidermal growth factor receptor (EGFR) gene in adenocarcinomas of lung confers sensitivity to tyrosine kinase inhibitor therapy. The prevalence of EGFR mutations varies among different ethnicities and demographic profile. This multi-institutional data was compiled to determine the EGFR mutation status in Indians patients with lung adenocarcinoma. Cohorts represented by 4 tertiary care hospitals participated in data discussion at a national conference entitled as ‘Lung Cancer Management in Indian Context’. The clinicopathologic data and EGFR mutation rate in the patients of lung adenocarcinoma screened in these cohorts were collected and analyzed. The sample types included both surgical and cytological specimens. A variety of methods were used including immunohistochemistry, polymerase chain reaction, Sanger sequencing and next generation sequencing. A total of 3436 cases of treatment naïve lung adenocarcinoma were tested for EGFR mutations. The overall frequency of EGFR mutations observed was 30.03%. The most common baseline mutation detected was exon 19 deletion followed by L858R point mutation in exon 21. Dual mutations were observed in 6.5% of cases and were predominantly combinations of exon 19 deletion and T790M point mutation in exon 20. Incidence of EGFR mutations was higher among females and non-smokers diagnosed with lung adenocarcinomas. The most common histology in EGFR mutant cases was acinar predominant adenocarcinomas. With nearly one-third of Indian patients with lung adenocarcinoma harboring EGFR mutations, routine testing for these mutations is important to get the benefit of targeted therapy.     

Impact of epidermal growth factor receptor mutations on intracranial treatment response and survival after brain metastases in lung adenocarcinoma patients

Introduction

Brain metastases (BM) commonly occur in patients with lung adenocarcinoma and usually lead to a poor prognosis and quality of life despite of radiotherapy. Epidermal growth factor receptor (EGFR) mutations have been widely demonstrated to be a predictive and prognostic factor for lung adenocarcinoma, however, its impact on BM from lung adenocarcinoma remains inconclusive. The present study aimed to elucidate the predictive role of EGFR mutations in BM treatment response and survival after BM in patients with lung adenocarcinoma.

Material and methods

From January 2006 through February 2012, 180 of 505 lung adenocarcinoma patients developed BM during their disease course were reviewed for eligibility, and 139 patients, including 89 EGFR-mutant and 50 EGFR wild-type patients, were identified for analysis.

Results

Of the patients eligible for evaluation of treatment response, up to 85% received radiotherapy and the remaining took EGFR tyrosine kinase inhibitors (TKIs) as the front modality for BM. EGFR-mutant patients, compared with EGFR wild-type patients, had significantly greater intracranial treatment response of BM (84% vs. 48%, P = 0.002), experienced higher therapeutic efficacy to radiotherapy (86% vs. 52%, P = 0.005), and had longer median survival after BM diagnosis (13.2 vs. 6.8 months, P < 0.001). Furthermore, EGFR mutation (P = 0.002) and performance status (P = 0.009) were independently associated with BM treatment response. Additionally, EGFR mutation (P = 0.005), good performance status (P < 0.001) and absence of extracranial metastases (P = 0.033) correlated with better survival.

Conclusion

EGFR mutation is an independent predictive factor for both BM treatment response and survival after BM in patients with lung adenocarcinoma. Further prospective studies on incorporation of EGFR mutation status into therapeutic strategy and survival prediction system for lung adenocarcinoma with BM are warranted.     

Additional prognostic role of EGFR activating mutations in lung adenocarcinoma patients with brain metastasis: Integrating with lung specific GPA score

ObjectiveWhile several prognostic models have been presented in NSCLC patients with brain metastasis, none of these models have included molecular markers as an index. The aim of our study was to evaluate the prognostic value of EGFR mutations and to integrate these EGFR mutations into the prognostic index in NSCLC patients with brain metastasis.Materials and methodsWe analyzed retrospectively 292 lung adenocarcinoma patients with brain metastasis. Clinico-pathological features and overall survival (OS) were compared between patients with EGFR mutations and patients with EGFR wild type. EGFR mutation status was integrated with lung specific graded prognostic assessment (GPA) score.ResultsAmong 292 patients, EGFR mutation status was tested in 183 patients. One hundred and five patients (57.4%) had EGFR activating mutations, 14 (7.7%) had EGFR non-activating mutations and 64 (35.0%) had EGFR wild type. OS was significantly longer in patients with EGFR activating mutations than in those with EGFR wild type patients (20.4 vs. 10.1 months, p = 0.002). However, patients with EGFR non-activating mutations did not show superior OS compared with EGFR wild type patients (14.6 vs. 10.1 months, p = 0.83). Multivariate analysis revealed that the presence of EGFR activating mutation is an independent positive prognostic factor for OS (adjusted hazard ratio 0.56, p = 0.002).ConclusionsEGFR activating mutations have a prognostic role in lung adenocarcinoma patients with brain metastasis that is independent of other known prognostic factors. The frequency of EGFR mutation was higher than expected. The presence of EGFR activating mutations should be included as an index in the prognostic models for lung adenocarcinoma patients with brain metastasis.     

Small-Cell Carcinoma With an Epidermal Growth Factor Receptor Mutation in a Never-Smoker With Gefitinib-Responsive Adenocarcinoma of the Lung

Activating mutations in the epidermal growth factor receptor (EGFR) gene are extremely rare in small-cell lung cancer (SCLC). Here, we present a case of an EGFR-mutant gefitinib-responsive non–small-cell lung cancer (NSCLC) of adenocarcinoma histology occurring in a never-smoker followed by subsequent diagnosis of metastatic SCLC carrying an EGFR mutation. Although gefitinib therapy of the primary NSCLC resulted in disease control for over 3 years, the patient subsequently developed metastatic SCLC to the liver. Epidermal growth factor receptor mutation analysis revealed that the exon 21 L858R activating mutation was present in both the original lung adenocarcinoma and the metastatic SCLC. We hypothesize that SCLC either evolved from the previously diagnosed NSCLC or that both arose from a common precursor. Further comparative molecular analysis of these histologically distinct tumors would be of value to better understand the potential role of EGFR in the pathogenesis of SCLC in never-smokers, and the role of selection for an EGFR-mutant SCLC subclone as an unusual mechanism of acquired resistance to EGFR inhibitors in NSCLC.     

Genomic Landscape and Immune Microenvironment Features of Preinvasive and Early Invasive Lung Adenocarcinoma

BackgroundUnderstanding the genomic landscape and immune microenvironment features of preinvasive and early invasive lung adenocarcinoma may provide critical insight and facilitate development of novel strategies for early detection and intervention.MethodsA total of 80 tumor tissue samples and 30 paired histologically normal lung tissue samples from 30 patients with adenocarcinoma in situ (AIS) (n = 8), minimally invasive adenocarcinoma (MIA) (n = 8), and invasive adenocarcinoma (IAC) (n = 14) were subjected to multiregion whole exome sequencing and immunohistochemistry staining for CD8 and programmed death ligand 1 (PD-L1).ResultsAll tumors, including AIS, exhibited evidence of genomic intratumor heterogeneity. Canonical cancer gene mutations in EGFR, erb-b2 receptor tyrosine kinase 2 gene (ERBB2), NRAS, and BRAF were exclusively trunk mutations detected in all regions within each tumor, whereas genes associated with cell mobility, gap junction, and metastasis were all subclonal mutations. EGFR mutation represented the most common driver alterations across AIS, MIA, and IAC, whereas tumor protein p53 gene (TP53) was identified in MIA and IAC but not in AIS. There was no difference in PD-L1 expression among AIS, MIA, and IAC, but the CD8 positivity rate was higher in IAC. Tumors positive for both PD-L1 and CD8 had a larger proportion of subclonal mutations.ConclusionsMutations in EGFR, ERBB2, NRAS, and BRAF are early clonal genomic events during carcinogenesis of lung adenocarcinoma, whereas TP53 and cell mobility, gap junction, and metastasis-related genes may be late events associated with subclonal diversification and neoplastic progression. Genomic intratumor heterogeneity and immunoediting are common and early phenomena that may have occurred before the acquisition of invasion.     

Gefitinib Combined with Cetuximab for the Treatment of Lung Adenocarcinoma Harboring the EGFR –Intergenic Region ( SEC61G ) Fusion and EGFR Amplification

EGFR fusions are rare genomic events in non‐small cell lung cancer (NSCLC), and a total of nine types have been previously reported in lung adenocarcinoma: EGFR‐RAD51, EGFR‐PURB, EGFR‐ANXA2, EGFR‐ZNF713, EGFR‐YAP1, USP42‐EGFR, EGFR‐SEPTIN14, EGFR‐TNS3, and EGFR‐ZCCHC6. EGFR fusion mutations combined with EGFR amplification are even rarer in NSCLC. The EGFR–intergenic region (IGR) fusion mutation is unreported, and thus, there are no studies targeting this fusion together with EGFR amplification in lung adenocarcinoma. Our brief study provides clinical evidence that combined targeted therapy with gefitinib and cetuximab could result in a significant antitumor response in patients with the EGFR‐IGR fusion and EGFR amplification.Key Points

• EGFR fusion mutations are rare, and EGFR fusion mutations combined with EGFR amplification are even rarer in non‐small cell lung cancer (NSCLC). To the authors’ knowledge, there is no previous report on the coexistence of the EGFR–intergenic region (IGR) fusion and EGFR amplification.
• This is the first report of a patient with NSCLC with the EGFR‐IGR fusion and EGFR amplification who achieved a significant antitumor response from treatment with gefitinib combined with cetuximab.

     

Efficacy Differences of First-line EGFR-TKIs Alone vs in Combination with Chemotherapy in Advanced Lung Adenocarcinoma Patients with Sensitive EGFR Mutation and Concomitant Non-EGFR Genetic Alterations

Background and objectiveEpidermal growth factor receptor (EGFR) mutations are often associated with non-EGFR genetic alterations, which may be a reason for the poor efficacy of EGFR tyrosine kinase inhibitors (TKIs). Here we conducted this study to explore whether EGFR-TKIs combined with chemotherapy would benefit advanced lung adenocarcinoma patients with both sensitive EGFR mutation and concomitant non-EGFR genetic alterations.Materials and methodsCases of advanced lung adenocarcinoma with EGFR mutation combined with concomitant non-EGFR genetic alterations were retrospectively collected. And the patients were required to receive first-line EGFR-TKIs and chemotherapy combination or EGFR-TKIs monotherapy. Demographic, clinical and pathological data were collected, and the electronic imaging data were retrieved to evaluate the efficacy and time of disease progression. Survival data were obtained through face-to-face or telephone follow-up. The differences between the two groups in objective response rate (ORR), disease control rate (DCR), progression-free survival (PFS) and overall survival (OS) were investigated.Results107 patients were included, including 63 cases in the combination group and 44 cases in the monotherapy group. The ORR were 78% and 50% (P=0.003), and DCR were 97% and 77% (P=0.002), respectively. At a median follow-up of 13.7 mon, a PFS event occurred in 38.1% and 81.8% of patients in the two groups, with median PFS of 18.8 mon and 5.3 mon, respectively (P < 0.000, 1). Median OS was unreached in the combination group, and 27.8 mon in the monotherapy group (P=0.31). According to the Cox multivariate regression analysis, combination therapy was an independent prognostic factor of PFS.ConclusionIn patients with EGFR-mutant advanced lung adenocarcinoma with concomitant non-EGFR genetic alterations, combination of TKIs and chemotherapy was significantly superior to EGFR-TKIs monotherapy, which should be the preferred treatment option.     

LUNG CARCINOSARCOMA A REPORT OF 15 CASES

ＬＵＮＧＣＡＲＣＩＮＯＳＡＲＣＯＭＡＡＲＥＰＯＲＴＯＦ１５ＣＡＳＥＳＸｕＺｈｉｌｏｎｇ徐志龙；ＤｉｎｇＪｉａａｎ丁嘉安；ＳｈｉＭｅｉｘｉｎ石美鑫；ＸｕＺｈｅｎｇｌａｎｇ徐正浪；ＸｉｅＸｉｕｈｕａ谢秀华（ＤｅｐａｒｔｍｅｎｔｏｆＴｈｏｒａｃｉｃ，Ｓｈａ...     

RET-Rearranged Lung Adenocarcinomas with Lymphangitic Spread,Psammoma Bodies,and Clinical Responses to Cabozantinib

Oncogenic rearrangements of the RET gene have recently been described in 1% to 2% of lung adenocarcinomas. We report five cases of RET-rearranged lung adenocarcinoma with an unusual constellation of clinical and histologic features that has not previously been described in tumors with this genomic alteration. The age at diagnosis of the five patients (4F, 1M) ranged from 44 to 77 years. All were never-smokers. Radiologically, four tumors showed lymphangitic spread within the lungs at presentation; three of these had multiple bilateral lung nodules. Histology showed psammoma bodies within the tumor in four of five cases. Molecular testing for activating EGFR mutations by standard genotyping and ALK expression by immunohistochemistry was negative in all cases. Additional molecular analysis was prompted by the clinical profile in that all five patients were never-smokers with metastatic, relapsed, and/or refractory disease; and also by unusual histologic findings in two cases. Comprehensive genomic profiling performed by means of a clinical grade cancer gene panel next-generation sequencing assay demonstrated a KIF5B-RET fusion in three; and fluorescence in-situ hybridization documented a RET rearrangement in two. Three of the patients were treated with the RET inhibitor cabozantinib. By Response Evaluation Criteria In Solid Tumors (RECIST) criteria, two had a confirmed partial response (at 6 weeks and 4 weeks) and one had stable disease. Our findings suggest that the combination of lymphangitic spread and psammoma bodies may be characteristic of a subset of advanced stage RET-rearranged lung adenocarcinomas. These findings should prompt additional molecular testing for RET translocations, particularly in never-smokers with EGFR- and ALK-negative lung adenocarcinoma.     

Potential Resistance Mechanisms Revealed by Targeted Sequencing from Lung Adenocarcinoma Patients with Primary Resistance to Epidermal Growth Factor Receptor (EGFR) Tyrosine Kinase Inhibitors (TKIs)

IntroductionEGFR tyrosine kinase inhibitors (TKIs) have greatly improved the prognosis of lung adenocarcinoma. However, approximately 5% to 10% of patients with lung adenocarcinoma with EGFR sensitive mutations have primary resistance to EGFR TKI treatment. The underlying mechanism is unknown.MethodsThis study used next-generation sequencing to explore the mechanisms of primary resistance by analyzing 11 patients with primary resistance and 11 patients sensitive to EGFR TKIs. Next-generation targeted sequencing was performed on the Illumina X platform for 483 cancer-related genes. EGFR mutation was initially detected using the amplification refractory mutation system.ResultsPotential primary resistance mechanisms were revealed by mutations unique to the EGFR TKI resistance group. Among the 11 resistant patients, 45% (five of 11) harbored a known resistance mechanism, such as MNNG HOS Transforming gene (MET) amplification de novo T790M mutation or overlapping T790M and phosphatase and tensin homolog gene (PTEN) loss and erb-b2 receptor tyrosine kinase 2 gene (ERBB2) amplification. In six of 11 resistant cases (54%), potential novel mutations that might lead to drug resistance were identified (including transforming growth factor beta receptor 1 gene [TGFBR1] mutation and/or EGFR structural rearrangement mechanistic target of rapamycin kinase gene [MTOR] mutation, transmembrane protease, serine 2 gene [TMPRSS2] fusion gene, and v-myc avian myelocytomatosis viral oncogene homolog gene [MYC] amplification). By analyzing somatic mutation patterns, the frequency of C:G→T:A transitions in the patients with primary resistance was significantly higher than that in sensitive group and occurred more frequently in the non-CpG region (Cp(A/C/T)→T).ConclusionThe mechanisms of primary resistance to EGFR TKIs may be highly heterogeneous. Mutations in EGFR and its downstream pathway, as well as mutations that affect tumor cell function, are related to primary resistance. Somatic single-nucleotide mutation patterns might be associated with primary resistance to EGFR TKIs.     

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.

Evidence That Established Lung Cancer Mortality Disparities in American Indians Are Not Due to Lung Cancer Genetic Testing and Targeted Therapy Disparities

BackgroundAmerican Indians and Alaska Natives (AI/AN) continue to experience extreme lung cancer health disparities. The state of Minnesota is home to over 70,000 AI/AN, and this population has a 2-fold increase in lung cancer mortality compared to other races within Minnesota. Genetic mutation testing in lung cancer is now a standard of high-quality lung cancer care, and EGFR mutation testing has been recommended for all adenocarcinoma lung cases, regardless of smoking status. However, genetic testing is a controversial topic for some AI/AN.Patients and MethodsWe performed a multisite retrospective chart review funded by the Minnesota Precision Medicine Grand Challenge as a demonstration project to examine lung cancer health disparities in AI/AN. We sought to measure epidemiology of lung cancer among AI receiving diagnosis or treatment in Minnesota cancer referral centers as well as rate of EGFR testing. The primary outcome was the rate of EGFR mutational analysis testing among cases and controls with nonsquamous, non–small-cell lung cancer. We secured collaborations with 5 health care systems covering a diverse geographic and demographic population.ResultsWe identified 200 cases and 164 matched controls from these sites. Controls were matched on histology, smoking status, sex, and age. In both groups, about one third of subjects with adenocarcinoma received genetic mutation testing.ConclusionThere was no significant difference in mutation testing in AI compared to non-AI controls at large health care systems in Minnesota. These data indicate that other factors are likely contributing to the higher mortality in this group.     

Aberrant large tumor suppressor 2 (LATS2) gene expression correlates with EGFR mutation and survival in lung adenocarcinomas

Background

Large tumor suppressor 2 (LATS2) gene is a putative tumor suppressor gene with potential roles in regulation of cell proliferation and apoptosis in lung cancer. The aim of this study is to explore the association of aberrant LATS2 expression with EGFR mutation and survival in lung adenocarcinoma (AD), and the effects of LATS2 silencing in both lung AD cell lines.

Methods

LATS2 mRNA and protein expression in resected lung AD were correlated with demographic characteristics, EGFR mutation and survival. LATS2-specific siRNA was transfected into four EGFR wild-type (WT) and three EGFR mutant AD cell lines and the changes in LATS2 expression and relevant signaling molecules before and after LATS2 knockdown were assayed.

Results

Fifty resected lung AD were included (M:F = 23:27, smokers:non-smokers = 19:31, EGFR mutant:wild-type = 21:29) with LATS2 mRNA levels showed no significant difference between gender, age, smoking and pathological stages while LATS2 immunohistochemical staining on an independent set of 79 lung AD showed similar trend. LATS2 mRNA level was found to be a significant independent predictor for survival status (disease-free survival RR = 0.217; p = 0.003; Overall survival RR = 0.238; p = 0.036). siRNA-mediated suppression of LATS2 expression resulted in augmentation of ERK phosphorylation in EGFR wild-type AD cell lines with high basal LATS2 expression, discriminatory modulation of Akt signaling between EGFR wild-type and mutant cells, and induction of p53 accumulation in AD cell lines with low baseline p53 levels.

Conclusions

LATS2 expression level is predictive of survival in patients with resected lung AD. LATS2 may modulate and contribute to tumor growth via different signaling pathways in EGFR mutant and wild-type tumors.     

Mutation of TP53 and Alteration of p14arf Expression in EGFR- and KRAS-Mutated Lung Adenocarcinomas

BackgroundIn lung adenocarcinoma, inactivation of the tumor suppressor p53 may abrogate a safeguard mechanism preventing the development of tumors with activating mutations in EGFR or KRAS. To assess this hypothesis, we analyzed TP53 mutations and downregulation of p14^arf, a negative regulator of p53 activated by oncogenic signals, in a retrospective series of 96 patients with primary adenocarcinoma of the lung.Patients and MethodsMutations in TP53 (exons 4-9), KRAS (exon 1), and EGFR (exons 18-21) were identified by direct sequencing of DNA from formalin-fixed, paraffin-embedded resected tumors. Expression of p14^arf was semiquantitatively evaluated by immunohistochemical analysis.ResultsTP53, KRAS, and EGFR mutations were detected in 42 of 93 (45.2%), 15 of 95 (15.8%), and 31 of 90 (34.4%) cases, respectively. Low p14^arf expression was observed in 19 of 91 cases (20.9%). Disruption of the p53/p14^arf pathway (defined as TP53 mutation or decreased p14^arf expression, or both) was observed in 18 of 31 EGFR-mutated (58.1%) tumors and in 9 of 13 KRAS-mutated (69.2%) tumors.ConclusionInactivation of the p53/p14^arf pathway is common but not systematic in EGFR- or KRAS-mutated lung adenocarcinomas. Our work highlights the need to better investigate the association between EGFR and KRAS mutations and alterations in tumor suppressor pathways.     

Concomitant EGFR mutation and ALK rearrangement in lung adenocarcinoma is more frequent than expected: Report of a case and review of the literature with demonstration of genes alteration into the same tumor cells

Oncogenic drivers in lung non-small-cell lung cancer (NSCLC) are considered mutually exclusive, but a review of the literature reveals that concomitant EGFR mutations and ALK rearrangement may occur in a subset of NSCLC. We report here a case of pulmonary adenocarcinoma with concomitant EGFR mutation in exon 21 (L858R) and ALK rearrangement in naive and relapsed tumors. Tumor cells seem to harbor both gene alterations and the patient had a long-lasting response both to EGFR inhibitor in second line and ALK inhibitor once tumor progressed. A speculative discussion on molecular mechanisms underlying this uncommon phenomenon and practical points about epidemiologic, clinicopathologic features and therapeutic options in this intriguing subset of double-positive tumor are reported.     

Effect of gefitinib on the survival of patients with recurrence of lung adenocarcinoma after surgery: A retrospective case-matching cohort study

BackgroundPatients with lung adenocarcinoma who carry epidermal growth factor receptor (EGFR) gene mutations respond remarkably well to EGFR tyrosine kinase inhibitor (EGFR-TKI), gefitinib, or erlotinib. However, the effect of EGFR-TKI treatment on the prolongation of overall survival (OS) of these patients remains uncertain, although several recent studies have shown prolongation of progression free survival compared with cytotoxic chemotherapy.MethodsA total of 304 patients with lung adenocarcinoma who had postoperative recurrent disease were studied. To eliminate potential biases as possible, the matching of four potential predictive factors of responsiveness to EGFR-TKI led to the identification of 81 pairs of patients (those who were treated with gefitinib and those who were not). A deletion mutation in exon 19 and a point mutation (L858R) in exon 21 of the EGFR gene were also analyzed. We compared the OS between the two groups.ResultsOS in the gefitinib group was significantly longer than in the control group (median, 63 vs. 41 months; p = 0.015). EGFR mutations were detected in 65 out of 129 patients (50%) in the whole sample. EGFR mutational status was not an independent prognostic factor of gefitinib benefit; rather, it was a predictive factor.ConclusionsThis study strongly suggested that gefitinib treatment improved OS of lung adenocarcinoma patients who had postoperative recurrence, especially those carrying EGFR mutations.     

Concurrence of EGFR amplification and sensitizing mutations indicate a better survival benefit from EGFR-TKI therapy in lung adenocarcinoma patients

ObjectivesTumor heterogeneity, which causes different EGFR mutation abundance, is believed to be responsible for varied progression-free survival (PFS) in lung adenocarcinoma (ADC) patients receiving EGFR-TKI treatment. Frequent EGFR amplification and its common affection in EGFR mutant allele promote the hypothesis that EGFR mutant abundance might be determined by EGFR copy number variation and therefore examination of EGFR amplification status in EGFR mutant patients could predict the efficacy of EGFR-TKI treatment.Materials and methodsIn this study, 86 lung ADC patients, who harbored EGFR activating mutations and received EGFR-TKI treatment, were examined for EGFR amplification and expression by Dual-color Silver in situ Hybridization (DISH) and immunohistochemistry analysis, respectively.Results and conclusionForty-one of 86 (47.7%) samples with EGFR activating mutations were identified with EGFR amplification. Patients with EGFR gene amplification had a significantly longer PFS than those without (16.3 vs. 9.1 months, p = 0.004). The EGFR expression was then examined by immunohistochemistry analysis. Thirty-nine of 86 (45%) tumors had EGFR overexpression, which was significantly correlated with EGFR amplification (p = 0.000). However, patients with EGFR overexpression exhibited no difference in PFS (14.1 vs. 13.3 months, p = 0.797). In conclusion, EGFR amplification occurs frequently in lung ADC patients harboring EGFR activating mutations, and could serve as an indicator for better response from EGFR-TKI treatment.     

The Incidence of EGFR-Activating Mutations in Bone Metastases of Lung Adenocarcinoma

Poor prognosis of lung adenocarcinoma is associated with early occurrence of distant metastases. This type of non-small-cell lung carcinoma more frequently involves EGFR gene abnormalities, which determine the efficacy of EGFR tyrosine kinase inhibitor therapies (EGFR TKIs). It is probable that genetic abnormalities present in primary tumor will also be present in metastases. Unfortunately little is known about the incidence of these mutations in the metastases and about the effectiveness of molecularly targeted therapy in such patients. Formalin-fixed, paraffin-embedded tumor tissue was prepared from 431 samples of primary adenocarcinoma, 61 of adenocarcinoma central nervous system (CNS) metastases and 8 of adenocarcinoma bone metastases. The presence of exon 19 deletions was examined using the PCR technique and amplified PCR product fragment length analysis. The ASP-PCR technique was used to evaluate the L858R substitutions in exon 21, and the results were analyzed using ALF Express II sequencer. In the adenocarcinoma metastases to bone obtained from 8 patients, deletions in exon 19 of the EGFR gene were revealed in 3 smoking men and one non-smoking woman, while L858R substitution in exon 21 was found in one smoking woman and one man of unknown smoking status. The incidence of EGFR gene mutations in the bone metastases was 75 %, in the primary adenocarcinoma - 12.8 %, and in the adenocarcinoma metastases to CNS - 14.75 %. Five patients with EGFR gene mutation revealed in bone metastases were treated with EGFR TKIs; the majority of them had a satisfactory response to therapy.     

Spectrum of gene mutations detected by next generation exome sequencing in brain metastases of lung adenocarcinoma

BackgroundBrain metastases (BM) are a life-threatening complication. We aimed to analyse gene mutations in lung adenocarcinoma BM.MethodsWe performed next generation sequencing (NGS) of a pre-defined set of 48 cancer-related genes in a cohort of 76 neurosurgical lung adenocarcinoma BM specimens using a cancer specific gene panel on the MiSeq platform (Illumina, San Diego, CA). NGS results were statistically correlated to patient characteristics. Data on ALK, ROS1, MET and FGFR1 gene status assessed by FISH were available from previous studies in the majority of patients.ResultsTwenty-nine (60.4%) of the 48 investigated cancer-related genes were mutated in at least one BM sample and 64 (84.2%) of the 76 BM samples carried at least one mutated gene. The number of mutated genes per sample ranged from 0 to 9 (median 2). The most commonly mutated genes were TP53, KRAS and CDKN2A, which were affected in 35/76 (46.1%), 29/76 (38.2%) and 17/76 (22.4%) samples, respectively. Other potentially druggable alterations included EGFR mutations (3/76, 3.9% of samples), PIK3CA mutation (2/76, 2.6%), BRAF mutation (1/76, 1.3%) and SMO mutation (1/76, 1.3%). Presence of KRAS mutations was associated with positive smoking history (p = 0.015, Chi square test) and presence of EGFR mutation correlated with unfavourable overall survival time from BM diagnosis (p = 0.019, log rank test).ConclusionsDeleterious gene mutations, some of them with potential therapeutic implications, are found in a high fraction of lung adenocarcinoma BM.