|
Advertisement |
|
|
||
 |
|
|||||
|
|||||
|
 |
||||||
|
||||||
|
||||||
|
© 1999 American Society for Clinical Oncology Childhood Acute Lymphoblastic Leukemia With the MLL-ENL Fusion and t(11;19)(q23;p13.3) TranslocationFrom the St. Jude Children's Research Hospital; the University of Tennessee College of Medicine, Memphis, TN; the Pediatric Oncology Group Statistical Office, University of Florida, Gainesville, FL; the Pediatric Oncology Group Operations Office, Northwestern University, Chicago, IL; Stanford University, Stanford, CA; the University of Mississippi Medical Center, Jackson, MS; and the Midwest Children's Cancer Center, Milwaukee, WI. Address reprint requests to Jeffrey E. Rubnitz, MD, PhD, Department of Hematology/Oncology, St. Jude Children's Research Hospital, 332 N Lauderdale St, Memphis, TN 38105–2794; Email: jeffrey.rubnitz@ stjude.org
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.
DESPITE OVERALL IMPROVEMENTS IN the treatment of acute lymphoblastic leukemia (ALL), patients with MLL gene rearrangements generally have a dismal prognosis.1-6 The MLL gene is disrupted in approximately 80% of infant ALL cases1-4,7,8 and in secondary acute myeloid leukemia (AML) that arises in patients treated with topoisomerase II inhibitors.9-11 Less frequently, MLL rearrangements are detected in ALL cases in older children and adults, as well as in de novo AML.12 MLL encodes a 431-kda protein that contains three AT-hook domains at the N-terminus, a region with homology to DNA methyltransferases, two central zinc finger domains, and a C-terminal region that shares homology with the Drosophila trithorax protein.13-16 In leukemias in humans, 11q23 translocations cluster in an 8.5-kb region of MLL and fuse the N-terminal portion of MLL, containing the AT-hook and methyltransferase domains, to a variety of different proteins.14,15,17-20 Although the roles of these partner proteins in leukemogenesis have not been determined, many of them likely contribute functional domains to the fusion. For example, the t(4;11), t(9;11), and t(11;19)(q23;p13.3) translocations fuse MLL to AF-4, AF-9, and ENL, respectively.14,15,17,18,21,22 All three of these partners are small serine/proline-rich proteins with nuclear localization signals, suggesting that they have similar biologic functions. In addition, the C-terminal of ENL displays transcriptional regulatory activity in vitro.22 Recently, MLL-ENL was shown to immortalize myelomonocytic precursors in vitro and to induce myeloid leukemia when introduced into recipient mice.23 Transformation was not seen with a truncated MLL, indicating that MLL-ENL mediates transformation through a gain-of-function mechanism.23 Three unrelated partner genes for MLL are located at 19p13: ENL at 19p13.3, ELL at 19p13.1, and EEN.19,20,24 In a molecular analysis of t(11;19) leukemias, we previously demonstrated MLL-ENL fusions in both ALL and AML but MLL-ELL fusions only in AML.25 Similarly, a cytogenetic review of 48 cases of acute leukemia containing the t(11;19) translocation revealed 19p13.3 breakpoints in 25 ALL and four AML cases, whereas 19p13.1 breakpoints were seen only in AML.26 The latter study, as well as a recent report of 21 ALL patients with the t(11;19)(q23;p13.3) translocation, indicated that these patients have a poor outcome.26,27 Although it was suggested that T-cell patients with this translocation may fare well, this impression was based on only four and three patients, in two separate studies, respectively.26,27 In the study presented here, the largest reported to date, we demonstrate that despite the consistent expression of the MLL-ENL fusion in ALL cases with the t(11;19) translocation, there is heterogeneity in clinical presentation and outcome. Our results demonstrate that T-cell cases with this genetic abnormality have a favorable prognosis. Moreover, among B-lineage cases with the t(11;19) translocation, noninfant cases fare significantly better than do those below 12 months of age.
Cases were identified by 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 from 1981 through 1997 or by the Pediatric Oncology Group (POG) from 1986 through 1997. Patients were treated on one of five consecutive trials for ALL at St. Jude (Total Studies X through XIIIB) or on lineage- or age-specific protocols by the POG (POG 8,602, 8,704, 9,005, 9,006, 9,107, 9,295, 9,296, and 9,297). Cytogenetic and immunophenotypic analyses were performed at the time of diagnosis as previously described.28-30 Molecular analyses were performed at the time of diagnosis for patients with recent diagnoses and on cell-bank samples for patients with earlier diagnoses.5,25 This article is descriptive, and because of the relatively small numbers of patients, no formal statistical comparisons were made. Event-free survival (EFS) curves were constructed by the Kaplan-Meier method31 with the standard errors (SEs) of Peto and colleagues.32 EFS estimates are reported as EFS ± 1 SE.
Sixteen of 1,034 (1.5%) cases at St. Jude Children's Research Hospital and 19 of 2,544 (0.7%) cases in the POG with successful cytogenetic studies demonstrated the t(11;19)(q23;p13.3) translocation. Thus altogether 35 cases of ALL, representing approximately 1% of successfully karyotyped cases, had this genetic abnormality. Additional karyotypic changes included +X in five cases, +8 in three cases, and 9p13 abnormalities in three cases (Table 1). The molecular abnormalities of 17 of the 35 cases were reported in our previous study.25 Southern-blot analyses performed on 24 cases demonstrated rearrangements of the MLL gene in every case (Table 1). Similarly, reverse transcriptase-polymerase chain reaction analyses performed on the 21 cases from whom diagnostic material was available revealed expression of MLL-ENL in all cases. Twenty of these 21 cases expressed similar fusion transcripts, whereas one had an alternative breakpoint in ENL, which suggests that the t(11;19) translocation represents a nearly uniform molecular event in childhood ALL. Interestingly, MLL-ENL fusion transcripts were expressed in both T-cell and B-precursor cases.
In contrast to the similarities seen at the cytogenetic and molecular levels, patients with the t(11;19) translocation demonstrated a variety of clinical and biologic features (Table 1). Thirteen infants (10 girls and three boys) and 11 older children (five girls and six boys) had B-precursor ALL; 11 patients (one female infant, seven girls, and four boys) had T-cell ALL. The median presenting leukocyte count was 80 x 109/L. Sixteen patients had presenting leukocyte counts greater than 100 x 109/L, whereas 12 cases had leukocyte counts less than 50 x 109/L. Only two patients had overt CNS leukemia at diagnosis. Although the number of cases is too small to permit definitive conclusions, the outcome for patients with the t(11;19) translocation appeared to vary with age and phenotype (Fig 1). Overall, 18 patients remain in first complete remission, 13 relapsed or failed to achieve remission, two developed AML, one died in remission, and one developed non–Hodgkin's lymphoma (Table 1). Outcome was particularly dismal for infants with B-precursor ALL: only two of 13 patients remain in complete remission (0.9+ and 3.8+ years from diagnosis; Fig 1). B-precursor patients older than 1 year of age had an intermediate prognosis, with a 5-year EFS estimate of 54% ± 16%. Notably, three of the four patients older than 10 years of age relapsed, compared with none of the seven children aged 1 to 9, although two of these seven developed second malignancies. The older patient who remains in remission had a low leukocyte count (4 x 109/L) at diagnosis. By contrast, T-cell patients with the t(11;19) translocation had an excellent outcome, with an 89% ± 17% EFS at 5 years (Fig 1). Among the 11 patients with T-cell ALL, all but one remain in remission for 0.9+ to 7.0+ years; the only treatment failure was a second malignancy (AML).
Detailed immunophenotyping characteristics are listed in Table 2. HLA-DR and CD19 antigens were expressed in all B-precursor cases, whereas only six of 20 B-precursor cases expressed the CD10 antigen, including four cases that showed only partial expression. In addition, the myeloid-associated antigen CD15 was expressed in eight of 14 B-precursor cases for which the data are available. Although CD24 was present in all B-precursor cases in which it was tested, 11 of these 17 cases showed partial expression. This pattern of antigen expression, with complete or partial loss of CD10 and CD24 along with expression of CD15, is similar to that reported for t(4;11) cases.2,33 There was no apparent association between expression of the CD10 antigen and outcome, or between CD15 antigen expression and outcome. Although B-precursor cases demonstrated a low frequency of CD10 antigen expression, 73% of T-cell cases expressed it.
The overall dismal prognosis for ALL patients with MLL rearrangements has spurred efforts to improve treatment options for these patients, including the use of hematopoietic stem-cell transplantation. To avoid overtreatment, numerous studies have been performed to identify subsets of patients with a more favorable outcome. Among infants, MLL rearrangements are associated with EFS estimates of only 10% to 20%.1-4 Although some studies have shown that MLL rearrangements confer a poor prognosis regardless of age at diagnosis or partner gene involved, others suggest that only the t(4;11) translocation is prognostically important.34 In our previous study, we showed that among t(4;11) cases, infants less than 12 months of age and children older than 10 years have dismal outcomes (21% ± 8% and 13% ± 8% 3-year EFS estimates, respectively), whereas those with an intermediate age (1 to 9 years) have a relatively favorable prognosis (75% ± 14% 3-year EFS).33,35 This observation was confirmed in a recent European 11q23 Workshop, which reported that the 3-year EFS rate for 17 children 2 to 9 years of age was 73%.36 Similarly, we have demonstrated here that age has a strong influence on treatment outcome in B-cell precursor ALL cases with the t(11;19) translocation: only two of 13 infants and one of four children older than 10 years of age, compared with five of seven children aged 1 to 9, are in complete remission. These differences in outcome were not accompanied by differences in molecular or immunophenotypic characteristics. It is possible that differences in treatment might provide a partial explanation for the differences in outcome. Infants treated at POG institutions were treated on infant ALL protocols, whereas those treated at St. Jude were treated on the same protocols as older children. However, because of the small number of patients, it is not possible to determine the effects of treatment protocol on outcome. Equally important is our finding that MLL rearrangements are also associated with a favorable outcome among patients with T-cell ALL and the t(11;19) translocation. Although all cases analyzed at the molecular level expressed MLL-ENL fusion transcripts, patients with T-cell ALL had a superior outcome, compared with those with B-precursor leukemia. In fact, none of these 11 patients have relapsed. A total of 18 T-cell patients with the t(11;19) translocation have now been reported; all but one remain in first complete remission, and none have relapsed.26,27 In childhood T-cell ALL, immunophenotypic or cytogenetic markers have not consistently been shown to have prognostic significance. One study reported a lack of CD2-antigen expression in 16% of T-cell cases and suggested that CD2-antigen negativity is associated with an adverse prognosis.37 In the study presented here, however, 45% of the T-cell cases were CD2-negative, yet none of these cases relapsed. Other studies have shown that the CD10 antigen is expressed in 35%-40% of T-cell cases and is a favorable prognostic factor.38-41 Notably, 73% of the T-cell cases described here expressed the CD10 antigen, a finding that might be expected in a group of T-cell cases with a good prognosis. Our results suggest that the t(11;19) translocation is a favorable prognostic factor in T-cell ALL. However, because of the small number of patients, we could not determine its independent significance. Moreover, because these patients were treated on different regimens, we could not directly compare T-cell cases carrying the t(11;19) translocation with those that did not. Larger collaborative studies are needed to determine the independent prognostic importance of the t(11;19) translocation in T-cell ALL. Our results have implications for the treatment of patients with the t(11;19) translocation. Because MLL rearrangements generally confer a dismal prognosis, they are sometimes used as an indicator for more aggressive modes of therapy, such as allogeneic stem-cell transplantation during first remission. The results of such treatments for ALL patients with MLL rearrangements are not yet known. Nevertheless, our study indicates that in some cases, this approach may be excessive. We have shown that among patients with the t(11;19) translocation, those with B-precursor ALL and age between 1 and 9 years, as well as those with the T-cell phenotype, are likely to be cured with chemotherapy. Although treatment intensity can certainly affect prognosis, the uniformly good outcome of these two groups of patients despite treatment on many different protocols suggests that for these patients, stem-cell transplantation should be reserved for those who relapse.
We thank Susan Watson for expert editorial review, Kim Juneau for assistance in data collection, and Pete Gieser for statistical assistance.
This work was supported in part by National Institutes of Health (NIH) Cancer Center Support (CORE) grant CA-21,765; Childhood Cancer Genes Project grant CA-71907; Leukemia Program Project grant CA-20,180; NIH grants CA-29,139, CA-31,566, CA-30,969, CA-33,603, CA-15,989, and CA-32,053; and by the American Lebanese Syrian Associated Charities (ALSAC). J.E.R. is supported, in part, by a Career Development Award from the American Society of Clinical Oncology.
1. Chen C-S, Sorensen PHB, Domer PH, et al: Molecular rearrangements on chromosome 11q23 predominate in infant acute lymphoblastic leukemia and are associated with specific biologic variables and poor outcome. Blood 81:2386-2393, 1993
2.
Pui CH, Behm FG, Downing JR, et al: 11q23/MLL rearrangement confers a poor prognosis in infants with acute lymphoblastic leukemia. J Clin Oncol 12:909-915, 1994
3.
Rubnitz JE, Link MP, Shuster JJ, et al: Frequency and prognostic significance of HRX rearrangements in infant acute lymphoblastic leukemia: A Pediatric Oncology Group study. Blood 84:570-573, 1994 4. Taki T, Ida K, Bessho F, et al: Frequency and clinical significance of the MLL gene rearrangements in infant acute leukemia. Leukemia 10:1303-1307, 1996[Medline]
5.
Behm FG, Raimondi SC, Frestedt JL, et al: Rearrangement of the MLL gene confers a poor prognosis in childhood acute lymphoblastic leukemia, regardless of presenting age. Blood 87:2870-2877, 1996 6. Rubnitz JE, Behm FG, Pui C-H, et al: Genetic studies of childhood acute lymphoblastic leukemia with emphasis on p16, MLL, and ETV6 gene abnormalities: Results of St. Jude Total Therapy Study XII. Leukemia 11:1201-1206, 1997[Medline]
7.
Cimino G, Lo Coco F Biondi A, et al: ALL-1 gene at chromosome 11q23 is consistently altered in acute leukemia of early infancy. Blood 82:544-546, 1993 8. Cimino G, Rapanotti MC, Rivolta A, et al: Prognostic relevance of ALL-1 gene rearrangement in infant acute leukemias. Leukemia 9:391-395, 1995[Medline] 9. Pui CH, Behm FG, Raimondi SC, et al: Secondary acute myeloid leukemia in children treated for acute lymphoid leukemia [see comments]. N Engl J Med 321:136-142, 1989[Abstract]
10.
Hunger SP, Tkachuk DC, Amylon MD, et al: HRX involvement in de novo and secondary leukemias with diverse chromosome 11q23 abnormalities [see comments]. Blood 81:3197-3203, 1993
11.
Super HJ, McCabe NR, Thirman MJ, et al: Rearrangements of the MLL gene in therapy-related acute myeloid leukemia in patients previously treated with agents targeting DNA-topoisomerase II. Blood 82:3705-3711, 1993 12. Rubnitz JE, Behm FG, Downing JR: 11q23 Rearrangements in acute leukemia. Leukemia 10:74-82, 1996[Medline]
13.
Ziemin-van der Poel S McCabe NR, Gill HJ, et al: Identification of a gene, MLL, that spans the breakpoint in 11q23 translocations associated with human leukemias [published erratum appears in Proc Natl Acad Sci U S A 89:4220, 1992]. Proc Natl Acad Sci U S A 88:10735-10739, , 1991 14. Tkachuk DC, Kohler S, Cleary ML: Involvement of a homolog of Drosophila trithorax by 11q23 chromosomal translocations in acute leukemias. Cell 71:691-700, 1992[Medline] 15. Gu Y Nakamura T, Alder H, et al: The t(4;11) chromosome translocation of human acute leukemias fuses the ALL-1 gene, related to Drosophila trithorax, to the AF- 4 gene. Cell 71:701-708, 1992[Medline] 16. Djabali M, Selleri L, Parry P, et al: A trithorax-like gene is interrupted by chromosome 11q23 translocations in acute leukemias. Nat Genet 2:113-118, 1992[Medline]
17.
Domer PH, Fakharzadeh SS, Chen CS, et al: Acute mixed-lineage leukemia t(4;11)(q21;q23) generates an MLL-AF4 fusion product. Proc Natl Acad Sci U S A 90:7884-7888, 1993
18.
Morrissey J, Tkachuk DC, Milatovich A, et al: A serine/proline-rich protein is fused to HRX in t(4;11) acute leukemias. Blood 81:1124-1131, 1993
19.
Thirman MJ, Levitan DA, Kobayashi H, et al: Cloning of ELL, a gene that fuses to MLL in a t(11;19)(q23; p13.1) in acute myeloid leukemia. Proc Natl Acad Sci U S A 91:12110-12114, 1994
20.
Mitani K, Kanda Y, Ogawa S, et al: Cloning of several species of MLL/MEN chimeric cDNAs in myeloid leukemia with t(11;19)(q23;p13.1) translocation. Blood 85:2017-2024, 1995
21.
Akao Y, Seto M, Takahashi T, et al: Rearrangements on chromosome 11q23 in hematopoietic tumor-associated t(11;14) and t(11;19) translocations. Cancer Res 51:6708-6711, 1991
22.
Rubnitz JE, Morrissey J, Savage PA, et al: ENL, the gene fused with HRX in t(11;19) leukemias, encodes a nuclear protein with transcriptional activation potential in lymphoid and myeloid cells. Blood 84:1747-1752, 1994 23. Lavau C, Szilvassy SJ, Slany R, et al: Immortalization and leukemic transformation of a myelomonocytic precursor by retrovirally transduced HRX-ENL. EMBO J 16:4226-4237, 1997[Medline]
24.
So CW Caldas C, Liu MM, et al: EEN encodes for a member of a new family of proteins containing an Src homology 3 domain and is the third gene located on chromosome 19p13 that fuses to MLL in human leukemia. Proc Natl Acad Sci U S A 94:2563-2568, 1997
25.
Rubnitz JE, Behm FG, Curcio-Brint AM, et al: Molecular analysis of t(11;19) breakpoints in childhood acute leukemias. Blood 87:4804-4808, 1996 26. Huret JL, Brizard A, Slater R, et al: Cytogenetic heterogeneity in t(11;19) acute leukemia: Clinical, hematological and cytogenetic analy-ses of 48 patients—updated published cases and 16 new observations. Leukemia 7:152-160, 1993[Medline] 27. Moorman AV, Hagemeijer A, Charrin C, et al: The translocations, t(11;19)(q23;p13.1) and t(11;19)(q23;p13.3): A cytogenetic and clinical profile of 53 patients. Leukemia 12:805-810, 1998[Medline] 28. Williams DL, Harris S, Williams KJ, et al: A direct bone marrow chromosome technique for acute lymphoblastic leukemia. Cancer Genet Cytogenet 13:239-257, 1984[Medline] 29. Borowitz MJ, Shuster JJ, Civin CI, et al: Prognostic significance of CD34 expression in childhood B-precursor acute lymphocytic leukemia: A Pediatric Oncology Group study. J Clin Oncol 8:1389-1398, 1990[Abstract]
30.
Crist WM, Carroll AJ, Shuster JJ, et al: Poor prognosis of children with pre-B acute lymphoblastic leukemia is associated with the t(1;19)(q23;p13): A Pediatric Oncology Group study. Blood 76:117-122, 1990 31. Kaplan EL, Meier P: Non-parametric estimation for incomplete observations. Am Stat Assoc 53:457-481, 1958 32. Peto R, Pike MC, Armitage P, et al: Design and analysis of randomized clinical trials requiring prolonged observation of each patient: II. Analysis and examples. Br J Cancer 35:1-39, 1977[Medline]
33.
Pui CH, Frankel LS, Carroll AJ, et al: Clinical characteristics and treatment outcome of childhood acute lymphoblastic leukemia with the t(4;11)(q21;q23): A collaborative study of 40 cases [see comments]. Blood 77:440-447, 1991
34.
Heerema NA, Arthur DC, Sather H, et al: Cytogenetic features of infants less than 12 months of age at diagnosis of acute lymphoblastic leukemia: Impact of the 11q23 breakpoint on outcome—A Report of the Childrens Cancer Group. Blood 83:2274-2284, 1994
35.
Pui C-H, Carroll AJ, Raimondi SC, et al: Childhood acute lymphoblastic leukemia with the t(4;11)(q21;q23): An update. Blood 83:2384-2385, 1994 36. Johansson B, Moorman AV, Haas OA, et al: Hematologic malignancies with t(4;11)(q21;q23)—a cytogenetic, morphologic, immunophenotypic and clinical study of 183 cases. Leukemia 12:779-787, 1998[Medline]
37.
Uckun FM, Steinherz PG, Sather H, et al: CD2 antigen expression on leukemic cells as a predictor of event-free survival after chemotherapy for T-lineage acute lymphoblastic leukemia: A Children's Cancer Group study. Blood 88:4288-4295, 1996
38.
Pui CH, Behm FG, Singh B, et al: Heterogeneity of presenting features and their relation to treatment outcome in 120 children with T-cell acute lymphoblastic leukemia. Blood 75:174-179, 1990
39.
Shuster JJ, Falletta JM, Pullen DJ, et al: Prognostic factors in childhood T-cell acute lymphoblastic leukemia: A Pediatric Oncology Group study. Blood 75:166-173, 1990 40. Pui CH, Rivera GK, Hancock ML, et al: Clinical significance of CD10 expression in childhood acute lymphoblastic leukemia. Leukemia 7:35-40, 1993[Medline]
41.
Pui CH, Behm FG, Crist WM: Clinical and biologic relevance of immunologic marker studies in childhood acute lymphoblastic leukemia. Blood 82:343-362, 1993 Submitted July 15, 1998; accepted October 5, 1998.
This article has been cited by other articles:
|
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
|
|||||||||||
|
|||||||||||
|
|
Copyright © 1999 by the American Society of Clinical Oncology, Online ISSN: 1527-7755. Print ISSN: 0732-183X
|
TOP
ABSTRACT
INTRODUCTION
