Co-occurrence of targetable mutations in Non-small cell lung cancer (NSCLC) patients harboring MAP2K1 mutations.

BACKGROUND: MAP2K1 mutations are rare in non-small cell lung cancer (NSCLC) and considered to be mutually exclusive from known driver mutations. Activation of the MEK1-cascade is considered pivotal in resistance to targeted therapy approaches, and MAP2K1 K57 N mutation could be linked to resistance in preclinical models. We set out this study to detect MAP2K1 mutations and potentially targetable co-mutations using a molecular multiplex approach. METHODS: Between 2012 and 2018, we routinely analyzed 14.512 NSCLC patients with two next-generation sequencing (NGS) panels. In a subset of patients, fluorescence in-situ hybridization was performed to detect rearrangements or amplifications. We assessed clinical parameters and co-occurring mutations and compared treatment outcomes of different forms of systemic therapy. RESULTS: We identified 66 (0.5%) patients with MAP2K1 mutations. Both adenocarcinoma (n = 62) and squamous cell carcinoma (n = 4) histology. The presence of the mutations was linked to smoking, and transversions were more common than transitions. K57 N was the most frequent MAP2K1 mutation (n = 25). Additional mutations were found in 57 patients (86.4%). Mutations of TP53 were detected in 33 patients, followed by KEAP1 mutations in 28.1%. 24 patients (36.4%) had either MAP2K1-only or a co-occurring aberration considered targetable, including EGFR mutations, a BRAF V600E mutation and ROS1 rearrangements. Outcome analyses revealed a trend toward benefit from pemetrexed treatment. CONCLUSION: Our analysis shows that MAP2K1-mutated NSCLC patients might frequently present with potentially targetable aberrations. Their role in providing resistance in these subtypes and the possible therapeutic opportunities justify further analyses of this rare NSCLC subgroup.

K-ras Mutation Subtypes in NSCLC and Associated Co-occuring Mutations in Other Oncogenic Pathways.

INTRODUCTION: Although KRAS mutations in NSCLC have been considered mutually exclusive driver mutations for a long time, there is now growing evidence that KRAS-mutated NSCLC represents a genetically heterogeneous subgroup. We sought to determine genetic heterogeneity with respect to cancer-related co-mutations and their correlation with different KRAS mutation subtypes. METHODS: Diagnostic samples from 4507 patients with NSCLC were analyzed by next-generation sequencing by using a panel of 14 genes and, in a subset of patients, fluorescence in situ hybridization. Next-generation sequencing with an extended panel of 14 additional genes was performed in 101 patients. Molecular data were correlated with clinical data. Whole-exome sequencing was performed in two patients. RESULTS: We identified 1078 patients with KRAS mutations, of whom 53.5% had at least one additional mutation. Different KRAS mutation subtypes showed different patterns of co-occurring mutations. Besides mutations in tumor protein p53 gene (TP53) (39.4%), serine/threonine kinase 11 gene (STK11) (19.8%), kelch like ECH associated protein 1 gene (KEAP1) (12.9%), and ATM serine/threonine kinase gene (ATM) (11.9%), as well as MNNG HOS Transforming gene (MET) amplifications (15.4%) and erb-b2 receptor tyrosine kinase 2 gene (ERBB2) amplifications (13.8%, exclusively in G12C), we found rare co-occurrence of targetable mutations in EGFR (1.2%) and BRAF (1.2%). Whole-exome sequencing of two patients with co-occurring phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha gene (PIK3CA) mutation revealed clonality of mutated KRAS in one patient and subclonality in the second, suggesting different evolutionary backgrounds. CONCLUSION: KRAS-mutated NSCLC represents a genetically heterogeneous subgroup with a high frequency of co-occurring mutations in cancer-associated pathways, partly associated with distinct KRAS mutation subtypes. This diversity might have implications for understanding the variability of treatment outcome in KRAS-mutated NSCLC and for future trial design.

Clinical and Pathological Characteristics of KEAP1- and NFE2L2-Mutated Non-Small Cell Lung Carcinoma (NSCLC).

Purpose:KEAP1 and NFE2L2 mutations are associated with impaired prognosis in a variety of cancers and with squamous cell carcinoma formation in non-small cell lung cancer (NSCLC). However, little is known about frequency, histology dependence, molecular and clinical presentation as well as response to systemic treatment in NSCLC.Experimental Design: Tumor tissue of 1,391 patients with NSCLC was analyzed using next-generation sequencing (NGS). Clinical and pathologic characteristics, survival, and treatment outcome of patients with KEAP1 or NFE2L2 mutations were assessed.Results:KEAP1 mutations occurred with a frequency of 11.3% (n = 157) and NFE2L2 mutations with a frequency of 3.5% (n = 49) in NSCLC patients. In the vast majority of patients, both mutations did not occur simultaneously. KEAP1 mutations were found mainly in adenocarcinoma (AD; 72%), while NFE2L2 mutations were more common in squamous cell carcinoma (LSCC; 59%). KEAP1 mutations were spread over the whole protein, whereas NFE2L2 mutations were clustered in specific hotspot regions. In over 80% of the patients both mutations co-occurred with other cancer-related mutations, among them also targetable aberrations like activating EGFR mutations or MET amplification. Both patient groups showed different patterns of metastases, stage distribution and performance state. No patient with KEAP1 mutation had a response on systemic treatment in first-, second-, or third-line setting. Of NFE2L2-mutated patients, none responded to second- or third-line therapy.Conclusions:KEAP1- and NFE2L2-mutated NSCLC patients represent a highly heterogeneous patient cohort. Both are associated with different histologies and usually are found together with other cancer-related, partly targetable, genetic aberrations. In addition, both markers seem to be predictive for chemotherapy resistance. Clin Cancer Res; 24(13); 3087-96. ©2018 AACR.

Clinicopathological Characteristics of RET Rearranged Lung Cancer in European Patients.

INTRODUCTION: Rearrangements of RET are rare oncogenic events in patients with non-small cell lung cancer (NSCLC). While the characterization of Asian patients suggests a predominance of nonsmokers of young age in this genetically defined lung cancer subgroup, little is known about the characteristics of non-Asian patients. We present the results of an analysis of a European cohort of patients with RET rearranged NSCLC. METHODS: Nine hundred ninety-seven patients with KRAS/EGFR/ALK wildtype lung adenocarcinomas were analyzed using fluorescence in situ hybridization for RET fusions. Tumor specimens were molecularly profiled and clinicopathological characteristics of the patients were collected. RESULTS: Rearrangements of RET were identified in 22 patients, with a prevalence of 2.2% in the KRAS/EGFR/ALK wildtype subgroup. Co-occurring genetic aberrations were detected in 10 patients, and the majority had mutations in TP53. The median age at diagnosis was 62 years (range, 39-80 years; mean ± SD, 61 ± 11.7 years) with a higher proportion of men (59% versus 41%). There was only a slight predominance of nonsmokers (54.5%) compared to current or former smokers (45.5%). CONCLUSIONS: Patients with RET rearranged adenocarcinomas represent a rare and heterogeneous NSCLC subgroup. In some contrast to published data, we see a high prevalence of current and former smokers in our white RET cohort. The significance of co-occurring aberrations, so far, is unclear.

Implementation of Amplicon Parallel Sequencing Leads to Improvement of Diagnosis and Therapy of Lung Cancer Patients.

INTRODUCTION: The Network Genomic Medicine Lung Cancer was set up to rapidly translate scientific advances into early clinical trials of targeted therapies in lung cancer performing molecular analyses of more than 3500 patients annually. Because sequential analysis of the relevant driver mutations on fixated samples is challenging in terms of workload, tissue availability, and cost, we established multiplex parallel sequencing in routine diagnostics. The aim was to analyze all therapeutically relevant mutations in lung cancer samples in a high-throughput fashion while significantly reducing turnaround time and amount of input DNA compared with conventional dideoxy sequencing of single polymerase chain reaction amplicons. METHODS: In this study, we demonstrate the feasibility of a 102 amplicon multiplex polymerase chain reaction followed by sequencing on an Illumina sequencer on formalin-fixed paraffin-embedded tissue in routine diagnostics. Analysis of a validation cohort of 180 samples showed this approach to require significantly less input material and to be more reliable, robust, and cost-effective than conventional dideoxy sequencing. Subsequently, 2657 lung cancer patients were analyzed. RESULTS: We observed that comprehensive biomarker testing provided novel information in addition to histological diagnosis and clinical staging. In 2657 consecutively analyzed lung cancer samples, we identified driver mutations at the expected prevalence. Furthermore we found potentially targetable DDR2 mutations at a frequency of 3% in both adenocarcinomas and squamous cell carcinomas. CONCLUSION: Overall, our data demonstrate the utility of systematic sequencing analysis in a clinical routine setting and highlight the dramatic impact of such an approach on the availability of therapeutic strategies for the targeted treatment of individual cancer patients.

ROS1 rearrangements in lung adenocarcinoma: prognostic impact, therapeutic options and genetic variability.

BACKGROUND: While recent data show that crizotinib is highly effective in patients with ROS1 rearrangement, few data is available about the prognostic impact, the predictive value for different treatments, and the genetic heterogeneity of ROS1-positive patients. PATIENTS AND METHODS: 1137 patients with adenocarcinoma of the lung were analyzed regarding their ROS1 status. In positive cases, next-generation sequencing (NGS) was performed. Clinical characteristics, treatments and outcome of these patients were assessed. Overall survival (OS) was compared with genetically defined subgroups of ROS1-negative patients. RESULTS: 19 patients of 1035 evaluable (1.8%) had ROS1-rearrangement. The median OS has not been reached. Stage IV patients with ROS1-rearrangement had the best OS of all subgroups (36.7 months, p < 0.001). 9 of 14 (64.2%) patients had at least one response to chemotherapy. Estimated mean OS for patients receiving chemotherapy and crizotinib was 5.3 years. Ten patients with ROS1-rearrangement (52.6%) harbored additional aberrations. CONCLUSION: ROS1-rearangement is not only a predictive marker for response to crizotinib, but also seems to be the one of the best prognostic molecular markers in NSCLC reported so far. In stage IV patients, response to chemotherapy was remarkable high and overall survival was significantly better compared to other subgroups including EGFR-mutated and ALK-fusion-positive NSCLC.

PIK3CA mutations in non-small cell lung cancer (NSCLC): genetic heterogeneity, prognostic impact and incidence of prior malignancies.

BACKGROUND: Somatic mutations of the PIK3CA gene have been described in non-small cell lung cancer (NSCLC), but limited data is available on their biological relevance. This study was performed to characterize PIK3CA-mutated NSCLC clinically and genetically. PATIENTS AND METHODS: Tumor tissue collected consecutively from 1144 NSCLC patients within a molecular screening network between March 2010 and March 2012 was analyzed for PIK3CA mutations using dideoxy-sequencing and next-generation sequencing (NGS). Clinical, pathological, and genetic characteristics of PIK3CA-mutated patients are described and compared with a control group of PIK3CA-wildtype patients. RESULTS: Among the total cohort of 1144 patients we identified 42 (3.7%) patients with PIK3CA mutations in exon 9 and exon 20. These mutations were found with a higher frequency in sqamous cell carcinoma (8.9%) compared to adenocarcinoma (2.9%, p<0.001). The most common PIK3CA mutation was exon 9 E545K. The majority of patients (57.1%) had additional oncogenic driver aberrations. With the exception of EGFR-mutated patients, non of the genetically defined subgroups in this cohort had a significantly better median overall survival. Further, PIK3CA-mutated patients had a significantly higher incidence of malignancy prior to lung cancer (p<0.001). CONCLUSION: PIK3CA-mutated NSCLC represents a clinically and genetically heterogeneous subgroup in adenocarcinomas as well as in squamous cell carcinomas with a higher prevalence of these mutations in sqamous cell carcinoma. PIK3CA mutations have no negative impact on survival after surgery or systemic therapy. However, PIK3CA mutated lung cancer frequently develops in patients with prior malignancies.

MET amplification status in therapy-naïve adeno- and squamous cell carcinomas of the lung.

PURPOSE: MET is a potential therapeutic target in lung cancer and both MET tyrosine kinase inhibitors and monoclonal antibodies have entered clinical trials. MET signaling can be activated by various mechanisms, including gene amplification. In this study, we aimed to investigate MET amplification status in adeno- and squamous cell carcinomas of the lung. We propose clearly defined amplification scores and provide epidemiologic data on MET amplification in lung cancer. EXPERIMENTAL DESIGN: We evaluated the prevalence of increased MET gene copy numbers in 693 treatment-naïve cancers by FISH, defined clear cutoff criteria, and correlated FISH results to MET IHC. RESULTS: Two thirds (67%) of lung cancers do not have gains in MET gene copy numbers, whereas 3% show a clear-cut high-level amplification (MET/centromer7 ratio ≥2.0 or average gene copy number per nucleus ≥6.0 or ≥10% of tumor cells containing ≥15 MET copies). The remaining cases can be subdivided into intermediate- (6%) and low-level gains (24%). Importantly, MET amplifications occur at equal frequencies in squamous and adenocarcinomas without or with EGFR or KRAS mutations. CONCLUSION: MET amplification is not a mutually exclusive genetic event in therapy-naïve non-small cell lung cancer. Our data suggest that it might be useful to determine MET amplification (i) before EGFR inhibitor treatment to identify possible primary resistance to anti-EGFR treatment, and (ii) to select cases that harbor KRAS mutations additionally to MET amplification and, thus, may not benefit from MET inhibition. Furthermore, our study provides comprehensive epidemiologic data for upcoming trials with various MET inhibitors.

Definition of a fluorescence in-situ hybridization score identifies high- and low-level FGFR1 amplification types in squamous cell lung cancer.

We recently reported fibroblast growth factor receptor-type 1 (FGFR1) amplification to be associated with therapeutically tractable FGFR1 dependency in squamous cell lung cancer. This makes FGFR1 a novel target for directed therapy in these tumors. To reproducibly identify patients for clinical studies, we developed a standardized reading and evaluation strategy for FGFR1 fluorescence in-situ hybridization (FISH) and propose evaluation criteria, describe different patterns of low- and high-level amplifications and report on the prevalence of FGFR1 amplifications in pulmonary carcinomas. A total of 420 lung cancer patients including 307 squamous carcinomas, 100 adenocarcinomas of the lung and 13 carcinomas of other types were analyzed for FGFR1 amplification using a dual color FISH. We found heterogeneous and different patterns of gene copy numbers. FGFR1 amplifications were observed in 20% of pulmonary squamous carcinomas but not in adenocarcinomas. High-level amplification (as defined by an FGFR1/centromer 8 (CEN8) ratio ≥2.0, or average number of FGFR1 signals per tumor cell nucleus ≥6, or the percentage of tumor cells containing ≥15 FGFR1 signals or large clusters ≥10%) was detected at a frequency of 16% and low-level amplification (as defined by ≥5 FGFR1 signals in ≥50% of tumor cells) at a frequency of 4%. We conclude that FGFR1 amplification is one of the most frequent therapeutically tractable genetic lesions in pulmonary carcinomas. Standardized reporting of FGFR1 amplification in squamous carcinomas of the lung will become increasingly important to correlate therapeutic responses with FGFR1 inhibitors in clinical studies. Thus, our reading and evaluation strategy might serve as a basis for identifying patients for ongoing and upcoming clinical trials.

Rationale for treatment of metastatic squamous cell carcinoma of the lung using fibroblast growth factor receptor inhibitors.

BACKGROUND: We previously identified amplification of the fibroblast growth factor receptor 1 gene (FGFR1) as a potential therapeutic target for small-molecule inhibitor therapy in squamous cell lung cancer (L-SCC). Currently, clinical phase I trials are underway to examine whether patients with FGFR1-amplified L-SCC benefit from a targeted therapy approach using small-molecule inhibitors. Because most patients with lung cancer present with metastatic disease, we investigated whether lymph node metastases in L-SCC share the FGFR1 amplification status of their corresponding primary tumor. METHODS: The study cohort consisted of 72 patients with L-SCC, 39 with regional lymph node metastases. Tissue microarrays were constructed from formalin-fixed, paraffin-embedded tissue of the primary tumors and, where present, of the corresponding lymph node metastasis. A biotin-labeled target probe spanning the FGFR1 locus (8p11.22-23) was used to determine the FGFR1 amplification status by fluorescence in situ hybridization. RESULTS: FGFR1 amplification was detected in 16% (12 of 72) of all primary L-SCCs. In metastatic tumors, 18% (seven of 39) of the lymph node metastases displayed FGFR1 amplification with an exact correlation of FGFR1 amplification status between tumor and metastatic tissue. CONCLUSIONS: FGFR1 amplification is a common genetic event occurring at a frequency of 16% in L-SCCs. Moreover, lymph node metastases derived from FGFR1-amplified L-SCCs also exhibit FGFR1 amplification. Therefore, we suggest that the FGFR1 amplification is a clonal event in tumor progression. Beyond this biologically relevant observation, the findings carry potential therapeutic implications in that small-molecule inhibitors may be applicable to the treatment of a subset of patients with metastatic L-SCC.