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.

The seventh international childhood acute lymphoblastic leukemia workshop report: Palermo, Italy, January 29--30, 2005.

Between 1995 and 2004, six International Childhood Acute Lymphoblastic Leukemia (ALL) Workshop have been held, and the completion of several collaborative projects has established the clinical relevance and treatment options for several specific genetic subtypes of ALL. This meeting report summarizes the data presented in the seventh meeting and the discussion.

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.

Augmented Berlin-Frankfurt-Munster therapy abrogates the adverse prognostic significance of slow early response to induction chemotherapy for children and adolescents with acute lymphoblastic leukemia and unfavorable presenting features: a report from the Children's Cancer Group.

PURPOSE: Compared with previous Children's Cancer Group (CCG) acute lymphoblastic leukemia (ALL) trials, therapy based on the Berlin-Frankfurt-Munster (BFM) 76 trial has effected an improvement in event-free survival (EFS). In an attempt to improve EFS further, CCG investigators formulated an augmented BFM (A-BFM) regimen that provides prolonged, intensified postinduction chemotherapy relative to the CCG-modified BFM regimen. PATIENTS AND METHODS: We tested A-BFM in 101 patients with ALL and unfavorable presenting features that showed slow early response (SER) to induction therapy who attained remission on day 28. Their outcome was compared with that of 251 concurrent patients with unfavorable presenting features, a rapid early response to therapy (RER), and remission by day 28, treated with CCG-BFM with or without cranial radiation (CRT). RESULTS: The 4-year EFS rate from the end of induction for SER patients treated with A-BFM was 70.8% +/- 4.6%. Seventeen patients remain in continuous remission beyond 5 years. Vincristine (VCR) neurotoxicity developed in 50% of patients, but was rarely debilitating. Allergies to Escherichia coli L-asparaginase (L-ASP) occurred in 35% of patients. Avascular necrosis of bone (AVN) developed in 9% of patients. In comparison, a concurrent RER group treated with standard BFM +/- CRT had a 4-year EFS rate of 73.1% +/- 4.6%. CONCLUSION: The toxicity of A-BFM is significant, but acceptable. Compared with historical control SER patients treated with CCG-modified BFM, A-BFM therapy appears to produce a significant improvement in EFS. This is the first study to show that intensive chemotherapy, as given in the A-BFM regimen, can abrogate the adverse prognostic significance of SER.

CNS-directed therapy for childhood acute lymphoblastic leukemia: Childhood ALL Collaborative Group overview of 43 randomized trials.

PURPOSE: A collaborative meta-analysis was performed to clarify the relative effects on relapse and survival of different types of therapies directed at the CNS in childhood acute lymphoblastic leukemia. MATERIALS AND METHODS: Data were sought for each individual patient in all trials started in or before 1993 that included unconfounded randomized comparisons of such treatments. Log-rank survival analyses were performed for each trial, and overall results for groups of trials addressing similar questions were obtained from the totals of the observed minus expected number of events and their variances. RESULTS: Radiotherapy and long-term intrathecal therapy gave similar outcomes, with no significant difference in event-free survival despite random assignment of treatment to 2,848 patients, 1,001 of whom suffered relapse or death. Intravenous methotrexate reduced non-CNS rather than CNS relapses, and hence, the addition of intravenous methotrexate to a treatment regimen including radiotherapy or long-term intrathecal therapy improved event-free survival, with a 17% reduction in the event rate (95% confidence interval, 6% to 27%; P =.003). The event-free survival at 10 years in these trials was 61.9% without intravenous methotrexate and 68.1% with intravenous methotrexate. There was no significant difference in survival (14% death rate reduction; P =.09). There were insufficient randomly assigned patients to adequately address other questions, such as effect of different doses. No evidence was found of differences, between trials or between subgroups of different types of patients, in the relative effects of treatment. CONCLUSION: Radiotherapy can be replaced by long-term intrathecal therapy. Intravenous methotrexate gives some additional benefit by reducing non-CNS relapses.

The effect of initial management of hyperleukocytosis on early complications and outcome of children with acute lymphoblastic leukemia.

Data were collected from 124 patients with newly diagnosed acute lymphoblastic leukemia (ALL) and WBC greater than 200,000/microL seen at institutions affiliated with the Children's Cancer Study Group (CCSG) from April 1981 to May 1983. The presenting characteristics, initial management, early complications, and outcome were reviewed. All the children received vigorous intravenous (IV) hydration, alkalinization of the urine, and allopurinol. Thirty-two patients were started on full therapy with no additional measure. One or more special measures believed to reduce the complications of leukostasis and blast cell lysis were administered to 92 patients as follows: small initial doses of prednisone, 63; emergency cranial irradiation, 26; exchange transfusion, 21; and leukopheresis, 19. The incidence of CNS hemorrhage was only 3% (4/124). Seven patients expired during induction and four failed to achieve a remission by day 28. Nineteen patients (15%) had documented bacterial or fungal sepsis. Mild to moderate electrolyte abnormalities occurred in 29 patients: three patients required renal dialysis. Pretreatment with small doses of prednisone did not decrease the incidence of electrolyte abnormalities in those patients when compared with patients who received full chemotherapy. The event-free survival (EFS) for the 106 patients treated on one of the three intensive pilot studies is 55% at 36 months. On multivariate analysis the two significant adverse prognostic factors were massive splenomegaly (P = .02) and WBC count greater than 600,000/microL (P = .05). In conclusion, in patients with hyperleukocytosis the complications of blast cell lysis and leukostasis were manageable with acceptable morbidity and minimal mortality in a group of patients treated with vigorous hydration, allopurinol, and alkalinization of the urine before beginning chemotherapy. Selected patients with severe hyperuricemia and renal dysfunction may benefit from leukopheresis. No beneficial role was demonstrated for the use of small initial doses of prednisone or emergency cranial irradiation.

Improved disease-free survival of children with acute lymphoblastic leukemia at high risk for early relapse with the New York regimen--a new intensive therapy protocol: a report from the Childrens Cancer Study Group.

An intensive multimodal therapy was developed for the treatment of a subpopulation of children with acute lymphoblastic leukemia (ALL) who had a predicted event-free survival of less than 40% on previously reported therapeutic regimens (at high risk for early relapse). Induction with multiagent chemotherapy and radiotherapy to bulky disease-bearing areas (peripheral lymph nodes and mediastinum) was followed by consolidation, CNS prophylaxis, and cyclical remission maintenance therapy. Ninety-six (96%) of 100 previously untreated patients, 1 to 17 years of age, attained a complete remission. Seven patients received other maintenance therapy or a bone marrow transplant in remission. Sixty-six of the remaining 89 (74%) are in continuous complete remission at 22+ to 72+ months (median, 44+ months). Marrow relapse occurred in 15 (17%), CNS relapse in 5 (6%), and testicular relapse in one. Sixty-six of the 93 evaluable patients (71%) (including the induction failures) are event-free survivors. Two patients died of infection during the induction phase. No patient died during consolidation or maintenance without recurrent disease. The patients spent a median of 19, 0, and 0 days hospitalized during induction, consolidation, and maintenance, respectively. The most common complications were bacteremia and mucositis during induction and mucositis and fever during periods of neutropenia in consolidation. Maintenance was well tolerated. We conclude that the treatment protocol is intensive, but the inherent toxicities are manageable with adequate supportive care. The life table--projected event-free survival of 69% +/- 5% 48 months from diagnosis is encouraging.

Response of children with high-risk acute lymphoblastic leukemia treated with and without cranial irradiation: a report from the Children's Cancer Group.

PURPOSE: Intensified intrathecal (i.t.) chemotherapy without cranial radiation therapy (CRT) prevents CNS relapse in children with low-risk and intermediate-risk acute lymphoblastic leukemia (ALL). In the current study, high-risk ALL patients who achieved a rapid early response (RER) to induction chemotherapy were randomized to receive intensive systemic chemotherapy and presymptomatic CNS therapy that consisted of either i.t. methotrexate (MTX) and CRT or intensified i.t. MTX alone. PATIENTS AND METHODS: Children (n = 636) with high-risk ALL (aged 1 to 9 years and WBC count > or = 50,000/microL or age > or = 10 years, excluding those with lymphomatous features) who achieved an RER (< or = 25% marrow blasts on day 7) to induction therapy and lacked CNS disease at diagnosis were randomized to receive systemic therapy with either i.t. MTX and CRT (regimen A, n = 317) or intensified i.t. MTX alone (regimen B, n = 319). RESULTS: Interim analysis in July 1993 revealed 3-year event-free survival (EFS) estimates of 82.1% +/- 4.0% (SD)and 70.4% +/- 4.2% for patients treated on regimens A and B, respectively (P = .004). As of January 1996, outcome had changed: 5-year EFS estimates were 69.1% +/- 3.4% and 75.0% +/- 2.7% for regimens A and B, respectively (P = 0.50). Marrow relapses comprised 57 events on regimen A and 43 events on regimen B. Fewer late events occurred on regimen B. CONCLUSION: For high-risk pediatric ALL patients who show an RER to induction therapy and are treated with systemic Children's Cancer Group (CCG)-modified Berlin-Frankfurt-Munster (BFM) chemotherapy, presymptomatic CNS therapy that consists of either i.t. MTX plus CRT or intensified i.t. MTX alone results in a similar 5-year EFS outcome. Furthermore, intensified i.t. MTX may protect against late bone marrow relapse.

Improved therapy for children with acute lymphoblastic leukemia and unfavorable presenting features: a follow-up report of the Childrens Cancer Group Study CCG-106.

PURPOSE: On past Childrens Cancer Group (CCG) trials, children with acute lymphoblastic leukemia and unfavorable presenting features had obtained an event-free survival (EFS) rate of no better than 50%. Following promising pilot experience, this study was conducted to determine the benefit and morbidity of two intensive experimental regimens, Reg A, based on the Berlin-Frankfurt-Münster (BFM) 1976 regimen, and Reg B, the New York regimen. PATIENTS AND METHODS: Between February 1983 and November 1984, 217 eligible children with acute lymphoblastic leukemia and unfavorable presenting features were entered and randomly assigned to receive Reg A, Reg B, or Reg C, the control regimen. Assignment to Reg C was halted in November 1984 after interim analyses showed an inferior outcome. Subsequently, between November 1984 and March 1987, an additional 328 patients were randomly allocated to receive Reg A or Reg B. RESULTS: The 7-year EFS rate was 63% (+/- 6%, 1 SD) for Reg A, 61% (+/- 6%) for Reg B, and 40% (+/- 6%) for Reg C (P < .006). The difference between Reg A or Reg B and Reg C remained greater than 20 percentage points for EFS at 7 years and 15 percentage points for survival. Relative to Reg C, patients on Reg A accrued 16.3 additional days of hospitalization on average and, on Reg B, 20.2 days. EFS and survival were similar on Reg A and Reg B, but Reg B required more days of parenteral therapy and greater exposure to anthracyclines and alkylating agents. CONCLUSION: Both Reg A and Reg B provided a better outcome than Reg C for children with acute lymphoblastic leukemia and unfavorable presenting features. Outcomes on Reg A and Reg B were similar. Use of the more effective but more toxic regimens resulted in 78 additional hospital days per relapse prevented on Reg A and 101 days on Reg B. The current CCG trial for this population builds on Reg A.

Duration of hospitalization as a measure of cost on Children's Cancer Group acute lymphoblastic leukemia studies.

PURPOSE: We used duration of hospitalization as a surrogate for cost and event-free survival as a measure of effectiveness to estimate the cost-effectiveness ratios of various treatment regimens on Children's Cancer Group trials for acute lymphoblastic leukemia. PATIENTS AND METHODS: The analyses included 4,986 children (2 to 21 years of age) with newly diagnosed acute lymphoblastic leukemia enrolled onto risk-adjusted protocols between 1988 and 1995. Analyses were based on a model of 100 patients. The marginal cost-effectiveness ratio (hospital days per additional patient surviving event-free) was the difference in total duration of hospitalization divided by the difference in number of event-free survivors at 5 years for two regimens. Relapse-adjusted marginal cost of frontline therapy was the difference in total duration of hospitalization for frontline therapy plus relapse therapy divided by the difference in number of event-free survivors at 5 years on the frontline therapy for two regimens. RESULTS: One or two delayed intensification (DI) phases, augmented therapy, and dexamethasone all improved outcome. Marginal cost-effectiveness of these regimens compared with the control regimens was 133 days per patient for DI, 117 days per patient for double DI, and 41 days per patient for augmented therapy. Dexamethasone resulted in 17 fewer days per patient. Relapse-adjusted marginal costs were 68 days per patient for DI and 52 days for double DI. Augmented therapy and dexamethasone-based therapy resulted in 16 and 82 fewer hospital days, respectively. The estimated cost-effectiveness for treating any first relapse was 250 days per patient. CONCLUSION: DI, double DI, augmented therapy, and dexamethasone-based therapy are cost-effective strategies compared with current treatment of first relapse.

Clinical features and treatment outcome of childhood T-lineage acute lymphoblastic leukemia according to the apparent maturational stage of T-lineage leukemic blasts: a Children's Cancer Group study.

PURPOSE: Leukemic cells from T-lineage acute lymphoblastic leukemia (ALL) patients are thought to originate from T-lymphocyte precursors corresponding to discrete stages of T-cell ontogeny. Here we sought to determine the influence of leukemic cell apparent maturational stage on treatment outcomes in pediatric T-lineage ALL. PATIENTS AND METHODS: From 1983 through 1993, 407 pediatric T-lineage ALL patients were enrolled onto two sequential series of risk-adjusted treatment protocols of the Children's Cancer Group. In the current analysis, T-lineage ALL patients were immunophenotypically classified as follows: CD7+ CD2- CD5- pro-thymocyte leukemia (pro-TL), CD7+ (CD2 or CD5)+ CD3- immature TL, and CD7+ CD2+ CD5+ CD3+ mature TL. RESULTS: Similar induction outcomes of 91.4%, 97.1%, and 98.3% were obtained by the pro-, immature, and mature TL groups, respectively. Four-year event-free survival (EFS) was lower for pro-TL patients (57.1%; SD = 8.4%,) compared with immature and mature TL patients (68.5%; SD = 3.5%; and 77.1%; SD = 4.0%, respectively) with an overall significance of .05 (log-rank test) or .04 (log-rank trend test). Relative hazards rates (RHR) were 2.11 and 1.22 for pro-TL and immature TL versus mature TL, respectively. Highly significant differences were found for overall survival (P = .005, log-rank test; P = .009, log-rank trend test). Multivariate analysis confirmed that the prognostic influence of ontogeny grouping was independent of that of other prognostic factors. CONCLUSION: Leukemic cells of the pro-TL maturation stage identify a small subgroup of T-lineage ALL patients who have a significantly worse EFS outcome than patients whose cells are of a more mature stage of development.

Prognostic impact of trisomies of chromosomes 10, 17, and 5 among children with acute lymphoblastic leukemia and high hyperdiploidy (> 50 chromosomes).

PURPOSE: Children with acute lymphoblastic leukemia (ALL) and high hyperdiploidy (> 50 chromosomes) have improved outcome compared with other ALL patients. We sought to identify cytogenetic features that would predict differences in outcome within this low-risk subset of ALL patients. MATERIALS AND METHODS: High-hyperdiploid ALL patients (N = 480) were enrolled between 1988 and 1995 on Children's Cancer Group (CCG) trials. Karyotypes were determined by conventional banding. Treatment outcome was analyzed by life-table methods. RESULTS: Patients with 54 to 58 chromosomes had better outcome than patients with 51 to 53 or 59 to 68 chromosomes (P = .0002). Patients with a trisomy of chromosome 10 (P<.0001), chromosome 17 (P = .0002), or chromosome 18 (P = .004) had significantly improved outcome compared with their counterparts who lacked the given trisomy. Patients with a trisomy of chromosome 5 had worse outcome than patients lacking this trisomy (P = .02). Patients with trisomies of both chromosomes 10 and 17 had better outcome than those with a trisomy of chromosome 10 (P = .09), a trisomy of chromosome 17 (P =.01), or neither trisomy (P<.0001). Multivariate analysis indicated that trisomy of chromosome 10 (P = .001) was the most significant prognostic factor for high-hyperdiploid patients, yet trisomy of chromosome 17 (P =.02) or chromosome 5 (P = .01) and modal chromosome number (P = .02) also had significant multivariate effects. CONCLUSION: Trisomy of chromosomes 10 and 17 as well as modal chromosome number 54 to 58 identify subgroups of patients with high-hyperdiploid ALL who have a better outcome than high-hyperdiploid patients who lack these cytogenetic features. Trisomy of chromosome 5 confers poorer outcome among high-hyperdiploid patients.

Cytoreduction and prognosis in acute lymphoblastic leukemia--the importance of early marrow response: report from the Childrens Cancer Group.

PURPOSE: To quantify the residual marrow lymphoblast fraction that best defines patients at high risk for relapse, and the optimal time for assessment during remission induction. PATIENTS AND METHODS: The residual lymphoblast percentage was evaluated on day 7 (n = 220) and day 14 (n = 205) during a four- or five-drug induction in patients with poor prognostic factors. The rate of cytoreduction was related to event-free survival (EFS) and other factors. RESULTS: On the New York (NY) regimen, 68%, 14%, and 18%, and on the Berlin-Frankfurt-Munster (BFM) regimen, 56%, 15%, and 29% of patients had M1 (< 5% blasts), M2 (5-25%), or M3 (> 25%) responses on day 7 (P = .075). On day 14, the corresponding values were 87%, 6%, 7% on NY and 84%, 8%, 8% on BFM. For patients who achieved remission by day 28 and a day-7 marrow rating of M1, M2, or M3, the 6-year EFS rate was 78%, 61%, and 49% (P < .001). The day-14 ratings predicted for a 72%, 32%, or 40% EFS (P < .001). Patients with 5% to 10% blasts day 7 had three times as many events as those with less than 5% and had no better EFS than those with 11% to 25% blasts. Patients with a WBC count more than 200,000/microL at diagnosis and an M1 day 7 marrow had an EFS rate of 69%, while for those with M2 or M3, the EFS rate was 41%. Day-7 marrow had greater prognostic significance than the day-14 evaluation. For slow responders on day 7, the day-14 marrow provided additional information. EFS for patients who achieved M1 by day 14 was 65%. EFS decreased to 20% for those still M2 or M3 on day 14. Day-7 and -14 evaluations had significance for patients of all ages and WBC levels. CONCLUSION: Marrow aspiration on day 7 of therapy provided more useful information than that on day 14. However, day-14 marrow provided additional information for patients with a poor day-7 response. The rate of cytoreduction is a powerful, independent prognostic factor that can identify patients with a slow early response who are at risk for a short remission duration.

Clinical significance of translocation t(1;19) in childhood acute lymphoblastic leukemia in the context of contemporary therapies: a report from the Children's Cancer Group.

PURPOSE: The nonrandom translocation t(1;19) has been associated with poor outcome in pediatric B-lineage acute lymphoblastic leukemia (ALL). Because most patients treated by contemporary therapies now achieve improved outcomes, we have reassessed the prognostic significance of t(1;19). PATIENTS AND METHODS: Cytogenetic data were accepted for 1,322 children (<21 years old) with newly diagnosed ALL enrolled between 1988 and 1994 on risk-adjusted studies of the Children's Cancer Group (CCG). Forty-seven patients (3.6%) were t(1;19) positive (+); 1,275 (96.4%) were t(1;19) negative (-). Clinical characteristics and treatment outcome were compared using standard methods. RESULTS: Translocation (1;19)+ patients were more likely than t(1;19)- patients to be 10 years of age or greater (P < .001) or CD10+ CD19+ CD34- (P < .0001), or nonwhite (P = .02). Patients with a balanced t(1;19) were less likely to be hyperdiploid than patients with an unbalanced der(19)t(1;19). Event-free survival (EFS) was similar for the overall group of t(1;19)+ and t(1;19)- patients, with 4-year estimates of 69.5% (SD, 6.8%) and 74.8% (SD, 1.3%; P = .48), respectively. However, patients with unbalanced der(19)t(1;19) had significantly better outcomes than patients with balanced t(1;19): 4-year EFS were 80.6% (SD, 7.1%) and 41.7% (SD, 13.5%), respectively (P = .003). These differences were maintained within the individual studies analyses and after exclusion of t(1;19)+ patients whose cells were hyperdiploid with more than 50 chromosomes. CONCLUSION: The overall group of t(1;19)+ patients, as well as the subgroup with an unbalanced der(19)+ (1;19) had outcomes similar to that of t(1;19)- patients, whereas patients with balanced t(1;19) had poorer outcomes. Thus, although the overall prognostic significance of t(1;19) has been obviated by contemporary risk-adjusted protocols, the balanced t(1;19) translocation remains an adverse prognostic factor.

Abnormalities of chromosome bands 13q12 to 13q14 in childhood acute lymphoblastic leukemia.

PURPOSE: Little is known about nonrandom deletions of chromosome bands 13q12 to 13q14 (13q12-14) in acute lymphoblastic leukemia (ALL). We determined the prognostic significance of cytogenetically identified breakpoints in 13q12-14 in children with newly diagnosed ALL treated on Children's Cancer Group protocols from 1988 to 1995. PATIENTS AND METHODS: Breakpoints in 13q12-14 were identified in 36 (2%) of the 1,946 cases with accepted cytogenetic data. Outcome analysis used standard life-table methods. RESULTS: Seventeen patients (47%) with an abnormal 13q12-14 were classified, according to the National Cancer Institute (NCI), as poor risk, and 15 patients (42%) were standard risk; four (11%) were infants less than 12 months of age. Eight cases had balanced rearrangements of 13q12-14, 27 patients had a partial loss of 13q, and one had both a partial gain and a partial loss. The most frequent additional abnormalities among these patients were an abnormal 12p, a del(6q), a del(9p), a 14q11 breakpoint, and an 11q23 breakpoint. Nineteen patients were pseudodiploid, 10 were hyperdiploid, and seven were hypodiploid. Patients with an abnormal 13q12-14 had significantly worse event-free survival than patients lacking such an abnormality, with estimates at 6 years of 61% (SD = 14%) and 74% (SD = 1%), respectively (P =.04; relative risk = 1.74). Overall survival, however, was similar for the two groups (P =.25). The prognostic effect of an abnormal 13q was attenuated in a multivariate analysis adjusted for NCI risk status and ploidy (P =.72). CONCLUSION: Aberrations of 13q12-14 may contribute to leukemogenesis of childhood ALL and confer increased risk of treatment failure but are associated with other poor-risk features.

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.

Expression of aberrantly spliced oncogenic ikaros isoforms in childhood acute lymphoblastic leukemia.

PURPOSE: We sought to determine if molecular abnormalities involving the Ikaros gene could contribute to the development of acute lymphoblastic leukemia (ALL) in children. PATIENTS AND METHODS: We studied Ikaros gene expression in normal human bone marrow, normal thymocytes, normal fetal liver-derived immature lymphocyte precursor cell lines, eight different ALL cell lines, and leukemic cells from 69 children with ALL (T-lineage ALL, n = 18; B-lineage ALL, n = 51). Expression of Ikaros protein and its subcellular localization were examined by immunoblotting and confocal laser-scanning microscopy, respectively. Polymerase chain reaction (PCR) and nucleotide sequencing were used to identify the specific Ikaros isoforms expressed in these cells. Genomic sequencing of splice junction regions of the Ikaros gene was performed in search for mutations. RESULTS: In each of the ALL cases, we found high-level expression of a non-DNA-binding or aberrant DNA-binding isoform of Ikaros with abnormal subcellular compartmentalization patterns. In contrast, only wild-type Ik-1 and Ik-2 isoforms with normal subcellular localization were found in normal bone marrow cells and thymus-derived or fetal liver-derived normal lymphocyte precursors. In leukemic cells expressing the aberrant Ikaros coding sequences with the 30-base-pair deletion, genomic sequence analysis of the intron-exon junctions between exons 6 and 7 yielded the wild-type sequence. We identified a single nucleotide polymorphism (SNP) affecting the third base of the triplet codon for a proline (CCC or CCA) in the highly conserved bipartite activation region (viz, A or C at position 1002 numbering from the translation start site of Ik-1) within our Ikaros clones. Bi-allelic expression of truncated and/or non-DNA-binding isoforms along with wild-type isoforms was observed in leukemic cells, which implicates trans-acting factor(s) affecting splice site recognition. CONCLUSION: Our findings link specific molecular defects involving the Ikaros gene to childhood ALL. Posttranscriptional regulation of alternative splicing of Ikaros RNA seems to be defective in leukemic lymphocyte precursors from most children with ALL. Consequently, leukemic cells from ALL patients, in contrast to normal lymphocyte precursors, express high levels of non-DNA-binding Ikaros isoforms that are reminiscent of the non-DNA-binding Ikaros isoforms that lead to lymphoblastic leukemia in mice.

Frequency and clinical significance of cytogenetic abnormalities in pediatric T-lineage acute lymphoblastic leukemia: a report from the Children's Cancer Group.

PURPOSE: Nonrandom chromosomal translocations are frequently observed in pediatric patients with acute lymphoblastic leukemia (ALL). Specific translocations, such as t(4;11) and t(9;22), identify subgroups of B-lineage ALL patients who have an increased risk of treatment failure. The current study was conducted to determine the prognostic significance of chromosomal translocations in T-lineage ALL patients. MATERIALS AND METHODS: The study included 169 children with newly diagnosed T-lineage ALL enrolled between 1988 and 1995 on risk-adjusted protocols of the Children's Cancer Group (CCG) who had centrally reviewed cytogenetics data. Outcome analyses used standard life-table methods. RESULTS: Presenting features for the current cohort were similar to those of concurrently enrolled patients for whom cytogenetic data were not accepted on central review. The majority of patients (80.5%) were assigned to CCG protocols for high-risk ALL and 86.4% had pseudodiploid (n = 80) or normal diploid (n = 66) karyotypes; modal chromosome number was not a significant prognostic factor. Overall, 103 of 169 (61%) patients had an abnormal karyotype, including 31 with del(6q), 29 with 14q11 breakpoints, 15 with del(9p), 11 with trisomy 8, nine with 11q23 breakpoints, nine with 14q32 translocations, and eight with 7q32-q36 breakpoints. Thirteen patients had the specific 14q11 translocation t(11;14)(p13;q11) and all were classified as poor risk. Patients with any of these translocations had outcomes similar to those with normal diploid karyotypes. CONCLUSION: Chromosomal abnormalities, including specific nonrandom translocations, were frequently observed in a large group of children with T-lineage ALL, but were not significant prognostic factors for this cohort. Thus, contemporary intensive treatment programs result in favorable outcomes for the majority of T-lineage ALL patients, regardless of karyotypic abnormalities, and such features do not identify patients at higher risk for relapse.