Comparison of MET gene amplification analysis by next-generation sequencing and fluorescence in situ hybridization

MET gene alterations are known to be involved in acquired resistance to epidermal growth factor receptor inhibition. MET amplifications present a potential therapeutic target in non-small cell lung cancer. Although next-generation sequencing (NGS) and fluorescence in situ hybridization (FISH) are conventionally used to assess MET amplifications, there are currently no clinically defined cut-off values for NGS, with FISH still being the gold standard. A collective of 20 formalin-fixed paraffin-embedded lung cancer tissue samples (mean age 64 years) were selected based on increased MET gene copy number (CNV) status or the presence of mutations detected by NGS (GeneReader, QIAGEN) and were further assessed by FISH (MET/CEN7, Zytomed). Of these, 17 tumor samples were MET-amplified and one patient was found to have a MET rearrangement by NGS, while two samples had no MET gene alteration. In contrast to the NGS result, FISH analysis showed only one highly amplified sample and 19 negative samples. The single highly amplified case detected by FISH was also positive by NGS with a fold change (FC) of 3.18 and a mean copy number (CN_{MV 10−100%}) of 20.5. Therefore, for the assessment of MET amplifications using the QIAGEN NGS workflow, we suggest detecting amplified cases with an FC value of ≥ 3.0 and a CN_{MV 10−100%} value of ≥ 20.0 by FISH. In summary, NGS allows for DNA- and RNA-based analysis of specific MET gene amplifications, point mutations or rearrangements.

Durable Response to Crizotinib in a Patient with Pulmonary Adenocarcinoma Harboring MET Intron 14 Mutation: A Case Report

Background

For patients with non-epidermal non–small-cell lung cancer (NSCLC), molecular alterations should always be investigated, especially in non-smokers, who have a very high frequency of targetable alterations (EGFR 52%; ALK 8% in particular). MET exon 14 alterations are identified in 3–4% of NSCLCs and MET gene amplification and high protein expression are associated with a poor prognosis. The French recommendations only authorize the use of capmatinib and crizotinib if the mutation concerns exon 14. However, several different types of mutation in exon 14 of MET and its flanking introns can induce a jump in exon 14, activate the MET gene and thus be sensitive to anti-MET tyrosine kinase inhibitors.

Case Summary

This case concerns a 76-year-old Caucasian male with a medical history including idiopathic thrombocytopenic purpura, chronic myelomonocytic leukemia (CMML), atrial fibrillation, arterial hypertension, obesity (BMI 36kg/m2), and a 5–10 pack-per-year smoking history. A left upper lobe pulmonary nodule of 12.4 mm was discovered in March 2019. The patient received adjuvant chemotherapy with carboplatin AUC 5 and vinorelbine 25.00 mg/m2. At the end of the adjuvant treatment, the patient was in complete remission for 5 months. In February 2020, the CT scan revealed a mediastinal lymph node progression. A complementary molecular analysis was realized on the initial surgical specimen. A c.3082+3A>T mutation in the MET gene was identified. This mutation confers susceptibility to anti-MET tyrosine kinase inhibitors. Treatment with crizotinib was initiated with an initial dose of 250 mg/day for 15 days and then increased to 250 mg twice a day. After 7 months of treatment with crizotinib, the disease was still stable according to RECIST 1.1.

Conclusion

We report here the original case of a patient presenting a lung adenocarcinoma with an intron 14 mutation and having a durable TKI response.

Analyzing biological and molecular characteristics and genomic damage induced by exposure to asbestos

Asbestos is one of the most important occupational carcinogens. Currently, about 125 million people worldwide are exposed to asbestos in the workplace. According to global estimates, at least 107,000 people die each year from lung cancer, mesothelioma, and asbestosis as a result of occupational exposure to asbestos. The high pathogenicity of this material is currently known, being associated with the development of pulmonary diseases, of which lung cancer is the main cause of death due to exposure to this mineral. Pulmonary diseases related to asbestos are a common clinical problem and a major health concern worldwide. Extensive research has identified many important pathogenic mechanisms; however, the precise molecular mechanisms involved, and the generated genomic damage that lead to the development of these diseases, are not completely understood. The modes of action that underlie this type of disease seem to differ depending on the type of fiber, lung clearance, and genetics. This evidences the need to increase our knowledge about these effects on human health. This review focuses on the characteristics of asbestos and the cellular and genomic damage generated in humans via exposure.

Prognostic value of MET copy number gain in non-small-cell lung cancer: an updated meta-analysis

The alterations of MET have been detected in non-small-cell lung cancer (NSCLC). However, the prognostic impact of MET gene copy number gain (CNG) has not been consistent among studies. We performed this meta-analysis to evaluate the prognostic value of high MET CNG in patients with NSCLC. A systematic computerized search of the electronic databases including PubMed, EMBASE, Google scholar, and Cochrane Library (up to November 2017) was carried out. From twenty-one studies, 7,647 patients were included in the pooled analysis of hazard ratios (HRs) with 95% confidence intervals (CIs) for disease-free survival or overall survival. Compared with patients with NSCLC showing low MET CNG, those with tumors harboring high MET CNG showed significantly worse survival (HR = 1.45, 95% CI: 1.16-1.80, p = 0.001). Subgroup analyses showed that high MET CNG significantly correlated with a poor prognosis especially in patients with adenocarcinoma (HR = 1.41, 95% CI: 1.11-1.79, p = 0.005) and Asian populations (HR = 1.58, 95% CI: 1.32-1.88, p < 0.00001).

In conclusion, this meta-analysis indicates that high MET CNG is an adverse prognostic factor in patients with NSCLC. Subgroup analyses suggest that high MET CNG is associated with a worse prognosis, especially in patients with adenocarcinoma and Asian populations. However, large prospective studies using standardized methods based on the homogeneous populations are warranted to validate the prognostic value of MET amplification in patients with NSCLC.

Updated Molecular Testing Guideline for the Selection of Lung Cancer Patients for Treatment With Targeted Tyrosine Kinase Inhibitors: Guideline From the College of American Pathologists, the International Association for the Study of Lung Cancer, and the Association for Molecular Pathology

CONTEXT

- In 2013, an evidence-based guideline was published by the College of American Pathologists, the International Association for the Study of Lung Cancer, and the Association for Molecular Pathology to set standards for the molecular analysis of lung cancers to guide treatment decisions with targeted inhibitors. New evidence has prompted an evaluation of additional laboratory technologies, targetable genes, patient populations, and tumor types for testing.

OBJECTIVE

- To systematically review and update the 2013 guideline to affirm its validity; to assess the evidence of new genetic discoveries, technologies, and therapies; and to issue an evidence-based update.

DESIGN

- The College of American Pathologists, the International Association for the Study of Lung Cancer, and the Association for Molecular Pathology convened an expert panel to develop an evidence-based guideline to help define the key questions and literature search terms, review abstracts and full articles, and draft recommendations.

RESULTS

- Eighteen new recommendations were drafted. The panel also updated 3 recommendations from the 2013 guideline.

CONCLUSIONS

- The 2013 guideline was largely reaffirmed with updated recommendations to allow testing of cytology samples, require improved assay sensitivity, and recommend against the use of immunohistochemistry for EGFR testing. Key new recommendations include ROS1 testing for all adenocarcinoma patients; the inclusion of additional genes ( ERBB2, MET, BRAF, KRAS, and RET) for laboratories that perform next-generation sequencing panels; immunohistochemistry as an alternative to fluorescence in situ hybridization for ALK and/or ROS1 testing; use of 5% sensitivity assays for EGFR T790M mutations in patients with secondary resistance to EGFR inhibitors; and the use of cell-free DNA to "rule in" targetable mutations when tissue is limited or hard to obtain.

Updated Molecular Testing Guideline for the Selection of Lung Cancer Patients for Treatment With Targeted Tyrosine Kinase Inhibitors: Guideline From the College of American Pathologists, the International Association for the Study of Lung Cancer, and the Association for Molecular Pathology

CONTEXT

In 2013, an evidence-based guideline was published by the College of American Pathologists, the International Association for the Study of Lung Cancer, and the Association for Molecular Pathology to set standards for the molecular analysis of lung cancers to guide treatment decisions with targeted inhibitors. New evidence has prompted an evaluation of additional laboratory technologies, targetable genes, patient populations, and tumor types for testing.

OBJECTIVE

To systematically review and update the 2013 guideline to affirm its validity; to assess the evidence of new genetic discoveries, technologies, and therapies; and to issue an evidence-based update.

DESIGN

The College of American Pathologists, the International Association for the Study of Lung Cancer, and the Association for Molecular Pathology convened an expert panel to develop an evidence-based guideline to help define the key questions and literature search terms, review abstracts and full articles, and draft recommendations.

RESULTS

Eighteen new recommendations were drafted. The panel also updated 3 recommendations from the 2013 guideline.

CONCLUSIONS

The 2013 guideline was largely reaffirmed with updated recommendations to allow testing of cytology samples, require improved assay sensitivity, and recommend against the use of immunohistochemistry for EGFR testing. Key new recommendations include ROS1 testing for all adenocarcinoma patients; the inclusion of additional genes (ERBB2, MET, BRAF, KRAS, and RET) for laboratories that perform next-generation sequencing panels; immunohistochemistry as an alternative to fluorescence in situ hybridization for ALK and/or ROS1 testing; use of 5% sensitivity assays for EGFR T790M mutations in patients with secondary resistance to EGFR inhibitors; and the use of cell-free DNA to "rule in" targetable mutations when tissue is limited or hard to obtain.

Updated Molecular Testing Guideline for the Selection of Lung Cancer Patients for Treatment With Targeted Tyrosine Kinase Inhibitors: Guideline From the College of American Pathologists, the International Association for the Study of Lung Cancer, and the Association for Molecular Pathology

CONTEXT

In 2013, an evidence-based guideline was published by the College of American Pathologists, the International Association for the Study of Lung Cancer, and the Association for Molecular Pathology to set standards for the molecular analysis of lung cancers to guide treatment decisions with targeted inhibitors. New evidence has prompted an evaluation of additional laboratory technologies, targetable genes, patient populations, and tumor types for testing.

OBJECTIVE

To systematically review and update the 2013 guideline to affirm its validity; to assess the evidence of new genetic discoveries, technologies, and therapies; and to issue an evidence-based update.

DESIGN

The College of American Pathologists, the International Association for the Study of Lung Cancer, and the Association for Molecular Pathology convened an expert panel to develop an evidence-based guideline to help define the key questions and literature search terms, review abstracts and full articles, and draft recommendations.

RESULTS

Eighteen new recommendations were drafted. The panel also updated 3 recommendations from the 2013 guideline.

CONCLUSIONS

The 2013 guideline was largely reaffirmed with updated recommendations to allow testing of cytology samples, require improved assay sensitivity, and recommend against the use of immunohistochemistry for EGFR testing. Key new recommendations include ROS1 testing for all adenocarcinoma patients; the inclusion of additional genes (ERBB2, MET, BRAF, KRAS, and RET) for laboratories that perform next-generation sequencing panels; immunohistochemistry as an alternative to fluorescence in situ hybridization for ALK and/or ROS1 testing; use of 5% sensitivity assays for EGFR T790M mutations in patients with secondary resistance to EGFR inhibitors; and the use of cell-free DNA to "rule in" targetable mutations when tissue is limited or hard to obtain.

MET amplification assessed using optimized FISH reporting criteria predicts early distant metastasis in patients with non-small cell lung cancer

To investigate the prognostic impact of MET copy number (MET-CN) in patients with non-small cell lung cancer (NSCLC), we retrospectively reviewed clinical and pathologic data of NSCLC patients whose tumors were assessed for MET-CN using fluorescence in situ hybridization (FISH). We correlated MET-CN status with patient overall survival (OS) and optimized MET-FISH reporting criteria. The study group included 384 patients with NSCLC of which 88% were adenocarcinoma and 55.7% of patients had distant metastases. There were 170 patients with stages I-III and 214 patients with stage IV disease. Based on the MET-CN and MET/CEP7 ratio the patients were classified into 3 categories: MET-amplification (METamp): MET/CEP7 ≥ 2 or MET-CN ≥ 5; MET-CN-gain (METcng): MET-CN ≥ 4 to < 5; and MET-negative (METneg): MET-CN < 4. METamp was associated with high fatality (P=.036) and stage IV tumors (P=.038). In patients with stages I-III NSCLC, patients in the METamp category had the shortest OS (P=.015) and more often developed distant metastases within 1 year (P=.004). In patients with stage IV tumors, METamp did not further impact the OS. Patients in the METcng category had the longest OS (P=.053). Multivariate analysis confirmed METamp to be an independent high-risk factor (HR 3.26; P=.026) and predicted earlier progression to distant metastasis (HR 4.86; P=.001). In conclusion, we suggest that the MET-FISH criteria presented optimizes risk stratification by defining 3 categories of NSCLC patients. METamp is an independent risk factor predicting early distant metastasis and patients with METcng could represent a lower-risk group.

Clinicopathological significance and concordance analysis of c-MET immunohistochemistry in non-small cell lung cancers: A meta-analysis

OBJECTIVE

The aim of this study was to investigate the clinicopathological significance and concordance rate of c-MET immunohistochemistry (IHC) in non-small cell lung cancer (NSCLC) through meta-analysis and diagnostic test accuracy review.

METHODS

The current study included 4454 NSCLC cases of 22 eligible studies. The meta-analysis examined the correlation between c-MET IHC expression and clinicopathological parameters. We investigated concordance rate between c-MET IHC and genetic alteration and performed subgroup analysis based on c-MET IHC cut-off value.

RESULTS

The estimated positive rate of c-MET IHC was 0.440 (95% confidence interval [CI] 0.355-0.529). The positive rate of c-MET IHC was significantly high in non-squamous cell carcinomas and tumors with stage III-IV. However, there was no significant difference between c-MET IHC positivity and sex, smoking, and lymph node metastasis. The c-MET IHC positivity was significantly correlated with poor overall survival (hazard ratio 1.551, 95% CI 1.101-2.184). In c-MET IHC-positive and negative groups, the concordance rate was 0.941 (95% CI 0.885-0.971) and 0.300 (95% CI 0.196-0.429), respectively. The pooled sensitivity and specificity of the high cut-off subgroup for c-MET IHC was 1.00 (95% CI 0.92-1.00) and 0.78 (95% CI 0.75-0.81), respectively. The diagnostic odds ratio and the area under curve on summary receiver operating characteristic curve were 76.56 (95% CI 8.23-712.41) and 0.9949, respectively.

CONCLUSION

The c-MET IHC could be useful for screening of c-MET genetic alteration in NSCLC patients. Detailed criteria for c-MET IHC evaluation are necessary to determine how to best apply this approach in daily practice.

Prognostic value of MET protein overexpression and gene amplification in locoregionally advanced nasopharyngeal carcinoma

This study assessed the incidence and prognostic value of MET protein overexpression and gene amplification in locoregionally advanced nasopharyngeal carcinoma (NPC). Specimens from 376 consecutive patients with locoregionally advanced NPC were subjected to immunohistochemistry to analyze MET protein expression and fluorescence in situ hybridization to assess MET amplification status. In total, 139/376 (37.0%) patients had MET protein overexpression; of whom, 7/139 (5.0%) had MET amplification. MET overexpression was significantly associated with locoregional failure (P = 0.009), distant metastasis (P = 0.006) and death (P < 0.001); MET amplification was significantly associated with death (P = 0.021). A positive correlation was observed between MET copy number status and MET protein expression (r = 0.629, P < 0.001). Multivariate analysis demonstrated MET overexpression was an independent prognostic factor for overall survival (OS; HR, 1.99; 95% CI, 1.38-2.87; P < 0.001) and disease-free survival (DFS; HR, 1.85; 95% CI, 1.33-2.57; P < 0.001), and MET amplification was independently associated with poorer OS (HR, 4.24; 95% CI, 1.78-10.08; P < 0.001) and DFS (HR, 5.44; 95% CI, 2.44-12.09; P < 0.001). In conclusion, MET protein overexpression and gene amplification are independent prognostic factors for OS and DFS in locoregionally advanced nasopharyngeal carcinoma, and may provide therapeutic biomarkers to identify patients in whom MET inhibitors may be beneficial.

Membranous Insulin-like Growth Factor-1 Receptor (IGF1R) Expression Is Predictive of Poor Prognosis in Patients with Epidermal Growth Factor Receptor (EGFR)-Mutant Lung Adenocarcinoma

BACKGROUND

Insulin-like growth factor-1 receptor (IGF1R) is a membrane receptor-type tyrosine kinase that has attracted considerable attention as a potential therapeutic target, although its clinical significance in non-small cell lung cancer (NSCLC) is controversial. This study aimed to clarify the clinical significance of IGF1R expression in human NSCLC.

METHODS

IGF1R protein expression was evaluated using immunohistochemistry in 372 patients with NSCLC who underwent curative surgical resection (146 squamous cell carcinomas [SqCCs] and 226 adenocarcinomas [ADCs]). We then analyzed correlations between expression of IGF1R and clinicopathological and molecular features and prognostic significance.

RESULTS

Membranous and cytoplasmic IGF1R expression were significantly higher in SqCCs than in ADCs. In patients with SqCC, membranous IGF1R expression was associated with absence of vascular, lymphatic, and perineural invasion; lower stage; and better progression-free survival (PFS) (hazard ratio [HR], 0.586; p = .040). In patients with ADC, IGF1R expression did not have a significant prognostic value; however, in the subgroup of epidermal growth factor receptor (EGFR)-mutant ADC, membranous IGF1R expression was associated with lymphatic and perineural invasion, solid predominant histology, and higher cancer stage and was significantly associated with worse PFS (HR, 2.582; p = .009).

CONCLUSIONS

Lung ADC and SqCC showed distinct IGF1R expression profiles that demonstrated prognostic significance. High membranous IGF1R expression was predictive of poor PFS in EGFR-mutant lung ADC, while it was predictive of better PFS in SqCC. These findings will help improve study design for subsequent investigations and select patients for future anti-IGF1R therapy.

Clinical and prognostic value of MET gene copy number gain and chromosome 7 polysomy in primary colorectal cancer patients

We aimed to explore the clinical and prognostic influence of numeric alterations of MET gene copy number (GCN) and chromosome 7 (CEP7) CN in colorectal cancer (CRC) patients. MET GCN and CEP7 CN were investigated in tissue arrayed tumors from 170 CRC patients using silver in situ hybridization (SISH). MET GCN gain was defined as ≥4 copies of MET, and CEP7 polysomy was prespecified as ≥3 copies of CEP7. Additionally, MET messenger RNA (mRNA) transcription was evaluated using mRNA ISH and compared with MET GCN. MET GCN gain was observed in 14.7 % (25/170), which correlated with advanced stage (P = 0.037), presence of distant metastasis (P = 0.006), and short overall survival (OS) (P = 0.009). In contrast, CEP7 polysomy was found in 6.5 % (11/170), which was related to tumor location in the left colon (P = 0.027) and poor OS (P = 0.029). MET GCN positively correlated with CEP7 CN (R = 0.659, P < 0.001) and mRNA transcription (R = 0.239, P = 0.002). Of note, MET GCN gain and CEP7 polysomy were also associated with poor OS (P = 0.016 and P < 0.001, respectively) in stage II/III CRC patients (n = 123). In multivariate analysis, CEP7 polysomy was an independent prognostic factor for poor OS in all patients (P = 0.009; hazard ratio [HR], 2.220; 95 % confidence interval [CI], 1.233-3.997) and in stage II/III CRC patients (P < 0.001; HR, 20.781; 95 % CI, 4.600-93.882). MET GCN gain and CEP7 polysomy could predict a poor outcome in CRC patients, especially CEP7 polysomy has the most powerful prognostic impact in stage II/III CRC patients.

Prognostic and predictive value of MET deregulation in non-small cell lung cancer

Recent progress in cancer biology has led to the discovery of increasing number of oncogene alterations that have dramatically changed the paradigm of lung cancer treatment. MET is a tyrosine kinase receptor for the hepatocyte growth factor (HGF) that is deregulated in several malignancies, including non-small cell lung cancer (NSCLC). Abnormal MET-HGF signaling pathway activation can occur via different mechanisms, including HGF and/or MET overexpression, MET gene amplification, mutations or rearrangements. MET protein overexpression and increased MET gene number have been identified as poor prognostic factors in several series of surgically resected NSCLC making this receptor an attractive target for cancer treatment. Several clinical trials have recently evaluated the activity of a variety of anti-MET strategies in NSCLC patients with or without molecular selection with a variable degree of success, underscoring the need of establishing the best predictive biomarker for the identification of responding patients.

Parallel screening for ALK, MET and ROS1 alterations in non-small cell lung cancer with implications for daily routine testing

OBJECTIVES

ALK, MET and ROS1 are prognostic and predictive markers in NSCLC, which need to be implemented in daily routine. To evaluate different detection approaches and scoring systems for optimal stratification of patients eligible for mutation testing in the future, we screened a large and unselected cohort of NSCLCs for all three alterations.

MATERIAL AND METHODS

Using tissue microarrays, 473 surgically resected NSCLCs were tested for ALK and MET expression by IHC and genomic alterations in the ALK, MET and ROS1 gene by FISH. For MET IHC, two different criteria (MetMAb and H-score), for MET FISH, three different scoring systems (UCCC, Cappuzzo, PathVysion) were investigated.

RESULTS

ALK and ROS1 positivity was seen in 2.6% and 1.3% of all ADCs, respectively, but not in pure SCCs. One ROS1 translocated tumor showed additional ROS1 amplification. MET IHC+/FISH+ cases were found in both histological subtypes (8.6% in all NSCLCs; 10.6% in ADCs; 5.0% in SCCs) and were associated with pleural invasion, lymphatic vessel invasion and lymph node metastasis. MET altered ADCs more frequently showed a papillary growth pattern. Whereas ALK testing revealed homogenous results in IHC and FISH, we saw discordant results for MET in about 10% of cases. Both METIHC scoring systems revealed almost identical results. We did not encounter any combined FISH positivity for ALK, MET or ROS1. However, three ALK positive cases harbored MET overexpression.

CONCLUSION

In daily routine, IHC could support FISH in the identification of ALK altered NSCLCs. Further research is needed to assess the role of discordant MET results by means of IHC and FISH as well as the relevance of tumors with an increased ROS1 gene copy number.

Increased MET Gene Copy Number but Not mRNA Level Predicts Postoperative Recurrence in Patients with Non-Small Cell Lung Cancer

The aim of the present study was to investigate the relationship of MET copy number (CN) and MET mRNA expression to other molecular alterations, clinicopathologic characteristics, and survival of patients with resected non–small cell lung cancer. One hundred fifty-one paired surgical samples of tumor and tumor-distant normal lung tissues were analyzed by comparative quantitative polymerase chain reaction (PCR) methods with commercially available assays and the CopyCaller software v. 1.0 for post-PCR data processing (downloadable from www.appliedbiosystems.com). MET copy gain (set as more than 3.0 copies per cell) was found in 18.5% of the samples and occurred more frequently in the adenocarcinomas (ADCs) with an increased epidermal growth factor receptor (EGFR) or human epidermal growth factor receptor 2 (HER2) CN (P = .001 and .030 for EGFR and HER2, respectively) and in the ADCs with EGFR activating mutations (P = .051) but did not correlate with KRAS dosage or mutational status. MET mRNA level was 1.76-fold higher [95% confidence interval (CI), 1.29-2.40] in the tumor compared to unaffected lung tissue and associated significantly with MET CN (beta coefficient, 1.51; 95% CI, 1.22-1.87; P < .001). In the multivariable analysis, patients diagnosed with ADC with increased MET CN had a significantly higher risk of disease recurrence (hazard ratio, 1.76; 95% CI, 1.20-2.57; P = .004). An increased MET CN in combination with histologic type appears to be a prognostic factor in patients with ADC after a curative surgery.

MET gene copy number predicts worse overall survival in patients with non-small cell lung cancer (NSCLC); a systematic review and meta-analysis

Objectives

MET is a receptor present in the membrane of NSCLC cells and is known to promote cell proliferation, survival and migration. MET gene copy number is a common genetic alteration and inhibition o MET emerges as a promising targeted therapy in NSCLC. Here we aim to combine in a meta-analysis, data on the effect of high MET gene copy number on the overall survival of patients with resected NSCLC.

Methods

Two independent investigators applied parallel search strategies with the terms “MET AND lung cancer”, “MET AND NSCLC”, “MET gene copy number AND prognosis” in PubMed through January 2014. We selected the studies that investigated the association of MET gene copy number with survival, in patients who received surgery.

Results

Among 1096 titles that were identified in the initial search, we retrieved 9 studies on retrospective cohorts with adequate retrievable data regarding the prognostic impact of MET gene copy number on the survival of patients with NSCLC. Out of those, 6 used FISH and the remaining 3 used RT PCR to assess the MET gene copy number in the primary tumor. We calculated the I² statistic to assess heterogeneity (I² = 72%). MET gene copy number predicted worse overall survival when all studies were combined in a random effects model (HR = 1.78, 95% CI 1.22–2.60). When only the studies that had at least 50% of adenocarcinoma patients in their populations were included, the effect was significant (five studies, HR 1.55, 95% CI 1.23–1.94). This was not true when we included only the studies with no more than 50% of the patients having adenocarcinoma histology (four studies HR 2.18, 95% CI 0.97–4.90).

Conclusions

Higher MET gene copy number in the primary tumor at the time of diagnosis predicts worse outcome in patients with NSCLC. This prognostic impact may be adenocarcinoma histology specific.