Search PubMed⌕ Search

Biomedical subjects

J C Kluin-Nelemans

Publications and source records attributed to J C Kluin-Nelemans.

At least 55 records · Page 3Linked to original sources
PubMed1997

Treatment of T-cell prolymphocytic leukemia with human CD52 antibody.

PURPOSE: T-prolymphocytic leukemia (T-PLL) is an aggressive malignancy of mature T cells refractory to conventional chemotherapy, with a median survival duration of 7.5 months. We report here promising results with the use of a genetically reshaped human CD52 antibody, CAMPATH-1H. PATIENTS AND METHODS: Fifteen patients with T-PLL, most of whom had received the purine analog deoxycoformycin (DCF), were treated with CAMPATH-1H. Results were compared with those of 25 patients treated with DCF. RESULTS: Major responses occurred in 11 patients (73%) treated with CAMPATH-1H compared with 40% with DCF. Complete remissions (CRs) were documented in nine (60%) of the CAMPATH-1H cases and only three (12%) were obtained with DCF. CRs with CAMPATH-1H were durable, and re-treatment with the antibody resulted in second CRs in three relapsed patients. Two of them were successfully autografted with peripheral-blood and bone marrow stem cells collected during the first CR. Apart from first-dose reactions, infusions of CAMPATH-1H were well tolerated. However, two responding patients developed severe bone marrow aplasia that was fatal in one; the second remained moderately pancytopenic 21 weeks after stopping CAMPATH-1H therapy. The cause of this adverse effect is unknown. CONCLUSION: CAMPATH-1H is an effective agent in T-PLL and represents a significant improvement over other types of therapy. However, CAMPATH-1H alone is not sufficient for long-term remissions, and the role of autologous stem-cell transplantation needs further investigation.

Adult↗
PubMed1997

Development of a "Myeloma Risk Score" using a population-based registry on paraproteinemia and myeloma.

Diagnostic systems for monoclonal gammopathies use bone marrow and X-ray examinations to exclude multiple myeloma (MM). Data from a population-based registry of unselected patients with paraproteinemia indicate that these tests are often done only when MM is suspected. We used 441 randomly selected patients to develop a simple four point "Myeloma Risk Score" based on two readily available laboratory tests. One point was given for paraprotein concentration > or = 10 g/l, one point for IgG and IgA, and two points for IgD and light chains only. A score of 0 or 1 indicated a low risk for MM, with scores of 2 and 3 signifying high risks. Sensitivity, specificity, positive and negative predictive value (PV) for the Myeloma Risk Score in the training sample were 92%, 88%, 79%, and 96% respectively. Extrapolating these results to a larger cohort showed that 90% of patients with a monoclonal gammopathy could be classified correctly as having MM or a non-myeloma condition. The Myeloma Risk Score can identify patients with a paraproteinemia at risk for MM, and who are therefore candidates for bone marrow and X-ray examination.

Biomarkers, Tumor↗
PubMed1997

Persistent improved results after adding vincristine and bleomycin to a cyclophosphamide/hydroxorubicin/Vm-26/prednisone combination (CHVmP) in stage III-IV intermediate- and high-grade non-Hodgkin's lymphoma. The EORTC Lymphoma Cooperative Group.

CHOP has been and still is regarded by many as the 'standard' treatment of advanced non-Hodgkin's lymphoma. In 1980 the EORTC Lymphoma Cooperative Group started a study to evaluate the addition of vincristine and bleomycin to its standard four-drug combination chemotherapy, CHVmP (cyclophosphamide, hydroxorubicin, Vm-26, prednisone). Eligible patients were stage III or IV, intermediate- to high-grade non-Hodgkin's lymphoma (Working Formulation E-I). One-hundred-eighty-nine patients were entered, of whom 140 were eligible and evaluable. A previous report showed an improved response rate and failure-free survival (FFS) and overall survival for the combination CHVmP-VB. At ten years, the outcome still favors the addition of vincristine and bleomycin. The FFS was 34% vs. 23% and the overall survival 34% vs 22%. This difference was mainly due to a difference in CR rate (74% vs. 49%), Relapse-free survival for patients reaching a CR was the same in both arms. When the patients were grouped according to the International Prognostic Factor Index, no statistically significant difference could be observed in favor of one treatment within either group. This trial clearly demonstrates the benefit gained by the addition of vincristine and bleomycin to 'standard' chemotherapy for intermediate and high-grade non-Hodgkin's lymphoma.

Adolescent↗
PubMed1997

Comparison of inflammatory cell counts in asthma: induced sputum vs bronchoalveolar lavage and bronchial biopsies.

BACKGROUND: Induced sputum potentially allows monitoring of airway inflammation in patients with asthma in a non-invasive way. However, the relationship between the cellular content in sputum and airway tissue has not been fully clarified. OBJECTIVE: We compared the cellular compositions of hypertonic saline-induced sputum, bronchoalveolar lavage fluid (BAL) and bronchial biopsies in 18 clinically stable patients with mild to moderate atopic asthma (baseline FEV1: range 61-114%pred, PC20 methacholine: 0.04-4.7 mg/mL). They were treated with inhaled short-acting bronchodilators on demand, with (n = 8) or without (n = 10) regular inhaled steroids. METHODS: Each patient underwent sputum induction and fiberoptic bronchoscopy on separate days in random order. Differential cell counts of induced sputum, bronchoalveolar lavage and bronchial wash were determined on May-Grünwald-Giemsa stained cytospins. Flow cytometry was performed on sputum and BAL samples. Immunohistochemical techniques were used to stain inflammatory cells in 6 microm cryostat sections of bronchial biopsies. RESULTS: Sputum cell differentials were not different between the patients with and without inhaled steroids, and showed a median value of 19.4% squamous cells, with 1.0% eosinophils, 3.3% lymphocytes, 28.7% neutrophils, 49.4% macrophages and 6.9% cylindric epithelial cells (in percentage non-squamous cells). The percentage eosinophils in sputum was significantly correlated with their percentage in bronchial wash (Rs = 0.52, P = 0.03) and in BAL (Rs = 0.55, P= 0.02), whilst there was a trend towards such a correlation between the number of eosinophils/mL sputum and the number of EG2+ eosinophils/mm2 lamina propria in bronchial biopsies (Rs = 0.44, P = 0.07). In addition, the percentage of CD4+ lymphocytes correlated between sputum and BAL (Rs = 0.55, P = 0.03). CONCLUSION: We conclude that the eosinophil counts in hypertonic saline-induced sputum from patients with asthma are related to those in bronchial wash and BAL and, to a lesser extent, with the counts in bronchial biopsies. This suggests that induced sputum can be used to monitor the presence and severity of airway inflammation in asthma.

Adolescent↗
PubMed1997

Cytogenetics on released DNA fibers.

DNA fibers can be released from cell suspensions and frozen tissue and can be used as a template for hybridization with multiple differently labeled probes. Simultaneous hybridization with 5-10 adjacent or partly overlapping probes generates a highly specific "color barcode" for individual DNA segments. Rearrangements in this barcode can be easily detected and mapped. The resolution of DNA fiber FISH is between 2 and 500kb. In mixing experiments of cell lines with different structural abnormalities, we found a sensitivity of approximately 10%. We applied DNA fiber FISH for detection of t(11;14) in mantle cell lymphoma (MCL) and immunoglobulin (Ig) class switching in hairy cell leukemia (HCL). Using a barcode for the Ig and BCL-1 loci at 14q32 and 11q13, we detected and mapped a t(11;14) breakpoint in 35 of 36 MCL. In 5 cases complex mono-allelic rearrangements at both sides of the cyclin D1 gene were identified. In 13 HCL with phenotypic evidence of Ig class switching, including 2 cases with solely IgD, fiber FISH revealed concordant Ig class switch deletions. In most cases both alleles were affected. These results indicate that DNA fiber FISH is a very powerful method to detect and map structural DNA alterations.

Chromosomes, Human, Pair 11↗
PubMed1996

Persistent clonal excess and skewed T-cell repertoire in T cells from patients with hairy cell leukemia.

Hairy cell leukemia (HCL) is characterized by a severe T-cell-mediated immune deficiency. At the same time, spontaneous T-cell activation is noted when splenic T cells are studied in vivo and in vitro. Therefore, we searched for oligoclonal T-cell populations in the blood and spleens of 25 patients with HCL using a T-cell receptor gamma-polymerase chain reaction (TCR gamma-PCR). Subsequently, in 6 patients, the CDR3 length and conformation from 22 different TCRBV subfamilies were analyzed after PCR amplification of cDNA using TCRBV subfamily-specific primers. T cells from 15 of 25 HCL patients showed clonal excess by the TCR gamma-PCR. In fluorescence-activated cell sorted T-cell subsets, more clonal bands were observed than in the unseparated T cells, with most of these in CD8+ subsets, but also in CD4+, CD3+ gamma/delta+, and a double-negative CD3+ alpha/beta+ subset. In other B-cell malignancies, 6 of 16 samples showed oligoclonal T cells, whereas only 2 of 18 normal spleen and blood samples showed abnormal bands. Analysis of the TCRBV subfamilies disclosed in all 6 HCL patients a markedly abnormal pattern, with many clonal bands in 5 to 15 subfamilies, and absent or abnormal weak patterns in another 1 to 8 subfamilies. In comparison, 6 normal samples (2 spleens and 4 blood samples) showed in only 1 blood donor 1 clonal band. Two patients with active HCL but without infections or treatment were tested several times during the course of the disease and showed a complete identical skewed T-cell repertoire with the same oligoclonal T-cell populations. In conclusion, T cells in the blood and spleen of HCL patients show impressive abnormalities with many oligoclonal T-cell populations and a very restricted and skewed TCRBV repertoire.

Base Sequence↗
PubMed1996

Serum neural cell adhesion molecule differentiates multiple myeloma from paraproteinemias due to other causes.

Serum neural cell adhesion molecule (NCAM) has been described as a prognostic marker in multiple myeloma (MM). Both C-reactive protein (CRP) and beta 2-microglobulin (beta 2M) are established prognostic markers in MM. We tested the diagnostic value of these markers in 212 serum samples of patients with paraproteinemia registered prospectively in a population-based registry. Sixty patients had MM and 152 had other monoclonal gammopathies (hematologic diseases [48], paraneoplastic disease [35], autoimmune disease [15], and monoclonal gammopathy of undetermined significance [56]). CRP and beta 2M had wide and overlapping ranges in all diagnostic categories. However, serum neural cell adhesion molecule (NCAM) was low (< 20 U/mL) in all but 4 of 152 nonmyeloma cases and high (> or = 20 U/mL) in 31 (52%) of the 60 MM cases. Two patients with non-Hodgkin's lymphoma, 1 with chronic lymphatic leukemia, and 1 with autoimmune disease had serum NCAM values between 20 and 30 U/mL. In a discriminant analysis in which serum NCAM, CRP, beta 2M, paraprotein type and concentration, hemoglobin, leukocyte and thrombocyte counts, creatinine, corrected calcium, lactate dehydrogenase, and alkaline phosphatase were included, paraprotein type and concentration and serum NCAM turned out to be the best combination of parameters predicting whether a patient had MM, with 89% of cases being correctly classified. Even without bone marrow and x-ray examinations, serum NCAM, in combination with paraprotein type and concentration, can differentiate between MM and nonmyeloma patients.

Adult↗
PubMed1996

Role of 67Ga scintigraphy in localization of lymphoma.

This review deals with the applications of 67Gallium (Ga) scintigraphy for the initial staging and follow-up during and after treatment of patients with Hodgkin's or non-Hodgkin's lymphoma (NHL). During the last decade, the technique of visualization has been largely improved by using higher doses and additional tomography. Here, the indications for 67Ga scintigraphy in comparison with CT and MRI are discussed. The conditions resulting in false positive and false negative results have been outlined. 67Ga may detect unusual involved sites during staging procedures. However, the major contribution to the management of Hodgkin's disease and NHL is the evaluation of residual masses, because 67Ga uptake reflects the metabolic activity of the tumor. The review ends with an additional short overview of other radionuclide imaging methods useful for malignant lymphoma.

Gallium Radioisotopes↗
PubMed1996

Proliferation of precursor B-lineage acute lymphoblastic leukaemia by activating the CD40 antigen.

No reliable culture system exists for B-lineage acute lymphoblastic leukaemia (ALL). Recently we found that many different mature B-cell malignancies proliferate upon stimulation via the CD40 antigen, and this led us to investigate whether a similar CD40 activation on ALL cells could also induce proliferation. First, we measured CD40 expression in 21 ALL cases; all were CD40+, although mostly weak. Next, we triggered the CD40 antigen by anti-CD40 antibodies and by a CD40 ligand-expressing cell line. In addition, we measured the influence of IL-3, IL-4 and IL-7 with and without these stimuli. In 8/10 cases proliferation, measured by 3H-thymidine incorporation, could be induced after CD40 crosslinking, especially in the presence of IL-3. Stimulation via the CD40 ligand was more successful than using crosslinked anti-CD40 antibodies. IL-4 inhibited the spontaneous proliferation found in three cases, but stimulated proliferation after CD40 crosslinking. IL-7 did not contribute to proliferation. Morphology, immunophenotyping and surface marker analysis, combined with DNA flow cytometry confirmed that the proliferation found could be ascribed to the ALL cells. In conclusion, B-lineage ALL cases are CD40+, and many can be cultured using CD40 stimulation and IL-3.

Burkitt Lymphoma↗
PubMed1996

Pitfalls in the immunophenotyping of leukaemia and leukaemic lymphomas: survey of 9 years of quality control in The Netherlands. Dutch Cooperative Study Group on Immunophenotyping of Haematological Malignancies (SIHON).

During the last decade, biannual quality controls were performed in the Netherlands focusing on the immunophenotyping of leukaemic haematological malignancies. All results on 48 specimens obtained by 18-34 laboratories were analysed. The interlaboratory variability and percentages of discordant results from 30 markers were measured by assessing false positive or negative (cut-off 10%) results in comparison with median results of the group. The quality of the immunophenotypic diagnoses obtained from the interpretation of these markers in relation to clinical data was evaluated by scoring them as 'correct', 'minor fault', 'major fault', 'not based upon the markers used', and 'no diagnosis', CD3, CD8, CD19, CD61 and Sm lambda had the lowest percentage discordancy (sum of total negative and positive discordant values 5-7.5% of assays): CD13, CD15, cyCD22, CD33 and TdT scored worst with 14-20% cumulative discordancy. The analysis of each diagnosis yielded 78% acceptable immunophenotypic conclusions (correct 54% and minor fault 24%). It appeared that the major faults in immunophenotyping were caused by suboptimal antibody selection and erroneous interpretation of the results obtained, rather than by technical errors. Large differences per diagnostic category were observed, with the best scores for mature B-cell leukaemias, AMLs and common-ALL, and the poorest scores for T-cell malignancies which were correctly diagnosed in only 24-60% of specimens. Mature T-NHL and T-PLL were mistakenly diagnosed as T-ALL by 40% of the centres. Misinterpretation of TdT immunofluorescence or omitting this marker contributed significantly to these wrong diagnoses. A median of 4% of immunophenotypic diagnoses were not based on a correct panel of antibodies, but upon the morphology of the accompanying blood smear, and was often flawed by overinterpretation. In conclusion, both the technical performance of immunophenotyping of haematological malignancies in The Netherlands and the procedure by which a final diagnosis is obtained needs improvement, especially for T-cell malignancies.

False Negative Reactions↗
PubMed1996

Involvement of the CCND1 gene in hairy cell leukemia.

BACKGROUND: Previous results suggested increased mRNA expression of CCND1 in hairy cell leukemia (HCL). The CCND1 gene is involved in the t(11;14)(q13;q32) chromosomal rearrangement, a characteristic abnormality in mantle cell lymphoma (MCL). We and others reported that, in contrast to other B-cell lymphomas, almost all MCL have over-expression of the CCND1 gene with a good correlation between RNA and protein analysis. Recent studies showed that overexpression of the cyclin D1 protein can be easily detected by immunohistochemistry (IHC) on formalin-fixed, paraffin embedded tissues. PATIENTS AND METHODS: To investigate whether the CCND1 gene is involved in HCL, we performed IHC on a series of 22 cases using formalin-fixed paraffin embedded splenectomy specimens. For IHC the sections were boiled in citrate buffer. The presence of rearrangements within the BCL-1 locus and the CCND1 gene was analyzed in 13 of 22 cases by Southern blot analysis using all available break-point probes. Expression of CCND1 was analyzed at the mRNA level (Northern blot) and protein level (IHC). RESULTS: Overexpression of the cyclin D1 protein using IHC was observed in all cases, with strong expression in 5 cases. Pre-existing B- and T-cell areas of the spleen did not express significant levels of the cyclin D1 protein. Seven of 9 cases analyzed by both IHC and Northern blotting showed overexpression of the CCND1 gene with both methods. No genomic abnormalities were observed in any of the 13 cases studied by Southern blot analysis. Additionally, no 11q13 abnormalities were detected by banding analysis of 19 of 22 cases. CONCLUSIONS: The elevated levels of CCND1 mRNA and protein in conjunction with the absence of overt rearrangements within the BCL-1 locus distinguish HCL from MCL and other B-cell malignancies. This suggests that activation of the CCND1 gene in HCL is due to mechanisms other than chromosomal rearrangement.

Adult↗
PubMed1996

Mantle-cell lymphoma: a population-based clinical study.

PURPOSE: From a population-based non-Hodgkin's lymphoma (NHL) registry, 41 patients with mantle cell lymphoma (MCL) -- a recently defined distinct B-cell NHL -- were selected and compared with patients with low- or intermediate-grade NHL from the same registry. PATIENTS AND METHODS: The incidence and behavior of MCL in the area of the Comprehensive Cancer Center West (CCCW) from 1981 to 1989 were analyzed. Age, performance, tumor bulk, extranodal localization, stage, response to therapy, and survival were registered. Expression of cyclin D1 protein and Ki-67 were measured in 29 patients. RESULTS: MCL made up 3.7% of NHLs. The median age was 68 years, and the male-to-female ratio was 1.6:1. Seventy-eight percent presented with stage IV, with the majority having bone marrow involvement. The complete response (CR) rate was 32% (13 of 41), with a median duration of 25 months. The median overall survival time was 31.5 months. The International Prognostic Index identified five patients with a low-risk score and a median survival time of 93+ months. In 23 of 29 patients, cyclin D1 overexpression was present, without any relation to overall or disease-free survival. In contrast, a proliferative index less than 10% was significantly related to a better overall survival time (50 v 24 months). CONCLUSION: MCL is a disease of the elderly, who present with widespread disease and with a poor response to therapy. Although it harbors features of an indolent NHL, it behaves clinically as an aggressive NHL with a short overall survival time.

Aged↗
PubMed1996

Clinical significance of bcl2 and p53 protein expression in diffuse large B-cell lymphoma: a population-based study.

PURPOSE: We studied the prognostic significance of bcl2 and p53 protein expression in relation to clinical and pathologic characteristics in patients with diffuse large B-cell lymphoma (LCL). PATIENTS AND METHODS: Three hundred seventy-two patients with LCL were retrieved from a population-based registry for non-Hodgkin's lymphoma (NHL). bcl2 and p53 protein expression was studied on paraffin-embedded tumor tissue by immunohistochemistry in relation to clinical factors. Response to therapy and survival were analyzed in 165 patients who were uniformly staged and treated and for whom all prognostic data were available according to the International Prognostic Index (IPI). RESULTS: Forty-five percent of tumors showed strong expression of the bcl2 protein (bcl2++), with a higher frequency in patients with primary nodal involvement. Disease-free survival (DFS) was significantly better in bcl2-negative/intermediate (bcl2-/+) cases as compared with bcl2++ cases (P = .0011). At 5 years, bcl2-/+ patients showed a DFS rate of 74%, in contrast to bcl2++ patients with a DFS rate of 41% (P = .002). Bcl2 was the strongest independent prognostic value in a multivariate analysis, with a relative risk (RR) of 3.0 in comparison to p53 expression and the clinical factors of the IPI. Overall survival (OS) was not significantly influenced by bcl2 protein expression. p53 protein expression was found in 13% of cases, with a higher frequency in patients with extensive disease. p53 expression did not influence the chance to achieve complete remission (CR) and survival. CONCLUSION: bcl2 protein is frequently expressed in LCL and is a strong independent prognostic factor for DFS. p53 expression is related with high tumor burden, but is not an independent risk factor for CR and survival.

Adult↗
PubMed1996

The role of the CD40 antigen on malignant B cells.

An increasing amount of literature has been published concerning the interaction of the CD40 antigen and its ligand with regard to normal B cell ontogeny. In this review, an overview of the CD40 antigen and the CD40 ligand is given, focussing on their possible role in B cell malignancies. Data on the expression of the CD40 antigen on various B cell malignancies (acute and chronic leukemias, non-Hodgkin's lymphoma and multiple myeloma) are presented. The recently developed novel culture "CD40 system" is described. This system is a powerful tool used to culture normal B cells, but also most malignant B cells. We demonstrate in addition a more prominent role of the human Fc receptor presenting murine fibroblasts in the "CD40 system", especially in relation to cultured plasma cells. Finally, some important applications of the "CD40 system" are also summarized.

Animals↗
PubMed1996

Granzyme B expression in Reed-Sternberg cells of Hodgkin's disease.

Reed-Sternberg (RS) and Hodgkin's (H) cells are considered to be the neoplastic cells in Hodgkin's disease. Although most data suggest a lymphoid origin, the nature of these cells still remains the subject of considerable controversy. Recently, monoclonal antibodies became available, directed against granzyme B, a serine protease specifically expressed by activated cytotoxic T cells (CTLs) and natural killer (NK) cells. Using two granzyme B-specific antibodies directed against different epitopes, we studied the expression of granzyme B in a well characterized group of Epstein-Barr virus (EBV)-positive and EBV-negative cases of Hodgkin's disease. Granzyme B expression was found in part of the H-RS cells in 11 out of 61 tested cases (18%, 9 of 46 cases of nodular sclerosing and 1 of 12 mixed cellularity Hodgkin's disease). In none of these cases did H-RS cells express B-cell markers, whereas in four cases, expression of either the T-cell marker CD3 or CD8 was found in a small minority of H-RS cells. The percentage of granzyme B-positive H-RS cells ranged from < 10% to > 50%. Granzyme B-positive H-RS cells were present in 6 of 26 EBV-positive cases and in 5 of 35 EBV-negative cases, indicating no relationship with the presence of EBV. Moreover, no significant differences were found regarding either stage at presentation or clinical outcome. We conclude that in a restricted number of cases of Hodgkin's disease, the H-RS cells express granzyme B, and therefore might be considered the neoplastic equivalent of either activated CTLs or NK cells.

Adolescent↗
PubMed1996

Proliferation of B cell malignancies in all stages of differentiation upon stimulation in the 'CD40 system'.

Stimulation of the CD40 antigen on normal B cells by crosslinking of anti-CD40 mAbs via their Fc receptor using a Fc gamma RII(CD32)-transfected mouse fibroblast cell line ('CD40 system') results in activation and proliferation. Not only normal B cells, but also malignant B cells fitting in the low-grade malignancy category such as chronic lymphocytic leukemia (CLL), hairy cell leukemia and follicular lymphoma could be induced to proliferation upon CD40 stimulation. Here, the 'CD40 system' has also been used to culture intermediate and high grade malignancies. Proliferation was measured by 3H-thymidine incorporation and cell counting after culture. Time curves showed that at day 7 most cultures were optimal. By flow cytometry, morphology and assessment of light chain restriction the monoclonal nature of the cultured B cells was proven. We confirmed that B cell malignancies with a more slowly evolving course, such as CLL (n=11), PLL (n=5), and low-grade NHL (immunocytoma and follicular cb/cc n=9), could successfully be cultured in the 'CD40 system'. In contrast, four out of seven cases of mantle cell lymphoma did not proliferate. Cases of precursor B lineage ALL (n=7), high grade NHL (n=3) and multiple myeloma (n=10) showed a heterogenous growth pattern. We conclude that the 'CD40 system', although not always successful, is a useful tool to culture a whole variety of B cell malignancies.

Animals↗
PubMed1996

Concurrent activation of MYC and BCL2 in B cell non-Hodgkin lymphoma cell lines by translocation of both oncogenes to the same immunoglobulin heavy chain locus.

Concurrent activation of BCL2 and MYC usually occurs in B cell non-Hodgkin lymphoma (B-NHL) by translocation of both oncogenes to both immunoglobulin heavy chain (IGH) alleles: this abrogates immunoglobulin synthesis. We have studied three B-NHL cell lines (DoHH2, VAL and ROS 50) and show that concurrent activation of BCL2 and MYC may follow translocation of both oncogenes to the same IGH allele. Conventional cytogenetics of DoHH2 suggested the presence of a t(14;18)(q32;q21) translocation. However, fluorescent in situ hybridization (FISH) studies using whole chromosome paints, alpha satellite probes and flow-sorted chromosomes as probes revealed an unexpected complexity of rearrangements involving chromosomes 8, 14 and 18, namely t(8;14;18)(q24;q32;q21). DNA blot and previous PCR analysis confirmed the juxtaposition of BCL2 major breakpoint region (mbr) with IGJH6, but also demonstrated a rearrangement within the first exon of MYC. The centromeric (5') MYC rearranged fragment comigrated with the BCL2-JH6 rearranged fragment in BamHI, EcoRI and Bg/II restriction digests. The der(8)t(8;14;18) therefore comprised 5' MYC (exon I)-Sgamma4-JH6-BCL2 mbr. Similar rearrangements were observed in both ROS 50 and VAL cell lines which contained two and three copies of the der(8)t(8;14;18) respectively. Quantitative flow cytometry for BCL2 and MYC expression showed abundant expression of both proteins in all three lines. These data indicate the der(14)t(14;18)(q32;q21) may itself be the target for any second translocation. The presence of the intact BCL2-JH fusion gene on the der(8)t(8;14;18) allowed concurrent activation of both BCL2 and MYC with no loss of immunoglobulin expression.

Aged↗