Enhanced Risk Stratification for Children and Young Adults with B-Cell Acute Lymphoblastic Leukemia: A Children's Oncology Group Report.

Current strategies to treat pediatric acute lymphoblastic leukemia rely on risk stratification algorithms using categorical data. We investigated whether using continuous variables assigned different weights would improve risk stratification. We developed and validated a multivariable Cox model for relapse-free survival (RFS) using information from 21199 patients. We constructed risk groups by identifying cutoffs of the COG Prognostic Index (PICOG) that maximized discrimination of the predictive model. Patients with higher PICOG have higher predicted relapse risk. The PICOG reliably discriminates patients with low vs. high relapse risk. For those with moderate relapse risk using current COG risk classification, the PICOG identifies subgroups with varying 5-year RFS. Among current COG standard-risk average patients, PICOG identifies low and intermediate risk groups with 96% and 90% RFS, respectively. Similarly, amongst current COG high-risk patients, PICOG identifies four groups ranging from 96% to 66% RFS, providing additional discrimination for future treatment stratification. When coupled with traditional algorithms, the novel PICOG can more accurately risk stratify patients, identifying groups with better outcomes who may benefit from less intensive therapy, and those who have high relapse risk needing innovative approaches for cure.

Phase-diverse Fresnel coherent diffractive imaging of malaria parasite-infected red blood cells in the water window.

Phase-diverse Fresnel coherent diffractive imaging has been shown to reveal the structure and composition of biological specimens with high sensitivity at nanoscale resolution. However, the method has yet to be applied using X-ray illumination with energy in the so-called 'water-window' that lies between the carbon and oxygen K edges. In this range, differences in the strength of the X-ray interaction for protein based biological materials and water is increased. Here we demonstrate a proof-of-principle application of FCDI at an X-ray energy within the water-window to a dehydrated cellular sample composed of red blood cells infected with the trophozoite stage of the malaria parasite, Plasmodium falciparum. Comparison of the results to both optical and electron microscopy shows that the correlative imaging methods that include water-window FCDI will find utility in studying cellular architecture.

The gene for enhancer binding proteins E12/E47 lies at the t(1;19) breakpoint in acute leukemias.

The gene (E2A) that codes for proteins with the properties of immunoglobulin enhancer binding factors E12/E47 was mapped to chromosome region 19p13.2-p13.3, a site associated with nonrandom translocations in acute lymphoblastic leukemias. The majority of t(1;19)(q23;p13)-carrying leukemias and cell lines studied contained rearrangements of E2A as determined by DNA blot analyses. The rearrangements altered the E2A transcriptional unit, resulting in the synthesis of a transcript larger than the normal-sized E2A mRNAs in one of the cell lines with this translocation. These observations indicate that the gene for a transcription factor is located at the breakpoint of a consistently recurring chromosomal translocation in many acute leukemias and suggest a direct role for alteration of such factors in the pathogenesis of some malignancies.

Optical diagnostics of mercury jet for an intense proton target.

An optical diagnostic system is designed and constructed for imaging a free mercury jet interacting with a high intensity proton beam in a pulsed high-field solenoid magnet. The optical imaging system employs a backilluminated, laser shadow photography technique. Object illumination and image capture are transmitted through radiation-hard multimode optical fibers and flexible coherent imaging fibers. A retroreflected illumination design allows the entire passive imaging system to fit inside the bore of the solenoid magnet. A sequence of synchronized short laser light pulses are used to freeze the transient events, and the images are recorded by several high speed charge coupled devices. Quantitative and qualitative data analysis using image processing based on probability approach is described. The characteristics of free mercury jet as a high power target for beam-jet interaction at various levels of the magnetic induction field is reported in this paper.

Mutations in the CCND1 and CCND2 genes are frequent events in adult patients with t(8;21)(q22;q22) acute myeloid leukemia.

Core-binding factor acute myeloid leukemia (CBF-AML) is defined by the presence of either t(8;21)(q22;q22)/RUNX1-RUNX1T1 or inv(16)(p13.1q22)/t(16;16)(p13.1;q22)/CBFB-MYH11. The resulting fusion genes require a 'second hit' to initiate leukemogenesis. Mutation assessment of 177 adults with CBF-AML, including 68 with t(8;21) and 109 with inv(16)/t(16;16), identified not only mutations well known in CBF-AML but also mutations in the CCND1 and CCND2 genes, which represent novel frequent molecular alterations in AML with t(8;21). Altogether, CCND1 (n=2) and CCND2 (n=8) mutations were detected in 10 (15%) patients with t(8;21) in our cohort. A single CCND2 mutation was also found in 1 (0.9%) patient with inv(16). In contrast, CCND1 and CCND2 mutations were detected in only 11 (0.77%) of 1426 non-CBF-AML patients. All CCND2 mutations cluster around the highly conserved amino-acid residue threonine 280 (Thr280). We show that Thr280Ala-mutated CCND2 leads to increased phosphorylation of the retinoblastoma protein, thereby causing significant cell cycle changes and increased proliferation of AML cell lines. The identification of CCND1 and CCND2 mutations as frequent mutational events in t(8;21) AML may provide further justification for cell cycle-directed therapy in this disease.

The mutational oncoprint of recurrent cytogenetic abnormalities in adult patients with de novo acute myeloid leukemia.

Recurrent chromosomal abnormalities and gene mutations detected at the time of diagnosis of acute myeloid leukemia (AML) are associated with particular disease features, treatment response and survival of AML patients, and are used to denote specific disease entities in the World Health Organization classification of myeloid neoplasms and acute leukemia. However, large studies that integrate cytogenetic and comprehensive mutational information are scarce. We created a comprehensive oncoprint of mutations associated with recurrent cytogenetic findings by combining the information on mutational patterns of 80 cancer- and leukemia-associated genes with cytogenetic findings in 1603 adult patients with de novo AML. We show unique differences in the mutational profiles among major cytogenetic subsets, identify novel associations between recurrent cytogenetic abnormalities and both specific gene mutations and gene functional groups, and reveal differences in cytogenetic and mutational features between patients younger than 60 years and those aged 60 years or older. The identified associations between cytogenetic and molecular genetic data may help guide mutation testing in AML, and result in more focused application of targeted therapy in patients with de novo AML.

High concordance from independent studies by the Children's Cancer Group (CCG) and Pediatric Oncology Group (POG) associating favorable prognosis with combined trisomies 4, 10, and 17 in children with NCI Standard-Risk B-precursor Acute Lymphoblastic Leukemia: a Children's Oncology Group (COG) initiative.

Chromosome aberrations have a major role in pediatric acute lymphoblastic leukemia (ALL) risk assignment. The Children's Cancer Group (CCG) and the Pediatric Oncology Group (POG) independently assessed the significance of trisomy for chromosomes 4, 10, and 17 in National Cancer Institute (NCI) Standard- and High-Risk ALL. Data from 1582 (CCG) and 3902 (POG) patients were analyzed. Eight-year event-free survivals (EFS) of 91% (CCG) and 89% (POG) (P < 0.001) were achieved in patients assigned to NCI Standard Risk whose leukemic cells had simultaneous trisomies 4, 10, and 17. Both groups showed the degree of favorable prognostic importance increased with the actual number of favorable trisomies. POG analyses also demonstrated hyperdiploidy (> or =53 chromosomes) was less of an independently significant prognostic factor in the absence of these key trisomies. This finding supported conclusions from previous CCG and POG studies that specific trisomies are more important than chromosome number in predicting outcome in pediatric B-precursor ALL. In NCI Higher Risk patients, the number of favorable trisomies was not prognostically significant, but showed the same trend. Moreover, specific trisomies 4, 10, and 17 remain associated with favorable prognosis in Standard-Risk B-precursor ALL, even in the context of very different treatment approaches between the groups.

No prognostic effect of additional chromosomal abnormalities in children with acute lymphoblastic leukemia and 11q23 abnormalities.

This study characterized the additional chromosomal abnormalities (ACA) associated with 11q23 rearrangements in 450 infants and children with acute lymphoblastic leukemia (ALL) and examined the impact of these ACA on survival. Overall, 213 (47%) cases had ACA but the incidence varied according to patient age and 11q23 subgroup. Infants and patients with t(4;11)(q21;q23) had the lowest incidence of ACA (50/182 (27%) and 57/216 (26%) respectively), whereas patients with del(11)(q23) had the highest incidence (66/93 (71%)). Del(11)(q23) abnormalities were heterogeneous and occasionally secondary to t(9;22)(q34;q11.2). Thus, patients with del(11)(q23) comprised a separate biological entity, which was clearly distinct from those with an 11q23 translocation. The most frequent specific ACA were trisomy X (n = 38), abnormal 12p (n = 32), abnormal 9p (n = 28) and del(6q) (n = 19). The presence of ACA did not change the 5 year event-free survival estimates among children (56% (95% Cl 46-65%) vs 62% (54-69%)) or infants (22% (15-29%) vs 18% (9-29%)), nor when the different 11q23 subgroups were analyzed separately. This study has conclusively demonstrated that there is no prognostic effect of secondary chromosomal changes in association with 11q23 abnormalities in childhood ALL. However, characterization of these ACA is important to determine their potential role in initiation of MLL driven leukemogenesis.

An altered 11-kilobase transcript in leukemic cell lines with the t(4;11)(q21;q23) chromosome translocation.

The 11q23 chromosome band is frequently associated with chromosomal aberrations in human leukemias. We have previously cloned a DNA fragment derived from chromosome 11 which could be used as a probe to detect rearrangements in DNAs from the leukemic cells of patients with the t(4;11), t(9;11), and t(11;19) translocations. In this study we now show that the same probe detects DNA rearrangements in malignant cells from patients with the t(1;11), t(6;11), t(10;11), and del (11q23) chromosomal abnormalities. A second probe obtained from a region located centrometric to the breakpoint cluster detects major and minor transcripts of 12.5 and 11.5 kilobases, respectively, in all cell lines examined. The same probe identifies an altered 11-kilobase RNA in all three independent cell lines with the t(4;11)(q21;q23) chromosome translocation.

Absence of the wild-type allele predicts poor prognosis in adult de novo acute myeloid leukemia with normal cytogenetics and the internal tandem duplication of FLT3: a cancer and leukemia group B study.

The FLT3 gene is mutated by an internal tandem duplication (ITD) in 20-25% of adults with acute myeloid leukemia (AML). We studied 82 adults <60 years of age with primary AML and normal cytogenetics, who received uniform high-dose therapy and found FLT3 ITD in 23 (28%) patients. When the 23 FLT3 ITD+ cases were compared with the 59 cases with wild-type (WT) FLT3, disease-free survival (DFS) was inferior (P = 0.03), yet overall survival (OS) was not different (P = 0.14). However, 8 (35%) of 23 FLT3 ITD/+ cases also lacked a FLT3 WT allele (FLT3(ITD-R)) as determined by PCR and loss of heterozygosity. Thus, three genotypic groups were identified: normal FLT3(WT/WT), heterozygous FLT3(ITD/WT), and hemizygous FLT3(ITD/-). DFS and OS were significantly inferior for patients with FLT3(ITD/-) (P = 0.0017 and P = 0.0014, respectively). Although DFS and OS for FLT3(WT/WT) and FLT3(ITD/WT) groups did not differ (P = 0.32 and P = 0.98, respectively), OS of the FLT3(ITD/-) group was worse than the FLT3(WT/WT) (P = 0.0005) and FLT3(ITD/WT) (P = 0.008) groups. We propose a model in which FLT3(ITD/-) represents a dominant positive, gain-of-function mutation providing AML cells with a greater growth advantage compared with cells having the FLT3(WT/WT) or FLT3(ITD/WT) genotypes. In conclusion, we have identified the FLT3(ITD/-) genotype as an adverse prognostic factor in de novo AML with normal cytogenetics. A poor prognosis of the relatively young FLT3(ITD/-) adults (median age, 37 years), despite treatment with current dose-intensive regimens, suggests that new treatment modalities, such as therapy with a FLT3 tyrosine kinase inhibitor, are clearly needed for this group of patients.

The t(3;5)(q25.1;q34) of myelodysplastic syndrome and acute myeloid leukemia produces a novel fusion gene, NPM-MLF1.

A t(3;5)(q25.1;q34) chromosomal translocation associated with myelodysplastic syndrome and acute myeloid leukemia (AML) was found to rearrange part of the nucleophosmin (NPM) gene on chromosome 5 with sequences from a novel gene on chromosome 3. Chimeric transcripts expressed by these cells contain 5' NPM coding sequences fused in-frame to those of the new gene, which we named myelodysplasia/myeloid leukemia factor 1 (MLF1). RNA-based polymerase chain reaction analysis revealed identical NPM-MLF1 mRNA fusions in each of the three t(3;5)-positive cases of AML examined. The predicted MLF1 amino acid sequence lacked homology to previously characterized proteins and did not contain known functional motifs. Normal MLF1 transcripts were expressed in a variety of tissues, most abundantly in testis, ovary, skeletal muscle, heart, kidney and colon. Anti-MLF1 antibodies detected the wild-type 31 kDa protein in K562 and HEL erythroleukemia cell lines, but not in HL-60, U937 or KG-1 myeloid leukemia lines. By contrast, t(3;5)-positive leukemia cells expressed a 54 kDa NPM-MLF1 protein, but not normal MLF1. Immunostaining experiments indicated that MLF1 is normally located in the cytoplasm, whereas NPM-MLF1 is targeted to the nucleus, with highest levels in the nucleolus. The nuclear/nucleolar localization of NPM-MLF1 mirrors that of NPM, indicating that NPM trafficking signals direct MLF1 to an inappropriate cellular compartment in myeloid leukemia cells.

Prognostic significance of CD34 expression in childhood B-precursor acute lymphocytic leukemia: a Pediatric Oncology Group study.

We studied the blasts from 795 children greater than 1 year of age with newly diagnosed, untreated B-precursor acute lymphoblastic leukemia (ALL) for expression of the hematopoietic stem cell-associated antigen CD34. All cases were confirmed as B-lineage lymphoblastic leukemia by virtue of expression of CD19 and/or CD22, lack of T-cell antigens, and lack of surface-membrane immunoglobulin (Ig). The CD34 antigen was present in at least 10% of blast cells in 587 (73.8%) of the patients. There was no significant difference in presenting clinical characteristics between CD34+ and CD34- patients save for an increased incidence of CNS involvement at diagnosis in the latter. Patients with CD34+ leukemia were more likely to have blasts expressing CD22, CD9, and CD13 antigens but were less likely to coexpress CD20. Patients with pre-B (cytoplasmic mu) ALL were significantly more likely to lack CD34 on their blasts, while children with hyperdiploid ALL were more likely to be CD34+. Although remission induction rates were not significantly different between patients with CD34+ and CD34-ALL (P = .23), event-free survival was shorter for patients with CD34- leukemia (P = .0014). Even though CD34 expression was associated with certain other known prognostically favorable variables including hyperdiploidy and lack of cytoplasmic Ig, it had an independent favorable effect on treatment outcome, even after adjusting for competing prognostic factors.

Consolidation therapy with antimetabolite-based therapy in standard-risk acute lymphocytic leukemia of childhood: a Pediatric Oncology Group Study.

PURPOSE: To develop antimetabolite-based consolidation regimens that minimize acute and long-term toxicities and improve the survival rate of children with standard-risk B-lineage acute lymphocytic leukemia (ALL). PATIENTS AND METHODS: Seven hundred twenty-seven eligible patients with standard-risk early pre-B ALL were registered onto the study. Seven hundred sixteen patients attained a complete remission (CR) after induction therapy. Of these, 114 patients were randomized to a different regimen and were the subject of a separate report. Six hundred two patients were randomized to receive one the following regimens: intermediate-dose methotrexate (IDMTX) with leucovorin rescue on weeks 7, 10, 13, 16, 19, and 22 (regimen A); regimen A plus asparaginase (ASP) administered intramuscularly (i.m.) weekly for 24 weeks (regimen B); or regimen A plus a 24-hour infusion of cytarabine (AraC) with each IDMTX (regimen C). After consolidation, patients were placed on maintenance therapy through week 156. Regimens A and C were opened in February 1986, and regimen B in May 1987. Comparisons are based on concurrently randomized patients (May 1987 to January 1991 between regimens A and B, and February 1986 to January 1991 between regimens A and C). RESULTS: The 5-year continuous CR (CCR) rates were not significantly different: A versus B, 78.1% (3.9 +/- SE) versus 83.3% +/- 3.5% and A versus C, 79.4% +/- 3.2% versus 83.5% +/- 2.9%; P by one-sided log-rank tests were .27 and .34, respectively. Significant treatment differences were not found with regard to sex, rate of testicular and CNS relapse, or CNS complications. During consolidation, regimen C had significantly more bacterial infections (P = .0032) and days spent in the hospital (P < .001) compared with regimen A. CONCLUSION: We were unable to show a statistical advantage of adding either ASP or AraC to IDMTX in terms of improvement in event-free survival (EFS).

Secondary cytogenetic changes in acute promyelocytic leukemia--prognostic importance in patients treated with chemotherapy alone and association with the intron 3 breakpoint of the PML gene: a Cancer and Leukemia Group B study.

PURPOSE: To examine, in newly diagnosed patients with acute promyelocytic leukemia (APL), the prognostic significance of secondary cytogenetic changes and the relationship between such changes and the two major promyelocytic leukemia-retinoic acid receptor alpha (PML-RAR alpha) mRNA types. PATIENTS AND METHODS: One hundred sixty-one patients with t(15;17)(q22;q11-12) enrolled onto Cancer and Leukemia Group B (CALGB) protocol 8461, a prospective study of cytogenetics in acute myeloid leukemia (AML), were studied. Eighty of these 161 patients were treated solely with chemotherapy and evaluated for response to treatment and survival. PML-RAR alpha mRNA type was determined using reverse transcriptase polymerase chain reaction (RT-PCR) in 56 patients. RESULTS: The incidence of secondary cytogenetic abnormalities was 32%. Among 80 patients treated with chemotherapy, the presence of a secondary chromosome abnormality was associated with longer complete remission (CR) duration (median, 29.9 v 15.7 months; P = .03) and longer event-free survival (EFS) duration (median, 17.0 v 12.2 months; P = .03). There was no difference in overall survival (P = .28). In a separate group of 56 patients with both cytogenetic and molecular data, 32 had the type L PML-RAR alpha transcript (intron 6 PML breakpoint). Of these 32 patients, four (12.5%) had chromosome changes in addition to t(15;17), whereas 12 of 20 patients (60%) with the type 5 PML-RAR alpha transcript (intron 3 PML breakpoint) had secondary cytogenetic changes (P < .001). CONCLUSION: (1) Secondary cytogenetic changes do not confer a poor prognosis in APL patients treated with anthracycline/cytarabine (Ara-C)-based chemotherapy; and (2) A highly significant relationship exists between the PML-RAR alpha 5 isoform (intron 3 PML genomic breakpoint) and secondary cytogenetic changes in APL.

Prognostic significance of sex in childhood B-precursor acute lymphoblastic leukemia: a Pediatric Oncology Group Study.

PURPOSE: In childhood B-precursor acute lymphoblastic leukemia (ALL), possible interactions among sex, time, and widely used prognostic factors (age, WBC count, and DNA index) were investigated for the first 5 years after diagnosis. PATIENTS AND METHODS: All eligible patients aged 1 to less than 22 years, registered between February 1986 and September 1994 in two B-precursor ALL studies from the Pediatric Oncology Group (POG), were included in the analysis. Cutpoints for age (3.0, 5.0, and 10.0 years), WBC count (10, 50, and 100 x 10(9)/L), and DNA index (DI; 1.16) were defined. Four time periods after diagnosis (years 1, 2, 3, and 4 and 5 combined) were selected for the study of prognostic significance over time. The cut-off date for analysis was April 1996. RESULTS: A total of 3,717 children (2,010 boys and 1,707 girls) were included in the outcome analysis. No major differences between the sexes were observed in age, duration of symptoms before registration, WBC count, hemoglobin level, platelet count, ploidy, presence of CNS disease at diagnosis, or induction failure rate. Event-free survival (EFS) differences between sexes became significantly different from 2 years following diagnosis. At 5 years, in all subsets analyzed, boys fared worse than girls, although not all differences were statistically significant. Major sex differences in EFS were observed in older children (10 to 22 years), in patients with intermediate WBC counts (10 to 50 x 10(9)/ L), and in children who fit both of these subgroups, in whom the 2-year EFS was almost 20% higher in girls than in boys, reaching a 38% difference at 5 years. CONCLUSION: This study shows an outcome interaction among sex, time, and commonly used prognostic variables. The important sex difference observed at 2 and 5 years suggests that more intensive consolidation and/or maintenance therapy in some boys with B-precursor ALL should be investigated.

Childhood acute lymphoblastic leukemia with the MLL-ENL fusion and t(11;19)(q23;p13.3) translocation.

PURPOSE: To determine the molecular characteristics, clinical features, and treatment outcomes of children with acute lymphoblastic leukemia (ALL) and the t(11;19)(q23,p13.3) translocation. PATIENTS AND METHODS: A retrospective analysis of leukemic cell karyotypes obtained from patients with new diagnoses of ALL who were treated at St. Jude Children's Research Hospital or by the Pediatric Oncology Group was performed to identify cases with the t(11;19)(q23;p13.3) translocation. Molecular analyses were performed on these cases to determine the status of the MLL gene and the presence of the MLL-ENL fusion transcript. RESULTS: Among 3,578 patients with ALL and successful cytogenetic analysis, we identified 35 patients with the t(11;19)(q23;p13.3) translocation: 13 infants and 11 older children had B-precursor leukemia, whereas 11 patients had a T-cell phenotype. Although all of the cases examined had MLL rearrangements and MLL-ENL fusion transcripts, outcome varied according to age and immunophenotype. Among B-precursor cases, only two of the 13 infants remain in complete remission, compared with six of the 11 older children. Most strikingly, no relapses have occurred among B-precursor patients 1 to 9 years of age or among T-cell patients. CONCLUSION: Although MLL gene rearrangements are generally associated with a dismal outcome in ALL, two distinct subsets with MLL-ENL fusions have an excellent prognosis. Our results suggest that patients with this genetic abnormality who have T-cell ALL or are 1 to 9 years of age should not be considered candidates for hematopoietic stem-cell transplantation during their first remission.

Uniform approach to risk classification and treatment assignment for children with acute lymphoblastic leukemia.

PURPOSE: To define more uniform criteria for risk-based treatment assignment for children with acute lymphoblastic leukemia (ALL), the Cancer Therapy Evaluation Program (CTEP) of the National Cancer Institute (NCI) sponsored a workshop in September 1993. Participants included representatives from the Childrens Cancer Group (CCG), Pediatric Oncology Group (POG), Dana-Farber Cancer Institute (DFCI), St Jude Children's Research Hospital (SJCRH), and the CTEP. METHODS: Workshop participants presented and reviewed data from ALL clinical trials, using weighted averages to combine outcome data from different groups. RESULTS: For patients with B-precursor (ie, non-T, non-B) ALL, the standard-risk category (4-year event-free survival [EFS] rate, approximately 80%) will include patients 1 to 9 years of age with a WBC count at diagnosis less than 50,000/microL. The remaining patients will be classified as having high-risk ALL (4-year EFS rate, approximately 65%). For patients with T-cell ALL, different treatment strategies have yielded different conclusions concerning the prognostic significance of T-cell immunophenotype. Therefore, some groups/institutions will classify patients with T-cell ALL as high risk, while others will assign risk for patients with T-cell ALL based on the uniform age/WBC count criteria. Workshop participants agreed that the risk category of a patient may be modified by prognostic factors in addition to age and WBC count criteria, and that a common set of prognostic factors should be uniformly obtained, including DNA index (DI), cytogenetics, early response to treatment (eg, day-14 bone marrow), immunophenotype, and CNS status. CONCLUSIONS: The more uniform approach to risk-based treatment assignment and to collection of specific prognostic factors should increase the efficiency of future ALL clinical research.

Extramedullary leukemia adversely affects hematologic complete remission rate and overall survival in patients with t(8;21)(q22;q22): results from Cancer and Leukemia Group B 8461.

PURPOSE: To examine the prognostic significance of extramedullary leukemia (EML) at presentation in patients with t(8;21)(q22;q22) karyotype. PATIENTS AND METHODS: Consecutive patients with t(8;21) treated on Cancer and Leukemia Group B de novo acute myeloid leukemia (AML) treatment studies were examined for the presence of EML (granulocytic sarcoma, subcutaneous nodules, leukemia cutis, or meningeal leukemia) at initial presentation. Clinical features and outcome of t(8;21) patients with and without EML were compared. RESULTS: Of 84 patients with t(8;21), eight (9.5%) had EML manifesting as granulocytic sarcoma (five paraspinal, one breast, and one subcutaneous) or symptomatic meningeal leukemia (n = 1). The pretreatment prognostic variables of t(8;21) patients with and without EML were similar. The hematologic complete remission (CR) rate for t(8;21) patients with EML was 50% versus 92% for those without EML (P=.006). The median CR duration for EML patients was 14.7 months. Patients with EML had a shorter survival (P = 0.002, median 5.4 months versus 59.5 months). This poor outcome may relate to inadequate local (radiation or intrathecal) therapy for patients with spinal or meningeal EML, resulting in residual/recurrent EML following induction chemotherapy (n = 2) or at relapse (n = 1) and permanent neurologic deficits (n = 4). Only one of the EML patients received high-dose cytarabine (HDAC) intensification; this is the only EML patient remaining alive in CR. CONCLUSION: Patients with t(8;21) and EML have a low CR rate and overall survival. An aggressive local and systemic induction therapy should be considered for this patient subset. The effectiveness of HDAC intensification in t(8;21) patients with EML is uncertain and warrants further study.

Comparison of cytogenetic and molecular genetic detection of t(8;21) and inv(16) in a prospective series of adults with de novo acute myeloid leukemia: a Cancer and Leukemia Group B Study.

PURPOSE: To prospectively compare cytogenetics and reverse transcriptase-polymerase chain reaction (RT-PCR) for detection of t(8;21)(q22;q22) and inv(16)(p13q22)/t(16;16)(p13;q22), aberrations characteristic of core-binding factor (CBF) acute myeloid leukemia (AML), in 284 adults newly diagnosed with primary AML. PATIENTS AND METHODS: Cytogenetic analyses were performed at local laboratories, with results reviewed centrally. RT-PCR for AML1/ETO and CBFbeta/MYH11 was performed centrally. RESULTS: CBF AML was ultimately identified in 48 patients: 21 had t(8;21) or its variant and AML1/ETO, and 27 had inv(16)/t(16;16), CBFbeta/MYH11, or both. Initial cytogenetic and RT-PCR analyses correctly classified 95.7% and 96.1% of patients, respectively (P =.83). Initial cytogenetic results were considered to be false-negative in three AML1/ETO-positive patients with unique variants of t(8;21), and in three CBFbeta/MYH11-positive patients with, respectively, an isolated +22; del(16)(q22),+22; and a normal karyotype. The latter three patients were later confirmed to have inv(16)/t(16;16) cytogenetically. Only one of 124 patients reported initially as cytogenetically normal was ultimately RT-PCR-positive. There was no false-positive cytogenetic result. Initial RT-PCR was falsely negative in two patients with inv(16) and falsely positive for AML1/ETO in two and for CBFbeta/MYH11 in another two patients. Two patients with del(16)(q22) were found to be CBFbeta/MYH11-negative. M4Eo marrow morphology was a good predictor of the presence of inv(16)/t(16;16). CONCLUSION: Patients with t(8;21) or inv(16) can be successfully identified in prospective multi-institutional clinical trials. Both cytogenetics and RT-PCR detect most such patients, although each method has limitations. RT-PCR is required when the cytogenetic study fails; it is also required to determine whether patients with suspected variants of t(8;21), del(16)(q22), or +22 represent CBF AML. RT-PCR should not replace cytogenetics and should not be used as the only diagnostic test for detection of CBF AML because of the possibility of obtaining false-positive or false-negative results.

Heterogeneity of the breakpoint localization in malignant cells with a 9p11 chromosomal abnormality.

The p11 band of the short arm of chromosome 9 is involved in various cytogenetic alterations occurring in several malignant diseases. Using probes isolated from the 9p11 band in the study of a case of alpha-heavy-chain disease (MAL) with t(9;14)(p11;q32), we studied the DNA from seven malignant cell samples, including four cases of acute lymphoblastic leukemia with tdic(9;12)(p11;p12). Using pulsed-field electrophoresis analysis we demonstrated that the breakpoints were 3-300 kb distant from the original MAL breakpoint without clustering within the subset of leukemias with the tdic(9;12).