Citations

Abstract Purpose: The expression of programmed cell death ligand 1 (PD-L1) provides limited predictive value in identifying patients most likely to respond to immunotherapy. As the heterogeneity of PD-L1 expression may lead to sampling error and the misclassification of PD-L1 status, we assessed the distribution of PD-L1 expression in paired, resected multifocal lung cancers. Experimental Design: PD-L1 was assessed by IHC. Paired lesions were defined as independent primaries or related lesions using mate pair next-generation sequencing. Agreement statistics were used for analysis. Results: Sixty-seven multifocal lung cancers from 32 patients were sequenced and stained for PD-L1. There was agreement of PD-L1 expression by the tumor cells in paired lesions of 20 patients and disagreement of PD-L1 expression by the tumor cells in paired lesions of 12 patients (κ = 0.01). Sequencing identified that 23 patients had independent primary lung cancers and that 9 patients had related cancers. In paired lesions of patients with independent cancers, there was agreement of PD-L1 expression by the tumor cells in 12 patients and disagreement in 11 patients (κ = 0.31). In paired lesions of patients with related lung cancers, there was agreement of PD-L1 expression by the tumor cells in 8 patients and disagreement in 1 patient (κ = 0.73). Conclusions: The expression of PD-L1 is heterogeneous among paired independent lung cancers, but there are high levels of agreement in intrapulmonary metastasis. Clin Cancer Res; 22(9); 2177–82. ©2015 AACR.

Transbronchial cryobiopsy technique yields larger biopsies with enhanced quality. The benefits and safety of cryobiopsies have not been thoroughly studied in lung allografts.Context.— To compare size, quality, reproducibility of interpretation of rejection and complications of cryobiopsies with those of conventional biopsies from lung allografts.Objective.— All cryobiopsies (March 2014–January 2015) of lung allografts performed at Mayo Clinic, Rochester, and medical records were reviewed. For comparison, conventional biopsies from the same patient or, if unavailable, from a random patient, were selected. Two pathologists blinded to outcome reviewed all biopsies. Specimen volume, number of alveoli, small airways, and pulmonary vessels were counted and statistically compared.Design.— Fifty-four biopsies (27 cryobiopsies) from 18 patients (11 men) were reviewed. A median of 3 (range, 2–5) and 10 (range, 6–12) specimens were obtained with cryobiopsies and conventional biopsies, respectively. Cryobiopsies were larger and contained more alveoli (P < .001, both) and small airways (P = .04). Conventional biopsies showed more fresh alveolar hemorrhage (procedural) and crush artifact/atelectasis (P < .001, both). Cryobiopsies contained more pulmonary veins and venules (P < .001). There was no significant difference between the types of biopsies with respect to the reviewers' agreement on grades of rejection. Complications were more frequent in the cryobiopsy group, though the difference was not statistically significant.Results.— Cryobiopsies of lung allografts are larger and have less artifact. However, complications occur and should be considered. Three cryobiopsy specimens appear sufficient for histopathologic evaluation of lung allografts.Conclusions.—

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 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

Abstract ASCL1 is an important regulatory transcription factor in pulmonary neuroendocrine cell development, but its value as a biomarker of neuroendocrine differentiation in lung adenocarcinoma (AD) and as a potential prognostic biomarker remains unclear. We examined ASCL1expression in lung cancer samples of varied histologic subtype, clinical outcome, and smoking status and compared to expression of traditional neuroendocrine markers. ASCL1 mRNA expression was found almost exclusively in smokers with AD, in contrast to non-smokers. ASCL1 protein expression by immunohistochemistry (IHC) correlated best with synaptophysin compared to chromogranin and CD56/NCAM. Analysis of a compendium of 367 microarray-based gene expression profiles in stage I lung adenocarcinomas identified significantly higher expression levels of the RET oncogene in ASCL1 positive tumors (ASCL1+) compared to ASCL1- tumors (q-value < 10 - 9). High levels of RET expression in ASCL1+ but not in ASCL1- tumors was associated with significantly shorter overall survival in stage 1 (p = 0.007) and in all AD (p = 0.037). RET protein expression by IHC had an association with overall survival in the context of ASCL1 expression. In silico gene set analysis and in vitro experiments by ASCL1 shRNA in AD cells with high endogenous expression of ASCL1 and RET implicated ASCL1 as a potential upstream regulator of the RET oncogene. Also, silencing ASCL1 in AD cells markedly reduced cell growth and motility. These results suggest that ASCL1 and RET expression define a clinically relevant subgroup of approximately 10% of AD characterized by neuroendocrine differentiation. Citation Format: Farhad Kosari, Cristiane M. Ida, Marie Christine Aubry, Lin Yang, Irina V. Kovtun, Janet L. Schaefer Klein, Sandra C. Tomaszek, Stephen J. Murphy, Ping Yang, Dennis Wigle, George Vasmatzis. ASCL1 and RET expression define a clinically relevant subgroup of lung adenocarcinoma characterized by neuroendocrine differentiation. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 5251. doi:10.1158/1538-7445.AM2014-5251

Introduction. We investigated the expression of microRNAs and mRNAs in pleural tissues from patients with either malignant pleural mesothelioma or benign asbestos-related pleural effusion.Methods. Fresh frozen tissues from a total of 18 malignant pleural mesothelioma and 6 benign asbestos-related pleural effusion patients were studied. Expression profiling of mRNA and microRNA was performed using standard protocols.Results. We discovered significant upregulation of multiple microRNAs in malignant pleural mesothelioma compared to benign asbestos-related pleural effusion. Hsa-miR-484, hsa-miR-320, hsa-let-7a, and hsa-miR-125a-5p were able to discriminate malignant from benign disease. Dynamically regulated mRNAs were also identified. MET was the most highly overexpressed gene in malignant pleural mesothelioma compared to benign asbestos-related pleural effusion. Integrated analyses examining microRNA-mRNA interactions suggested multiple altered targets within the Notch signaling pathway.Conclusions. Specific microRNAs and mRNAs may have diagnostic utility in differentiating patients with malignant pleural mesothelioma from benign asbestos-related pleural effusion. These studies may be particularly helpful in patients who reside in a region with a high incidence of mesothelioma.

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.

AbstractThe development of adenocarcinoma of the lung is believed to proceed from in situ disease (adenocarcinoma in situ, AIS) to minimally invasive disease with prominent lepidic growth (minimally invasive adenocarcinoma, MIA), then to fully invasive adenocarcinoma (AD), but direct evidence for this model has been lacking. Because some lung adenocarcinomas show prominent lepidic growth (AD-L), we designed a study to address the lineage relationship between the lepidic (noninvasive) component (L) and the adjacent nonlepidic growth component representing invasive disease within individual tumors. Lineage relationships were evaluated by next-generation DNA sequencing to define large genomic rearrangements in microdissected tissue specimens collected by laser capture. We found a strong lineage relationship between the majority of adjacent lepidic and invasive components, supporting a putative AIS–AD transition. Notably, many rearrangements were detected in the less aggressive lepidic component, although the invasive component exhibited an overall higher rate of genomic rearrangement. Furthermore, a significant number of genomic rearrangements were present in histologically normal lung adjacent to tumor, but not in host germline DNA, suggesting field defects restricted to zonal regions near a tumor. Our results offer a perspective on the genetic pathogenesis underlying adenocarcinoma development and its clinical management. Cancer Res; 74(11); 3157–67. ©2014 AACR.

Transthoracic fine needle aspiration (TFNA)/core needle biopsy (CNB) under computed tomography (CT) guidance has proved useful in the assessment of pulmonary nodules. We sought to determine the TFNA false‐negative (FN) rate at our institution and identify potential causes of FN diagnoses. Medical records were reviewed from 1,043 consecutive patients who underwent CT‐guided TFNA with or without CNB of lung nodules over a 5‐year time period (2003–2007). Thirty‐seven FN cases of “negative” TFNA/CNB with malignant outcome were identified with 36 cases available for review, of which 35 had a corresponding CNB. Cases were reviewed independently (blinded to original diagnosis) by three pathologists with 15 age‐ and sex‐matched positive and negative controls. Diagnosis (i.e., nondiagnostic, negative or positive for malignancy, atypical or suspicious) and qualitative assessments were recorded. Consensus diagnosis was suspicious or positive in 10 (28%) of 36 TFNA cases and suspicious in 1 (3%) of 35 CNB cases, indicating potential interpretive errors. Of the 11 interpretive errors (including both suspicious and positive cases), 8 were adenocarcinomas, 1 squamous cell carcinoma, 1 metastatic renal cell carcinoma, and 1 lymphoma. The remaining 25 FN cases (69.4%) were considered sampling errors and consisted of 7 adenocarcinomas, 3 nonsmall cell carcinomas, 3 lymphomas, 2 squamous cell carcinomas, and 2 renal cell carcinomas. Interpretive and sampling error cases were more likely to abut the pleura, while histopathologically, they tended to be necrotic and air‐dried. The overall FN rate in this patient cohort is 3.5% (1.1% interpretive and 2.4% sampling errors). Diagn. Cytopathol. 2014;42:1063–1068;. © 2014 Wiley Periodicals, Inc.