Thymic epithelial tumors (TETs) are one of the rarest adult malignancies. Among TETs, thymoma is the most predominant, characterized by a unique association with autoimmune diseases, followed by thymic carcinoma, which is less common but more clinically aggressive. Using multi-platform omics analyses on 117 TETs, we define four subtypes of these tumors defined by genomic hallmarks and an association with survival and World Health Organization histological subtype. We further demonstrate a marked prevalence of a thymoma-specific mutated oncogene, GTF2I, and explore its biological effects on multi-platform analysis. We further observe enrichment of mutations in HRAS, NRAS, and TP53. Last, we identify a molecular link between thymoma and the autoimmune disease myasthenia gravis, characterized by tumoral overexpression of muscle autoantigens, and increased aneuploidy.

Understanding patterns of etiologic commonality and heterogeneity for nonHodgkin lymphomas may illuminate lymphomagenesis. We present the first systematic comparison of risks by lymphoma subtype for a broad range of putative risk factors in a population-based case-control study, including diffuse large B-cell (DLBCL; N ‫؍‬ 416), follicular (N ‫؍‬ 318), and marginal zone lymphomas (N ‫؍‬ 106), and chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/ SLL; N ‫؍‬ 133). We required at least 2 of 3 analyses to support differences in risk:(1) polytomous logistic regression, (2) homogeneity tests, or (3)

Nasopharyngeal carcinoma (NPC) is an epithelial tumor with a distinct geographic distribution and characteristic histologic appearance. It is rare in Europe and North America, but it is among the most common cancers in southern China. Genetic predisposition, environmental factors, and Epstein-Barr virus (EBV) all have been associated with the pathogenesis of this tumor. There is an increasing body of evidence that among all these factors, EBV appears to be the strongest and most consistently related factor. According to the current sensitive in situ hybridization methods for the detection of EBV-encoded small RNAs (EBER), almost 100% of cases of NPC, irrespective of their histologic subtypes, have demonstrable EBERs in the nuclei of the tumor cells. In this review paper, we discuss the predisposing genetic and environmental factors and the role of EBV in the pathogenesis of this tumor with particular emphasis on the role of EBV.

Indeterminate and interdigitating cell tumors are rare proliferations of immunoregulatory cells that demonstrate morphologic, immunologic, and ultrastructural features similar to their cells of origin. Although an association of lymphoproliferative disease with Langerhans' cell histiocytosis is well described, only sporadic cases of non-Langerhans' dendritic cell proliferations have been published. The authors describe three patients with low grade B-cell lymphoproliferative disease who developed subsequent indeterminate cell or interdigitating cell tumors. When the two cases of indeterminate cell tumor are added to those previously described in the literature, it appears that 4 of 13 cases (31%) are associated with a history of low grade B-cell malignancy. Possible explanations for the relationship between these two disorders are discussed.

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