Long-Term Outcomes of Surgical and Nonsurgical Management of Stage IV Thymoma: A Population-Based Analysis of 282 Patients

HNRNPA2B1 as a potential therapeutic target for thymic epithelial tumor recurrence: An integrative network analysis

Thymic epithelial tumors (TETs) are rare malignant tumors, and the molecular mechanisms of both primary and recurrent TETs are poorly understood. Here we established comprehensive proteomic signatures of 15 tumors (5 recurrent and 10 non-recurrent) and 15 pair wised tumor adjacent normal tissues. We then proposed an integrative network approach for studying the proteomics data by constructing protein-protein interaction networks based on differentially expressed proteins and a machine learning-based score, followed by network modular analysis, functional enrichment annotation and shortest path inference analysis. Network modular analysis revealed that primary and recurrent TETs shared certain common molecular mechanisms, including a spliceosome module consisting of RNA splicing and RNA processing, but the recurrent TET was specifically related to the ribosome pathway. Applying the shortest path inference to the collected seed gene module identified that the ribonucleoprotein hnRNPA2B1 probably serves as a potential target for recurrent TET therapy. The drug repositioning combined molecular dynamics simulations suggested that the compound ergotamine could potentially act as a repurposing drug to treat recurrent TETs by targeting hnRNPA2B1. Our study demonstrates the value of integrative network analysis to understand proteotype robustness and its relationships with genotype, and provides hits for further research on cancer therapeutics.

Deciphering tissue-based proteome signatures revealed novel subtyping and prognostic markers for thymic epithelial tumors

Thymic epithelial tumors (TETs) belong to a group of tumors that rarely occur, but have unresolved mechanisms and heterogeneous clinical behaviors. Current care of TET patients demands biomarkers of high sensitivity and specificity for accurate histological classification and prognosis management. In this study, 134 fresh‐frozen tissue samples (84 tumor, 40 tumor adjacent, and 10 normal thymus) were recruited to generate a quantitative and systematic view of proteomic landscape of TETs. Among them, 90 samples were analyzed by data‐independent acquisition mass spectrometry (DIA‐MS) leading to discovery of novel classifying molecules among different TET subtypes. The correlation between clinical outcome and the identified molecules was probed, and the prioritized proteins of interest were further validated on the remaining samples (n = 44) via parallel reaction monitoring (PRM) as well as immunohistochemical and confocal imaging analysis. In particular, two proteins, the cellular mRNA deadenylase CCR4 (carbon catabolite repressor 4)‐NOT (negative on TATA) complex subunit 2/9 (CNOT2/9) and the serine hydroxymethyltransferase that catalyzes the reversible interconversions of serine and glycine (SHMT1), were found at dramatic low levels in the thymic epithelia of more malignant subtype, thymic squamous cell carcinoma (TSCC). Interestingly, the mRNA levels of these two genes were shown to be closely correlated with prognosis of the TET patients. These results extended the existing human tissue proteome atlas and allowed us to identify several new protein classifiers for TET subtyping. Newly identified subtyping and prognosis markers, CNOT2/9 and SHMT1, will expand current diagnostic arsenal in terms of higher specificity and prognostic insights for TET diagnosis and management.

Long-term, disease-specific outcomes of thymic malignancies presenting with de novo pleural metastasis

OBJECTIVE

Treatment of patients with thymic malignancies metastatic to the pleura or pericardium is challenging, and benefits of aggressive treatment are unclear. We sought to characterize the long-term outcomes in this population.

METHODS

We retrospectively identified patients who underwent resection for de novo thymic malignancies metastatic to the pleura between May 1997 and December 2017. Patients with pleural recurrence after prior thymectomy were excluded. Patient demographics, perioperative treatments, pathologic findings, and postoperative outcomes were collected. Descriptive statistics and Kaplan-Meier analyses were performed.

RESULTS

Seventy-two patients were included (median age, 51 years [range 25-80]; 36/72 women [50%]). Pathologic diagnosis was thymoma in 57 patients (79%) and thymic carcinoma in 15 patients (21%). Most patients (67/72; 93%) received chemotherapy, radiation, or both. Forty-eight patients underwent thymectomy with pleurectomy, 7 patients underwent extrapleural pneumonectomy, 10 patients underwent thymectomy alone, and 7 patients were unresectable. Macroscopic complete resection was achieved in 52 patients (73%). Five-, 10-, and 15-year overall survivals were 73%, 51%, and 18%, respectively, and median overall survival was 11 years (median follow-up, 5.9 years). Forty-six patients (64%) had disease progression (median time to progression, 2.2 years). Repeat episodes of progression and treatment were common (median, 3 episodes/patient). The longest disease-free interval was 12.4 years. Thirteen patients (18%) remain disease-free; 7 patients (10%) were disease-free for more than 5 years. The longest ongoing survival without progression or reintervention is 9.9 years.

CONCLUSIONS

Prolonged survival and, in some cases, cure can be achieved in patients with thymic malignancies metastatic to the pleura or pericardium. Aggressive multimodality therapy may be appropriate for select patients.

Genomic Analysis of Thymic Epithelial Tumors Identifies Novel Subtypes Associated with Distinct Clinical Features

Purpose: To reconcile the heterogeneity of thymic epithelial tumors (TET) and gain deeper understanding of the molecular determinants of TETs, we set out to establish a clinically relevant molecular classification system for these tumors.Experimental Design: Molecular subgrouping of TETs was performed in 120 patients from The Cancer Genome Atlas using a multidimensional approach incorporating analyses of DNA mutations, mRNA expression, and somatic copy number alterations (SCNA), and validated in two independent cohorts.Results: Four distinct molecular subtypes of TETs were identified. The most commonly identified gene mutation was a missense mutation in General Transcription Factor II-I (GTF2I group), which was present in 38% of patients. The next group was identified by unsupervised mRNA clustering of GTF2I wild-type tumors and represented TETs enriched in expression of genes associated with T-cell signaling (TS group; 33%). The remaining two groups were distinguished by their degree of chromosomal stability (CS group; 8%) or instability (CIN group; 21%) based upon SCNA analyses. Disease-free survival and overall survival were favorable in the GTF2I group and unfavorable in the CIN group. These molecular subgroups were associated with TET histology and clinical features including disease-free survival. Finally, we demonstrate high expression of PD1 mRNA and correlation of PD1 and CD8A in the TS subgroup.Conclusions: Molecular subtyping of TETs is associated with disease-free and overall survival. Classification of TETs by a molecular framework could aid in the refinement of staging and in the discovery and development of rational treatment options for patients with TETs. Clin Cancer Res; 23(16); 4855-64. ©2017 AACR.

Thymoma Metastasis to the Semimembranosus Muscle

Thymoma is the most common thymic epithelial tumor whose classification was first introduced in 1999. Type B2 thymoma is considered a moderate/high-risk tumor; however, extrathoracic metastases are extremely rare with limited reports to date. In this report, we present a rare thymoma metastasis to the semimembranosus muscle, which was resected with a wide margin after confirmation by open biopsy. At the final follow-up after 1 year, no local recurrence has been observed.