Arun Rajan

Anti-cytokine autoantibodies are associated with opportunistic infection in patients with thymic neoplasia

Patients with thymic malignancy have high rates of autoimmunity leading to a variety of autoimmune diseases, most commonly myasthenia gravis caused by anti-acetylcholine receptor autoantibodies. High rates of autoantibodies to cytokines have also been described, although prevalence, spectrum, and functionality of these anti-cytokine autoantibodies are poorly defined. To better understand the presence and function of anti-cytokine autoantibodies, we created a luciferase immunoprecipitation system panel to search for autoantibodies against 39 different cytokines and examined plasma from controls (n = 30) and patients with thymic neoplasia (n = 17). In this screen, our patients showed statistically elevated, but highly heterogeneous immunoreactivity against 16 of the 39 cytokines. Some patients showed autoantibodies to multiple cytokines. Functional testing proved that autoantibodies directed against interferon-α, interferon-β, interleukin-1α (IL-1α), IL-12p35, IL-12p40, and IL-17A had biologic blocking activity in vitro. All patients with opportunistic infection showed multiple anti-cytokine autoantibodies (range 3-11), suggesting that anti-cytokine autoantibodies may be important in the pathogenesis of opportunistic infections in patients with thymic malignancy. This study was registered at http://clinicaltrials.gov as NCT00001355.

A Phase I/II Trial of Belinostat in Combination with Cisplatin, Doxorubicin and Cyclophosphamide in Thymic Epithelial Tumors: A Clinical And Translational Study

Purpose: This phase I/II study sought to determine the safety and maximum tolerated dose (MTD) of a novel schedule of belinostat, a histone deacetylase inhibitor (HDAC) administered before and in combination with cisplatin (P), doxorubicin (A), and cyclophosphamide (C) in thymic epithelial tumors (TET). Antitumor activity, pharmacokinetics, and biomarkers of response were also assessed. Experimental Design: Patients with advanced, unresectable TET received increasing doses of belinostat as a continuous intravenous infusion over 48 hours with chemotherapy in 3-week cycles. In phase II, belinostat at the MTD was used. Results: Twenty-six patients were enrolled (thymoma, 12; thymic carcinoma, 14). Dose-limiting toxicities at 2,000 mg/m2 belinostat were grade 3 nausea and diarrhea and grade 4 neutropenia and thrombocytopenia, respectively, in two patients. Twenty-four patients were treated at the MTD of 1,000 mg/m2 with chemotherapy (P, 50 mg/m2 on day 2; A, 25 mg/m2 on days 2 and 3; C, 500 mg/m2 on day 3). Objective response rates in thymoma and thymic carcinoma were 64% (95% confidence interval, 30.8%-89.1%) and 21% (4.7%–50.8%), respectively. Modulation of pharmacodynamic markers of HDAC inhibition and declines in regulatory T cell (Treg) and exhausted CD8+ T-cell populations were observed. Decline in Tregs was associated with response (P = 0.0041) and progression-free survival (P = 0.021). Declines in TIM3+ CD8+ T cells were larger in responders than nonresponders (P = 0.049). Conclusion: This study identified the MTD of belinostat in combination with PAC and indicates that the combination is active and feasible in TETs. Immunomodulatory effects on Tregs and TIM3+ CD8+ T cells warrant further study. Clin Cancer Res; 20(21); 5392–402. ©2014 AACR.

Mutations of epigenetic regulatory genes are common in thymic carcinomas

Genetic alterations and etiology of thymic epithelial tumors (TETs) are largely unknown, hampering the development of effective targeted therapies for patients with TETs. Here TETs of advanced-stage patients enrolled in a clinical trial of molecularly-guided targeted therapies were employed for targeted sequencing of 197 cancer-associated genes. Comparative sequence analysis of 78 TET/blood paired samples obtained from 47 thymic carcinoma (TC) and 31 thymoma patients revealed a total of 86 somatic non-synonymous sequence variations across 39 different genes in 33 (42%) TETs. TCs (62%; 29/47) showed higher incidence of somatic non-synonymous mutations than thymomas (13%; 4/31; p < 0.0001). TP53 was the most frequently mutated gene in TETs (n = 13; 17%), especially in TCs (26%), and was associated with a poorer overall survival (p < 0.0001). Genes in histone modification [BAP1 (n = 6; 13%), SETD2 (n = 5; 11%), ASXL1 (n = 2; 4%)], chromatin remodeling [SMARCA4 (n = 2; 4%)], and DNA methylation [DNMT3A (n = 3; 7%), TET2 (n = 2; 4%), WT1 (n = 2; 4%)] pathways were recurrently mutated in TCs, but not in thymomas. Our results suggest a potential disruption of epigenetic homeostasis in TCs, and a substantial difference in genetic makeup between TCs and thymomas. Further investigation is warranted into the roles of epigenetic dysregulation in TC development and its potential for targeted therapy.

A population-based assessment of mortality and morbidity patterns among patients with thymoma†

Thymomas are rare tumors of the mediastinum; a limited number of small studies have evaluated the outcomes in these patients. We identified 668 patients with thymoma from the Swedish Cancer Registry, and 2,719 population‐based matched controls. We obtained information on autoimmunity from the nationwide inpatient/outpatient hospital discharge Registry. We constructed Kaplan‐Meier curves for survival analysis, conditional regression and Cox proportional hazards models to evaluate the association between thymoma and autoimmune diseases, and standardized incidence ratios (SIRs) to evaluate the risk for second cancers following thymoma. Compared with controls, patients with benign or malignant thymoma had a poorer (p < 0.001) 5‐year (79%, 53% vs. 91%), 10‐year (65%, 39% vs. 78%) and 20‐year (43%, 18% vs. 55%) overall survival. For thymoma patients, younger age at diagnosis and being diagnosed in recent years were associated with a better survival. Compared with controls, thymoma patients were more likely to have an autoimmune disease at some point during their lives (32.7% vs. 2.4%, respectively, p < 0.001), most frequently myasthenia gravis (24.5%), systemic lupus erythematosus (2.4%) and red cell aplasia (1.2%). Thymoma patients had twofold excess risk for second cancers compared with the general population, most notably: non‐melanoma skin cancer (SIR = 10.6, 95% confidence intervals (CI) = 6.0–17.3), non‐Hodgkin lymphoma (SIR = 6.8, 95% CI = 3.00–13.0), and cervical (SIR = 6.9, 95% CI = 1.4–20.1), endocrine (SIR = 4.7, 95% CI = 1.3–12.0), and prostate cancer (SIR = 3.0, 95% CI = 1.7–4.8). Despite the improved survival for thymoma patients over time, they have worse survival than controls. Thymoma patients are in need for follow‐up to detect and manage autoimmune diseases and cancer.

Tropomyosin expression and dynamics in developing avian embryonic muscles

The expression of striated muscle proteins occurs early in the developing embryo in the somites and forming heart. A major component of the assembling myofibrils is the actin-binding protein tropomyosin. In vertebrates, there are four genes for tropomyosin (TM), each of which can be alternatively spliced. TPM1 can generate at least 10 different isoforms including the striated muscle-specific TPM1alpha and TPM1kappa. We have undertaken a detailed study of the expression of various TM isoforms in 2-day-old (stage HH 10-12; 33 h) heart and somites, the progenitor of future skeletal muscles. Both TPM1alpha and TPM1kappa are expressed transiently in embryonic heart while TPM1alpha is expressed in somites. Both RT-PCR and in situ hybridization data suggest that TPM1kappa is expressed in embryonic heart whereas TPM1alpha is expressed in embryonic heart, and also in the branchial arch region of somites, and in the somites. Photobleaching studies of Yellow Fluorescent Protein-TPM1alpha and -TPM1kappa expressed in cultured avian cardiomyocytes revealed that the dynamics of the two probes was the same in both premyofibrils and in mature myofibrils. This was in sharp contrast to skeletal muscle cells in which the fluorescent proteins were more dynamic in premyofibrils. We speculate that the differences in the two muscles is due to the appearance of nebulin in the skeletal myocytes premyofibrils transform into mature myofibrils.

State of the Art of Genetic Alterations in Thymic Epithelial Tumors

The rapid advent of technology in recent years has resulted in a substantial increase in our knowledge of the molecular underpinnings of thymic epithelial tumors. In addition to previously described chromosomal aberrations and alterations in DNA methylation, genome sequencing has helped unravel hitherto unknown mutations in these tumors. Attempts are also being made to develop gene signatures to help in the identification of patients likely to benefit from adjuvant therapy. Some of the recently identified genetic alterations have the potential to serve as targets for biological therapy, thus opening newer avenues for treatment of thymic epithelial tumors and increasing the number of effective options for treatment of recurrent or refractory disease.

Targeted Therapy for Advanced Thymic Tumors

The use of targeted therapies for the treatment of thymic malignancies is documented in the literature. However, only a few drugs have undergone evaluation in phase II trials. Most of the evidence for the benefit of biologic therapies for thymic malignancies is in the form of case reports and small case series. No major activity has been observed with any agent so far, likely due to the lack of selection of patients for targeted therapies and the small numbers studied. A better understanding of the biology of these tumors will be essential in furthering the field.

Biomarkers in Early-Stage Non–Small-Cell Lung Cancer: Current Concepts and Future Directions

Advances in molecular biology and bioinformatics have resulted in the identification of a number of potential biomarkers that could be relevant in the management of patients with non–small-cell lung cancer (NSCLC). Although there is an increasing amount of literature related to these biomarkers, major issues need to be resolved including validity and reproducibility of results. Additionally, in order to interpret the existing literature accurately, a clear distinction must be made between the prognostic and predictive value of biomarkers. The practical applicability of biomarker discovery for patients with lung cancer includes the identification of patients with early-stage NSCLC who are most likely to benefit from adjuvant therapy. Information gleaned from biomarkers has the potential to help in evaluating the role of targeted therapies including immunotherapy in the neoadjuvant and adjuvant setting. The role of gene signatures and the use of newer platforms such as RNA, methylation, and protein signatures is being explored in patients with early-stage NSCLC. This review focuses on the applications of biomarker discovery in patients with early-stage NSCLC.

18F-Fluorodeoxyglucose Positron Emission Tomography in the Management of Patients with Thymic Epithelial Tumors

Purpose: There are limited data regarding the role of 18F-fluorodeoxyglucose positron emission tomography ([18F]-FDG PET) imaging in management of patients with thymic epithelial tumors (TET). The primary objective of this study was to assess the usefulness of early [18F]-FDG PET to monitor treatment efficacy and its correlation with Response Evaluation Criteria in Solid Tumors (RECIST) in patients with TETs. Experimental Design: [18F]-FDG PET/computed tomographic (CT) scans were conducted at baseline and after 6 weeks of treatment in patients enrolled in two phase II and one phase I/II clinical trials. On the basis of data from other solid tumors, metabolic response was defined as a reduction of [18F]-FDG uptake by more than 30% as assessed by average standardized uptake values (SUV) of up to five most metabolically active lesions. Results: Fifty-six patients with unresectable Masaoka stage III or IV TETs were included. There was a close correlation between early metabolic response and subsequent best response using RECIST (P < 0.0001–0.0003): sensitivity and specificity for prediction of best response were 95% and 100%, respectively. Metabolic responders had significantly longer progression-free survival (median, 11.5 vs. 4.6 months; P = 0.044) and a trend toward longer overall survival (median, 31.8 vs. 18.4 months; P = 0.14) than nonresponders. [18F]-FDG uptake was significantly higher in thymic carcinoma than in thymoma (P = 0.0004–0.0010). Conclusion: In patients with advanced TETs, early metabolic response closely correlates with outcome of therapy. [18F]-FDG PET may be used to monitor treatment efficacy and assess histologic differences in patients with advanced TETs. Clin Cancer Res; 19(6); 1487–93. ©2013 AACR.

Low-molecular-weight heparin may alter point-of-care assay for international normalized ratio.

Study Objective. To compare the international normalized ratio (INR) measured by a point‐of‐care testing device with that measured by a reference laboratory method for patients receiving either warfarin only or warfarin plus low‐molecular‐weight heparin (LMWH).