e19013 Background: Mutation profiling to assess for potentially druggable mutations in NSCLC is being offered at an increasing number of cancer centers throughout North America and internationally. Although data continue to accumulate for the potential value of mutation testing in designing chemotherapeutic regimens, the treatment impact of obtaining information beyond assessment of EGFR and ALK status remains unclear. How best to obtain and clinically utilize these data, including information from exome and whole genome sequencing, also remains unclear. Methods: Patients were reviewed electronically in a multidisciplinary conference regarding indications for testing and results of mutation profiling from various methods, including the mass-spec based LungCarta test, targeted NexGen sequencing, exome, and whole genome sequencing. Outcomes of the multidisciplinary review were communicated back to treating physicians. Results: Mutation testing was performed on 200 patients using a variety of approaches. The majority (>150) were surgically resected stage I and II tumors. Mutations in at least 1 major cancer driver gene, including EGFR, KRAS, MET, BRAF and PIK3CA, were found in 47% of all patients tested. EGFR mutations were present in 14.8% of patients tested, KRAS 21.3%, BRAF 2.6%, PIK3CA 3.2%, and MET 4.5%. A total of 8 patients underwent either exome or whole genome sequencing. A limited number of patients (<10) had mutation results that impacted treatment decisions from this cohort. Conclusions: Mutation profiling can influence treatment decisions in NSCLC, but at a low frequency. The role of exome and or whole genome sequencing for patients with NSCLC is evolving and remains undefined.
Genomic rearrangements in lung adenocarcinoma: Lineage relationships between the in situ and invasive components.
7568 Background: The molecular events in the initiation and progression of invasive lung adenocarcinoma remain poorly characterized. These tumors are thought to develop through an adenocarcinoma in situ (AIS), minimally invasive adenocarcinoma (MIA), invasive adenocarcinoma (AD) sequence. The goal of our study was to assess lineage relationships between in situ and invasive components within adenocarcinomas with prominent lepidic growth patterns. Methods: Frozen tissue from fourteen lung adenocarcinomas with mixtures of AD together with an adjacent in situ component (AIS), varying in ratio between 40 to 80%, were selected from our Lung Specimen Registry. Laser capture microdissection (LCM) of each component was performed separately for each tumor. Genomic DNA was isolated using a direct in situ whole genome amplification (WGA) methodology, and Next Generation Sequencing performed using an Illumina Mate Pair (MP) library protocol. MP sequence reads were mapped to the human genome and primers spanning the fusion junctions were used in validation PCRs. Results: Genomic break points identical and unique to a specific patient were identified between the AIS and AD components in 13 (of 14) cases. The total number of events per case ranged from 4-215, and the number of identical events shared between the AIS and AD components ranged from 30 to 90%. Recurrent genomic breakpoints between cases were also observed, with the 2 most common involving 8q24.3 in 5 cases and FAM19A2 on chromosome 12 in 4 cases. PCR validation of selected genomic alterations confirmed the genomic break points identified from sequencing in both the AIS and AD in all cases. Interestingly, we also observed a limited number of genomic alterations present in a zonal distribution of surrounding normal lung around the tumor mass. Conclusions: Our study demonstrates unique chromosomal alterations present in both the AIS and AD components of individual lung tumors with features of lepidic growth. These data provide evidence for lineage relationship and clonal relatedness between the two components, and provide genomic evidence for a model of stepwise progression from AIS to invasive AD in this subset of lung adenocarcinomas.
Abstract 728: Genomic alterations in lung adenocarcinoma precursor lesions
Abstract Background: Adenocarcinoma of the lung is the most common type of non-small cell lung cancer and is the subtype found in approximately 50% of all lung cancer cases. Adenocarcinoma in situ (AIS) and minimally invasive adenocarcinoma (MIA) are thought to be precursor lesions of invasive disease. It has been hypothesized that there is a step-wise progression to lung adenocarcinoma, but little is known about genomic alterations in these precursor lesions. Methods: Genomic analysis including whole genome and exome sequencing, and SNP array analysis were performed on 9 AIS and 18 MIA pathologically confirmed samples to identify single nucleotide variants (SNVs), structural variations and copy number variations. Mutation significance and signature analysis were determined by MutSig and NMF analyses. Altered pathways were determined by Ingenuity variant effect pathway analysis. Results: The tumor mutation burden (TMB) for AIS and MIA ranged from 0.8 to 23.1 mut/Mb with a median of 3.0mut/Mb and a mean of 5.1mut/Mb. Highly mutated genes identified in AIS and MIA were RPL10, NBPF1, KRAS, GPR52, CAMK2A, ATOX1, STK11, TP53, MET and EGFR. Genes with recurrent mutations included SPTA1, USH2A, CACNA1E, EGFR, KRAS, MUC16, MUC17, OTOG, RYR2, COL20A1, CSMD3, RFX6 and XIRP2, which implicated pathways involving the EGFR-KRAS-TP53-MAPK axis. Somatic mutations were characterized by a C>T, T>C transitions and C>A transversion signature. There were comparable structural variations in the AIS cases compared to MIA. Conclusion: In contrast to hypothesized models of tumor progression, AIS and MIA can harbor significant genomic alterations and tumor mutation burden, which suggests an intriguing concept of immunotherapeutic options for either treatment or chemoprevention. Deregulation of EGFR-KRAS-TP53-MAPK pathway indicates a role in early events of carcinogenesis. Citation Format: Michael K. Asiedu, Nanette R. Reed, Marie Christine Aubry, Anja C. Roden, Dennis A. Wigle. Genomic alterations in lung adenocarcinoma precursor lesions [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 728.
Identification of independent primary tumors and intra-pulmonary metastasis using DNA rearrangements in non-small cell lung cancer.
AbstractMost FDA‐approved drugs are not equally effective in all patients, suggesting that identification of biomarkers to predict responders to a chemoprevention agent will be needed to stratify patients and achieve maximum benefit. The goal of this study was to investigate both patient‐specific and cell context‐specific heterogeneity of metformin response, using fibroblast cell lines and induced pluripotent stem cells differentiated into lung epithelial lineages. We performed cell survival analysis, transcriptome and whole exome sequencing analysis on both patient‐derived cell lines and cancer cell lines to assess differential metformin response and identify response genes. We found differences in response to metformin treatment across a variety of cell lines and cellular contexts, suggesting that heterogeneity may be patient‐ and cell type‐specific. Gene expression profiling and analysis of metformin‐sensitive and metformin‐resistant cells identified differentially expressed genes that may be able to stratify patients into metformin responders and non‐responders. Sequencing analysis found genomic alterations that correlated with metformin response. These results suggest that the identification of genomic biomarkers for patients who may respond to metformin treatment can provide an opportunity for individualizing metformin chemoprevention in the clinical setting.
Transcriptional Induction of Periostin by a Sulfatase 2–TGFβ1–SMAD Signaling Axis Mediates Tumor Angiogenesis in Hepatocellular Carcinoma
Abstract Introduction: Pulmonary carcinoid tumors account for up to 5% of all lung malignancies in adults, and comprise 30% of all carcinoid malignancies. They are defined histologically as typical carcinoid (TC) and atypical carcinoid (AC) tumors, and are characterized by neuroendocrine differentiation and the potential to metastasize. Method: We characterized genomic alterations in pulmonary carcinoid tumors using whole genome and exome sequencing in addition to mRNA expression and SNP genotyping from specimens of normal lung, typical and atypical carcinoid, and SCLC. Results: Analysis of the sequencing data identified novel mutations in the pulmonary neuroendocrine tumor spectrum, including KRAS, ABCA9, GALNT10, HSFX1, PTHLH, RANBP2, BRIP1, FXR1, BACE2, NCOR2, DGKI, HERC1, HERC5 and GLI3. Pathway analysis found 45% of the cases to harbor a mutation in genes that are involved in protein-protein interaction with ubiquitin c (UBC) and may therefore play a role in ubiquitin protein degradation pathway. We also identified genes differentially expressed in corresponding regions of copy number variation, 52 of which were linked to ubiquitination pathways in 88% of the samples genotyped. Genes amplified in 15 to 23% of the cases included ITM2A, MAOA, EGR2, HAGH, TSC22D3, NBEA, TCEAL2, and TSPYL2 whereas deleted regions in 15% of the cases implicated CFD, GDI1, IFITM1 and IFITM2. Conclusion: These results suggest that in addition to previously identified pathways, dysregulation of the ubiquitin pathway may contribute to lung carcinoid tumorigenesis and could be exploited for therapeutic purposes. Citation Format: Michael K. Asiedu, Charles L. Thomas, Jie Dong, Prasidda Khadka, Zhifu Sun, Farhad Kosari, Jin Jen, Julian Molina, George Vasmatzis, Marie Christine Aubry, Ping Yang, Dennis Wigle. Genomic alterations modify ubiquitination pathways in pulmonary carcinoid tumors. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 3895. doi:10.1158/1538-7445.AM2015-3895
Abstract 1897: Metformin as a chemoprevention agent for lung squamous cancer
Abstract Background: Squamous cell carcinoma is a common type of lung cancer and accounts for about 25-30% of all non-small cell lung cancers. Metformin is a drug commonly prescribed as first-line treatment for type-2 diabetes, with some evidence showing that the drug can also act directly on cancer cells. One of the mechanisms of action is through activation of the AMP-activated protein kinase (AMPK) which is involved in control of energy homeostasis in cells. The goal of this study was to determine metformin response in different cell lines and different cellular contexts, and to use that information to work towards the generation of a metformin “sensitivity index” that could be used guide individualized chemoprevention. Methods: We performed cell survival analysis on squamous cell carcinoma lines, skin fibroblast lines and differentiated IPS cell lines to identify differences in metformin response both for different cell lines and for cells in different cell context. Microarray profiling was used to determine differentially expressed genes that are regulated by metformin treatment in order to generate signatures of metformin response. Results: Cell survival analysis showed that different cell lines respond differently to metformin, and cells of identical genotypes in a variety of differentiated states or cellular contexts also show differential response to metformin. Gene expression profiling of metformin treated cells identified differentially expressed genes that may mediate metformin response. Conclusion: Differences in response to metformin treatment across a variety of cell lines and cellular contexts suggest heterogeneity that may be patient-specific. Using genes that are differentially expressed following metformin treatment, we identified a 55-gene set that can be used as a metformin “sensitivity index” to stratify patients into metformin responders and non-responders and guide individualized chemoprevention. Citation Format: Michael K. Asiedu, Matthew R. Barron, Marie Christine Aubry, Dennis Wigle. Metformin as a chemoprevention agent for lung squamous cancer. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 1897. doi:10.1158/1538-7445.AM2015-1897
Identification of Independent Primary Tumors and Intrapulmonary Metastases Using DNA Rearrangements in Non–Small-Cell Lung Cancer
Purpose Distinguishing independent primary tumors from intrapulmonary metastases in non–small-cell carcinoma remains a clinical dilemma with significant clinical implications. Using next-generation DNA sequencing, we developed a chromosomal rearrangement–based approach to differentiate multiple primary tumors from metastasis. Methods Tumor specimens from patients with known independent primary tumors and metastatic lesions were used for lineage test development, which was then applied to multifocal tumors. Laser capture microdissection was performed separately for each tumor. Genomic DNA was isolated using direct in situ whole-genome amplification methodology, and next-generation sequencing was performed using an Illumina mate-pair library protocol. Sequence reads were mapped to the human genome, and primers spanning the fusion junctions were used for validation polymerase chain reaction. Results A total of 41 tumor samples were sequenced (33 adenocarcinomas [ADs] and eight squamous cell carcinomas [SQCCs]), with a range of three to 276 breakpoints per tumor identified. Lung tumors predicted to be independent primary tumors based on different histologic subtype did not share any genomic rearrangements. In patients with lung primary tumors and paired distant metastases, shared rearrangements were identified in all tumor pairs, emphasizing the patient specificity of identified breakpoints. Multifocal AD and SQCC samples were reviewed independently by two pulmonary pathologists. Concordance between histology and genomic data occurred in the majority of samples. Discrepant tumor samples were resolved by genome sequencing. Conclusion A diagnostic lineage test based on genomic rearrangements from mate-pair sequencing demonstrates promise for distinguishing independent primary from metastatic disease in lung cancer.