RESUMO
Nodular lymphocyte predominant Hodgkin lymphoma (NLPHL)-a subtype of Hodgkin lymphoma (HL)-is characterized by a low content of tumor cells, the lymphocyte predominant (LP) cells. Transformation into diffuse large B-cell lymphoma (DLBCL) occurs in about 10% of patients. We performed whole-genome mutation analysis of the DLBCL components from two composite lymphomas consisting of clonally related NLPHL and DLBCL as a means to identify candidate tumor suppressor genes and oncogenes in NLPHL. The analysis of LP cells for selected mutations of the DLBCL revealed that most mutations are also present in the LP cells, indicating a close relationship between the two components. The analysis of 62 selected genes in NLPHL by targeted ultra-deep sequencing revealed three novel highly recurrently mutated genes (each mutated in ~50% of cases), that is, DUSP2, SGK1 and JUNB. SGK1 was expressed in the LP cells of primary NLPHL cases and in the NLPHL cell line DEV. Administration of an SGK1 inhibitor induced apoptosis in the NLPHL cell line DEV and the DLBCL cell line Farage, suggesting a pathogenetic role of SGK1 in the LP and DLBCL cells. In summary, the present study identifies SGK1, DUSP2 and JUNB as novel key players in the pathogenesis of NLPHL.
Assuntos
Fosfatase 2 de Especificidade Dupla/genética , Doença de Hodgkin/genética , Proteínas Imediatamente Precoces/genética , Mutação/genética , Proteínas Serina-Treonina Quinases/genética , Fatores de Transcrição/genética , Adulto , Análise Mutacional de DNA , Sequenciamento de Nucleotídeos em Larga Escala , Doença de Hodgkin/patologia , Humanos , Imunofenotipagem , Linfonodos/metabolismo , Linfonodos/patologia , Linfócitos/metabolismo , Linfócitos/patologia , Linfoma Folicular/genética , Linfoma Folicular/patologia , Linfoma Difuso de Grandes Células B/genética , Linfoma Difuso de Grandes Células B/patologia , Masculino , Pessoa de Meia-Idade , Estadiamento de Neoplasias , PrognósticoRESUMO
Mature T-cell lymphomas (MTCLs) have an extremely poor prognosis and are much less frequent than immature T-cell leukemias. This suggests that malignant outgrowth of mature T lymphocytes is well controlled. Indeed, in a previous study we found that mature T cells are resistant to transformation with known T-cell oncogenes. Here, however, we observed that T-cell receptor (TCR) mono-/oligoclonal mature T cells from TCR transgenic (tg) mice (OT-I, P14) expressing the oncogenes NPM/ALK or ΔTrkA readily developed MTCLs in T-cell-deficient recipients. Analysis of cell surface markers largely ruled out that TCR tg lymphomas were derived from T-cell precursors. Furthermore, cotransplanted non-modified TCR polyclonal T cells suppressed malignant outgrowth of oncogene expressing TCR tg T lymphocytes. A dominant role of an anti-leukemic immune response or Tregs in the control of MTCLs seems unlikely as naïve T cells derived from oncogene expressing stem cells, which should be tolerant to leukemic antigens, as well as purified CD4 and CD8 were resistant to transformation. However, our results are in line with a model in which homeostatic mechanisms that stabilize the diversity of the normal T-cell repertoire, for example, clonal competition, also control the outgrowth of potentially malignant T-cell clones. This study introduces a new innate mechanism of lymphoma control.