Alteration in gene expression profiles of thymoma: Genetic differences and potential novel targets.

BACKGROUND: This study was conducted to investigate the gene expression profiles associated with thymoma to better understand the molecular mechanism underlying the pathogenesis of thymoma. METHODS: Eight patients with thymomas (type A, AB, B1, and B2) and four controls with thymic cysts were analyzed using microarray profiling to identify changes in gene expression. RESULTS: Across all of our samples, 2319 messenger RNAs were upregulated and 2776 were downregulated in thymomas relative to thymic cysts. Gene ontology and pathway analyses revealed that a large number of genes participate in cellular functions, among which MHC class II protein complex assembly, assembly with peptide antigen, calcium activated phosphatidylcholine scrambling, and release of cytoplasmic sequestered NF-κB were dysregulated, whereas intestinal immune network for immunoglobulin A production, cytokine-cytokine receptor interaction, the calcium signaling pathway, and pathways related to autoimmune diseases were downregulated. CONCLUSIONS: Our results revealed gene expression differences between thymomas and thymic cysts, and identified key candidate genes/pathways that might be used as diagnostic markers and potential therapeutic targets to treat cancer metastasis.

Conditioned deletion of ephrinB1 and/or ephrinB2 in either thymocytes or thymic epithelial cells alters the organization of thymic medulla and favors the appearance of thymic epithelial cysts.

Our understanding about medullary compartment, its niches composition and formation is still limited. Previous studies using EphB2 and/or EphB3 knockout mice showed an abnormal thymic development that affects mainly to the epithelial component, including the cortex/medulla distribution, thymic epithelial cell (TEC) morphology and different epithelial-specific marker expression. We have already demonstrated that the lack of ephrinB1 and/or ephrinB2, either on thymocytes or on TECs, alters the cell intermingling processes necessary for thymus organization and affect cortical TEC subpopulations. In the present work, we have used the Cre-LoxP model to selectively delete ephrinB1 and/or ephrinB2 in thymocytes (EfnB1(thy/thy), EfnB2(thy/thy), EfnB1(thy/thy)EfnB2(thy/thy) mice) or TECs (EfnB1(tec/tec), EfnB2(tec/tec), EfnB1(tec/tec)EfnB2(tec/tec) mice) and have analyzed their role on the medullary compartment. In all the studied mutants, medullary areas are smaller and more compact than in the wt thymuses. In most of them, we observe abundant big cysts and a higher proportion of UEA(hi)MTS10(-) cells than in wt mice, which are often forming small cysts. On EfnB1(tec/tec)EfnB2(tec/tec), changes affecting organ size and medullary compartment start at perinatal stage. Our data shed some light on knowledge about wt medulla histological structure and cysts meaning and formation process and on the role played by ephrinB in them.

Pleuropericardial cysts: treatment by videothoracoscopy.

Four cases of pleuropericardial cyst (three symptomatic, one in an unusual location) were treated by videothoracoscopy. Complete resection of the cyst was possible in all cases. The postoperative course was uneventful and patients were discharged on the 4th or 5th day. Pleuropericardial cysts account for 5 to 10% of all mediastinal tumors. Clinical latency and a benign course are characteristic features. In most cases, computed tomography (CT) confirms the diagnosis. When the cyst is symptomatic or the diagnosis is in doubt (atypical location, high density on CT scans), videothoracoscopy offers an alternative to transpleural puncture with evacuation or excision via thoracotomy.