Heterogeneous Mechanisms of Primary and Acquired Resistance to Third-Generation EGFR Inhibitors.

PURPOSE: To identify novel mechanisms of resistance to third-generation EGFR inhibitors in patients with lung adenocarcinoma that progressed under therapy with either AZD9291 or rociletinib (CO-1686). EXPERIMENTAL DESIGN: We analyzed tumor biopsies from seven patients obtained before, during, and/or after treatment with AZD9291 or rociletinib (CO-1686). Targeted sequencing and FISH analyses were performed, and the relevance of candidate genes was functionally assessed in in vitro models. RESULTS: We found recurrent amplification of either MET or ERBB2 in tumors that were resistant or developed resistance to third-generation EGFR inhibitors and show that ERBB2 and MET activation can confer resistance to these compounds. Furthermore, we identified a KRASG12S mutation in a patient with acquired resistance to AZD9291 as a potential driver of acquired resistance. Finally, we show that dual inhibition of EGFR/MEK might be a viable strategy to overcome resistance in EGFR-mutant cells expressing mutant KRAS CONCLUSIONS: Our data suggest that heterogeneous mechanisms of resistance can drive primary and acquired resistance to third-generation EGFR inhibitors and provide a rationale for potential combination strategies. Clin Cancer Res; 22(19); 4837-47. ©2016 AACR.

Comprehensive genomic profiles of small cell lung cancer.

We have sequenced the genomes of 110 small cell lung cancers (SCLC), one of the deadliest human cancers. In nearly all the tumours analysed we found bi-allelic inactivation of TP53 and RB1, sometimes by complex genomic rearrangements. Two tumours with wild-type RB1 had evidence of chromothripsis leading to overexpression of cyclin D1 (encoded by the CCND1 gene), revealing an alternative mechanism of Rb1 deregulation. Thus, loss of the tumour suppressors TP53 and RB1 is obligatory in SCLC. We discovered somatic genomic rearrangements of TP73 that create an oncogenic version of this gene, TP73Δex2/3. In rare cases, SCLC tumours exhibited kinase gene mutations, providing a possible therapeutic opportunity for individual patients. Finally, we observed inactivating mutations in NOTCH family genes in 25% of human SCLC. Accordingly, activation of Notch signalling in a pre-clinical SCLC mouse model strikingly reduced the number of tumours and extended the survival of the mutant mice. Furthermore, neuroendocrine gene expression was abrogated by Notch activity in SCLC cells. This first comprehensive study of somatic genome alterations in SCLC uncovers several key biological processes and identifies candidate therapeutic targets in this highly lethal form of cancer.

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.

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.

Rationale for co-targeting IGF-1R and ALK in ALK fusion-positive lung cancer.

Crizotinib, a selective tyrosine kinase inhibitor (TKI), shows marked activity in patients whose lung cancers harbor fusions in the gene encoding anaplastic lymphoma receptor tyrosine kinase (ALK), but its efficacy is limited by variable primary responses and acquired resistance. In work arising from the clinical observation of a patient with ALK fusion-positive lung cancer who had an exceptional response to an insulin-like growth factor 1 receptor (IGF-1R)-specific antibody, we define a therapeutic synergism between ALK and IGF-1R inhibitors. Similar to IGF-1R, ALK fusion proteins bind to the adaptor insulin receptor substrate 1 (IRS-1), and IRS-1 knockdown enhances the antitumor effects of ALK inhibitors. In models of ALK TKI resistance, the IGF-1R pathway is activated, and combined ALK and IGF-1R inhibition improves therapeutic efficacy. Consistent with this finding, the levels of IGF-1R and IRS-1 are increased in biopsy samples from patients progressing on crizotinib monotherapy. Collectively these data support a role for the IGF-1R-IRS-1 pathway in both ALK TKI-sensitive and ALK TKI-resistant states and provide a biological rationale for further clinical development of dual ALK and IGF-1R inhibitors.

CD74-NRG1 fusions in lung adenocarcinoma.

UNLABELLED: We discovered a novel somatic gene fusion, CD74-NRG1, by transcriptome sequencing of 25 lung adenocarcinomas of never smokers. By screening 102 lung adenocarcinomas negative for known oncogenic alterations, we found four additional fusion-positive tumors, all of which were of the invasive mucinous subtype. Mechanistically, CD74-NRG1 leads to extracellular expression of the EGF-like domain of NRG1 III-ß3, thereby providing the ligand for ERBB2-ERBB3 receptor complexes. Accordingly, ERBB2 and ERBB3 expression was high in the index case, and expression of phospho-ERBB3 was specifically found in tumors bearing the fusion (P < 0.0001). Ectopic expression of CD74-NRG1 in lung cancer cell lines expressing ERBB2 and ERBB3 activated ERBB3 and the PI3K-AKT pathway, and led to increased colony formation in soft agar. Thus, CD74-NRG1 gene fusions are activating genomic alterations in invasive mucinous adenocarcinomas and may offer a therapeutic opportunity for a lung tumor subtype with, so far, no effective treatment. SIGNIFICANCE: CD74­NRG1 fusions may represent a therapeutic opportunity for invasive mucinous lung adenocarcinomas, a tumor with no effective treatment that frequently presents with multifocal unresectable disease.

Fibroblast growth factor receptor 1 (FGFR1) amplification is a potential therapeutic target in small-cell lung cancer.

Small-cell lung cancer (SCLC) comprises about 13-15% of all lung cancers, and more than 29 400 new cases have been diagnosed in the United States in the year 2012. SCLC is a biologically complex tumor typically occurring in heavy smokers. Its medical treatment has almost remained unchanged over the last decades and selected treatment options have not been established so far, mainly due to the lack of targetable genetic alterations. In this study we analyzed a cohort of 307 SCLC samples for fibroblast growth factor receptor 1 (FGFR1) amplification using a dual color FISH probe. FGFR1 status was correlated with clinical data. FGFR1 amplifications were observed in 5.6% of evaluable pulmonary SCLCs. Most of them (93%) fulfilled the criteria for high-level amplification and only one case showed low-level amplification. Amplification patterns were homogenous in the entire tumor area without occurrence of any 'hot spot' areas. FGFR1 amplification status was not associated with age, sex, stage, smoking status or overall survival. FGFR1 amplification analysis by FISH analysis in SCLC is, under respect of certain technical issues, applicable in the routine clinical setting. However, the FGFR1 amplification patterns in SCLC differs strongly from the previously described FGFR1 amplification pattern in squamous cell carcinoma of the lung, as positive SCLC harbor mostly homogeneous high-level amplifications. We provide evidence that an estimated number of 1640 newly diagnosed FGFR1-positive SCLC cases in the United States annually could benefit from targeted therapy. Therefore, we recommend including SCLC in the screening for ongoing clinical trials with FGFR1 inhibitors.

Cell-autonomous and non-cell-autonomous mechanisms of transformation by amplified FGFR1 in lung cancer.

UNLABELLED: The 8p12 locus (containing the FGFR1 tyrosine kinase gene) is frequently amplified in squamous cell lung cancer. However, it is currently unknown which of the 8p12-amplified tumors are also sensitive to fibroblast growth factor receptor (FGFR) inhibition. We found that, in contrast with other recurrent amplifications, the 8p12 region included multiple centers of amplification, suggesting marked genomic heterogeneity. FGFR1-amplified tumor cells were dependent on FGFR ligands in vitro and in vivo. Furthermore, ectopic expression of FGFR1 was oncogenic, which was enhanced by expression of MYC. We found that MYC was coexpressed in 40% of FGFR1-amplified tumors. Tumor cells coexpressing MYC were more sensitive to FGFR inhibition, suggesting that patients with FGFR1-amplified and MYC-overexpressing tumors may benefit from FGFR inhibitor therapy. Thus, both cell-autonomous and non-cell-autonomous mechanisms of transformation modulate FGFR dependency in FGFR1-amplified lung cancer, which may have implications for patient selection for treatment with FGFR inhibitors. SIGNIFICANCE: Amplification of FGFR1 is one of the most frequent candidate targets in lung cancer. Here, we show that multiple factors affect the tumorigenic potential of FGFR1, thus providing clinical hypotheses for refinement of patient selection.

Activated RET and ROS: two new driver mutations in lung adenocarcinoma.

Rearrangements of ROS1 and RET have been recently described as new driver mutations in lung adenocarcinoma with a frequency of about 1% each. RET and ROS1 rearrangements both represent unique molecular subsets of lung adenocarcinoma with virtually no overlap with other known driver mutations described so far in lung adenocarcinoma. Specific clinicopathologic characteristics have been described and several multitargeted receptor kinase inhibitors have shown in vitro activity against NSCLC cells harbouring these genetic alterations. In addition, the MET/ALK/ROS inhibitor crizotinib has already shown impressive clinical activity in patients with advanced ROS1-positive lung cancer. Currently, several early proof of concept clinical trials are testing various kinase inhibitors in both molecular subsets of lung adenocarcinoma patients. Most probably, personalized treatment of these genetically defined new subsets of lung adenocarcinoma will be implemented in routine clinical care of lung cancer patients in the near future.

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.