Loss of heterozygosity on chromosome 6q14-q24 is associated with poor outcome in children and adolescents with T-cell lymphoblastic lymphoma.

Deletions of chromosome 6q have been reported in several hematological malignancies, but data are not conclusive regarding their biological and prognostic impact. Therefore, we focused on pediatric patients diagnosed with T-cell lymphoblastic lymphoma (T-LBL) treated uniformly according to the NHL-BFM95 protocol. We used loss-of-heterozygosity (LOH) analysis of 25 microsatellite markers located on chromosome 6q14-q24. Fragment-length analysis was performed on ABI-PRISM3100 Genetic-Analyzer. Eligibility criterion was > or =3 informative markers. Between April 1995 and March 2003, 185 T-LBL patients were treated according to the NHL-BFM95 protocol. Five-year event-free (EFS) and disease-free survival (DFS) were 79+/-3 and 87+/-3% (median follow-up 4.7 [1.2-10.1] years). Sixty-one patients were evaluable for LOH analysis, including 18 out of 23 patients with relapse. EFS and DFS were 67+/-6 and 69+/-6% for these 61 patients. Testing of 853 markers in the 61 patients identified the presence of LOH in 19 patients (31%): 13 of the 18 relapse patients and five of the 41 in complete remission (odds ratio 18.7, 95% confidence interval 4.7-75.3). One LOH-positive patient died from treatment-related toxicity. We conclude that LOH on chromosome 6q14-q24 may have conferred a high risk of relapse on our group of children with T-LBL treated according to the NHL-BFM95 protocol.

Immunologic proliferation marker Ki-S2 as prognostic indicator for lymph node-negative breast cancer.

BACKGROUND: Proper treatment of lymph node-negative breast cancer depends on an accurate prognosis. To improve prognostic models for this disease, we evaluated whether an immunohistochemical marker for proliferating cells, Ki-S2 (a monoclonal antibody that binds to a 100-kd nuclear protein expressed in S, G2, and M phases of the cell cycle), is an accurate indicator of prognosis. METHODS: We studied 371 Swedish women with lymph node-negative breast cancer; the median follow-up time was 95 months. The fraction of tumor cells in S phase was assessed by flow cytometry, and tumor cell proliferation was measured immunohistochemically with the monoclonal antibodies Ki-S2 and Ki-S5 (directed against the nuclear antigen Ki-67). A combined prognostic index was calculated on the basis of the S-phase fraction, progesterone receptor content, and tumor size. RESULTS: In multivariate analyses that did or did not (263 and 332 observations, respectively) include the S-phase fraction and the combined prognostic index, the Ki-S2 labeling index (percentage of antibody-stained tumor cell nuclei) emerged as the most statistically significant predictor of overall survival, disease-specific survival, and disease-free survival (all two-sided P<.0001). In the risk group defined by a Ki-S2 labeling index of 10% or less, life expectancy was not statistically significantly different from that of age-matched women without breast cancer, whereas the group with a high Ki-S2 labeling index had an increased risk of mortality of up to 20-fold. CONCLUSIONS: Cellular proliferation is a major determinant of the biologic behavior of breast cancer. Prognosis is apparently best indicated by the percentage of cells in S through M phases of the cell cycle. Measurement of the Ki-S2 labeling index of a tumor sample may improve a clinician's ability to make an accurate prognosis and to identify patients with a low risk of recurrence who may not need adjuvant therapy.

Amplification of c-myc but not of c-erbB-2 is associated with high proliferative capacity in breast cancer.

Proliferative capacity provides an independent prognostic marker of progression in breast cancer. Little is known about the molecular mechanisms influencing the cell division rate in mammary carcinomas. In order to address this issue, the copy numbers of c-erbB-2 (HER/neu) and c-myc protooncogenes that have been shown to be amplified in aggressive types of cancers were determined in 60 mammary carcinomas and related to the proliferation rate. The proliferative activity was determined by labeling of the proliferation-associated nuclear antigen which is defined by the recently described monoclonal antibody Ki-S1. Approximately one-third of samples under investigation displayed a Ki-S1 labeling index exceeding 30%. In this subgroup, amplification of c-myc was found in 52.6%, whereas in the remaining cases, 26.1% exhibited an enhanced copy number of c-myc (P < 0.025). By contrast, c-erbB-2 amplification was not found to be associated with a higher proliferation index. Except for one case of invasive lobular carcinoma, both protooncogenes exhibited regular copy numbers in the low proliferation subgroup (< 20%; P < 0.03). We conclude from our findings that c-myc amplification may be one of the molecular causes underlying the highly proliferating phenotype of mammary carcinoma, known to be associated with an unfavorable clinical course.

Regulation of telomerase activity in quiescent immortalized human cells.

Telomerase is a key enzyme in carcinogenesis; telomerase activity has been found in more than 90% of human tumors. Understanding the regulation of this enzyme will improve our knowledge of tumor biology and may lead to novel strategies in cancer therapy. We examined effects of growth arrest on telomerase activity in the human immortalized cell lines U 937 (lymphoma) and L 428 (Hodgkin's disease). Cells were starved by serum depletion for 4 days. After readdition of serum, a recovery phase followed. Cell proliferation was monitored with the monoclonal antibody Ki-S5. In the absence of serum, telomerase levels declined fivefold. After serum readdition, recovery to threefold increased level was observed. Furthermore, the prevalence of telomerase-positive cells in normal tissues is an important issue for understanding tumorigenesis. Our TRAP assay is robust against false positives and in mixed cell samples, we found a rather limited sensitivity of the telomere repeat amplification protocol (TRAP) assay. This means that adequate screenings for telomerase-positive somatic cells have to include enrichment steps.

Non-Hodgkin's lymphomas of childhood and adolescence: results of a treatment stratified for biologic subtypes and stage--a report of the Berlin-Frankfurt-Münster Group.

PURPOSE: To prove the efficacy of a treatment stratified according to histology for children with non-Hodgkin's lymphoma (NHL), including acute B-cell leukemia (B-ALL). PATIENTS AND METHODS: From October 1986 to March 1990, 302 assessable patients, 0.6 to 17.8 years of age, with newly diagnosed NHL were enrolled onto study ALL/NHL-BFM 86. Fifty percent of patients had Burkitt-type lymphomas, including B-ALL; 24% had lymphoblastic lymphoma; 18% had diffuse large-cell lymphoma; and 8% had an NHL not further classified. Therapy group B included Burkitt's-type lymphomas, B-ALL, and most large-cell lymphomas including Ki-1 anaplastic large-cell lymphoma. Patients with stage I and II disease resected received three, while all others received six, 5-day therapy courses (dexamethasone, methotrexate [MTX] 0.5 g/m2 [5 g/m2 for stage IV and B-ALL], and intrathecal [IT] therapy in each course, plus ifosfamide, cytarabine, and etoposide alternating with cyclophosphamide and doxorubicin). Therapy for group non-B patients (lymphoblastic lymphoma and pleomorphic T-cell lymphoma [PTCL]) consisted of a Berlin-Frankfurt-Münster (BFM) acute lymphoblastic leukemia protocol, including cranial irradiation for advanced stage. Local therapy was restricted to patients with incomplete tumor regression. RESULTS: The probabilities of event-free survival (pEFS) at 7 years were 80% +/- 2% for the whole group, 81% +/- 3% for group B (n = 225), and 78% +/- 5% for group non-B (n = 77) with a follow-up duration of 3.6 to 7 years (median 5 years). Treatment results were comparable between NHL subtypes, except for PTCL, in which three of four patients suffered from relapse. Local disease manifestations were the most frequent site of failure. CONCLUSION: This therapy strategy provided patients of all NHL subtypes with an equally high chance to survive event-free, except patients with PTCL. With reduced systemic failure, local tumor control may become more important.

Primary mediastinal large B-cell lymphoma with sclerosis in pediatric and adolescent patients: treatment and results from three therapeutic studies of the Berlin-Frankfurt-Münster Group.

PURPOSE: Primary mediastinal large B-cell lymphoma with sclerosis (PMLBL) is a rare entity of non-Hodgkin's lymphoma (NHL) arising from thymic mature B cells. Optimal treatment strategies remain to be established, especially in pediatric patients. PATIENTS AND METHODS: This study analyzes clinical characteristics and treatment outcome of 30 pediatric patients with PMLBL, diagnosed in multicenter therapy NHL-Berlin-Frankfurt-Münster Group (BFM) trials. Treatment was stratified by stage and serum lactate dehydrogenase (LDH) and consisted of four to six 5-day courses of chemotherapy using steroids, oxazaphosphorine alkylating agents, methotrexate, cytarabine, etoposide, and doxorubicin. Radiation was not part of the protocol. RESULTS: From April 1986 to August 1999, 1,650 patients with newly diagnosed NHL were enrolled in the NHL-BFM trials; 30 patients (1.8%) had PMLBL. Median age was 14.3 years (range, 1.4 to 16.7 years); 15 patients were male and 15 patients were female. With a median observation time of 5 years (range, 1 to 12 years), probability of event-free survival (pEFS) at 5 years was 0.70 (SE, 0.08). Two patients erroneously diagnosed as T-cell NHL received non-B-cell therapy and died from progress of disease. Events in 28 patients receiving B-cell therapy included early progress during therapy (n = 1) and relapse (n = 6). Residual mediastinal masses were present in 23 patients after two courses of therapy and in 15 patients after the end of therapy. LDH > or = 500 U/L was associated with increased risk of failure in multivariate analysis. CONCLUSION: PMLBL mainly is found in adolescents. Dose-intense chemotherapy including high-dose methotrexate yields a pEFS at 5 years of 0.70 (SE, 0.08). LDH is of prognostic value in pediatric patients with PMLBL.

Successful treatment strategy for Ki-1 anaplastic large-cell lymphoma of childhood: a prospective analysis of 62 patients enrolled in three consecutive Berlin-Frankfurt-Munster group studies.

PURPOSE: To prove prospectively the efficacy of a short-pulse chemotherapy for treatment of Ki-1 anaplastic large-cell lymphoma (ALCL) of childhood. PATIENTS AND METHODS: From October 1983 to December 1992, 62 patients (median age, 9.7 years) with newly diagnosed Ki-1 ALCL were enrolled onto Non-Hodgkin's Lymphoma-Berlin-Frankfurt-Munster (NHL-BFM) studies 83, 86, and 90. The most frequent immunophenotype was T cell. Ki-1 ALCL differed from other subsets of NHL of childhood by the more frequent involvement of bone, soft tissue, and skin, and by the lack of bone marrow (BM) disease. A 5-day prephase course (prednisone/cyclophosphamide) was followed by two different 5-day courses of chemotherapy: course A consisted of dexamethasone, methotrexate (MTX) 0.5 g/m2 (24-hour infusion), intrathecal chemotherapy, ifosfamide, cytarabine (Ara-C), and etoposide (VP-16); course B consisted of cyclophosphamide and doxorubicin instead of ifosfamide, and Ara-C/VP-16, respectively. Treatment was stratified into three branches. Branch 1 (stage I and stage II resected) received three courses; branch 2 (stage II not resected, stage III), six courses; and branch 3 (stage IV), six intensified courses containing MTX 5 g/m2, and Ara-C 2 g/m2. Local radiotherapy was not performed. RESULTS: Four patients failed to enter remission, and one died of infection. Seven patients relapsed within 9 months after diagnosis; two patients had isolated local relapses, but BM and CNS were never involved. Fifty patients have been in first continuous complete remission (CR) for 0.6 to 9.7 years (median, 2.5), and 56 are alive. The probabilities for survival and event-free survival (EFS) at 9 years are 83% +/- 7% (SE) and 81% +/- 5%. Skin involvement was the only negative prognostic parameter. CONCLUSION: Short-pulse chemotherapy over 2 to 5 months without local therapy modalities is effective in the treatment of Ki-1 ALCL.

Mantle-cell lymphomas have more widespread disease and a slower response to chemotherapy compared with follicle-center lymphomas: results of a prospective comparative analysis of the German Low-Grade Lymphoma Study Group.

PURPOSE: To compare mantle-cell lymphomas (MCLs) and follicle-center lymphomas (FCLs) for their features of clinical presentation, response to chemotherapy, and prognosis on the basis of a prospective randomized clinical trial. PATIENTS AND METHODS: Patients with MCL and FCL who entered onto the prospective randomized comparison of cyclophosphamide, vincristine, and prednisone (COP) versus prednimustine and mitoxantrone (PmM) followed by a second randomization for interferon (IFN) maintenance versus observation only. RESULTS: One hundred sixty-five of 234 patients had FCL and 45 of 234 patients had MCL. With FCL, both sexes were equally affected (men, 47%); patients with MCL were predominantly men (78%; P < .0004) and had a higher median age (64 v 53 years; P < .0001). Patients with MCL also had more widespread disease, reflected by the proportion of patients with two or greater extranodal manifestations (43% v 21%; P < .005) and nine or greater involved nodal areas (64% v 45%; nonsignificant [NS]). Response to chemotherapy was significantly lower in patients with MCL (complete remission [CR] + partial remission [PR], 69% v 88%; P < .05) and occurred at a slower pace. Patients with MCL also had a shorter event-free interval (median, 8 v 24 months; P < .0001) and overall survival (median, 28 v 77 months; P < .0001). In both subtypes, however, patients with less than two residual lymphoma manifestations in remission experienced a relatively good prognosis with an estimated 5-year survival of greater than 60% for MCL and greater than 75% for FCL. CONCLUSION: MCL and FCL differ substantially in their features of presentation, response to chemotherapy, and long-term prognosis. The extent of residual disease after completion of chemotherapy discriminates patients with different prognosis and may be used for the stratification of postremission strategies.

Primary gastrointestinal non-Hodgkin's lymphoma: I. Anatomic and histologic distribution, clinical features, and survival data of 371 patients registered in the German Multicenter Study GIT NHL 01/92.

PURPOSE: The study was initiated to obtain epidemiologic data and information on anatomic and histologic distribution, clinical features, and treatment results in patients with primary gastrointestinal non-Hodgkin's lymphomas (PGI NHL). PATIENTS AND METHODS: Between October 1992 and November 1996, 371 PGI NHL patients were eligible to evaluate clinical features. Radiotherapy and chemotherapy were stratified according to histologic grading, stage, and whether surgery had been carried out or not. RESULTS: A total of 74.8% patients had gastric NHL (PGL). Within the intestine, the small bowel and the ileocecal region were involved in 8.6% and 7.0% of the cases, respectively. Multiple GI involvement (MGI) was 6.5%. Approximately 90% of the GI NHL were in stages IE/IIE. Aggressive NHL accounted for the majority, with a distinguishable pattern in several sites. Forty percent of PGL were of low-grade mucosa-associated lymphatic tissue type. One third of large-cell lymphomas had low-grade components. Most intestinal NHL were germinal-center lymphomas. The site of origin was prognostic. In gastric and ileocecal lymphoma, event-free (EFS) and overall survival (OS) were significantly higher as compared with the small intestine or MGI (median time of observation, 51 months). In PGL, localized disease was prognostic for EFS and OS. Histologic grade influenced only EFS significantly. Numbers in intestinal lymphomas were too small for subanalyses. CONCLUSION: PGI NHL are heterogeneous diseases. The number of localized PGL allowed for detailed analyses. Larger studies are needed for stages III and IV and for intestinal NHL. A uniform reporting system for PGI NHL, in terms of definitions and histologic and staging classifications, is needed to facilitate comparison of treatment results.

Primary gastrointestinal non-Hodgkin's lymphoma: II. Combined surgical and conservative or conservative management only in localized gastric lymphoma--results of the prospective German Multicenter Study GIT NHL 01/92.

PURPOSE: The aim of the study was to obtain data on anatomic and histologic distribution, clinical features, and treatment results of patients with primary gastrointestinal non-Hodgkin's lymphomas, particularly combined surgical and conservative treatment (CSCT) versus conservative treatment (CT) alone for primary gastric lymphoma (PGL) in localized stages. PATIENTS AND METHODS: Whether the treatment included surgery was left to the discretion of each participating center. Radiotherapy (Rx) and chemotherapy were stratified according to histologic grading, stage, and the inclusion or omission of surgery as follows: patients with low-grade PGL were treated with extended-field (EF) Rx (30 Gy). In case of residual tumor after surgery or in case of CT only (in stage IIE after six cycles of cyclophosphamide, vincristine, and prednisone), an additional boost of 10 Gy was given. All patients with high-grade PGL were treated with four (stage IE) or six (stage IIE) cycles of cyclophosphamide, doxorubicin, vincristine, and prednisone followed by EF Rx (stage IE) or involved-field (IF) Rx (stage IIE). Rx dosage corresponded to low-grade NHL. RESULTS: Between October 1992 and November 1996, 106 patients had CT only. The survival rate (SR) after 5 years was 84.4% and was influenced neither by patients' characteristics nor by stage or histologic grade. Seventy-nine patients had CSCT. Their SR was 82.0%. Complete resection of the tumor (R0) was prognostic for the overall survival (P =.0165) as compared with incomplete resection. CONCLUSION: Although the study was not randomized, a stomach-conserving approach may be favored.

Sequential application of chemotherapy and monoclonal CD 20 antibody: successful treatment of advanced composite-lymphoma.

We describe successful treatment of a 38-year-old patient with composite lymphoma stage IV(A), who presented with multifocal enlarged lymph nodes. The lymph node histology showed classic morphologic features of Hodgkin's disease, mixed cellularity subtype and follicular B-cell lymphoma. Immunophenotypic analysis showed immunoreactivity for CD20, CD10 and Ki-67 in the malignant small cell population. The areas of Hodgkin's disease demonstrated positive immunoreactivity for CD30 and CD20 in the Hodgkin's cells. Both cell populations were bcl2-oncoprotein positive. Eight courses of dose-escalated BEACOPP were administered. Restaging after chemotherapy showed radiological partial remission, but biopsy confirmed persisting follicular B-cell lymphoma without bone marrow infiltration and no evidence of Hodgkin's disease. He was treated with monoclonal CD 20-antibody (Rituximab) 10 mg/kg weekly for eight consecutive weeks due to marked positivity of CD 20-antigen in follicular lymphoma cells. This treatment was well tolerated and final staging showed complete remission of the composite lymphoma. This patient continues to be in remission 28 months after the end of the treatment. In conclusion, in the very rare case of composite lymphoma a combination of chemotherapy and subsequent immunotherapy might be considered as a promising therapeutic option.

DNA damage transiently increases TRF2 mRNA expression and telomerase activity.

Telomerase activity transiently increases when HL60 cells are treated with the topoisomerase II inhibitor etoposide. A quantitative assessment revealed that telomerase is activated by etoposide treatment in a number of cell lines and that the increase is reversible after withdrawal of etoposide from the cell culture. Telomerase activation correlated with the occurrence of DNA damage but not with cell cycle arrest. We did not detect any transcriptional upregulation of hTERT mRNA, suggesting a post-transcriptional mechanism of telomerase activation. Furthermore, the mRNA expression of the telomere binding protein TRF2 was upregulated early and reversibly after etoposide treatment. TRF1 mRNA expression levels were unchanged after DNA damage, but increased when the cells accumulated in the G2/M phase. The data show that the telosome reacts after DNA damage by upregulating telomerase activity and TRF2 expression in malignant cells. It has previously been shown that overexpression of TRF2 can repress senescence signals arising from critically shortened telomeres. We show here that TRF2 is upregulated by undirected DNA damage that also affects the telomeric DNA. These data suggest that upregulation of telomerase activity and TRF2 expression might act as antiapoptotic mechanisms in the DNA-damage response of malignant cells.

Cell lineage specificity in G-CSF receptor gene methylation.

In hematopoiesis the evolution of specialized cell lineages from a common stem cell is mediated by lineage-specific growth factors. The role of DNA methylation in the multilevel regulation of the differential gene expression, especially in the case of growth factor receptor genes, has remained elusive. In earlier studies we showed a lineage-specific methylation pattern of the M-CSF receptor gene c-fms in blood monocytes and tissue macrophages. Here, we provide evidence that a lineage-specific hypomethylation exists for the G-CSF receptor gene for myelomonocytic cells but not in lymphocytes without any interindividual differences. Constant differences were found between alveolar and peritoneal macrophages with a lesser degree of methylation in peritoneal macrophages. Acute myelomonocytic leukemias showed an increased methylation as compared with normal granulocytes and monocytes. All permanent cell lines analyzed revealed hypermethylation of the G-CSF receptor gene. Lymphocytes of B-CLL showed a strong hypermethylation of this gene. Increased methylation has been shown to be inversely correlated with transcriptional gene activities. We conclude that the methylation pattern of growth factor receptor genes may be one of the regulatory mechanisms in multi-lineage differentiation.

Identification and structural analysis of rearranged immunoglobulin heavy chain genes in lymphomas and leukemias.

The third complementarity determining region (CDR3) of the hypervariable domain of immunoglobulin heavy chain (IgH) genes represents a highly variable and clone-specific IgH-CDR3 sequences in 10 non-Hodgkin's lymphomas (NHL), five chronic lymphocytic leukemias (CLL) and five acute lymphoblastic leukemias (ALL) of B cell lineage. The IgH-CDR3 sequences were amplified using DNA extracted from clinical specimens (bone marrow, peripheral blood and fresh-frozen or paraffin-embedded lymph nodes) by a semi-nested PCR with consensus primers directed to conserved regions within the variable (VH) and the joining (JH) gene segments. In 17/20 samples (85%), a distinct IgH-CDR3 PCR product was obtained. Individual PCR products were sequenced after cloning. The nucleotide sequences of 134 randomly chosen recombinant vectors were determined demonstrating in 17/20 cases (85%) monoclonal VH-N-DH-N-JH junctions. Analysis of PCR products by temperature-gradient gel electrophoresis (TGGE) confirmed the specificity of the IgH-CDR3 PCR/sequencing results. Moreover, the combination of PCR/TGGE technology allowed the rapid and specific characterization of clonal IgH-CDR3 junctions in B cell proliferations by direct sequencing even in the presence of admixed polyclonal B cells.

Topoisomerase IIalpha expression in mantle cell lymphoma: a marker of cell proliferation and a prognostic factor for clinical outcome.

Mantle cell lymphoma (MCL) is a malignant lymphoma associated with a relatively aggressive clinical course and a median overall survival time of 3-4 years. Treatment usually consists of combination chemotherapy, often including topoisomerase (topo) inhibitors such as doxorubicin, etoposide and mitoxantrone. Topo IIalpha is an enzyme that is needed whenever uncoiling of DNA is necessary during the cell cycle. The enzyme is a marker of cell proliferation. We analyzed the expression of topo IIalpha in relation to Ki-67 and the clinical outcome in patients with MCL. Biopsy specimens from 95 untreated patients enrolled in two multicenter trials (1975-1985) were investigated immunohistochemically with monoclonal antibodies against topo IIalpha (Ki-S4) and Ki-67 (Ki-S5). Patients with low (0-10%) topo IIalpha expression had a median overall survival time of 49.0 months, compared to 17.0 months for patients with high (more than 10%) topo IIalpha expression. The Kaplan-Meier analysis showed a significant difference in the overall survival time related to the percentage of topo IIalpha (P<0.001) and Ki-67 (P<0.001) positive tumor cells. Multivariate Cox regression analysis revealed the expression of topo IIalpha as the most important prognostic factor (P<0.001) in MCL superior to the international prognostic index (IPI), the Ki-67 index and other clinical characteristics.

A prospective multicenter trial with human recombinant alpha 2c-interferon in hairy cell leukemia before and after splenectomy.

Our multicenter study on the treatment of hairy cell leukemia (HCL) started in December 1984 and the present data cover the time up to June 30, 1986. Ninety-seven patients were enrolled. For induction of response daily doses (6 micrograms) of low dose human recombinant alpha 2c-interferon (arg) was chosen. Further dose reduction (3 micrograms) was possible for patients who improved within the first 3-4 weeks. Patients with known risk factors started at lower doses (0.6 microgram daily). As infections are known to be the main cause of death in HCL, splenectomy was not mandatory before treatment. Thirty-nine patients received treatment with interferon. Nevertheless, infections remained the major cause of death in the study. The protocol did not prevent fatal infections in nine of the 34 splenectomized patients. The regimen proved safe for all but one of the nonsplenectomized patients. According to this experience, new criteria are needed for the choice of primary treatment in HCL. In our opinion splenectomy should become restricted to selected cases.

Structure of Bcl-1 and IgH-CDR3 rearrangements as clonal markers in mantle cell lymphomas.

Mantle cell lymphoma represent a clinicopathologically distinct entity of malignant non-Hodgkin's lymphoma (NHL) and are characterized by a specific chromosomal translocation t(11;14)(q13;q32) involving the cyclin D1 gene also designated as bcl-1/PRAD1 gene on chromosome 11 and the heavy chain immunoglobulin joining region on chromosome 14. We have established a PCR method to amplify t(11;14) junctional sequences in DNA from fresh frozen and paraffin-embedded tissue by bcl-1-specific primers in combination with a consensus immunoglobulin JH primer. A total of 65 cases histologically classified as mantle cell lymphoma (MCL) were analyzed for the presence of a t(11;14) translocation and monoclonal IgH-CDR3 rearrangements. From 26 patients with classical MCL and three cases with the anaplastic variant of MCL fresh frozen biopsy material was available for DNA extraction. We detected a bcl-1/JH rearrangement in 12 out of 29 samples (41%). In 36 cases paraffin-embedded lymph node tissue was the only source of DNA. In this material we found a bcl-1/JH rearrangement in six out of 31 samples with intact DNA (20%). To confirm the specificity of the PCR and to determine the bcl-1/JH junctional region sequences as clone-specific marker in individual patients we characterized the junctional DNA sequences by direct PCR sequencing in 16 cases. Interestingly we found that six bcl-1/JH junctions harbored DH segments in their N regions indicating that bcl-1/JH rearrangements can occur in a later stage of B cell ontogeny during which the complete VH to DH-JH joining or VH-replacement takes place. To investigate the suitability of IgH-CDR3 as sensitive molecular marker for those MCL patients in which a t(11;14) translocation can not easily be amplified, we additionally analysed 60 cases for the presence of monoclonally rearranged IgH genes by IgH-CDR3-PCR. A monoclonal IgH-CDR3 PCR product could be identified in 24 out of 29 fresh frozen samples (79%) whereas only 11 out of 31 samples (36%) with paraffin-derived DNA were positive. We demonstrate that automated fluorescence detection of monoclonal IgH-CDR3 PCR products allows the rapid and sensitive monitoring of minimal residual disease also in cases that lack a PCR amplifiable t(11;14) translocation. In combination with allele-specific primers the procedure may improve current experimental approaches for detection of occult MCL cells at initial staging and residual disease during and after therapy.

Segmental chromosomal aberrations and centrosome amplifications: pathogenetic mechanisms in Hodgkin and Reed-Sternberg cells of classical Hodgkin's lymphoma?

Tumor cell metaphases of classical Hodgkin's lymphoma (cHL) characteristically display highly rearranged karyotypes with chromosome numbers in the hyperploid range and marked intraclonal variability. The causes of this cytogenetic pattern remain largely unknown. An unusual type of chromosomal abnormality coined as segmental chromosomal aberration (SCA) has been recurrently observed in HL cell lines and was suggested to be associated with ribosomal DNA (rDNA) rearrangements. Moreover, centrosome abnormalities provoking deficient chromosome segregation have been reported in many solid tumors and also in cHL cell lines. Whether SCA, rDNA rearrangements or centrosome abnormalities also occur in primary cHL is not yet known. Thus, we performed extensive molecular cytogenetic and immunohistological studies in two cHL cases. Both cases presented SCA associated with genomic gains of the REL and JAK2 loci, respectively. The SCA involving JAK2 was associated with rDNA rearrangements. The absolute centrosome size of HRS cells in both cases was significantly larger than in non-HRS cells, but the relative centrosome size of HRS cells corrected for nuclear size was in the same range as that of the non-neoplastic cells. These findings demonstrate that the various mechanisms associated with chromosomal instability warrant a more detailed characterization in cHL.

Prednimustine, mitoxantrone (PmM) vs cyclophosphamide, vincristine, prednisone (COP) for the treatment of advanced low-grade non-Hodgkin's lymphoma. German Low-Grade Lymphoma Study Group.

The current study was initiated to compare the anti-lymphoma activity and side-effects of prednimustine/mitoxantrone (PmM) vs cyclophosphamide, vincristine, prednisone (COP) in patients with advanced low-grade non-Hodgkin's lymphomas in way of a prospective randomized multicenter trial. Two hundred and forty-six patients with stage III or IV centroblastic-centrocytic (CB-CC (Kiel-classification)) or follicle center lymphoma (FCL (REAL classification)) and centrocytic (CC) or mantle-cell-lymphoma (MCL) were randomized for therapy with either PmM or COP and are fully evaluable for response and toxicity. PmM consisted of prednimustine 100 mg/m2/day on days 1-5 and mitoxantrone 8 mg/m2 /day days 1 and 2, while COP comprised cyclophosphamide 400 mg/m2/day on days 1-5, vincristine 1.4 mg/m2/day on day 1 and prednisone 100 mg/m2/day on days 1-5. Both regimens were repeated for a total of six cycles followed by an additional two courses for consolidation in responding cases and a subsequent second randomization for interferon alpha maintenance vs observation only. Overall response rates were comparable with 83% complete and partial remissions after COP and 84% remissions after PmM. PmM revealed a significantly higher rate of complete remissions (36 vs 18%, P < 0.006), the majority being achieved after four courses. The more rapid and possibly also more effective reduction of the lymphoma cell mass by PmM resulted in a tendency to a longer event-free interval for patients achieving remissions after PmM as compared to COP with estimated median event-free intervals of 31 vs 14 months, respectively (P=0.04). Separate analysis of lymphoma subtypes showed a tendency to a lower rate of complete remission in CC or MCL as compared to CB-CC or FCL (16 vs 30%, P=0.12, NS) while overall response rates were in a similar range (81 vs 85%). In both subtypes, PmM induced a higher rate of complete remission while overall response rates were comparable after PmM or COP. Treatment associated side-effects comprised predominantly myelosuppression and granulocytopenia in particular which was more frequently observed after PmM than COP (43 vs 31 %, P < 0.0001). This difference was clinically irrelevant, however, since serious infectious complications were encountered in less than 3% of cycles after both regimens. COP therapy was associated with a significantly higher incidence and degree of hair loss and complete alopecia (31 vs 2%) as well as of peripheral neurotoxicity (23 vs 2%). These data show that both PmM and COP reveal a high anti-lymphoma activity in patients with advanced stage non-Hodgkin's lymphoma. PmM appears advantageous with a higher rate of complete remissions and a better tolerability with regard to secondary side-effects. A longer follow-up is needed to assess the long-term effects of initial treatment on disease-free and overall survival and the impact on additional maintenance therapy with interferon alpha.

Monoclonal antibodies Ki-S3 and Ki-S5 yield new data on the 'Ki-67' proteins.

The monoclonal antibody (mab) Ki-67 has been used for about 10 years, mainly in tissue sections, to monitor proliferating cells, but so far only very little is known about the proteins it recognizes. The new mabs Ki-S3 and Ki-S5 detect proliferating cells in frozen and paraffin-embedded tissues. They recognize proteins with the same molecular mass as Ki-67 in Western blot and for the first time also in immunoprecipitation experiments. With these mabs we were able to enrich and purify the Ki-67 proteins. Protein sequencing of four peptides of the digested proteins corresponded to the cDNA-deduced amino acid sequence already published for the Ki-67 proteins. Since we were able to immunoprecipitate the Ki-67 proteins, we performed various immunoprecipitation experiments to obtain more information about the nature of these proteins. After radiolabelling L428 cells with [35S]-methionine we were able to immunoprecipitate the Ki-67 proteins after only 5 min of labelling time. In turnover experiments the Ki-67 proteins could not be detected 3 h after the end of labelling. These data indicate a half-life of the Ki-67 proteins of about 90 min. Labelling experiments with [32P]-orthophosphate revealed that the Ki-67 proteins are phosphorylated. After dephosphorylation was blocked with okadaic acid or cell growth was arrested by means of Colcemid, the phosphorylation of the Ki-67 proteins was greatly increased, indicating that the Ki-67 proteins are phosphorylated via serine and threonine, and that the phosphorylation of the Ki-67 proteins increases in cycling cells. Labelling experiments with [3H]-mannose and [3H]-glucose revealed that the protein is weakly N-glycosylated.