Ki-67 Proliferation Index Is Associated With Tumor Grade and Survival in Pleural Epithelioid Mesotheliomas

Pleural epithelioid mesothelioma (PEM) is divided into low and high grades based on nuclear atypia, mitoses, and necrosis in the tumor. Assessing mitoses and nuclear atypia tend to be labor-intensive with limited reproducibility. Ki-67 proliferation index was shown to be a prognostic factor in PEM, but its performance has not been directly correlated with tumor grade or mitotic score. This study evaluated the potential of Ki-67 index as a surrogate of tumor grade. We also compared the predictability of mitoses and Ki-67 index for overall survival (OS). Ninety-six PEM samples from 85 patients were identified from the surgical pathology file during 2000-2021 at our institution, and all glass slides were reviewed by 2 pulmonary pathologists to confirm the diagnosis and assign the tumor grade. Digital image analysis (DIA) was done for Ki-67 index. The agreement on tumor grading between 2 reviewers was moderate (kappa value = 0.47). The correlation between mitotic count (average count by 2 reviewers) and Ki-67 index was 0.65. The areas under the curve for predicting tumor grade by mitotic score and Ki-67 index were 0.84 and 0.74 (reviewer 1) and 0.85 and 0.81 (reviewer 2), respectively. High Ki-67 index and mitoses were significantly associated with poor OS ( P =0.03 and 0.0005, using 30% and 10/2 mm 2 as cutoffs, respectively). In conclusion, Ki-67 index by DIA was associated with tumor grade as well as mitotic count, and its predictability for OS was comparable to that of mitotic score, thus being a potential surrogate for tumor grade.

Prognostic Immunohistochemistry for Ki-67 and OTP on Small Biopsies of Pulmonary Carcinoid Tumors: Ki-67 Index Predicts Progression-free Survival and Atypical Histology

Prognostic stratification of pulmonary carcinoids into "typical" and "atypical" categories requires examination of large tissue volume. However, there is a need for tools that provide similar prognostic information on small biopsy samples. Ki-67 and OTP immunohistochemistry have shown promising prognostic value in studies of resected pulmonary carcinoids, but prognostic value when using biopsy/cytology specimens is unclear. Ki-67 immunohistochemistry was performed on small biopsy/cytology specimens from pulmonary carcinoid tumors (n=139), and labeling index was scored via automated image analysis of at least 500 cells. OTP immunohistochemistry was performed on 70 cases with sufficient tissue and scored as positive or negative (<20% tumor nuclei staining). Higher Ki-67 index was associated with worse disease-specific progression-free survival (ds-PFS), with 3% and 4% thresholds having similarly strong associations with ds-PFS (P<0.001, hazard ratio ≥11). Three-year ds-PFS was 98% for patients with Ki-67 <3% and 89% for patients with Ki-67≥3% (P=0.0006). The optimal Ki-67 threshold for prediction of typical versus atypical carcinoid histology on subsequent resection was 3.21 (AUC 0.68). Negative OTP staining approached significance with atypical carcinoid histology (P=0.06) but not with ds-PFS (P=0.24, hazard ratio=3.45), although sample size was limited. We propose that Ki-67 immunohistochemistry may contribute to risk stratification for carcinoid tumor patients based on small biopsy samples. Identification of a 3% hot-spot Ki-67 threshold as optimal for prediction of ds-PFS is notable as a 3% Ki-67 threshold is currently used for gastrointestinal neuroendocrine tumor stratification, allowing consideration of a unified classification system across organ systems.

A case-control autopsy series of liver pathology associated with novel coronavirus disease (COVID-19)

BACKGROUND

Although severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) responsible for coronavirus disease 2019 (COVID-19) is most well-known for causing pulmonary injury, a significant proportion of patients experience hepatic dysfunction. The mechanism by which SARS-CoV2 causes liver injury is not fully understood. The goal of this study was to describe the hepatic pathology in a large cohort of deceased patients with COVID-19 as compared to a control group of deceased patients without COVID-19.

METHODS

Consented autopsy cases at two institutions were searched for documentation of COVID-19 as a contributing cause of death. A group of consecutive consented autopsy cases during the same period, negative for SARS-CoV-2 infection, was used as a control group. The autopsy report and electronic medical records were reviewed for relevant clinicopathologic information. H&E-stained liver sections from both groups were examined for pertinent histologic features. Select cases underwent immunohistochemical staining for CD 68 and ACE2 and droplet digital polymerase chain reaction (ddPCR) assay for evaluation of SARS-CoV2 RNA.

RESULTS

48 COVID-19 positive patients (median age 73, M:F 3:1) and 40 COVID-19 negative control patients (median age 67.5, M:F 1.4:1) were included in the study. The COVID-19 positive group was significantly older and had a lower rate of alcoholism and malignancy, but there was no difference in other comorbidities. The COVID-19 positive group was more likely to have received steroids (75.6 % vs. 36.1 %, p < 0.001). Hepatic vascular changes were seen in a minority (10.6 %) of COVID-19 positive cases. When all patients were included, there were no significant histopathologic differences between groups, but when patients with chronic alcoholism were excluded, the COVID-19 positive group was significantly more likely to have steatosis (80.9 % vs. 50.0 %, p = 0.004) and lobular inflammation (45.7 % vs. 20.7 %, p = 0.03). Testing for viral RNA by ddPCR identified 2 of the 18 (11.1 %) COVID-19 positive cases to have SARS-CoV-2 RNA detected within the liver FFPE tissue.

CONCLUSIONS

The most significant findings in the liver of COVID-19 positive patients were mild lobular inflammation and steatosis. The high rate of steroid therapy in this population may be a possible source of steatosis. Hepatic vascular alterations were only identified in a minority of patients and did not appear to play a predominant role in COVID-19 mediated hepatic injury. Low incidence of SARS-CoV-2 RNA positivity in liver tissue in our cohort suggests hepatic injury in the setting of COVID-19 may be secondary in nature.

Two tumors with combined features of bronchiolar adenoma/ciliated muconodular papillary tumor and sclerosing pneumocytoma

OBJECTIVES

Bronchiolar adenoma/ciliated muconodular papillary tumor (BA/CMPT) and sclerosing pneumocytoma (SP) are both rare and morphologically unique peripheral lung tumors with indolent behavior. These tumors have not been previously described as showing overlapping morphologic features and are generally genetically distinct.

METHODS

Two cases were recently encountered that show hybrid morphologic features between BA/CMPT and SP, and the morphology and immunophenotype are described in detail.

RESULTS

Both cases showed interstitial round cells typical of SP (TTF1+, EMA+), as well as areas more typical of BA/CMPT. One case showed BRAFV600E expression in the BA/CMPT areas but not in the SP-like cells.

CONCLUSIONS

Although it is possible that these cases represent collision tumors or are examples of unusual metaplastic epithelial changes in SP, they also raise the possibility that these 2 entities could occasionally coexist in true hybrid tumors.

Late Complications of COVID-19: A Morphologic, Imaging, and Droplet Digital Polymerase Chain Reaction Study of Lung Tissue

CONTEXT

Studies of lungs in patients with COVID-19 have focused on early findings.

OBJECTIVE

To systematically study histopathologic, imaging features and presence of SARSCoV-2 RNA in lung tissue from patients in later stages of COVID-19.

DESIGN

Autopsies, explants, surgical lung biopsies; and transbronchial, cryo, and needle biopsies were studied from patients with COVID-19, whose onset of symptoms/confirmed diagnosis was more than 28 days before the procedure. Available images were reviewed. Reverse transcription droplet digital polymerase chain reaction (RT-ddPCR) for SARS-CoV-2 RNA was performed on lung tissue.

RESULTS

Forty-four specimens (43 patients, median age 59.3 years, 26 [60.5%] male) showed features of acute lung injury (ALI) in 39 (88.6%), predominantly organizing pneumonia (OP) and diffuse alveolar damage (DAD), up to 298 days after onset of COVID-19. Fibrotic changes were found in 33 specimens (75%), most commonly fibrotic DAD (N=22) and cicatricial OP (N=12). Time between acquiring COVID-19 and specimen was shorter in patients with diffuse ALI (median 61.5 days) compared to patients with focal (140 days) or no ALI (130 days) (P=.009). Sixteen (of 20, 80%) SARS-CoV-2 RT-ddPCR tests were positive, up to 174 days after COVID-19 onset. Time between COVID-19 onset and most recent CT in patients with consolidation on imaging was shorter (median 43.0 days) versus patients without consolidation (87.5 days; P=.02). Reticulations were associated with longer time after COVID-19 onset to CT (median 82 days vs 23.5 days, P=.006).

CONCLUSIONS

ALI and SARS-CoV-2 RNA can be detected in patients with COVID-19 for many months. ALI may evolve into fibrotic interstitial lung disease.

Loss of Methylthioadenosine Phosphorylase by Immunohistochemistry Is Common in Pulmonary Sarcomatoid Carcinoma and Sarcomatoid Mesothelioma

OBJECTIVES

Differentiating malignant pleural mesothelioma from benign reactive mesothelial processes can be quite challenging. Ancillary tests such as BRCA1-associated protein 1 (BAP1) immunohistochemistry and p16 fluorescence in situ hybridization (FISH) are helpful tools to aid in this distinction. Immunohistochemistry for methylthioadenosine phosphorylase (MTAP) has recently been proposed as an effective surrogate marker for p16 FISH and is an attractive alternative test due to shorter turnaround time. There are little data regarding the specificity of MTAP loss for mesothelioma or whether it may be useful to distinguish mesothelioma from the most common entity in the differential diagnosis, sarcomatoid carcinoma.

METHODS

We studied well-characterized cases of sarcomatoid carcinoma (n = 34) and sarcomatoid mesothelioma (n = 62), which were stained for MTAP (clone 2G4) and BAP1 (clone C-4).

RESULTS

Loss of MTAP expression was observed in 17 (50%) of 34 pulmonary sarcomatoid carcinomas; BAP1 expression was retained in all of the cases in which it was performed (n = 31). MTAP expression was lost in 38 (61%) of 62 sarcomatoid mesotheliomas; BAP1 was lost in 6 (10%) of 62. In the six cases with BAP1 loss, five also had loss of MTAP, while MTAP expression was retained in one.

CONCLUSIONS

Loss of MTAP expression by immunohistochemistry is common in pulmonary sarcomatoid carcinoma, as it is present in half of cases. This rate is similar to what is observed in sarcomatoid mesothelioma (61%). Therefore, this stain is not useful to distinguish between these two malignancies. MTAP loss is more common than BAP1 loss in the setting of sarcomatoid mesothelioma (61% vs 10%, respectively).

Utility of Immunohistochemistry for MUC4 and GATA3 to Aid in the Distinction of Pleural Sarcomatoid Mesothelioma From Pulmonary Sarcomatoid Carcinoma

CONTEXT.—

Distinguishing pulmonary sarcomatoid carcinoma from pleural sarcomatoid mesothelioma is challenging because of overlapping histology, immunophenotype, and clinical features. Reliable immunohistochemical markers to aid in this distinction would be very valuable. Recent studies have proposed that MUC4 expression is common in sarcomatoid carcinoma but not in sarcomatoid mesothelioma, with the converse pattern reported for GATA3.

OBJECTIVE.—

To further explore the utility of MUC4 and GATA3 in distinguishing pulmonary sarcomatoid carcinoma from sarcomatoid mesothelioma.

DESIGN.—

Well-characterized cases of sarcomatoid carcinoma (n = 32) and sarcomatoid mesothelioma (n = 64) were included. Diagnoses were confirmed by thoracic pathologists with incorporation of immunophenotype, clinical, and radiographic features. Whole-tissue sections were stained for GATA3 and MUC4.

RESULTS.—

Patients with sarcomatoid carcinoma and sarcomatoid mesothelioma had similar mean age and male predominance. GATA3 was positive in 63 of 64 sarcomatoid mesotheliomas (98%; 42 diffuse, 16 patchy, 5 focal), and 15 of 32 sarcomatoid carcinomas (47%; 3 diffuse, 8 patchy, 4 focal). MUC4 was positive in 2 of 64 sarcomatoid mesotheliomas (3%; 1 patchy, 1 focal), and in 12 of 32 sarcomatoid carcinomas (38%; 5 diffuse, 6 patchy, 1 focal).

CONCLUSIONS.—

Diffuse GATA3 expression favors sarcomatoid mesothelioma over sarcomatoid carcinoma, which rarely shows diffuse expression (sensitivity and specificity of diffuse staining 66% and 94%, respectively). Focal and patchy GATA3 expression is observed in both tumor types, and therefore is not helpful in this distinction. Sensitivity of MUC4 for sarcomatoid carcinoma was low in our cohort, positive in only 38% with frequent patchy staining, but it was quite specific.

Optimizing clinical cytology touch preparations for next generation sequencing

Intraoperative diagnosis is routinely performed on cytology touch preparations (TPs) from core needle biopsies (CNBs). Current interest promotes their utility as an important source of patient tissue for clinical genomic testing. Herein we present whole genome structural variant analysis (SVA) from mate-pair sequencing (MPseq) and whole exome sequencing (WES) mutation calling in DNA directly whole genome amplified (WGA) from TPs. Chromosomal copy changes and somatic DNA junction detection from MPseq of TPs were highly consistent with associated CNBs and bulk resected tissues in all cases. While increased frequency coverage noise from limitations of amplification of limited sample input was significant, this was effectively compensated by natural tumor enrichment during the TP process, which also enhanced variant detection and loss of heterozygosity evaluations from WES. This novel TP methodology enables expanded utility of frequently limited CNB for both clinical and research genomic testing.

The Spectrum of Histopathologic Findings in Lungs of Patients With Fatal Coronavirus Disease 2019 (COVID-19) Infection

Context.—

Respiratory failure appears to be the ultimate mechanism of death in most patients with severe coronavirus disease 2019 (COVID-19) infection. Studies of postmortem COVID-19 lungs largely report diffuse alveolar damage and capillary fibrin thrombi, but we have also observed other patterns.

Objective.—

To report demographic and radiographic features along with macroscopic, microscopic, and microbiologic postmortem lung findings in patients with COVID-19 infections.

Design.—

Patients with confirmed COVID-19 infection and postmortem examination (March 2020–May 2020) were included. Clinical findings were abstracted from medical records. Lungs were microscopically reviewed independently by 4 thoracic pathologists. Imaging studies were reviewed by a thoracic radiologist.

Results.—

Eight patients (7 men, 87.5%; median age, 79 years; range, 69–96 years) died within a median of 17 days (range, 6–100 days) from onset of symptoms. The median lung weight was 1220 g (range, 960–1760 g); consolidations were found in 5 patients (62.5%) and gross thromboemboli were noted in 1 patient (12.5%). Histologically, all patients had acute bronchopneumonia; 6 patients (75%) also had diffuse alveolar damage. Two patients (25%) had aspiration pneumonia in addition. Thromboemboli, usually scattered and rare, were identified in 5 patients (62.5%) in small vessels and in 2 of these patients also in pulmonary arteries. Four patients (50%) had perivascular chronic inflammation. Postmortem bacterial lung cultures were positive in 4 patients (50%). Imaging studies (available in 4 patients) were typical (n = 2, 50%), indeterminate (n = 1, 25%), or negative (n = 1, 25%) for COVID-19 infection.

Conclusions.—

Our study shows that patients infected with COVID-19 not only have diffuse alveolar damage but also commonly have acute bronchopneumonia and aspiration pneumonia. These findings are important for management of these patients.

Antifibrotics Modify B-cell Induced Fibroblast Migration and Activation in IPF Patients

Background

Acute respiratory exacerbations in idiopathic pulmonary fibrosis (IPF), often triggered by infection, are life threatening events characterized by rapid deterioration of lung function and associated with poor prognosis. Since microbial antigens modulate immunity by activating different pattern recognition receptors (PRR) expressed by innate immune cells (including B-cells), we sought to investigate how the activation of human B-cells through PRR stimulation by different microbial (CpG and β-glucan) and non-microbial (Mitochondrial DAMPs; MTDs) antigens resulted in the release of an inflammatory/fibrotic milieu that contributed to the pathogenesis of fibrosis in patients with IPF.

Results

Our results show that an inflammatory milieu is induced by stimulating circulating B-cells with both noninfectious (MTDs) and infectious antigens (CpG and β-glucan) commonly found in bacteria and fungi. Moreover, we show that the inflammatory milieu produced was specific to the inducing antigen, and that the microbial antigens (CpG and β-glucan) triggered distinct signaling pathways in B-cells. Specifically, CpG induced mTOR-activation while β-glucan was mTOR-independent and activated Src and p38. Furthermore, our results also show that B-cell aggregates are present within fibrotic areas of the lung in IPF patients and activated B-cells induce fibroblast migration, which was modified by antifibrotics (nintedanib and pirfenidone).

Conclusion

Our results highlight the potential contribution of activated B-cells through PRRs to the proinflammatory and profibrotic milieu seen in patients with idiopathic pulmonary fibrosis.

A Randomized Double-Blind Phase II Study of the Seneca Valley Virus (NTX-010) versus Placebo for Patients with Extensive-Stage SCLC (ES SCLC) Who Were Stable or Responding after at Least Four Cycles of Platinum-Based Chemotherapy: North Central Cancer Treatment Group (Alliance) N0923 Study

INTRODUCTION

The Seneca Valley virus (NTX-010) is an oncolytic picornavirus with tropism for SCLC. This phase II double-blind, placebo-controlled trial evaluated NTX-010 in patients with extensive-stage (ES) SCLC after completion of first-line chemotherapy.

METHODS

Patients with ES SCLC who did not progress after four or more cycles of platinum-based chemotherapy were randomized 1:1 to a single dose of NTX-010 or placebo within 12 weeks of chemotherapy. The primary end point was progression-free survival (PFS). A prespecified interim analysis for futility was performed after 40 events. Viral clearance and the development of neutralizing antibodies were followed.

RESULTS

From January 15, 2010, to January 10, 2013, a total of 50 patients were randomized and received therapy on study (26 received NTX-010 and 24 received placebo). At the specified interim analysis, the median PFS was 1.7 months (95% confidence interval [CI]: 1.4-3.1 months) for the NTX-010 group versus 1.7 months (95% CI: 1.4-4.3 months) for the placebo group (hazard ratio = 1.03, p = 0.92), and the trial was terminated owing to futility. In the NTX-010 group, PFS was shorter in patients with detectable virus at days 7 and 14 versus in those in whom it was not detected after treatment (1.0 month [95% CI: 0.4-1.5 months] versus 1.8 months [95% CI: 1.3-5.5 months, p = 0.008] and 0.9 months [95% CI: 0.4-2.6 months] versus 1.3 months [95% CI: 1.0-5.3 months], respectively [p = 0.04]).

CONCLUSIONS

Patients with ES SCLC did not benefit from NTX-010 treatment after chemotherapy with a platinum doublet. Persistence of NTX-010 in the blood 1 or 2 weeks after treatment was associated with a shorter PFS.

Abstract 4577: Anti-tumor immunity is a key determinant of small cell lung cancer survivorship

Introduction: While most small cell lung cancer (SCLC) patients die within a few months, a sub-group of patients survive for many years. Factors determining long-term survivorship remain largely unknown. We present the first comprehensive comparative genomic and tumor microenvironment analyses of small cell lung cancer (SCLC) between patients with long term (LTS) and expected (EXS) survival times.

Methods: We compared surgically resected tumors of 23 LTS (survival &gt; 4 years) and 18 EXS (survival ≤ 2 years). There were no differences in clinical variables including TNM staging and curative versus non-curative intend surgery between the groups. Gene expression profiling was performed by microarrays and tumor microenvironment analyses were by IHC of prominent immune related markers.

Results: Immune related genes and pathways represented the majority of the differentially overexpressed genes in LTS compared to the EXS. The differences in the immunological tumor-microenvironment were confirmed by quantitative immuno-staining. Increased numbers of tumor infiltrating and associated lymphocytes were present throughout tumors of LTS. Several differentiating patterns of enhanced anti-tumor immunity were identified. While some areas of LTS tumors also harbored higher numbers of suppressive immune cells (monocytes, regulatory lymphocytes, and macrophages), ratios of these suppressive cells to CD3+ lymphocytes were generally lower in LTS tumors indicating a more tumor suppressive microenvironment.

Conclusions: Our data demonstrate that long-term survivorship of SCLC patients is strongly influenced by the presence of anti-tumor immune cells in the tumor microenvironment. Characterization of the anti-tumor immune responses may identify opportunities for individualized immunotherapies for SCLC.

Citation Format: Farhad Kosari, Prasuna Muppa, Simone Terra, Anurag Sharma, Aaron Mansfield, Marie Christine Aubry, Nafiseh Janaki, Aqsa Nasir, Tobias Peikert. Anti-tumor immunity is a key determinant of small cell lung cancer survivorship [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 4577.

Abstract 728: Genomic alterations in lung adenocarcinoma precursor lesions

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&gt;T, T&gt;C transitions and C&gt;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.

Neoantigenic Potential of Complex Chromosomal Rearrangements in Mesothelioma

INTRODUCTION

Malignant pleural mesothelioma is a disease primarily associated with exposure to the carcinogen asbestos. Whereas other carcinogen-related tumors are associated with a high tumor mutation burden, mesothelioma is not. We sought to resolve this discrepancy.

METHODS

We used mate-pair (n = 22), RNA (n = 28), and T cell receptor sequencing along with in silico predictions and immunologic assays to understand how structural variants of chromosomes affect the transcriptome.

RESULTS

We observed that inter- or intrachromosomal rearrangements were present in every specimen and were frequently in a pattern of chromoanagenesis such as chromoplexy or chromothripsis. Transcription of rearrangement-related junctions was predicted to result in many potential neoantigens, some of which were proven to bind patient-specific major histocompatibility complex molecules and to expand intratumoral T cell clones. T cells responsive to these predicted neoantigens were also present in a patient's circulating T cell repertoire. Analysis of genomic array data from the mesothelioma cohort in The Cancer Genome Atlas suggested that multiple chromothriptic-like events negatively impact survival.

CONCLUSIONS

Our findings represent the discovery of potential neoantigen expression driven by structural chromosomal rearrangements. These results may have implications for the development of novel immunotherapeutic strategies and the selection of patients to receive immunotherapies.

Abstract 5726: Rearrangement-related peptides with neoantigenic potential in malignant pleural mesothelioma

Malignant pleural mesothelioma is a disease primarily associated with exposure to the carcinogen asbestos. Consistent with this carcinogenic exposure, cytogenetic analyses have identified multiple recurrent structural chromosomal abnormalities in this malignancy, but more recent high-throughput sequencing evaluations of point mutations suggest that there is a low mutational burden in mesothelioma. Since tumor mutational burden has been correlated with responses to treatment with immune checkpoint inhibitors such as nivolumab, it was not consistent that patients with mesothelioma and low mutation burdens would have similar response rates in clinical trials with immune checkpoint inhibitors as patients with non-small cell lung cancer which is associated with a high mutation burden. In order to reconcile these differences, and given the potential for an improved understanding of the molecular pathogenesis of mesothelioma to improve therapeutic options, we used mate-pair sequencing (MPseq) and RNA sequencing (RNAseq) to understand how structural variants affect the transcriptome. MPseq differs from standard next generation sequencing approaches by tiling the whole genome with larger fragments (2-5kb) to reliably detect structural variants such as insertions, deletions and rearrangements. Amongst 22 mesothelioma specimens there were 1535 chromosomal rearrangements (median 41, range 3-298 per specimen), that resulted in junctions or novel fusions of non-coding DNA or genes. Six-hundred thirty-seven of these rearrangements (median 22, range 5-103 range per specimen) resulted in novel fusions of genes. Many of these inter- or intra-chromosomal rearrangements were consistent with a pattern of chromoanagesis such as chromoplexy or chromothripsis. Chromosomal rearrangements detected by MPseq were used to guide analysis of RNAseq data and revealed that these chromosomal junctions resulted in the expression of 179 novel amino acid sequences (median 5, 0-51 range per specimen). To determine whether transcription of chromosomal rearrangement-related junctions have neoantigenic potential, we used in silico tools to determine whether any of the expressed junctions contained peptides that could be presented by patient-specific HLA molecules. The top candidate rearrangement-related peptides with neoantigenic potential bound patient-specific HLA molecules nearly as well or as well as a positive control in competitive binding assays. Our findings represent the discovery of potential neoantigen expression driven by structural chromosomal rearrangements. These results may have implications for the development of novel therapeutic strategies, the selection of patients to receive immunotherapy, and blood-based treatment monitoring strategies.

Citation Format: Aaron S. Mansfield, Tobias Peikert, James B. Smadbeck, Julia B. Udell, Farhad Kosari, Stephen J. Murphy, Hongzheng Ren, Vishnu V. Serla, Janet L. Schaefer Klein, Giannoula Karagouga, Faye R. Harris, Carlos Sosa, Sarah H. Johnson, Wendy Nevala, Svetomir N. Markovic, Aaron O. Bungum, Eric S. Edell, Haidong Dong, John C. Cheville, Marie Christine Aubry, Jin Jen, George Vasmatzis. Rearrangement-related peptides with neoantigenic potential in malignant pleural mesothelioma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5726.

EGFR mediates activation of RET in lung adenocarcinoma with neuroendocrine differentiation characterized by ASCL1 expression

Achaete-scute homolog 1 (ASCL1) is a neuroendocrine transcription factor specifically expressed in 10-20% of lung adenocarcinomas (AD) with neuroendocrine (NE) differentiation (NED). ASCL1 functions as an upstream regulator of the RET oncogene in AD with high ASCL1 expression (A⁺AD). RET is a receptor tyrosine kinase with two main human isoforms; RET9 (short) and RET51 (long). We found that elevated expression of RET51 associated mRNA was highly predictive of poor survival in stage-1 A⁺AD (p=0.0057). Functional studies highlighted the role of RET in promoting invasive properties of A⁺AD cells. Further, A⁺AD cells demonstrated close to 10 fold more sensitivity to epidermal growth factor receptor (EGFR) inhibitors, including gefitinib, than AD cells with low ASCL1 expression. Treatment with EGF robustly induced phosphorylation of RET at Tyr-905 in A⁺AD cells with wild type EGFR. This phosphorylation was blocked by gefitinib and by siRNA-EGFR. Immunoprecipitation experiments found EGFR in a complex with RET in the presence of EGF and suggested that RET51 was the predominant RET isoform in the complex. In the microarray datasets of stage-1 and all stages of A⁺AD, high levels of EGFR and RET RNA were significantly associated with poor overall survival (p < 0.01 in both analyses). These results implicate EGFR as a key regulator of RET activation in A⁺AD and suggest that EGFR inhibitors may be therapeutic in patients with A⁺AD tumors even in the absence of an EGFR or RET mutation.

Contraction of T cell richness in lung cancer brain metastases

Very little is known about how the adaptive immune system responds to clonal evolution and tumor heterogeneity in non-small cell lung cancer. We profiled the T-cell receptor β complementarity determining region 3 in 20 patients with fully resected non-small cell lung cancer primary lesions and paired brain metastases. We characterized the richness, abundance and overlap of T cell clones between pairs, in addition to the tumor mutation burden and predicted neoantigens. We found a significant contraction in the number of unique T cell clones in brain metastases compared to paired primary cancers. The vast majority of T cell clones were specific to a single lesion, and there was minimal overlap in T cell clones between paired lesions. Despite the contraction in the number of T cell clones, brain metastases had higher non-synonymous mutation burdens than primary lesions. Our results suggest that there is greater richness of T cell clones in primary lung cancers than their paired metastases despite the higher mutation burden observed in metastatic lesions. These results may have implications for immunotherapy.

Computer-Aided Nodule Assessment and Risk Yield (CANARY) may facilitate non-invasive prediction of EGFR mutation status in lung adenocarcinomas

Computer-Aided Nodule Assessment and Risk Yield (CANARY) is quantitative imaging analysis software that predicts the histopathological classification and post-treatment disease-free survival of patients with adenocarcinoma of the lung. CANARY characterizes nodules by the distribution of nine color-coded texture-based exemplars. We hypothesize that quantitative computed tomography (CT) analysis of the tumor and tumor-free surrounding lung facilitates non-invasive identification of clinically-relevant mutations in lung adenocarcinoma. Comprehensive analysis of targetable mutations (50-gene-panel) and CANARY analysis of the preoperative (≤3 months) high resolution CT (HRCT) was performed for 118 pulmonary nodules of the adenocarcinoma spectrum surgically resected between 2006–2010. Logistic regression with stepwise variable selection was used to determine predictors of mutations. We identified 140 mutations in 106 of 118 nodules. TP53 (n = 48), KRAS (n = 47) and EGFR (n = 15) were the most prevalent. The combination of Y (Yellow) and G (Green) exemplars, fibrosis within the surrounding lung and smoking status were the best discriminators for an EGFR mutation (AUC 0.77 and 0.87, respectively). None of the EGFR mutants expressing TP53 (n = 5) had a good prognosis based on CANARY features. No quantitative features were significantly associated with KRAS mutations. Our exploratory analysis indicates that quantitative CT analysis of a nodule and surrounding lung may noninvasively predict the presence of EGFR mutations in pulmonary nodules of the adenocarcinoma spectrum.

Patient- and Cell Type-Specific Heterogeneity of Metformin Response

Most 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.

Local and systemic immunity predict survival in patients with pulmonary sarcomatoid carcinoma

Pulmonary sarcomatoid cancer (PSC) is a rare, aggressive subtype of non-small cell lung cancer, and measures of local and systemic immunity as biomarkers are incompletely known. We performed this study to characterize the leukocyte composition within the tumor, stroma, and peripheral blood in patients with PSC and correlated our findings with overall survival. Tissue from 30 patients diagnosed with PSC was evaluated by IHC for the presence of CD3⁺, CD14⁺, and CD19⁺ cells and PD-L1 expression. A lymphocyte-to-monocyte ratio (LMR) was calculated for the tumor microenvironment (TME) and peripheral blood. Survival analyses were performed based on IHC scores or groups defined by receiver operating characteristic curve cutoffs. CD3⁺ and CD14⁺ cells were found throughout the TME. CD19⁺ cells were almost exclusive to the stroma and correlated with superior overall survival (HR 0.40, 95% CI 0.21-0.72, p = 0.003). Most patients expressed PD-L1 on the tumor and/or the infiltrating immune cells, but neither the presence nor PD-L1 expression level impacted survival. A more prolific immune infiltration of the TME was associated with improved survival (HR 0.82, 95% CI 0.70-0.98, p = 0.029). PSC patients with a TME LMR ≥1.2 had a median survival of 1598 versus 488 days for a TME LMR <1.2 (p = 0.010). In the peripheral blood, an LMR ≥2.3 was associated with improved median survival (1579 vs. 332 days, p < 0.001). Our data demonstrate multiple measures of the local and systemic immunity are associated with patient survival in PSC.

Management of Multifocal Lung Cancer: Results of a Survey

INTRODUCTION

Multifocal lung cancer is an increasingly common clinical scenario, but there is lack of high-level evidence for its optimal treatment. Thus, we surveyed members of the interdisciplinary International Association for the Study of Lung Cancer on their therapeutic approaches and analyzed the resultant practice patterns.

METHODS

We described the clinical scenario of an otherwise healthy 60-year-old man with bilateral pulmonary nodules and asked the 6373 members of the International Association for the Study of Lung Cancer whether they would recommend surgery, and if so, the extent of surgery. We also asked what other measures would be recommended to complete the staging and whether radiation therapy or chemotherapy would be suggested.

RESULTS

We received 221 responses (response rate 3.5%) from multiple specialists. Most respondents (140 [63%]) recommended surgery for this scenario. Surgeons were significantly more likely to recommend surgery than were those in other specialties. Of those who recommended surgery, most would obtain a PET/CT scan to rule out distant metastases and a magnetic resonance imaging scan to rule out brain metastases; but in the absence of radiographic lymph node involvement, most would not stage the mediastinum by bronchoscopy or mediastinoscopy before resection. When surgery was not recommended or declined, respondents commonly recommended radiation.

CONCLUSIONS

This survey suggests that therapeutic recommendations for multifocal lung cancer are influenced to a large extent by physicians' specialty training, probably because of the lack of high-level evidence for its standard treatment. Ongoing systematic and multidisciplinary approaches with robust short-term and long-term patient outcomes may improve the quality of evidence for the optimal management of this clinical entity.

Diagnosis of Acute Cellular Rejection and Antibody-Mediated Rejection on Lung Transplant Biopsies: A Perspective From Members of the Pulmonary Pathology Society

Context.—

The diagnosis and grading of acute cellular and antibody-mediated rejection (AMR) in lung allograft biopsies is important because rejection can lead to acute graft dysfunction and/or failure and may contribute to chronic graft failure. While acute cellular rejection is well defined histologically, no reproducible specific features of AMR are currently identified. Therefore, a combination of clinical features, serology, histopathology, and immunologic findings is suggested for the diagnosis of AMR.

Objective.—

To describe the perspective of members of the Pulmonary Pathology Society (PPS) on the workup of lung allograft transbronchial biopsy and the diagnosis of acute cellular rejection and AMR in lung transplant.

Data Sources.—

Reports by the International Society for Heart and Lung Transplantation (ISHLT), experience of members of PPS who routinely review lung allograft biopsies, and search of literature database (PubMed).

Conclusions.—

Acute cellular rejection should be assessed and graded according to the 2007 working formulation of the ISHLT. As currently no specific features are known for AMR in lung allografts, the triple test (clinical allograft dysfunction, donor-specific antibodies, pathologic findings) should be used for its diagnosis. C4d staining might be performed when morphologic, clinical, and/or serologic features suggestive of AMR are identified.

A Randomized Phase IIb Trial of myo-Inositol in Smokers with Bronchial Dysplasia

Previous preclinical studies and a phase I clinical trial suggested that myo-inositol may be a safe and effective lung cancer chemopreventive agent. We conducted a randomized, double blind, placebo-controlled phase IIb study to determine the chemopreventive effects of myo-inositol in smokers with bronchial dysplasia. Smokers with ≥1 site of dysplasia identified by autofluorescence bronchoscopy-directed biopsy were randomly assigned to receive oral placebo or myo-inositol, 9 g once a day for 2 weeks, and then twice a day for 6 months. The primary endpoint was change in dysplasia rate after 6 months of intervention on a per-participant basis. Other trial endpoints reported herein include Ki-67 labeling index, blood and bronchoalveolar lavage fluid (BAL) levels of proinflammatory, oxidant/antioxidant biomarkers, and an airway epithelial gene expression signature for PI3K activity. Seventy-four (n = 38 myo-inositol and n = 36 placebo) participants with a baseline and 6-month bronchoscopy were included in all efficacy analyses. The complete response and the progressive disease rates were 26.3% versus 13.9% and 47.4% versus 33.3%, respectively, in the myo-inositol and placebo arms (P = 0.76). Compared with placebo, myo-inositol intervention significantly reduced IL6 levels in BAL over 6 months (P = 0.03). Among those with a complete response in the myo-inositol arm, there was a significant decrease in a gene expression signature reflective of PI3K activation within the cytologically normal bronchial airway epithelium (P = 0.002). The heterogeneous response to myo-inositol suggests a targeted therapy approach based on molecular alterations is needed in future clinical trials to determine the efficacy of myo-inositol as a chemopreventive agent. Cancer Prev Res; 9(12); 906-14. ©2016 AACR.

Primary angiomatoid fibrous histiocytoma of the lung with mediastinal lymph node metastasis

Angiomatoid fibrous histiocytoma (AFH), a rare soft tissue tumor of borderline malignancy, typically occurs in the subcutis of the accessible soft tissues, most often in children and young adults. Lymph node and/or distant metastasis is seen in less than 2% of patients with AFH. Exceptionally rare examples of AFH have been reported in visceral locations, including the lung. We report a genetically confirmed primary pulmonary AFH in a 70-year-old woman with mediastinal lymph node metastasis, representing to the best of our knowledge the first report of metastases from a visceral AFH.

Temporal and spatial discordance of programmed cell death-ligand 1 expression and lymphocyte tumor infiltration between paired primary lesions and brain metastases in lung cancer

The tumor microenvironments of paired primary lung cancers and brain metastases are significantly different, such that many of the metastases lose PD-L1 expression, lymphocyte infiltration or both with greater discrepancies over time. The spatial and temporal heterogeneity of PD-L1 expression may limit its use as a tissue-based predictive biomarker in lung cancer.

Background

The dynamics of PD-L1 expression may limit its use as a tissue-based predictive biomarker. We sought to expand our understanding of the dynamics of PD-L1 expression and tumor-infiltrating lymphocytes (TILs) in patients with lung cancer-related brain metastases.

Experimental design

Paired primary lung cancers and brain metastases were identified and assessed for PD-L1 and CD3 expression by immunohistochemistry. Lesions with 5% or greater PD-L1 expression were considered positive. Agreement statistics and the χ² or Fisher's exact test were used for analysis.

Results

We analyzed 146 paired lesions from 73 cases. There was disagreement of tumor cell PD-L1 expression in 10 cases (14%, κ = 0.71), and disagreement of TIL PD-L1 expression in 19 cases (26%, κ = 0.38). Most paired lesions with discordant tumor cell expression of PD-L1 were obtained 6 or more months apart. When specimens were categorized using a proposed tumor microenvironment categorization scheme based on PD-L1 expression and TILs, there were significant changes in the classifications because many of the brain metastases lacked either PD-L1 expression, tumor lymphocyte infiltration or both even when they were present in the primary lung cancer specimens (P = 0.009).

Conclusions

We identified that there are significant differences between the tumor microenvironment of paired primary lung cancers and brain metastases. When physicians decide to treat patients with lung cancer with a PD-1 or PD-L1 inhibitor, they must do so in the context of the spatial and temporal heterogeneity of the tumor microenvironment.

Abstract 4513: A prognostic model for pulmonary carcinoid tumors based on large chromosomal alterations

PURPOSE: Previous mutational analyses have failed to identify a predictive or prognostic marker for pulmonary carcinoid tumors (PCT). The heterogeneity of PCTs coupled with a lack of detailed information about the tumor biology, impedes patient stratification into groups based on tumor phenotypes or treatment response. We sought to use high-throughput next-generation sequencing to improve prognostication.

METHODS: We stratified 37 patients with resected PCTs as low risk (n = 17) and high risk (n = 20) based on a 5 year long follow up for recurrence. Patients with no recurrence within 5 years from initial treatment were deemed low risk. Macrodissection was followed by genomic DNA isolation 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:

Carcinoids commonly harbor rearrangements (median 3.5, range 1-167). Large chromosomal gains or losses were found in 24 of the cases (64.8%). We developed a prognostic score that included the total amount of genetic alterations (deletions and translocations). ROC analysis revealed an AUC of 0.76. High risk patients had a mean score of 20 and low risk patients had a mean score of 5.45 (p value = 0.03, Welch Two Sample t-test). Further analysis of the specific genetic alterations harbored by high and low risk PCTs and correlation with the pathologic and immunohistochemical information is currently underway.

CONCLUSION:

Large chromosomal rearrangements and aneuploidy portend a poor prognosis for patients with PCTs. Mate Pair sequencing of PCTs provides valuable prognostic information for this highly heterogeneous group of cancers.

Citation Format: Konstantinos Leventakos, Aaron S. Mansfield, Stephen J. Murphy, Sarah H. Johnson, Sarah E. Kerr, Marie Christine Aubry, George Vasmatzis, Julian R. Molina. A prognostic model for pulmonary carcinoid tumors based on large chromosomal alterations. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4513.

Abstract 1129: EGFR-mediated activation of RET in ASCL1+ lung adenocarcinoma

Lung cancer accounts for about 27% of the cancer related deaths in the USA annually. Pathologically, it is a very complex disease broadly classified into small cell lung cancer (SCLC) and non-small cell lung cancer (NSCLC). NSCLCs are further classified into squamous cell carcinoma, large cell carcinoma and adenocarcinoma. Achaete-scute homolog 1 (ASCL1), an important transcription factor essential in the development of neuroendocrine cells (NE) in lungs is shown to be specifically expressed in lung NE cancers and 10-20% of adenocarcinomas (AD) with NE differentiation (NED), thus suggesting a role in the pathogenesis of these tumors. Our previous study showed that ASCL1 is a regulator of the RET oncogene in AD with NED. RET is a receptor tyrosine kinase with two isoforms in humans: RET9 (short) and RET51 (long). We performed survival analysis to study implications of RET isoforms in ASCL1+ tumors and found that elevated expression of the long RET mRNA was associated with poor survival. Subsequent in vitro experiments demonstrated that treatment with EGF robustly induced phosphorylation of RET in HCC1833 and H1755 cell lines which have high endogenous levels of ASCL1 and RET but not in VMRC-LCD cell line which has high level of ASCL1 but low level of RET. EGF induced phosphorylation of RET was diminished by gefitinib and by EGFR siRNA. Immunoprecipitation results indicated direct binding between EGFR and RET in presence of EGF. Furthermore, a high throughput drug screening found 8 EGFR inhibitors that were 10 - 250 fold more cytotoxic in ASCL1+ compared with ASCL1- AD cells. These results implicate EGFR as a key regulator of RET activation in ASCL1+ AD and suggest that EGFR inhibitors may be therapeutic for this population of patients.

Citation Format: Kaustubh N. Bhinge, Yang Lin, Hamed Rahi, Marie Christine Aubry, Aaron Mansfield, Irina Kovtun, Stephen Murphy, Ping Yang, Dennis Wigle, Joanne (Eunhee) Yi, Aqsa Nasir, Simone Terra, Julian Molina, George Vasmatzis, Farhad Kosari. EGFR-mediated activation of RET in ASCL1+ lung adenocarcinoma. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 1129.

Adenocarcinoma in situ, minimally invasive adenocarcinoma, and invasive pulmonary adenocarcinoma--analysis of interobserver agreement, survival, radiographic characteristics, and gross pathology in 296 nodules

The International Association for the Study of Lung Cancer/American Thoracic Society/European Respiratory Society and 2015 World Health Organization classifications of lung adenocarcinoma recommend designating tumors showing entirely lepidic growth as adenocarcinoma in situ (AIS) and lepidic tumors with invasion less than or equal to 5 mm as minimally invasive adenocarcinoma (MIA), both of which have superior outcome to conventional invasive adenocarcinoma (IA). Data on interobserver variability within this classification are limited, and further validation of the superior survival of AIS and MIA is needed. A total of 296 surgically excised pulmonary adenocarcinomas were reviewed from 254 patients (1997-2009). Slides were independently reviewed by 2 pulmonary pathologists who categorized tumors as AIS, MIA, or IA. Of 296 nodules, 244 (82.4%) were agreed upon by both observers: 10 AIS, 61 MIA, and 173 IA (κ = 0.63, good agreement). In 6 cases (2%), there was disagreement between AIS and MIA; in 45 cases (15%), there was disagreement between MIA and IA; and in 1 case, there was disagreement between AIS and IA. Overall survival was significantly different among categories as determined by both observers. Cases with disagreement between MIA and IA had similar survival to agreed MIA. Disease-specific 10-year survival was 100% for AIS (both observers) and 97.3% and 97.6% for MIA, although this did not reach statistical significance compared to IA for either observer. Good agreement was present between observers when classifying tumors as AIS, MIA, and IA. Significant differences in overall survival were present between the 3 groups for both observers, and interobserver variability was evident. Patients with AIS and MIA experienced excellent DSS.

Heterogeneity of Programmed Cell Death Ligand 1 Expression in Multifocal Lung Cancer

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 Cryobiopsies in the Evaluation of Lung Allografts: Do the Benefits Outweigh the Risks?

CONTEXT

Transbronchial cryobiopsy technique yields larger biopsies with enhanced quality. The benefits and safety of cryobiopsies have not been thoroughly studied in lung allografts.

OBJECTIVE

To compare size, quality, reproducibility of interpretation of rejection and complications of cryobiopsies with those of conventional biopsies from lung allografts.

DESIGN

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.

RESULTS

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.

CONCLUSIONS

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.

Abstract 1897: Metformin as a chemoprevention agent for lung squamous cancer

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 3895: Genomic alterations modify ubiquitination pathways in pulmonary carcinoid tumors

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 5251: ASCL1 and RET expression define a clinically relevant subgroup of lung adenocarcinoma characterized by neuroendocrine differentiation

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 &lt; 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

Immunohistochemical study of 36 cases of pulmonary sarcomatoid carcinoma--sensitivity of TTF-1 is superior to napsin

Immunohistochemistry is often used to distinguish pulmonary sarcomatoid carcinoma from morphologic mimics. Napsin-A is a pulmonary adenocarcinoma marker, but literature on expression in sarcomatoid carcinoma is limited. Thirty-six cases of sarcomatoid carcinoma were stained for napsin, TTF-1, Oscar, CAM5.2, AE1/AE3, desmin, SMA, S-100, CK5/6, calretinin, D2-40, and WT1. Patients were 24 men and 12 women (mean, 70 years; range, 46-93). There were 27 pleomorphic carcinomas, 5 spindle cell carcinomas, 3 carcinosarcomas, and 1 giant cell carcinoma. Cases were positive for at least 1 keratin: AE1/3 was positive in all 36 cases; Oscar, in 34 cases (94%); and CAM5.2, in 32 cases (89%, weaker/more focal). Napsin was positive in 14 cases (39%): 8 diffuse, 3 focal, and 3 rare cells. TTF-1 was positive in 22 cases (61%): 15 diffuse, 3 focal, and 4 rare cells. No cases were napsin positive and negative for TTF-1. Variable staining for mesothelial markers was observed, including positivity for calretinin (12 cases, 33%), WT1 (6 cases, 17%), D2-40 (5 cases, 14%), and CK5/6 (9 cases, 25%). Mesenchymal markers were also sometimes positive (usually focal), including S-100 (4 cases, 11%), desmin (4 cases, 11%), and SMA (7 cases, 19%, 1 diffuse). In conclusion, TTF-1 is more sensitive than napsin for detection of sarcomatoid carcinoma, and no cases were positive for napsin but negative for TTF-1. CAM5.2 is less sensitive than AE1/AE3 and Oscar. Use of a thoughtful immunohistochemical panel is important in the evaluation of sarcomatoid carcinoma because mesothelial and mesenchymal markers can be expressed.

Systemic karyomegaly with primary pulmonary presentation

Systemic karyomegaly is a distinct disorder characterized by progressive renal failure and enlarged, bizarre renal tubular epithelial cells. We report the first case of systemic karyomegaly with primary pulmonary presentation and present the first detailed characterization of the karyomegalic cells in lung tissue. A 33-year-old woman was evaluated for chronic and progressive restrictive lung disease, ultimately necessitating single-lung transplantation. Her post-transplant course was marked by graft dysfunction, respiratory decline and renal failure culminating in her death 97 days post-transplant. At autopsy, karyomegalic cells were identified in her kidneys, prompting a careful examination of her native lung and other tissue. Karyomegalic cells were identified in the alveolar epithelium and airway walls. Viral studies were negative. DNA ploidy studies revealed an abnormal ploidy status of the karyomegalic cells. The identification and characterization of systemic karyomegaly with symptomatic lung involvement expands the differential diagnosis for relatively young patients presenting with interstitial lung disease.

Outside Case Review of Surgical Pathology for Referred Patients: The Impact on Patient Care

Context.— Original surgical pathology materials from external sources are reviewed by our pathologists for referred patients before their clinical evaluation and treatment.

Objective.— To identify the rate of major disagreements with diagnoses from external institutions and to characterize the nature and impact of discordant diagnoses on patient care.

Design.— We identified and reviewed all surgical pathology cases, except for medical liver, medical renal, and cardiac pathology cases, for the period between January 1, 2005, and December 31, 2010, to determine the overall frequency of major disagreements, defined as any change in diagnosis having a substantial impact on patient management.

Results.— Our review of 71 811 cases initially examined between 2005 and 2010 identified 457 major disagreements (0.6%). The most frequent areas of disagreement were gastrointestinal (80 cases; 17.5%), lymph node (73; 16.0%), bone/soft tissue (47; 10.3%), and genitourinary (43; 9.4%). For a subset of 166 cases reviewed between July 1, 2009, and December 31, 2010, follow-up data were available for 140 (84.3%). Treatment was affected by a changed diagnosis in 126 cases (90.0%), and prognosis was affected in 129 cases (92.1%). For 86 (51.8%) of the 166 cases, additional tissue was obtained. Revised diagnoses concurred with follow-up tissue diagnosis in 84.9% (73 cases), whereas they differed from follow-up tissue diagnosis in 15.1% (13 cases).

Conclusions.— Our findings demonstrate the value of outside case review of pathology materials for referred patients, and suggest that it decreases the likelihood of diagnostic errors and provides better protection for patients.

Outcome of septal myectomy in patients with Fabry's disease

Fabry's disease has cardiac manifestations that may mimic hypertrophic cardiomyopathy, including left ventricular outflow tract (LVOT) obstruction. It is important to distinguish hypertrophic cardiomyopathy from Fabry's disease, which can be treated with enzyme replacement therapy (ERT). However, after adequate ERT, some patients have no resolution of cardiac symptoms; thus, septal myectomy might be considered. We present 2 cases of extended septal myectomy in patients with LVOT obstruction secondary to Fabry's disease.

Randomized phase II trial of sulindac for lung cancer chemoprevention

INTRODUCTION

Sulindac represents a promising candidate agent for lung cancer chemoprevention, but clinical trial data have not been previously reported. We conducted a randomized, phase II chemoprevention trial involving current or former cigarette smokers (≥30 pack-years) utilizing the multi-center, inter-disciplinary infrastructure of the Cancer Prevention Network (CPN).

METHODS

At least 1 bronchial dysplastic lesion identified by fluorescence bronchoscopy was required for randomization. Intervention assignments were sulindac 150mg bid or an identical placebo bid for 6 months. Trial endpoints included changes in histologic grade of dysplasia (per-participant as primary endpoint and per lesion as secondary endpoint), number of dysplastic lesions (per-participant), and Ki67 labeling index.

RESULTS

Slower than anticipated recruitment led to trial closure after randomizing participants (n=31 and n=30 in the sulindac and placebo arms, respectively). Pre- and post-intervention fluorescence bronchoscopy data were available for 53/61 (87%) randomized, eligible participants. The median (range) of dysplastic lesions at baseline was 2 (1-12) in the sulindac arm and 2 (1-7) in the placebo arm. Change in dysplasia was categorized as regression:stable:progression for 15:3:8 (58%:12%:31%) subjects in the sulindac arm and 15:2:10 (56%:7%:37%) subjects in the placebo arm; these distributions were not statistically different (p=0.85). Median Ki67 expression (% cells stained positive) was significantly reduced in both the placebo (30 versus 5; p=0.0005) and sulindac (30 versus 10; p=0.0003) arms, but the difference between arms was not statistically significant (p=0.92).

CONCLUSIONS

Data from this multi-center, phase II squamous cell lung cancer chemoprevention trial do not demonstrate sufficient benefits from sulindac 150mg bid for 6 months to warrant additional phase III testing. Investigation of pathway-focused agents is necessary for lung cancer chemoprevention.

Tumor B7-H1 and B7-H3 expression in squamous cell carcinoma of the lung

BACKGROUND

Pulmonary squamous cell carcinoma has a poor prognosis, and new therapeutic targets are needed. The aberrant expression of the immunomodulatory proteins B7-H1 and B7-H3 by malignant cells may contribute to tumoral immune evasion. Data about the expression of these proteins by squamous cell carcinoma of the lung are limited.

MATERIALS AND METHODS

Immunohistochemistry for B7-H1 and B7-H3 was performed on 214 resected pulmonary squamous cell carcinoma specimens.

RESULTS

At the last follow-up, 171 of 214 (80%) of patients were deceased (median survival time, 3.76 years). Forty-two (19.6%) of 214 cases showed positivity with B7-H1, with a range of 5% to 60% of cells that stained positively. A total of 189 (88.3%) of 214 cases showed positivity with B7-H3, with a range of 5% to 80% of cells staining positively. By using multivariate analysis, no degree of B7-H1 or B7-H3 positivity was significantly associated with patient outcome.

CONCLUSIONS

Although B7-H1 and B7-H3 are not of independent prognostic value, they are commonly expressed on a subset of tumor cells in pulmonary squamous cell carcinomas. Known interaction of the B7-H proteins with cytotoxic T-lymphocyte antigen-4 may make them attractive candidate biomarkers for response to immunomodulatory therapeutics, eg, ipilimumab, and warrants further study.

Increased miR-708 expression in NSCLC and its association with poor survival in lung adenocarcinoma from never smokers

PURPOSE

miRNA plays an important role in human disease and cancer. We seek to investigate the expression status, clinical relevance, and functional role of miRNA in non-small cell lung cancer.

EXPERIMENTAL DESIGN

We conducted miRNA expression profiling in matched lung adenocarcinoma and uninvolved lung using 56 pairs of fresh-frozen (FF) and 47 pairs of formalin-fixed, paraffin-embedded (FFPE) samples from never smokers. The most differentially expressed miRNA genes were evaluated by Cox analysis and log-rank test. Among the best candidate, miR-708 was further examined for differential expression in two independent cohorts. Functional significance of miR-708 expression in lung cancer was examined by identifying its candidate mRNA target and through manipulating its expression levels in cultured cells.

RESULTS

Among the 20 miRNAs most differentially expressed between tested tumor and normal samples, high expression level of miR-708 in the tumors was most strongly associated with an increased risk of death after adjustments for all clinically significant factors including age, sex, and tumor stage (FF cohort: HR, 1.90; 95% CI, 1.08-3.35; P = 0.025 and FFPE cohort: HR, 1.93; 95% CI, 1.02-3.63; P = 0.042). The transcript for TMEM88 gene has a miR-708 binding site in its 3' UTR and was significantly reduced in tumors high of miR-708. Forced miR-708 expression reduced TMEM88 transcript levels and increased the rate of cell proliferation, invasion, and migration in culture.

CONCLUSIONS

miRNA-708 acts as an oncogene contributing to tumor growth and disease progression by directly downregulating TMEM88, a negative regulator of the Wnt signaling pathway in lung cancer.

Recurrent pulmonary intimal sarcoma involving the right ventricular outflow tract

Intimal sarcoma of the pulmonary artery is commonly misdiagnosed as chronic pulmonary embolism. Rarely, it can involve the right ventricular outflow tract and the pulmonary valve. We report a patient who was treated surgically for an intimal sarcoma of the pulmonary artery involving the right ventricular outflow tract and the pulmonary valve. The sarcoma recurred in about 8 weeks. It responded favorably to chemoradiation therapy and shows some signs of regression.