Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.7.7.7 (DNA polymerase)
 17,007 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Primary effusion lymphoma (PEL) is a unique form of malignant lymphoma associated with infection by the Kaposi's sarcoma-associated herpesvirus (KSHV)/human herpesvirus-8 (HHV-8). The majority of PELs also contain the EBV genome. Although viral infection is believed to play a critical role in the pathogenesis of PEL, it has been suggested that additional molecular lesions are required for the development of PEL. Alternative splicing of pre-mRNA is an important mechanism in the regulation of cellular and viral gene expression. Deregulation of pre-mRNA splicing may shift the gene expression balance and lead to the development of cancer. In order to investigate mRNA splicing in PELs, we examined mRNA splicing of three genes, DNA polymerase beta (pol beta), Bcl-x and CD45, in eight PEL cell lines. We found that the average variant percentage of pol beta in PEL cell lines is two times higher than in peripheral blood mononuclear cells (PBMC) and that the variant pattern of genes bcl-x and CD45 is quite different in PEL cell lines than in PBMC. In addition, we also found that the percentage of variant pol beta increased two-fold in PBMC following Epstein-Barr virus (EBV) infection. Therefore, viral infection may contribute to mRNA alternative splicing in PEL. In order to explore the mechanism by which viral infection affects mRNA splicing, we also examined the roles of genes KS-SM, SM and EBERs and viral copies in mRNA splicing. Our findings indicate that various factors acting as positive or negative regulators may be involved in mRNA alternative splicing caused by viral infection. In conclusion, mRNA splicing in PEL can be altered by viral infection and this alteration may contribute to the pathogenesis of PEL.
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PMID:Alterations of mRNA splicing in primary effusion lymphomas. 1280 23

Merkel cell carcinoma (MCC) is a high-grade neuroendocrine carcinoma of skin characterized by cells with a "blastic" appearance, scant cytoplasm, and fine, evenly distributed chromatin. Terminal deoxynucleotidyl transferase (TdT) is a DNA polymerase present in thymic T cells, lymphoblastic lymphoma/leukemia, and some cases of acute myeloid leukemia. After observing TdT immunoreactivity in a case of MCC, we analyzed 26 tumors by immunohistochemical analysis to determine their spectrum of reactivity with TdT and identified TdT in 19 (73%) of 26 MCCs. Staining intensity was variable but was often moderate to strong and present in a significant percentage of cells. Because MCC has cytomorphologic features similar to those of lymphoblastic lymphoma and may manifest as metastatic disease, reactivity with TdT in MCC could represent a diagnostic pitfall in the differential diagnosis with lymphoblastic lymphoma, particularly because the latter may lack CD45 and/or CD20, yet both neoplasms may express PAX-5, a B-cell-associated marker.
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PMID:Reactivity with TdT in Merkel cell carcinoma: a potential diagnostic pitfall. 1848 5

Combination of the splenic marginal zone B-cell lymphoma (SMZL) and classical Hodgkin lymphoma (cHL) is extremely rare. We report a unique case with concurrent SMZL and cHL. The patient was a 63-year-old man who presented with fatigue and anemia, showing a splenomegaly and retroperitoneal lymphadenopathy. A splenectomy revealed monotonous marginal zone lymphocytic infiltrates and numerous large Reed-Sternberg-like cells. Flow cytometry revealed a kappa light-chain-restricted CD5 (-), CD23 (-) B-cell population. DNA polymerase chain reaction analysis confirmed the presence of clonal rearrangement of the immunoglobulin heavy-chain gene. Immunohistochemical studies revealed that the large atypical cells were CD30 (+), CD15 (weakly +), CD20 (-), CD45 (-), Pax5 (weakly +), BOB.1 (-), and Oct2 (-), indicating the coexistence of SMZL with cHL. After the chemotherapy, the patient achieved a clinical/radiologic remission, whereas cHL was detected in liver and bone marrow subsequently. The case indicates that both components of lymphoma can present concurrently as a composite form of lymphoma and both need to be treated adequately.
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PMID:Classical Hodgkin lymphoma concurrently evolving in a patient with marginal zone B-cell lymphoma of the spleen. 1848 99

Seminomas are the most frequent testicular tumors and in spite of specific markers some histological subtypes can be diagnostically challenging due to the potential overlap of morphologic features and a variant antigen expression. Terminal deoxynucleotidyl transferase (TdT) is a DNA polymerase present in hematogones, thymic T cells, lymphoblastic lymphoma/leukemia (LBL), and in some cases of acute myeloid leukemia but so far has not been described to be expressed in seminomas. After observing a reactivity of TdT in one case of seminoma, we analyzed ten additional tumors by immunohistochemistry to determine their spectrum of reactivity for TdT. In all seminoma cases investigated (10/10) as well as in two tumor-associated germ cell neoplasias in situ (2/2) the TdT staining intensity was variable but was often moderate to strong and restricted to the nucleus. We conclude that TdT expression in seminomas could represent a diagnostic pitfall in the differential diagnosis of LBL, particularly because both may lack CD45 and/or CD20 expression and-concerning relapse in long-term survivors of testicular cancer-LBL is the most frequent secondary neoplasm in the patients.
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PMID:Expression of terminal deoxynucleotidyl transferase (TdT) in classical seminoma: a potential diagnostic pitfall. 2945 18