Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:5.99.1.2 (topoisomerase)
 9,166 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Gene copy number and protein expression of topoisomerase IIalpha were correlated to benefit from anthracyclines in various tumors. A retrospective series of 69 patients with DLBCL managed with CHOP chemotherapy were studied for immunohistochemical TopoIIalpha expression and numerical gene abnormalities by fluorescent in situ hybridization (FISH). The results were analyzed in relation to the expression of cell cycle proteins (Ki67, p53, HDM2, p21, p14, pRb, p16, and cyclins A, B1, D1, D2, D3, and E) and BCL6/CD10/MUM1/CD138 B-cell differentiation immunophenotype and outcome. High levels of TopoIIalpha protein were found in 91% of DLBCL cases. No evidence of TopoIIalpha gene amplification or deletion was found. The TopoIIalpha expression showed significant positive correlations with the proliferation index Ki67 (p = 0.002), cell cycle proteins pRb and cyclin D2 (p = 0.018 and p = 0.028, respectively), and the germinal center proteins bcl6 and CD10 (p = 0.010 and p < 0.0001, respectively). TopoIIalpha expression was significantly higher in germinal center B-cell like (GCB) DLBCL than in non-germinal center B-cell like (non-GCB) DLBCL (p = 0.048). TopoIIalpha protein was significantly associated with response to chemotherapy (chi(2), p = 0.024), but not with relapse-free or overall survival (p = 0.5). On multivariate analysis, only stage of disease retained independent prognostic significance (HR 0.33 for early stage, p = 0.008). Although TopoIIa gene copy number abnormalities were not found in DLBCL, high levels of protein expression are associated with GCB-cell differentiation immunophenotype, high proliferation, and response to treatment.
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PMID:High levels of topoisomerase IIalpha protein expression in diffuse large B-cell lymphoma are associated with high proliferation, germinal center immunophenotype, and response to treatment. 2049 3

Mixed-phenotype acute leukemia is a rare form of leukemia that is associated with a poor prognosis. Most cases of mixed-phenotype acute leukemia are de novo. However, therapy-related mixed-phenotype acute leukemia can occur, and are often associated with exposure to topoisomerase-II inhibitors and alkylating agents. There are no known treatment guidelines for therapy-related mixed-phenotype acute leukemia. We present a patient with T/myeloid mixed-phenotype acute leukemia secondary to rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone R-CHOP chemotherapy for primary cutaneous diffuse large B-cell lymphoma. The patient's leukemic cells express CD34, an immaturity marker, CD3, a T-cell marker, and myeloperoxidase, a myeloid marker, and her history of chemotherapy for previous lymphoma supports the diagnosis of therapy-related T/myeloid mixed phenotype acute leukemia. Clinicians should be aware that this entity could be associated with R-CHOP chemotherapy. Given the complexity in diagnosis, and lack of treatment guidelines, a further understanding of the pathological and genetic principles of therapy-related mixed-phenotype acute leukemia will assist in future efforts to treat and categorize these patients. Mixed phenotype acute leukemia is a rare entity that accounts for two to five percent of all acute leukemias. Therapy- related mixed phenotype acute leukemia is an exceedingly rare hematological neoplasm that accounts for less than one percent of acute leukemias. We describe a case of therapy-related T/myeloid mixed phenotype acute leukemia following rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone R-CHOP chemotherapy for primary cutaneous diffuse large B-cell lymphoma DLBCL. The patient is a 63-year-old female who presented with several cutaneous nodules diagnosed as primary cutaneous DLBCL. The patient received R-CHOP chemotherapy and achieved remission. She remained in remission for four years until she presented with dyspnea, night sweats, weakness, and diffuse lymphadenopathy. Her presentation was initially concerning for recurrent lymphoma; however, a bone marrow biopsy and aspirate and a lymph node biopsy revealed a distinct blast population consistent with T/myeloid mixed phenotype acute leukemia T/M-MPAL. Given the patient's history of previous chemotherapy exposure, our patient represents a case of therapy-related T/myeloid mixed phenotype acute leukemia t-MPAL.
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PMID:THERAPY-RELATED T/MYELOID MIXED PHENOTYPE ACUTE LEUKEMIA IN A PATIENT TREATED WITH CHEMOTHERAPY FOR CUTANEOUS DIFFUSE LARGE B CELL LYMPHOMA. 2698 62