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Biomedical subjects

F G Behm

Publications and source records attributed to F G Behm.

At least 73 records · Page 4Linked to original sources
PubMed1997

Randomized study of intensive MOPP-ABVD with or without low-dose total-nodal radiation therapy in the treatment of stages IIB, IIIA2, IIIB, and IV Hodgkin's disease in pediatric patients: a Pediatric Oncology Group study.

PURPOSE: To determine whether the addition of low-dose total-nodal irradiation (TNI) in pediatric patients with advanced-stage Hodgkin's disease who have received eight cycles of alternating mechlorethamine, vincristine, procarbazine, and prednisone (MOPP) and doxorubicin, bleomycin, vinblastine, and dacarbazine (ABVD) will improve the event-free survival (EFS) and overall survival (OS) when compared with patients who have received chemotherapy only. PATIENTS AND METHODS: At diagnosis, 183 children and adolescents with stages IIB, IIIA2, IIIB, and IV Hodgkin's disease were randomized to receive eight cycles of alternating MOPP-ABVD with or without low-dose TNI. RESULTS: Of 183 patients, four were rendered ineligible before treatment was initiated. One hundred sixty-one of 179 patients (90%) were in complete remission (CR) at the completion of eight cycles of alternating MOPP-ABVD; 81 were in the chemotherapy-only group and proceeded to observation off therapy, whereas 80 of 161 were to receive combined modality therapy (CMT). Nine of 80 patients randomized at the time of diagnosis to receive CMT did not receive radiation (RT) because of a protocol violation, but were monitored for EFS and OS and included in all analyses. The estimated EFS and OS rates at 5 years for the 179 eligible patients are 79% and 92%, respectively. The actuarial EFS at 5 years was 80% for patients who received CMT and 79% for patients who received MOPP-ABVD only. The OS for the former group is estimated to be 87% and for the latter patients 96%. Age < or = 13 years of age at diagnosis and the attainment of a clinical CR after three cycles of chemotherapy were associated with a statistically significant improved EFS. CONCLUSION: Our results indicate that after the delivery of eight cycles of MOPP-ABVD, the addition of low-dose RT does not improve the estimated EFS or OS in pediatric patients with advanced-stage Hodgkin's disease.

Adolescent↗
PubMed1996

cDNA cloning, tissue distribution, and chromosomal localization of myelodysplasia/myeloid leukemia factor 2 (MLF2).

A fusion gene between nucleophosmin (NPM) and myelodysplasia/myeloid leukemia factor 1 (MLF1) is formed by a recurrent t(3;5)(q25.1;q34) in myelodysplastic syndrome and acute myeloid leukemia. Here we report the identification of a novel gene, MLF2, which contains an open reading frame of 744 bp encoding a 248-amino-acid protein highly related to the previously identified MLF1 protein (63% similarity, 40% identity). In contrast to the tissue-restricted expression pattern of MLF1, the MLF2 messenger RNA is expressed ubiquitously. The MLF2 gene locus was mapped by fluorescence in situ hybridization to human chromosome 12p13, a chromosomal region frequently involved in translocations and deletions in acute leukemias of lymphoid or myeloid lineage. In a physical map of chromosome 12, MLF2 was found to reside on the yeast artificial chromosome clone 765b9. Southern blotting analysis of malignant cell DNAs prepared from a series of acute lymphoblastic leukemia cases with translocations involving chromosome arm 12p, as well as a group of acute myeloid leukemias with various cytogenetic abnormalities, failed to reveal MLF2 gene rearrangements.

Amino Acid Sequence↗
PubMed1996

A subtle deletion of 12p by routine cytogenetics is found to be a translocation to 21q by fluorescence in situ hybridization: t(12;21)(p13;q22).

A 4-year-old boy with acute lymphoblastic leukemia (ALL) whose leukemic cells contained at diagnosis a del(6q) had a different clone at relapse, characterized by an abnormal short arm of chromosome 12 (12p). Fluorescence in situ hybridization (FISH) analysis using a cosmid probe from the 12p12-13 region indicated a translocation of the 12p to another unknown chromosome of "G-group" size. Further analysis by dual chromosome painting confirmed the presence of a translocation, identified as t(12;21)(p13;q22). Previously reported cases showed this translocation at diagnosis of ALL, whereas this is the first case showing the specific t(12;21)(p13;q22) at relapse. This case study illustrates the value of FISH in resolving subtle recurrent chromosomal rearrangements that escape detection by routine cytogenetic analysis. Subsequent molecular evaluation of the patient's leukemic cells with the t(12;21) demonstrated a TEL/AML1 fusion protein.

Child, Preschool↗
PubMed1996

Molecular analysis of t(11;19) breakpoints in childhood acute leukemias.

MLL is fused to ENL or ELL in acute leukemias that contain t(ll;19)(q23;p13). Although ENL and ELL localize to chromosome 19, bands p13.3 and p13.1, respectively, these breakpoints are not always readily distinguished by standard cytogenetics. We therefore used reverse transcriptase-polymerase chain reaction (RT-PCR) assays to analyze 26 cases of childhood acute leukemia containing t(11;19) to determine the frequencies of ENL and ELL involvement. All 17 cases of acute lymphoblastic leukemia (ALL) had MLL/ENL fusion transcripts. By contrast, of the 9 cases of acute myeloid leukemia (AML) analyzed, 6 had MLL/ENL fusions, 2 had MLL/ELL fusions, and 1 case had no RT-PCR-detectable MLL fusion mRNA. These data suggest that the majority of 11;19 translocations involve ENL, whereas involvement of ELL is relatively uncommon in childhood acute leukemia and may be restricted to AML.

Acute Disease↗
PubMed1996

Rearrangement of the MLL gene confers a poor prognosis in childhood acute lymphoblastic leukemia, regardless of presenting age.

MLL gene rearrangements are associated with an extremely poor prognosis in infants with acute lymphoblastic leukemia (ALL), but little is known about their clinical significance in older children. Therefore, we studied 45 cases of childhood ALL with abnormalities of chromosome 11q23 for rearrangement of the MLL gene to determine if this feature confers a uniformly poor prognosis. MLL gene rearrangements were detected in all 18 cases with the common t(4;11), t(9;11) or t(11;19) translocations, whereas only 5 of 12 patients with either unbalanced or uncommon balanced translocations demonstrated a rearrangement. Abnormalities of the MLL gene were not detected in any of the 15 cases with a deletion or inversion of the chromosomes 11q23 region. The presence of an MLL rearrangement was significantly associated with age less than 1 year (P < .001), leukocyte count >50 x 10(9)/L (P = .003), and the absence of leukemic cell CD10 expression (P < .001). In a stratified statistical analysis adjusted for age and treatment protocol, MLL gene rearrangement was correlated with an inferior treatment outcome (P = .028). The 4-year event-free survival estimate (+/- SE) was 10% +/- 6.5% for cases with a rearranged MLL gene and 64% +/- 19.2% for other cases. When infants were excluded from the analysis, MLL rearrangement was still significantly associated with a poor outcome (P = .02), and remained so with the exclusion of t(4;11)-positive cases (P = .05). Thus, regardless of presenting age, MLL gene rearrangement identifies a high-risk subgroup of patients who are not likely to be cured with conventional treatment.

Age Factors↗
PubMed1996

Stroma-supported culture in childhood B-lineage acute lymphoblastic leukemia cells predicts treatment outcome.

We developed a stroma cell culture system that suppresses apoptosis of malignant cells from cases of B-lineage acute lymphoblastic leukemia. By multiparameter flow cytometric measurements of cell recovery after culture on stromal layers, we assessed the growth potential of 70 cases of newly diagnosed B-lineage acute lymphoblastic leukemia and related the findings of treatment outcome in a single program of chemotherapy. The numbers of leukemic cells recovered after 7 d of culture ranged from < 1 to 292% (median, 91%). The basis of poor cell recoveries from stromal layers appeared to be a propensity of the lymphoblasts to undergo apoptosis. The probability of event-free survival at 4 yr of follow-up was 50 +/- 9% (SE) among patients with higher cell recoveries ( > 91%), and 94 +/- 6% among those with reduced cell recoveries (+/- 91%; P = 0.0003). The prognostic value of leukemic cell recovery after culture exceeded estimates for all other recognized high-risk features and remained the most significant after adjustment with all competing covariates. Thus, the survival ability of leukemic cells on bone marrow-derived stromal layers reflects aggressiveness of the disease and is a powerful, independent predictor of treatment outcome in children with B-lineage acute lymphoblastic leukemia.

Analysis of Variance↗
PubMed1996

Human homologue of the rat chondroitin sulfate proteoglycan, NG2, detected by monoclonal antibody 7.1, identifies childhood acute lymphoblastic leukemias with t(4;11)(q21;q23) or t(11;19)(q23;p13) and MLL gene rearrangements.

Monoclonal antibody 7.1, which recognizes the chondroitin sulfate proteoglycan molecule NG2, was used to screen prospectively blast cells from 104 consecutive children at initial presentation with acute lymphoblastic leukemia (ALL). Reactivity with this antibody was found in 9 cases (8.6%), of whom 5 had a t(4;11)(q21;q23) and 4 had a t(11;19)(p13;q23). None of the NG2- cases had either translocation. Southern blot analysis disclosed MLL gene rearrangement in only the 9 cases with 7.1 reactivity plus the t(4;11)(q21;q23) or t(11;19)(q23;p13) translocation. MLL gene rearrangements were not detected in 89 patient leukemic samples that did not express NG2, including 7 patients with del(11)(q23) or inv(11)(p13q23). As expected from the association with t(4;11) and t(11;19), NG2+ cases were significantly more likely to be infants, to have hyperleukocytosis and central nervous system involvement, to be CD10-, and to express myeloid-associated antigens CD15 and CD65. Despite short follow-up duration, 3 of the NG2+ cases have relapsed while the other 101 patients remain in remission. Thus, blast cell surface expression of NG2 is useful for identifying patients with ALL having t(4;11) or t(11;19) translocations that are associated with poor prognosis, especially in the infant age group.

Adolescent↗
PubMed1996

Clinical relevance of BCL-2 overexpression in childhood acute lymphoblastic leukemia.

Enforced BCL-2 gene expression in leukemic cell lines suppresses apoptosis and confers resistance to anticancer drugs, but the clinical significance of increased BCL-2 protein levels in acute lymphoblastic leukemia (ALL) is unknown. Among 52 children with newly diagnosed ALL, BCL-2 expression in leukemic lymphoblasts ranged widely, from 4,464 to 59,753 molecules of equivalent soluble fluorochrome per cell (MESF), as determined by flow cytometry. The mean (+/- SD) level of MESF in 43 cases of B-lineage ALL (19,410 +/- 11,834) was higher than that detected in CD10+ B-lymphoid progenitors from normal bone marrow (450 +/- 314; P < .001), and CD19+ peripheral blood B lymphocytes (7,617 +/- 1,731; P = .02). Levels of BCL-2 in T-ALL cases (17,909 +/- 18,691) were also generally higher than those found in normal CD1a+ thymocytes (1,762 +/- 670), or in peripheral blood T lymphocytes (9,687 +/- 3,019). Although higher levels of BCL-2 corresponded to higher leukemic cell recoveries after culture in serum-free medium, they did not correlate with higher cell recoveries after culture on stromal layers, or with in vitro resistance to vincristine, dexamethasone, 6-thioguanine, cytarabine, teniposide, daunorubicin or methotrexate. BCL-2 protein levels did not correlate with presenting clinical features. Unexpectedly, however, lower-than-median MESF values were significantly associated with the presence of chromosomal translocations (P = .010). Notably, all six cases with the Philadelphia chromosome, a known high-risk feature, had low levels of BCL-2 expression (P = .022). Higher levels of BCL-2 were not associated with poorer responses to therapy among 33 uniformly treated patients, and were not observed in three patients studied at relapse. In conclusion, increased BCL-2 expression in childhood ALL appears to enhance the ability of lymphoblasts to survive without essential trophic factors, and is inversely related to the presence of chromosomal translocations. However, it does not reflect increased disease aggressiveness or resistance to chemotherapy.

Adolescent↗
PubMed1996

The translocation t(8;16)(p11;p13) of acute myeloid leukaemia fuses a putative acetyltransferase to the CREB-binding protein.

The recurrent translocation t(8;16)(p11;p13) is a cytogenetic hallmark for the M4/M5 subtype of acute myeloid leukaemia. Here we identify the breakpoint-associated genes. Positional cloning on chromosome 16 implicates the CREB-binding protein (CBP), a transcriptional adaptor/coactivator protein. At the chromosome 8 breakpoint we identify a novel gene, MOZ, which encodes a 2,004-amino-acid protein characterized by two C4HC3 zinc fingers and a single C2HC zinc finger in conjunction with a putative acetyltransferase signature. In-frame MOZ-CBP fusion transcripts combine the MOZ finger motifs and putative acetyltransferase domain with a largely intact CBP. We suggest that MOZ may represent a chromatin-associated acetyltransferase, and raise the possibility that a dominant MOZ-CBP fusion protein could mediate leukaemogenesis via aberrant chromatin acetylation.

Acetyltransferases↗
PubMed1996

11q23 rearrangements in acute leukemia.

The MLL gene, located at chromosome 11, band q23, is frequently disrupted by a variety of chromosomal rearrangements that occur in acute lymphoblastic leukemias and in a subset of de novo and secondary acute myeloid leukemias. In both scenarios, MLL rearrangements are associated with distinct clinical features and a poor prognosis. MLL encodes a large protein (MLL) that shares homology with the Drosophila trithorax protein. 11q23 translocations result in the generation of a series of acute leukemia-specific chimeric proteins that contain the N-terminus of MLL and are thought to be crucial to leukemogenesis. In this article, we review the structural features of the MLL fusion proteins as well as the clinical features and molecular diagnosis of acute leukemias containing MLL arrangements.

Acute Disease↗
PubMed1996

Heterogeneity of hyperdiploid (51-67) childhood acute lymphoblastic leukemia.

We studied the fully banded chromosomes of 182 children with hyperdiploid (51-67) acute lymphoblastic leukemia (ALL) to better delineate the heterogeneity of this disease subtype. Forty-six percent of the cases had numerical changes exclusively, while the remainder had structural as well as numerical changes. Chromosome 21 was added most often (97% of cases), followed by chromosomes 6 (86%), X (81%), 14 (80%), 4 (76%), 18 (68%), 17 (68%), 10 (56%), 8 (34%) and 5 (26%). Chromosomal translocations, including the t(1;19)(q23;p13) and t(9;22)(q34;q11), were detected in only 20% of the cases, as compared with 50% in ALL in general. The most common structural alterations were duplication of the 1q arm and isochromosome of 17q, present in 25 (14%) and nine (5%) cases, respectively. The presence of absence of structural abnormalities in these cases did not influence event-free survival, as assessed in 168 patients enrolled in three successive protocols for children with newly diagnosed ALL. By contrast, patients with 51-55 chromosomes per leukemic cell (n=105) appeared to fare worse than the 56-67 subgroup (n=63) (5-year probability of event-free survival = 72 +/- 5% (s.e.) vs 86 +/- 5%; P=0.04 by the stratified log-rank test). The poorer prognosis of the 51-55 subgroup was partly due to the higher frequency of isochromosome of 17q; 6/7 patients with the isochromosome in this group have had an adverse event. Other unfavorable features within the hyperdiploid (51-55) ALL subgroup include a low prevalence of trisomies of chromosomes 4 and 10 and a higher proportion of patients with leukocyte counts greater than 50 X 10(9)/l when compared to hyperdiploid (56-67). Thus, ALL defined by 51-55 chromosomes appears to be a clinicobiologic entity quite distinct from cases with higher modal numbers.

Adolescent↗
PubMed1996

Prognostic factors in the acute lymphoid and myeloid leukemias of infants.

The age boundaries and prognostic factors that define the infant leukemias are still controversial. We therefore analyzed event-free survival according to age group in 96 children treated for acute lymphoblastic leukemia (ALL) and 51 treated for acute myeloid leukemia (AML) before the age of 2 years. The study population was registered in consecutive institutional trials of multiagent chemotherapy conducted between 1980 and 1994. Among infants with ALL, event-free survival was significantly poorer in the 0- to 6-month-old group than in patients treated between 6 and 12 months of age (P = 0.03), whose outcome was in turn inferior to that in the 12- to 18-month and 18- to 24-month age groups (P = 0.013). Leukemic cells from ALL patients younger than 12 months had a significantly higher frequency of 11q23/MLL abnormalities, as well as better growth in stromal cell culture, compared to lymphoblasts from the older groups (P < 0.01). The only independent predictor of adverse prognosis among infants diagnosed with ALL before age 12 months was the presence of an 11q23/MLL rearrangement (P = 0.03). These findings contrast sharply with results for the AML cohort, whose event-free survival did not vary significantly by age group (P = 0.58). Male sex (P = 0.01) and leukocyte count > or = 50 x 10(9/l) (P = 0.04), but not 11q23 abnormalities, were independently associated with a poorer outcome for children with AML younger than 12 months at diagnosis. Thus, in very young children with ALL (but not AML), the rearrangement status of the 11q23/MLL region supersedes age group as a determinant of treatment outcome.

Age Factors↗
PubMed1996

Molecular analysis of the PML/RAR alpha chimeric gene in pediatric acute promyelocytic leukemia.

Acute promyelocytic leukemia (APL) is characterized cytogenetically by the t(15;17)(q22;q11-21) translocation. To compare molecular events among pediatric and adult APL cases, we designed two sets of oligonucleotide primers using published cDNA sequence for PML/RAR alpha fusion transcripts, and undertook reverse transcriptase-polymerase chain reaction (RT-PCR) analysis of 22 US pediatric cases of APL. PML/RAR alpha fusion transcripts were detected in all APL cases, including two cases lacking cytogenetic evidence of t(15;17). Breakpoint usage in PML was determined using a combination of PCR amplification with differing 5' primers, junction-specific probes, and sequence analysis in selected cases. Consistent with previously published data, case analysis demonstrated fusion products resulting from three breakpoint cluster regions (bcr) in PML, and a single breakpoint region in intron 2 of RAR alpha. Transcripts resulting from breakpoints in bcr1 were detected in 59 percent of cases, bcr2 in 27 percent and bcr3 in 14 percent. This distribution is dissimilar to that observed in adults, where bcr2 comprises a lesser and bcr3 a greater portion of cases. These results suggest that the pathogenesis of the t(15;17) in APL may differ among patient sets. RT-PCR with these primer sets is a reliable method for detecting PML/RAR alpha chimeric transcript in t(15; 17)-containing APL.

Adult↗
PubMed1995

Acute lymphoblastic leukemias with deletion of 11q23 or a novel inversion (11)(p13q23) lack MLL gene rearrangements and have favorable clinical features.

Balanced translocations affecting the 11q23 region are among the most frequent chromosomal abnormalities in childhood acute lymphoblastic leukemia (ALL), comprising 5% to 6%. These cases consistently have a rearranged MLL gene and are associated with high-risk presenting features, hyperleukocytosis and younger age, and a poor treatment outcome. To assess the clinical and biologic significance of 11q23-associated structural chromosomal abnormalities other than translocations, we studied 17 cases of childhood ALL [14 with del(11)(q23) and 3 with inv(11)(p12q23)] that were identified among 785 cases with successful chromosome analysis. In contrast to reported cases with 11q23 and MLL gene rearrangement, our series was characterized by relatively low leukocyte counts (median, 15.1 x 10(9)/L), expression of CD10 antigen but not myeloid-associated CD15 and CDw65 antigens, a relatively high frequency of T-cell immunophenotypes, and a generally favorable prognosis. All 13 cases with interpretable molecular analysis lacked MLL gene rearrangements. We suggest that most cases with deletions or inversions affecting the 11q23 region represent clinically and biologically different entities as compared with those defined by 11q23 translocation.

Adolescent↗
PubMed1995

Molecular detection of the (2;5) translocation of non-Hodgkin's lymphoma by reverse transcriptase-polymerase chain reaction.

The t(2;5)(p23;q35) translocation was initially identified in cases of anaplastic large-cell lymphoma (ALCL) that expressed the Ki-1 (CD30) antigen. We have recently cloned this translocation and shown it to encode a chimeric product consisting of the N-terminal portion of a nonribosomal nucleolar phosphoprotein, nucleophosmin (NPM), from chromosome 5, fused to the kinase domain of a novel transmembrane tyrosine-specific protein kinase, anaplastic lymphoma kinase (ALK), from chromosome 2. To better define the spectrum of lymphomas that contain this translocation, we have analyzed 70 cases of non-Hodgkin's lymphoma (NHL) for expression of the t(2;5)-derived NPM/ALK chimeric message by reverse transcriptase-polymerase chain reaction (RT-PCR). Using a previously described set of oligonucleotide primers, NPM/ALK chimeric transcripts were detected in 21 of 22 cases that contained the t(2;5) by cytogenetic analysis and in 10 of 48 cases that either lacked evidence of the t(2;5) or had unsuccessful cytogenetics. In all but 1 case, the NPM/ALK PCR products were of identical size and sequence, suggesting that the genomic chromosome breaks are clustered in a single intron in both NPM and ALK. The NPM/ALK-expressing cases were not confined to NHLs with anaplastic morphology and included 15 ALCLs, 6 immunoblastic lymphomas, and 10 diffuse large-cell lymphomas. Moreover, only slightly greater than half of the cases with anaplastic morphology and 59% of CD30-expressing cases were NPM/ALK positive. Thus, neither anaplastic morphology nor the expression of CD30 accurately predicted the presence of this molecular genetic subtype of lymphoma.

Adult↗
PubMed1995

Childhood acute lymphoblastic leukemia with equivocal chromosome markers of the t(1;19) translocation.

The t(1;19)(q23;p13) or its derivative encodes an E2A-PBXI fusion transcript and protein that has been shown to have important prognostic and therapeutic implications in patients with acute lymphoblastic leukemia (ALL). We describe two childhood cases in which a der(22)t(1;22)(q21-23;p13) cytogenetically mimicked a der(19)t(1;19)(q23;p13). In one case, which was phenotyped as early pre-B ALL with hyperdiploidy but lacked evidence of an E2A-PBX1 gene fusion by molecular study, the poor banding quality of chromosomes led to misinterpretation of the cytogenetic findings; a correct diagnosis was established only after analysis by the fluorescence in situ hybridization (FISH) method. The second case, which was classified as pseudodiploid pre-B ALL, had both a derivative 19 and a derivative 22 but lacked sufficient cells for evaluation of E2A-PBX1 gene fusion. This case was included in order to compare the der(19)t(1;19) and the der(22)t(1;22) and to pinpoint the difficulty in distinguishing these markers. FISH analysis can resolve diagnostic uncertainty in cases of ALL with equivocal chromosome 19 markers.

Child, Preschool↗
PubMed1995

Intrauterine monoclonal origin of neonatal concordant acute lymphoblastic leukemia in monozygotic twins.

We report detailed immunological, cytogenetic and molecular evidence for complete identity of the leukemic cell populations in monozygotic female twins with concordant leukemia diagnosed at two months of age. Both infants had early pre-B acute lymphoblastic leukemia with the (11;19)(q23;p13) chromosomal translocation. A common clonal origin of leukemia in these infants was suggested by the finding of identical oligoclonal heavy chain immunoglobulin gene rearrangements. Leukemic cell DNA was examined for 11q23 rearrangements by Southern blotting and restriction fragments of identical size were found in the two cases, in contrast to the diversity of rearrangements observed in other unrelated and nontwinned control infants with t(11;19)(q23;p13). Similar restriction fragments were absent in blood mononuclear DNA from both parents, liver tissue from one twin and remission bone marrow of the other, indicating that the 11q23 rearrangement was acquired and not inherited as a chromosomal abnormality or polymorphism. These findings provide a definitive evidence for intrauterine single cell origin, with twin to twin transmission, of concordant leukemia in this infant twin pair.

Blotting, Southern↗