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Reza Parwaresch

Publications and source records attributed to Reza Parwaresch.

At least 19 recordsLinked to original sources
PubMed2006

Characterization and expression of CT45 in Hodgkin's lymphoma.

PURPOSE: The monoclonal antibody Ki-A10 (IgG1) generated after immunization of mice with Hodgkin's lymphoma cell line L428 detects a nuclear antigen in human tissues with a restricted distribution pattern similar to cancer/testis antigens. The aim of this study was to characterize the antigen and to determine the expression profile in Hodgkin's lymphoma. EXPERIMENTAL DESIGN: The half-life and phosphorylation of the antigen were determined by radiolabeling. The antigen was characterized by immunopurification and sequencing. Demethylation of genes is used to induce cancer/testis antigens. Ki-A10-negative cells were treated with 5-aza-2'-deoxycytidine. The Ki-A10 expression in paraffin-embedded tumors was determined immunohistochemically. RESULTS: Immunopurification of the 25/22-kDa antigen and sequencing revealed a peptide of 14 amino acids corresponding to the gene product of the newly described gene family MGC27005, located on chromosome Xq26.3, now termed CT45. CT45 is significantly phosphorylated and down-regulated during mitosis. Demethylation of CT45-negative HeLa cells and stimulated peripheral blood lymphocytes induced CT45 expression. Except testis, immunohistochemical stainings of normal tissues, reactive lymphoid lesions, and most malignant tumors were negative. In comparison, 54 of 99 (55%) samples from pediatric and adolescent Hodgkin's lymphoma patients enrolled in the multicenter trial HD-95 stained Ki-A10 positive. Ki-A10 expression correlated with histologic subtypes (nodular sclerosis Hodgkin's lymphoma 68% versus mixed cellularity Hodgkin's lymphoma 40% versus nodular lymphocyte predominant Hodgkin's lymphoma 9%; P < 0.001). CONCLUSIONS: Ki-A10 is the first monoclonal antibody that detects CT45. As benign lymphoid lesions did not express CT45, the use of Ki-A10 antibody will facilitate the discrimination of Hodgkin's lymphoma from reactive lymphadenopathies.

Adolescent↗
PubMed2006

Human EML4, a novel member of the EMAP family, is essential for microtubule formation.

Human EML4 (EMAP-like protein 4) is a novel microtubule-associated WD-repeat protein of 120 kDa molecular weight, which is classified as belonging to the conserved family of EMAP-like proteins. Cosedimentation assays demonstrated that EML4 associates with in vitro polymerized microtubules. Correspondingly, immunofluorescence stainings and transient expression of EGFP-labeled EML4 revealed a complete colocalization of EML4 with the interphase microtubule array of HeLa cells. We present evidence that the amino-terminal portion of EML4 (amino acids 1-249) is essential for the association with microtubules. Immunoprecipitation experiments revealed that EML4 is hyperphosphorylated on serine/threonine residues during mitosis. In addition, immunofluorescence stainings demonstrated that hyperphosphorylated EML4 is associated with the mitotic spindle, suggesting that the function of EML4 is regulated by phosphorylation. siRNA-mediated knockdown of EML4 in HeLa cells led to a significant decrease in the number of cells. In no case mitotic figures could be observed in EML4 negative HeLa cells. Additionally, we observed a significant reduction of the proliferation rate and the uptake of radioactive [3H]-thymidine as a result of EML4 silencing. Most importantly, EML4 negative cells showed a completely modified microtubule network, indicating that EML4 is necessary for correct microtubule formation.

Animals↗
PubMed2006

Diffuse large B-cell lymphoma in pediatric patients belongs predominantly to the germinal-center type B-cell lymphomas: a clinicopathologic analysis of cases included in the German BFM (Berlin-Frankfurt-Munster) Multicenter Trial.

Diffuse large B-cell lymphoma (DLBCL) in adults is a heterogeneous disease. Biologic subgroups of DLBCL with a favorable prognosis (germinal center B-cell-like, GCB) and with a poor prognosis (activated B-cell-like, ABC) have been defined by gene expression profiling and can be distinguished by immunohistochemistry. In contrast to their adult counterparts, children with DLBCL have an excellent prognosis. We analyzed 63 cases of DLBCL in pediatric patients by immunohistochemistry and fluorescence in situ hybridization (FISH) and found a striking predominance of a GCB subtype, which might explain the good clinical outcome in these lymphomas. Interestingly, FISH applied to 50 of these cases, as well as conventional cytogenetics available in 3 cases, revealed absence of the translocation t(14;18) involving the BCL2 gene, which is present in about 15% of adult GCB subtype DLBCL. Our data indicate that pediatric DLBCL differs from adult DLBCL and might comprise a biologically unique subgroup of DLBCL from which important insights into the pathogenesis and biology of this disease might be gained.

Child↗
PubMed2006

Frequency of chromosomal aneuploidies and deletions of the RB and TP53 genes in MALT lymphomas harboring the t(14;18)(q32;q21).

The t(14;18)(q32;q21) involving the MALT1/MLT and IGH genes has been identified recently as a recurrent abnormality in mucosa-associated lymphoid tissue (MALT) lymphomas. The frequency of secondary chromosomal aberrations in MALT lymphomas harboring the t(14;18) is largely unknown. We therefore analyzed six t(14;18)-positive MALT lymphomas (five parotid, one conjunctiva) by interphase fluorescence in situ hybridization for aneuploidies of chromosomes 3, 7, 12, 18, and X, gains or disruption of the CMYC/8q24 and BCL6/3q27 genes, as well as deletions of the retinoblastoma and TP53 tumor suppressor genes. Except for one MALT lymphoma of the parotid with trisomy 3, neither aneuploidies nor deletions were detected in any of our cases.

Aneuploidy↗
PubMed2006

Allogeneic haematopoietic stem cell transplantation in relapsed or refractory anaplastic large cell lymphoma of children and adolescents--a Berlin-Frankfurt-Münster group report.

Patients with refractory or early relapsed anaplastic large cell lymphoma (ALCL) have a poor chance of survival. We report 20 children and adolescents with high-risk relapsed or refractory ALCL who underwent allogeneic haematopoietic stem cell transplantation (HSCT). We retrospectively analysed 20 patients who relapsed between December 1991 and April 2003 during (six patients) or soon after first-line Berlin-Frankfurt-Münster-type chemotherapy (14 patients) and underwent allogeneic HSCT. Nine patients received allogeneic HSCT after the first relapse and 11 after multiple relapses. Eight patients received their transplants from matched sibling donors, eight from unrelated donors and four from haploidentical family donors. The conditioning regimen was based on total body irradiation in 15 patients. Two patients relapsed after allogeneic HSCT and died. Three patients died of transplant-related toxicity. Event-free survival at 3 years after allogeneic transplant was 75 +/- 10%. There was no influence of donor type or conditioning regimen on outcome. Two of six patients with progressive disease during frontline therapy survived compared with 13/14 patients with a first relapse after frontline therapy. Two of three patients who were transplanted with active lymphoma and all five patients who received allogeneic HSCT for relapse following autologous HSCT survived disease-free. Allogeneic HSCT is effective and has acceptable toxicity as rescue therapy for high-risk ALCL relapse. It even offers cure for patients refractory to chemotherapy, suggesting a graft-versus-ALCL effect.

Adolescent↗
PubMed2005

Treatment results in localized primary gastric lymphoma: data of patients registered within the German multicenter study (GIT NHL 02/96).

PURPOSE: In the prospective study 02/96 on primary GI lymphoma, we have collected data on histology, clinical features, and treatment results. In particular, in stages I and II localized primary gastric lymphoma (PGL), our objectives were to reduce treatment intensity and to confirm our hypothesis from study 01/92, which maintained that an organ-preserving approach is not inferior to primary surgery. PATIENTS AND METHODS: Patients receiving radiotherapy and/or chemotherapy were stratified for histologic grade, stage, and whether surgery had been carried out or not (as decided by each participating center). Patients with aggressive PGL received six cycles of CHOP-14 (cyclophosphamide, doxorubicin, vincristine, and prednisone) followed by involved-field radiotherapy (40 Gy). Patients with indolent PGL (including patients experiencing treatment failure with antibiotic therapy for Helicobacter pylori) were treated with extended-field radiotherapy. The volume depended on stage. The irradiation dose was 30 Gy, followed by a boost of 10 Gy (the latter omitted after complete resection) to the tumor region. RESULTS: Seven hundred forty-seven patients were accrued. Of these patients, 393 with localized PGL were treated with radiotherapy and/or chemotherapy only or additional surgery between December 1996 and December 2003. The survival rate at 42 months for patients treated with surgery was 86% compared with 91.0% for patients without surgery. CONCLUSION: In this nonrandomized study (02/96), we reproduced the previous results of study 01/92 showing no disadvantage for an organ-preserving treatment. Therefore, primary stomach resection should be questioned.

Adult↗
PubMed2005

Frontline therapy with rituximab added to the combination of cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) significantly improves the outcome for patients with advanced-stage follicular lymphoma compared with therapy with CHOP alone: results of a prospective randomized study of the German Low-Grade Lymphoma Study Group.

Phase 2 studies suggest that the monoclonal antibody rituximab may improve the prognosis of patients with follicular lymphoma (FL) when it is added to chemotherapy. In the current study, 428 patients with untreated, advanced-stage FL were randomly assigned for therapy with cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) alone (n = 205) or CHOP combined with rituximab (R-CHOP) (n = 223). R-CHOP reduced the relative risk for treatment failure by 60% and significantly prolonged the time to treatment failure (P < .001). In addition, a significantly higher overall response rate (96% vs 90%; P = .011) and a prolonged duration of remission (P = .001) were achieved. In spite of a relatively short observation time, these beneficial effects even translated to superior overall survival (P = .016), with 6 deaths in the R-CHOP group compared with 17 deaths in the CHOP group within the first 3 years. The predominant treatment-related adverse effect was myelosuppression. Severe granulocytopenia was more frequently observed after R-CHOP (63% vs 53%; P = .01). However, severe infections were rare and of similar frequency after R-CHOP and CHOP (5% and 7%). Hence, adding rituximab to CHOP significantly improves the outcome for patients with previously untreated advanced-stage FL and does not induce major adverse effects.

Adult↗
PubMed2005

Vesicular monoamine transporter 2 (VMAT2) expression in hematopoietic cells and in patients with systemic mastocytosis.

Uptake of monoamines into secretory granules is mediated by the vesicular monoamine transporters VMAT1 and VMAT2. In this study, we analyzed their expression in inflammatory and hematopoietic cells and in patients suffering from systemic mastocytosis (SM) and chronic myelogenous leukemia (CML). Normal human and monkey tissue specimens and tissues from patients suffering from SM and CML were analyzed by means of immunohistochemistry, radioactive in situ hybridization, real time RT-PCR, double fluorescence confocal laser scanning microscopy, and immunoelectron microscopy. In normal tissue specimens, VMAT2, but not VMAT1, was expressed in mast cells, megakaryocytes, thrombocytes, basophil granulocytes, and cutaneous Langerhans cells. Further hematopoietic and lymphoid cells showed no expression of VMATs. VMAT2 was expressed in all types of SM, as indicated by coexpression with the mast cell marker tryptase. In CML, VMAT2 expression was retained in neoplastic megakaryocytes and basophil granulocytes. In conclusion, the identification of VMAT2 in mast cells, megakaryocytes, thrombocytes, basophil granulocytes, and cutaneous Langerhans cells provides evidence that these cells possess molecular mechanisms for monoamine storage and handling. VMAT2 identifies normal and neoplastic mast cells, megakaryocytes, and basophil granulocytes and may therefore become a valuable tool for the diagnosis of mastocytosis and malignant systemic diseases involving megakaryocytes and basophil granulocytes.

Animals↗
PubMed2005

Growth pattern and distribution of follicular dendritic cells in mantle cell lymphoma: a clinicopathological study of 96 patients.

Mantle cell lymphoma (MCL) is an aggressive lymphoma with accepted risk factors such as proliferation markers. To date, the different follicular dendritic cell (FDC) patterns have never been analyzed in comparison with the overall survival time. Lymph node biopsy specimens from 96 patients were analyzed by conventional morphology and immunohistochemistry with antibodies against cluster differentiation (CD)20, CD5, CD23, cyclin D1, and FDC (Ki-M4P). Two groups can be distinguished with different FDC patterns: a nodular pattern in 79 cases and a diffuse pattern in 17 cases. A Kaplan-Meier analysis revealed significantly better survival for the nodular group (p=0.0312). This group was subdivided into a group with a nodular FDC pattern similar to the FDC distribution in primary follicles (PF-nodular in 72 cases) and one with a nodular FDC pattern resembling the colonization of germinal centers (GCs) by tumor cells (GC-nodular in seven cases). A Kaplan-Meier analysis showed that patients with MCL with a PF-nodular FDC pattern had a significantly better clinical outcome than patients with the other two patterns (p=0.0033). If only cases with classical cytology (n=79) were analyzed (blastoid types excluded), patients with a PF-nodular FDC pattern had a better clinical outcome (p=0.0008). The distribution of FDC in MCL is a diagnostic tool for identifying patients with a better clinical prognosis.

Antigens, CD20↗
PubMed2005

Impact of latent Epstein-Barr virus infection on outcome in children and adolescents with Hodgkin's lymphoma.

PURPOSE: The prognostic significance of latent Epstein-Barr virus (EBV) infection in Hodgkin's lymphoma (HL) is debated controversially. Especially in the pediatric age group, no conclusive data are available. PATIENTS AND METHODS: Eight hundred forty-two children and adolescents (median age, 13.7 years) from pediatric multicenter treatment studies HD-90 and HD-95 were studied for latent EBV infection in Hodgkin's and Reed-Sternberg cells by immunostaining against latent membrane protein 1 (LMP-1). Results were compared with established risk factors. RESULTS: Two hundred sixty-three patients (31%) were LMP positive. EBV infection correlated with sex (39% male v 23% female; P < .001), histologic subtype (69% mixed cellularity v 22% nodular sclerosis v 6% lymphocyte predominance; P < .001) and young age. With a median follow-up of 4.9 years, 820 patients (97%) are alive. Probability of overall survival at 10 years (+/- standard deviation) for EBV-negative and -positive patients was 98.1% +/- 0.6% and 95.1% +/- 1.4%, respectively (P = .017 by log-rank test). A negative effect of EBV infection became evident for patients with nodular sclerosis subtype Bennett II (P = .02), and those treated for advanced stages (P = .003). In multivariate analysis, LMP positivity was an independent factor for adverse outcome (RR = 3.08). Probability of failure-free survival (FFS) in LMP positive and negative patients was 89.1% +/- 2.3% and 84.1% +/- 3.9%, respectively (P = .86). CONCLUSION: With effective combined treatment modalities in pediatric HL, latent EBV infection has no influence on FFS but is associated with an inferior overall survival in crucial subgroups.

Adolescent↗
PubMed2005

AIDS-related B-cell lymphoma (ARL): correlation of prognosis with differentiation profiles assessed by immunophenotyping.

This study was undertaken to analyze the differentiation profiles assessed by immunophenotyping in AIDS-related B-cell lymphoma (ARL) and their relation to the clinical course. Paraffin-embedded sections of 89 ARL cases during 1989 to 2004 were stained immunohistochemically with antibodies to CD3, CD10, CD20, CD38, CD138/Syndecan-1 (Syn-1), multiple myeloma-1/interferon regulatory factor-4 (MUM1/IRF4), B-cell lymphoma protein-2 (BCL-2), BCL-6, latent membrane protein-1 (LMP-1), and Ki-67. Expression of CD10 and CD20 were associated with better overall survival (OS; P = .009 and P = .04, respectively). Expression of CD20 was associated with longer disease-free survival (DFS; P = .03), whereas expression of CD138/Syn-1 was associated with shorter DFS (P = .03). OS and DFS were worse in patients with immunophenotypic profiles related to post-germinal center (GC) differentiation (BCL-6 and CD10 negative, MUM1/IRF4 and/or CD138/Syn-1 positive) when compared with GC differentiation (P = .01). When controlled for age-adjusted International Prognostic Index (IPI), prior AIDS-defining illness (ADI), and year of ARL diagnosis, a post-GC differentiation remained significantly associated with poor OS and DFS. Expression of CD10 was associated with a preserved immunocompetence, whereas CD20 was less frequent in patients developing ARL while on highly active antiretroviral therapy (P = .04). In summary, lack of CD20 or CD10 expression and a post-germinal center signature are associated with a worse prognosis in ARL.

Adult↗
PubMed2005

Immunochemotherapy with rituximab and cyclophosphamide, doxorubicin, vincristine, and prednisone significantly improves response and time to treatment failure, but not long-term outcome in patients with previously untreated mantle cell lymphoma: results of a prospective randomized trial of the German Low Grade Lymphoma Study Group (GLSG).

PURPOSE: Mantle cell lymphoma (MCL) is characterized by a poor prognosis with a low to moderate sensitivity to chemotherapy and a median survival of only 3 to 4 years. In an attempt to improve outcome, the German Low Grade Lymphoma Study Group (GLSG) initiated a randomized trial comparing the combination of cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) and rituximab (R-CHOP) with CHOP alone as first-line therapy for advanced-stage MCL. PATIENTS AND METHODS: One hundred twenty-two previously untreated patients with advanced-stage MCL were randomly assigned to six cycles of CHOP (n = 60) or R-CHOP (n = 62). Patients up to 65 years of age achieving a partial or complete remission underwent a second randomization to either myeloablative radiochemotherapy followed by autologous stem-cell transplantation or interferon alfa maintenance (IFNalpha). All patients older than 65 years received IFNalpha maintenance. RESULTS: R-CHOP was significantly superior to CHOP in terms of overall response rate (94% v 75%; P = .0054), complete remission rate (34% v 7%; P = .00024), and time to treatment failure (TTF; median, 21 v 14 months; P = .0131). No differences were observed for progression-free survival. Toxicity was acceptable, with no major differences between the two therapeutic groups. CONCLUSION: The combined immunochemotherapy with R-CHOP resulted in a significantly higher response rate and a prolongation of the TTF as compared with chemotherapy alone. Hence, R-CHOP may serve as a new baseline regimen for advanced stage MCL, but needs to be further improved by novel strategies in remission.

Aged↗
PubMed2005

Breast carcinoma malignancy grading by Bloom-Richardson system vs proliferation index: reproducibility of grade and advantages of proliferation index.

Questions of reproducibility and efficacy of histologic malignancy grading relative to alternative proliferation index measurements for outcome prediction remain unanswered. Microsections of specimens from the Cooperative Breast Cancer Tissue Resource (CBCTR) were evaluated by seven pathologists for reproducibility of grade and classification. Nuclear figure classification was assessed using photographs. Grade was assigned by the Bloom-Richardson method, Nottingham modification. Proliferation index was evaluated prospectively by deoxyribose nucleic acid precursor uptake with thymidine (autoradiographic) or bromodeoxyuridine (immunohistochemical) labeling index using fresh tissue from 631 node-negative breast cancer patients accessioned at St Luke's Hospital. A modified Nottingham-Bloom-Richardson grade was derived from histopathologic data. Median post-treatment observation was 6.4 years. Agreement on classification of nuclear figures (N=43) was less than good by kappa statistic (kappa=0.38). Grade was moderately reproducible in four trials (N=10,10,19, 10) with CBCTR specimens (kappa=0.50-0.59). Of components of Bloom-Richardson grade, agreement was least for nuclear pleomorphism (kappa=0.37-0.50), best for tubularity (kappa=0.57-0.83), and intermediate for mitotic count (kappa=0.45-0.64). Bloom-Richardson grade was a univariate predictor of prognosis in node-negative St Luke's patients, and was improved when mitotic count was replaced by labeling index (low, mid, or high). When labeling index was added to a multivariate model containing tumor size and vessel invasion, grade was no longer a significant predictor of tumor-specific relapse-free or overall survival. Mitotic index predicted best when intervals were lowered to 0-2, 3-10, and >10 mitotic figures per ten 0.18 mm(2) high-power fields. We conclude that Nottingham-Bloom-Richardson grades remain only modestly reproducible. Prognostically useful components of grade are mitotic index and tubularity. The Nottingham-Bloom-Richardson system can be improved by lowering cutoffs for mitotic index and by counting 20-30 rather than 10 high-power fields. Measurement of proliferation index by immunohistochemically detectable markers will probably give superior prognostic results in comparison to grade.

Breast Neoplasms↗
PubMed2005

Proliferation characteristics in pediatric Hodgkin's lymphoma point to a cell cycle arrest in the G(1) phase.

This study was undertaken to determine the prognostic relevance of the proliferation rate in neoplastic cells in children and adolescents with Hodgkin's lymphoma. Paraffin-embedded biopsy specimens were immunostained with the proliferation-associated monoclonal antibodies Ki-S5 (Ki-67 antigen) and Ki-S2 (which detects the repp86 protein). Repp86 is a protein of about 100 kDa encoded by a gene located on human chromosome band 20q11.2. In contrast to the Ki-67 antigen, repp86 expression is restricted to the cell cycle phases G(2), S and M. Immunohistochemical results on diagnostic lymph node biopsy specimens from 224 patients included in two pediatric multicenter Hodgkin's trials, GPOH HD-90 and HD-95, were compared with clinical data. High Ki-67 antigen expression was a striking feature of Hodgkin's and Reed-Sternberg cells as well as lymphocytic and histiocytic cells (median: 80%, range: 20-100%), in contrast to low repp86 expression (median: 20%, range: 10-80%; P<0.001). The proliferation rate was independent of histological subtype, stage and presence of B symptoms. The probability of event-free and overall survival (+/-standard error) of all patients at 5 years was 91.6+/-2.0 and 98.1+/-1.0%, respectively. The proliferation rate of tumor cells did not influence the outcome. The difference between Ki-67 and repp86 expression in Hodgkin's and Reed-Sternberg or lymphocytic and histiocytic cells points to a possible cell cycle arrest in the G(1) phase, which may explain the obvious paradox of a highly proliferating but slowly growing paucicellular tumor. High Ki-67 expression does not seem to be an adverse prognostic factor in pediatric and adolescent patients with Hodgkin's lymphoma treated by effective risk-adapted chemo-radiotherapy regimens.

Adolescent↗
PubMed2005

Proliferation rate and outcome in children with T-cell rich B-cell lymphoma: a clinicopathologic study from the NHL-BFM-study group.

T-cell rich B-cell lymphoma (TCRBCL) is considered a rare variant of aggressive B-cell lymphoma characterized by few neoplastic cells and a large reactive infiltrate with striking similarities to nodular lymphocyte predominant Hodgkin's lymphoma (NLPHL). In childhood, these tumors occur even less frequently. Biopsy specimens at diagnosis from 16 children (13 boys) with a median age of 12 years (range, 7 to 18) were immunophenotyped. The proliferation rate was assessed with monoclonal antibodies against Ki-67 and repp86 antigens and additional clonality analyses were performed. Ten patients had localized disease and only two had B symptoms. All patients showed high Ki-67 expression (median: 80%, range 40% to 90%), but low repp86 expression (median: 25%, range 10% to 50%). PCR-based clonality studies of the hypervariable CDR III region of the immunoglobuline heavy chain and the T-cell receptor gamma-chain genes demonstrated predominant clones in nine and five patients, respectively. Three patients had previous or concomitant NLPHL and two of them received initial treatment for Hodgkin's disease. All patients achieved remission after a brief polychemotherapy regimen. Two patients subsequently relapsed and one was rescued by salvage therapy including autologous stem cell transplantation. At a median follow-up of 23 months, 15 patients (94%) are alive. The striking contrast between the proliferation rates determined by Ki-67 and repp86 expression points to a possible arrest in the G1 cell cycle phase because repp86 expression is restricted to the S, G2 and M cell cycle phases. This G1 arrest may explain the paradoxon of high Ki-67 expression in a paucicellular lymphoma with a favorable prognosis in young patients.

Adolescent↗