Pathologic Features of Down Syndrome Myelodysplastic Syndrome and Acute Myeloid Leukemia: A Report From the Children's Oncology Group Protocol AAML0431

CONTEXT.—

Detailed diagnostic features of acute myeloid leukemia in Down syndrome are lacking, leading to potential misdiagnoses as standard acute myeloid leukemia occurring in patients with Down syndrome.

OBJECTIVE.—

To evaluate diagnostic features of acute myeloid leukemia and myelodysplastic syndrome in patients with Down syndrome.

DESIGN.—

Diagnostic bone marrow samples from 163 patients enrolled in the Children's Oncology Group study AAML0431 were evaluated by using central morphologic review and institutional immunophenotyping. Results were compared to overall survival, event-free survival, GATA1 mutation status, cytogenetics, and minimal residual disease results.

RESULTS.—

Sixty myelodysplastic syndrome and 103 acute myeloid leukemia samples were reviewed. Both had distinctive features compared to those of patients without Down syndrome. They showed megakaryocytic and erythroid but little myeloid dysplasia, and marked megakaryocytic hyperplasia with unusual megakaryocyte morphology. In acute myeloid leukemia cases, megakaryoblastic differentiation of blasts was most common (54 of 103, 52%); other cases showed erythroblastic (11 of 103, 11%), mixed erythroid/megakaryoblastic (20 of 103, 19%), or no differentiation (10 of 103, 10%). Myelodysplastic syndrome and acute myeloid leukemia cases had similar event-free survival and overall survival. Leukemic subgroups showed interesting, but not statistically significant, trends for survival and minimal residual disease. Cases with institutional diagnoses of French American British M1-5 morphology showed typical features of Down syndrome disease, with survival approaching that of other cases.

CONCLUSIONS.—

Myelodysplastic syndrome and acute myeloid leukemia in Down syndrome display features that allow discrimination from standard cases of disease. These distinctions are important for treatment decisions, and for understanding disease pathogenesis. We propose specific diagnostic criteria for Down syndrome-related subtypes of acute myeloid leukemia and myelodysplastic syndrome.

Data-Driven Iterative Refinement of Bone Marrow Testing Protocols Leads to Progressive Improvement in Cytogenetic and Molecular Test Utilization

OBJECTIVES

To determine the effect of iterative refinement of standard ordering protocols on test utilization and results for bone marrow biopsy specimens.

METHODS

Eighteen months of test utilization and result data were used to revise the protocols that determine cytogenetic and molecular test selection on bone marrow specimens and then compared with data obtained following protocol revision.

RESULTS

Revision of protocols resulted in reduction in total tests and associated charges, due to a decrease in tests both concordant and discordant with the protocols. These reductions only occurred in diseases for which revisions were made and were limited to cases in which reflex testing was performed. There was an increase in the fraction of positive tests, which was also limited to reflex testing.

CONCLUSIONS

Data-driven iterative revision of protocols further improves test utilization and performance, while reducing cost. Analysis of testing data can be used to continuously improve test ordering decisions.

Quantitative assessment of myeloid nuclear differentiation antigen distinguishes myelodysplastic syndrome from normal bone marrow

By using flow cytometry, we analyzed myeloid nuclear differentiation antigen (MNDA) expression in myeloid precursors in bone marrow from patients with myelodysplastic syndrome (MDS) and control samples from patients undergoing orthopedic procedures. The median percentage of MNDA-dim myeloid precursors in MDS cases was 67.4% (range, 0.7%-97.5%; interquartile range, 44.9%-82.7%) of myeloid cells, with bimodal MNDA expression in most MDS samples. Control samples demonstrated a median MNDA-dim percentage in myeloid precursors of 1.2% (range, 0.2%-13.7%; interquartile range, 0.6%-2.7%), with no bimodal pattern in most samples. The area under the receiver operating characteristic curve for MNDA-dim percentage in myeloid precursors was 0.96 (P = 9 × 10(-7)). Correlation of MNDA-dim levels with World Health Organization 2008 morphologic diagnoses was not significant (P = .21), but correlation with patient International Prognostic Scoring System scores suggested a trend (P = .07). Flow cytometric assessment of MNDA in myeloid precursors in bone marrow may be useful for the diagnosis of MDS.

PCR detection of Histoplasma capsulatum var. capsulatum in whole blood of a renal transplant patient with disseminated histoplasmosis

We report the identification of Histoplasma capsulatum var. capsulatum from whole blood in a renal transplant patient with disseminated histoplasmosis using colorimetric microtiter-plate PCR. This modality demonstrated utility in reaching a definitive diagnosis in a timely manner. Blood fungal cultures in this case remained negative, suggesting that molecular assays may facilitate the laboratory diagnosis of disseminated histoplasmosis.

Phase II evaluation of an intensified induction therapy with standard daunomycin and cytarabine followed by high dose cytarabine for adults with previously untreated acute myeloid leukemia: a Southwest Oncology Group study (SWOG-9500)

Induction therapy for acute myeloid leukemia (AML) usually consists of 7 days of cytarabine at 100-200 mg/m(2)/day and an anthracycline. Such combinations produce complete response (CR) rates of 60-80% in patients with de novo AML. On the basis of a previous report, suggesting a higher CR rate using a regimen of standard daunomycin and cytarabine followed by 3 days of high-dose cytarabine (HDAC), 101 eligible patients received this regimen in a phase II trial. Sixty patients [59%, 95% confidence interval (CI) 49-69%] achieved a CR, and 10 patients died of infection during induction. Although cytogenetic risk group affected overall survival (P = 0.0016) and relapse-free survival (P = 0.0043), it had no impact on CR rate (P = 0.63). Patients received postremission therapy with repetitive courses of alternate day high-dose cytarabine; this was associated with considerable toxicity and the majority of patients could not receive all of the scheduled postremission therapy. The estimated median survival was 23 months (95% CI 15-34 months), and the estimated probability of surviving 5 years was 34% (95% CI 24-43%). The results of this intensive induction regimen were similar to that seen in previous trials and were not as promising as reported in the previous pilot study.

Dysregulated human myeloid nuclear differentiation antigen expression in myelodysplastic syndromes: evidence for a role in apoptosis

Reduced levels of human myeloid nuclear differentiation antigen (MNDA) gene transcripts have been detected in both familial and sporadic cases of myelodysplastic syndromes (MDS). Numerous reports implicate elevated apoptosis/programmed cell death and death ligands and their receptors in the pathogenesis of MDS. MNDA and related proteins contain the pyrin domain that functions in signaling associated with programmed cell death and inflammation. We tested the hypothesis that MNDA is involved in the regulation of programmed cell death in human myeloid hematopoietic cells. Clones of K562 cells (MNDA-null) that expressed ectopic MNDA protein were established using retroviral transduction. MNDA-expressing K562 clones were resistant to tumor necrosis factor-related apoptosis inducing ligand (TRAIL)-induced apoptosis, but were not protected from programmed cell death induced with genotoxic agents or H(2)O(2). MNDA protein expression assessed in control and intermediate and high-grade MDS marrows showed several patterns of aberrant reduced MNDA. These variable patterns of dysregulated MNDA expression may relate to the variable pathophysiology of MDS. We propose that MNDA has a role regulating programmed cell death in myeloid progenitor cells, and that its down-regulation in MDS is related to granulocyte-macrophage progenitor cell sensitivity to TRAIL-induced programmed cell death.

Age and acute myeloid leukemia

We conducted a retrospective analysis of 968 adults with acute myeloid leukemia (AML) on 5 recent Southwest Oncology Group trials to understand how the nature of AML changes with age. Older study patients with AML presented with poorer performance status, lower white blood cell counts, and a lower percentage of marrow blasts. Multidrug resistance was found in 33% of AMLs in patients younger than age 56 compared with 57% in patients older than 75. The percentage of patients with favorable cytogenetics dropped from 17% in those younger than age 56 to 4% in those older than 75. In contrast, the proportion of patients with unfavorable cytogenetics increased from 35% in those younger than age 56 to 51% in patients older than 75. Particularly striking were the increases in abnormalities of chromosomes 5, 7, and 17 among the elderly. The increased incidence of unfavorable cytogenetics contributed to their poorer outcome, and, within each cytogenetic risk group, treatment outcome deteriorated markedly with age. Finally, the combination of a poor performance status and advanced age identified a group of patients with a very high likelihood of dying within 30 days of initiating induction therapy. The distinct biology and clinical responses seen argue for age-specific assessments when evaluating therapies for AML.

Overexpression of GSTA2 protects against cell cycle arrest and apoptosis induced by the DNA inter-strand crosslinking nitrogen mustard, mechlorethamine

The effectiveness of bifunctional alkylating nitrogen mustard compounds in chemotherapy is related to their ability to form DNA inter-strand crosslinks. Patients exposed to DNA inter-strand crosslinking (ICL) agents subsequently experience an elevated incidence of myelodysplastic syndromes (MDS) and MDS related acute myeloid leukemia. Fanconi's anemia (FA) patients are deficient in the repair of crosslink DNA damage and they experience a high incidence of MDS. These observations indicate that hematopoietic cells are specific target for the transforming effects of DNA crosslinking damage. Changes in transcript levels were characterized in human hematopoietic cells occurring in response to the nitrogen mustard, mechlorethamine (HN2), but not in response to monofunctional analogs. Only modest changes in a few gene transcripts were detected in HL60 cells exposed to levels of HN2 tittered to maximal dose that caused growth suppression with minimal cell death and allowed eventual resumption of normal cell growth. Under conditions of transient growth suppression, a subset of glutathione-S-transferase (GST) isoenzyme genes was consistently upregulated three to fourfold by HN2, but not by monofunctional analogs. Subsequent efforts to confirm the changes detected by microarray analyses revealed an unexpected dependence on treatment conditions. The GST alpha class A2 subfamily member transcripts were upregulated 24 h after a 1 h exposure to HN2 that caused an extensive, but transient block in late S/G2 cell cycle phase, but were minimally altered with continuous exposure. The 1-h exposure to HN2 caused a transient late S/G2 cell cycle arrest in both the HL-60 cell line and the Colo 320HSR human colon cancer cell line. Overexpression of GSTA2 by transient transfection protected Colo 320HSR cells against both cycle arrest and apoptosis following exposure to HN2. Overexpression of GSTA2 in Colo 320HSR cells induced after exposure to HN2 did not alter cycle arrest or apoptosis. The results indicate that human GSTA2 facilitates the protection of cells from HN2 damage and not repair. Our results are consistent with the possibility that GSTA2 polymorphisms, variable isoenzyme expression, and variable induced expression may be factors in the pathogenesis of MDS.

Randomized use of cyclosporin A (CsA) to modulate P-glycoprotein in children with AML in remission: Pediatric Oncology Group Study 9421

Relapse is a major obstacle in the cure of acute myeloid leukemia (AML). The Pediatric Oncology Group AML Study 9421 tested 2 different strategies to improve event-free survival (EFS) and overall survival (OS). Patients were randomized to receive standard-dose DAT (daunorubicin, cytarabine, and thioguanine) or high-dose DAT during induction. To interfere with P-glycoprotein (P-gp)-dependent drug efflux, the second randomization tested the benefit of cyclosporine (CsA) added to consolidation chemotherapy. Of the 282 children randomly assigned to receive standard DAT induction, 248 (87.9%) achieved remission compared to 253 (91%) of the 278 receiving high-dose DAT (P = ns). Children with HLA-identical sibling donors who achieved a complete remission received an allogeneic bone marrow transplant as consolidation. For the 83 patients receiving a matched related donor bone marrow transplantation (BMT), the 3-year disease-free survival (DFS) is 67%. Of the 418 children who achieved remission and went on to consolidation with and without CsA, the DFS was 40.6% and 33.9%, respectively (P = .24). Overexpression of P-gp was infrequent (14%) in this pediatric population. In this study, intensifying induction with high-dose DAT and the addition of CsA to consolidation chemotherapy did not prolong the durations of remission or improve overall survival for children with AML.

S100P is selectively upregulated in tumor cell lines challenged with DNA cross-linking agents

Bifunctional alkylating agents that cross-link DNA are implicated in the pathogenesis of therapy related myelodysplastic syndromes (MDS) and MDS related acute myeloid leukemia (MDR-AML). We exposed HL60 cells to the highest level of bifunctional alkylating nitrogen mustard mechlorethamine (HN2) that was consistent with recovery following suppressed growth. Microarray analyses showed minor changes in transcripts in HN2 treated cells. A moderate up-regulation of S100P mRNA was consistently observed after 1 day of exposure to bifunctional alkylating agents and expression was not induced with monofunctional agents. Elevated S100P protein/antigen was not detected until days later in a subset of non-mitotic G2 cells. Elevated S100P protein persisted over the course of a delayed recovery phase. The results confirm recent reports indicating that S100P is a survival factor. In addition, our results indicate that S100P has a specific role in G2 cell function associated with a prolonged phase of recovery after exposure to bifunctional alkylating agents.

Cyclophosphamide followed by fludarabine for untreated chronic lymphocytic leukemia: a phase II SWOG TRIAL 9706

B-cell chronic lymphocytic leukemia (CLL) accounts for 95% of chronic leukemia cases and 25% of all leukemia. Despite the prevalence of CLL, progress in its treatment has been only modest over the past three decades. Based upon the ability of fludarabine to produce high-grade remissions especially among patients with low initial tumor mass, and the ability of alkylators to reduce tumor mass, we hypothesized that sequential administration of a limited number of cycles of intermediate-dose cyclophosphamide followed by fludarabine could result in a larger percentage of patients with complete remissions (CRs). In all, 27 of the 49 eligible patients achieved overall responses of CR, unconfirmed complete remission (UCR), or PR, for a total response rate of 55% (95% confidence interval (CI) 40-69%). Considering the confounding medical issues of this patient population with advanced aggressive disease, the regimen was generally well tolerated. This study demonstrates that high-dose cyclophosphamide followed by fludarabine was relatively well tolerated in this group of advanced CLL patients. The study's criterion for testing whether the regimen is sufficiently effective to warrant further investigation was met: 14 (32%) of the first 44 eligible patients achieved CR or UCR.

Pulmonary hypertension complicating bone marrow transplantation for idiopathic myelofibrosis

Idiopathic myelofibrosis is a rare hematologic disorder that is occasionally associated with pulmonary hypertension and has been cured with bone marrow transplantation (BMT). Most cases occur in older adults, but children with similar clinical and pathologic findings have been described. The authors describe a critically ill male infant with idiopathic myelofibrosis and subtle findings suggestive of pulmonary hypertension who was treated with BMT after failing to respond to chemotherapy. After BMT, the patient's clinical course improved in all respects, but he ultimately died of progressive pulmonary hypertension.

Revised recommendations of the International Working Group for Diagnosis, Standardization of Response Criteria, Treatment Outcomes, and Reporting Standards for Therapeutic Trials in Acute Myeloid Leukemia

An International Working Group met to revise the diagnostic and response criteria for acute myelogenous leukemia originally published in 1990, as well as to provide definitions of outcomes and reporting standards to improve interpretability of data and comparisons among trials. Since the original publication, there have been major advances in our understanding of the biology and molecular genetics of acute leukemia that are clinically relevant and warrant incorporation into response definitions. Differences from the 1990 recommendations included a category of leukemia-free state, new criteria for complete remission, including cytogenetic and molecular remissions and remission duration. Storage of viable blasts for correlative studies is important for future progress in the therapy of these disorders.

A pediatric approach to the WHO classification of myelodysplastic and myeloproliferative diseases

Myelodysplastic and myeloproliferative disorders are rare in childhood and there is no widely accepted system for their diagnosis and classification. We propose minimal diagnostic criteria and a simple classification scheme which, while based on accepted morphological features and conforming with the recent suggestions of the WHO, allows for the special problems of myelodysplastic diseases in children. The classification recognizes three major diagnostic groups: (1) juvenile myelomonocytic leukemia (JMML), previously named chronic myelomonocytic leukemia (CMML) or juvenile chronic myeloid leukemia (JCML); (2) myeloid leukemia of Down syndrome, a disease with distinct clinical and biological features, encompassing both MDS and AML occurring in Down syndrome; and (3) MDS occurring both de novo and as a complication of previous therapy or pre-existing bone marrow disorder (secondary MDS). The main subtypes of MDS are refractory cytopenia (RC) and refractory anemia with excess of blasts (RAEB). It is suggested retaining the subtype of RAEB-T with 20-30% blasts in the marrow until more data are available. Cytogenetics and serial assessments of the patients are essential adjuncts to morphology both in diagnosis and classification.

Retroviral mediated expression of the human myeloid nuclear antigen in a null cell line upregulates Dlk1 expression

The human myeloid nuclear differentiation antigen (MNDA) is a hematopoietic cell specific nuclear protein. MNDA and other related gene products interact with and alter the activity of a large number of proteins involved in regulating specific gene transcription. MNDA and related genes exhibit expression characteristics, which suggest functions unique to specific lineages of cells, in addition to mediating the effects of interferons. Cells of the human K562 myeloid line do not express MNDA and are relatively immature compared to lines that express MNDA (HL-60, U937, and THP1). The hypothesis that MNDA influences the expression of specific genes was tested by creating MNDA expressing K562 cells using stable retroviral mediated gene transfer followed by evaluation of transcription profiles. Two macroarrays containing a total of 2,350 cDNAs of known genes showed a specific up-regulation of Dlk1 expression in MNDA expressing K562 cell clones. Real time quantitative RT-PCR analysis confirmed an average of over 3- and 7-fold upregulation of Dlk1 in two clones of MNDA expressing K562 cells. The effects on Dlk1 were also confirmed by Northern blotting. Dlk1 is essential for normal hematopoiesis and abnormal expression is a proposed marker of myelodysplastic syndrome. Additional screening of transcription profiles after induced erythroid and megakaryoblastic differentiation showed no additional gene transcripts altered by the presence of MNDA. These results indicate that MNDA alters expression of a gene essential for normal hematopoiesis.

Cyclosporine inhibition of P-glycoprotein in chronic myeloid leukemia blast phase

Chronic myeloid leukemia blast phase (CML-BP) cells commonly express the multidrug transporter, P-glycoprotein (Pgp). To determine whether Pgp inhibition improves treatment outcome in CML-BP, the Southwest Oncology Group performed a randomized, controlled trial testing the benefit of the Pgp modulator, cyclosporin A (CsA). Seventy-three eligible patients were assigned to treatment with cytarabine and infusional daunorubicin with or without intravenous CsA. Treatment with CsA yielded no improvement in treatment outcome as measured by the frequency of induction resistance (68% vs 53%), rate of complete remission or restored chronic phase (CR/CP, 8% vs 30%), and survival (3 vs 5 months). Blast expression of Pgp (63%) and LRP (71%) was common, whereas only Pgp adversely impacted the rate of CR/CP (P =.025). We conclude that Pgp has prognostic relevance in CML-BP but that the modulation of Pgp function with CsA as applied in this trial is ineffective.

Aberrant p16(INK4A) and DPC4/Smad4 expression in intraductal papillary mucinous tumours of the pancreas is associated with invasive ductal adenocarcinoma

BACKGROUND AND AIMS

Intraductal papillary mucinous tumours (IPMT) of the pancreas constitute a unique pathological entity with an overall incidence of associated invasive malignancy of 20%. The malignant potential of an individual IPMT cannot be accurately predicted. Preoperative estimation of the risk of associated invasive malignancy with IPMT would be of significant clinical benefit. As aberrations in cell cycle regulatory genes are associated with the progression of precursor pancreatic ductal lesions to invasive adenocarcinoma, we examined expression of key cell cycle regulatory genes in the cyclin D1/retinoblastoma pathway and the transforming growth factor beta/Smad4 signalling pathway in a cohort of patients with surgically resected IPMT.

METHODS

Sections of formalin fixed paraffin embedded pancreatic tissue from a cohort of 18 patients with IPMT were examined using immunohistochemistry for protein expression of cell cycle regulatory genes p16(INK4A), p21(CIP1), p27(KIP1), cyclin D1, pRb, and p53, as well as the cell signalling molecule Smad4. A comparison of expression levels was made between adenoma/borderline IPMT (10 patients) and intraductal papillary mucinous carcinoma (IPMC) (eight patients, four of whom harboured invasive carcinoma). Statistical analysis was performed using the chi(2) and Fisher's exact tests.

RESULTS

Aberrant expression of the proteins examined increased in frequency from adenoma/borderline IPMT to IPMC. Specifically, there was a significantly greater incidence of loss of p16(INK4A) expression in IPMC: 8/8 lesions (100%) compared with 1/10 (10%) adenoma/borderline IPMT (p<0.001). Similarly, loss of Smad4 expression was associated with IPMC: 3/8 (38%) versus adenoma/borderline IPMT 0/10 (p<0.03). Loss of Smad4 expression within the IPMT was the best marker for the presence of invasive carcinoma (p<0.001).

CONCLUSIONS

These data indicate that loss of p16(INK4A) and Smad4 expression occur more frequently in IPMC alone, or with associated invasive carcinoma, compared with adenoma/borderline IPMT. Aberrant protein expression of these cell cycle regulatory genes in IPMT and pancreatic intraepithelial neoplasia in the current model of pancreatic cancer progression suggest similarities in their development and may also represent the subsequent risk of invasive carcinoma.

11q23 balanced chromosome aberrations in treatment-related myelodysplastic syndromes and acute leukemia: report from an international workshop

Among 511 patients with therapy-related myelodysplastic syndrome or acute leukemia (t-MDS/t-AL) and balanced chromosome aberrations, 162 (32%) had translocations involving 11q23. The recurring translocation partners were 9p22 (48%), 19p13.3 (11%), 19p13.1 (10%), 4q21 (9%), 6q27 (6%), 1p32 (2%), 16p13.1 (2%), 10p13 (1%), and 17q25 (1%); in 9%, the translocations were seen only once. The remaining 349 patients were divided into five subgroups based on the balanced aberration: 21q22, inv(16), t(15;17), Rare, and Unique aberrations. Patients in the 11q23 subgroup had a sole cytogenetic abnormality more often than those in the 21q22, inv(16), Rare, and Unique subgroups, and a complex karyotype or -5/del(5q) and/or -7/del(7q) less often than patients in the 21q22, Rare, and Unique subgroups. Clinically, 11q23 patients had acute lymphoblastic leukemia (ALL) more often as their primary disease and a shorter latency from start of treatment for the primary disease to their t-MDS/t-AL diagnosis, except when compared with the inv(16) subgroup. The 11q23 subgroup demonstrated a younger age at t-MDS/t-AL diagnosis, but this finding was not significant when patients with AL as their primary diagnosis were excluded. Survival from the time of diagnosis of t-MDS/t-AL was significantly shorter for the 11q23 subgroup compared with that of the 21q22, inv(16), and t(15;17) subgroups (median 8 vs. 14, 28, and 29 months, respectively). Inferior survival occurred even though 11q23 patients were younger and more often received blood or marrow transplantation (BMT). Even among patients receiving BMT, 11q23 patients had a shorter median survival (9 vs. 12-31 months for the other subgroups). However, among 11q23 patients, those receiving BMT survived longer, with 1- and 5-year survivals of 43% and 18% compared with 23% and 7% for patients not transplanted. With regard to prior therapy, 11q23 patients, compared with other patients, received radiotherapy less often as their sole therapy and chemotherapy more often. They had received VP16, methotrexate, 6MP/6TG, L-asparaginase, daunorubicin, cytarabine, and VM26 more often, likely attributed to the high frequency of AL as their primary disease. More patients in the 11q23 subgroup had received doxorubicin, except in comparison with the 21q22 subgroup; more vincristine, except in comparison with the Rare and Unique subgroups; and more prednisone, except in comparison with the Unique subgroup. Patients in the 11q23 subgroup more often received alkylating agents (AAs) (86% vs. 59-82% for the other subgroups), and topoisomerase II inhibitors (TIs) (84% vs. 49-75%), and they more often reported exposure to AAs plus TIs without radiotherapy (33% vs. 12-21%), except in comparison with the 21q22 subgroup (36%). We performed a multivariate analysis to determine whether the adverse survival of 11q23 patients compared to other Workshop patients was explained by factors other than the presence of the 11q23 abnormality. Covariates in the final model were the five cytogenetic subgroup indicators, where the 11q23 subgroup was the referent (P < 0.0001); age at t-MDS/t-AL (P = 0.0036); previous exposure to lomustine (P < 0.0001) and mitoxantrone (P = 0.0225); BMT for t-MDS/t-AL (P = 0.0006); and karyotype complexity (P = 0.0114). The risk of death for 11q23 patients relative to patients in the 21q22, inv(16), t(15;17), and Unique subgroups was significant, even after adjustment for other risk factors (relative risks 2.3, 3.6, 3.1, and 1.5, respectively; P < 0.0001 for the first three comparisons and P = 0.0125 for the last). When a multivariable model was constructed, excluding patients with AL or MDS as their primary diagnosis, the relative risk of death for 11q23 patients was significantly higher than that of all five other cytogenetic subgroups. We conclude that among t-MDS/t-AL patients with balanced aberrations, 11q23 translocations are an independent adverse risk factor. Although BMT is the current therapy of choice, new treatment is required.

Proposed changes in the definitions of acute myeloid leukemia and myelodysplastic syndrome: are they helpful?

For most of the 20th century, subclassification of acute myeloid leukemia (AML) was based on the resemblance of blasts to normal hematopoiesis. This approach was standardized by the French-American-British (FAB) group. Because of limited clinical relevance, clinicians resorted to other patient characteristics to determine treatment and predict outcome in AML. A different approach based on the relationship of a case to myelodysplastic syndrome (MDS) has been proposed. The new World Health Organization (WHO) subclassification of AML includes elements of this new proposal but retains as a major category the historical subclassification. The WHO group has also proposed modifications of the FAB subclassification of MDS. These MDS proposals have generated discussion of diagnostic criteria for MDS and a philosophical discussion of whether MDS should still be considered a syndrome, or rather a specific set of diseases characterized by genetic instability and poor outcome.

Overexpression of p21(WAF1/CIP1) is an early event in the development of pancreatic intraepithelial neoplasia

Pancreatic cancer (PC) is thought to develop through a series of duct lesions termed pancreatic intraepithelial neoplasia (PanIN). Characterization of the molecular pathology of these lesions may lead to additional understanding of pancreatic ductal carcinogenesis. We examined the protein expression of four functionally related genes, p21(WAF1/CIP1) (CDKN1A), p53, cyclin D1 (CCND1), and DPC4/Smad4 (MADH4), aberrations of which are associated with PC, within 451 PanIN lesions present in the pancreata of 60 patients. p21(WAF1/CIP1) overexpression was present in the normal ducts of 9% of patients and increased progressively to 16% of patients with PanIN-1A lesions, to 32% of patients with PanIN-1B lesions, 56% of patients with PanIN-2 lesions, 80% of patients with PanIN-3 lesions, and 85% of patients with invasive carcinomas (P < 0.01). p53 and cyclin D1 overexpression occurred predominantly in PanIN-3 lesions (P < 0.01), and loss of DPC4/Smad4 expression occurred predominantly in PanIN-3 lesions and invasive carcinoma (P < 0.01). In addition, p21(WAF1/CIP1) overexpression occurred independently of p53 and DPC4/Smad4 expression within invasive carcinoma and PanIN-3 lesions. Cyclin D1 overexpression or loss of DPC4/Smad4 expression was apparent in 85% of invasive carcinomas but in only 14% of PanIN-2 lesions. These data demonstrate that overexpression of p21(WAF1/CIP1) occurs early in the development of PanIN, before aberrations in p53, cyclin D1, and DPC4/Smad4 expression. p21(WAF1/CIP1) overexpression, independent of p53 and/or DPC4/Smad4 expression, may reflect increased Ras activity, either directly through activating K-ras mutations or as a consequence of HER-2/neu (ERBB2) overexpression, both of which are common in PC and in early events in the development of PanIN. These data support further the current progression model for PC and demonstrate that aberrant expression of key cell cycle regulatory genes may be important in the early development and progression of PanIN.

Benefit of cyclosporine modulation of drug resistance in patients with poor-risk acute myeloid leukemia: a Southwest Oncology Group study

Cyclosporine A (CsA) inhibits P-glycoprotein (Pgp)-mediated cellular export of anthracyclines at clinically achievable concentrations. This randomized controlled trial was performed to test the benefit of CsA addition to treatment with cytarabine and daunorubicin (DNR) in patients with poor-risk acute myeloid leukemia (AML). A total of 226 patients were randomly assigned to sequential treatment with cytarabine and infusional DNR with or without intravenous CsA. Remitting patients received one course of consolidation chemotherapy that included DNR with or without CsA as assigned during induction. Addition of CsA significantly reduced the frequency of resistance to induction chemotherapy (31% versus 47%, P =.0077). Whereas the rate of complete remission was not significantly improved (39% versus 33%, P =.14), relapse-free survival (34% versus 9% at 2 years, P =.031) and overall survival (22% versus 12%, P =.046) were significantly increased with CsA. The effect of CsA on survival was greatest in patients with moderate or bright Pgp expression (median 12 months with CsA versus 4 months for controls) compared to patients with absent or low Pgp expression (median 6 months in both arms). The frequency of induction deaths was 15% with CsA and 18% in controls. Steady-state serum concentrations of DNR (P =.0089) and daunorubicinol (P <.0001) were significantly higher in CsA-treated patients. Survival (P =.0003) and induction response (P =.028) improved with increasing DNR concentration in CsA-treated patients but not in controls, suggesting a targeted interaction by CsA to enhance anthracycline cytotoxicity. These results indicate that addition of CsA to an induction and consolidation regimen containing infusional DNR significantly reduces resistance to DNR, prolongs the duration of remission, and improves overall survival in patients with poor-risk AML.

Frequent loss of estrogen receptor-beta expression in prostate cancer

The role of estrogen and its receptors in the etiology and progression of prostate cancer (PC) is poorly understood. In normal and malignant human prostate, estrogen receptor-alpha is expressed only in the stroma, whereas estrogen receptor-beta (ERbeta) is present in both normal stroma and epithelium. Because loss of ERbeta expression is associated with prostate hyperplasia in ERbeta-null mice, this study determined patterns of ERbeta expression in normal, hyperplastic, and malignant human prostate and associations with clinical outcome. Five normal prostates from organ donors and 159 radical prostatectomy specimens from patients with clinically localized PC were assessed for ERbeta expression using immunohistochemistry. ERbeta-positivity was defined as > or =5% of cells demonstrating nuclear immunoreactivity. All of the five normal prostates showed strong ERbeta-nuclear staining in >95% of the epithelium and 35% of the stromal cells. The number of ERbeta-positive cases declined to 24.2% (38/157) in hyperplasia adjacent to carcinoma and 11.3% (18/159) in PCs. ERbeta-positivity was related to decreased relapse-free survival (log-rank P = 0.04). Thus, loss of ERbeta expression is associated with progression from normal prostate epithelium to PC, whereas those cancers that retained ERbeta expression were associated with a higher rate of recurrence. These data identify the need to further investigate the potential role of ERbeta in the regulation of prostate epithelial cell proliferation and the functional consequences of decreased ERbeta expression in the evolution of PC.

Biology and outcome of childhood acute megakaryoblastic leukemia: a single institution's experience

To describe the clinical and biologic features of pediatric acute megakaryoblastic leukemia (AMKL) and to identify prognostic factors, experience at St Jude Children's Research Hospital was reviewed. Of 281 patients with acute myeloid leukemia treated over a 14-year period, 41 (14.6%) had a diagnosis of AMKL. Six patients had Down syndrome and AMKL, 6 had secondary AMKL, and 29 had de novo AMKL. The median age of the 22 boys and 19 girls was 23.9 months (range, 6.7-208.9 months). The rate of remission induction was 60.5%, with a 48% rate of subsequent relapse. Patients with Down syndrome had a significantly higher 2-year event-free survival (EFS) estimate (83%) than did other patients with de novo AMKL (14%) or with secondary AMKL (20%; P < or =.038). Among patients who had de novo AMKL without Down syndrome, 2-year EFS was significantly higher after allogeneic bone marrow transplantation (26%) than after chemotherapy alone (0%; P =.019) and significantly higher when performed during remission (46%) than when performed during persistent disease (0%; P =.019). The 5-year survival estimates were significantly lower for de novo AMKL (10%) than for other forms of de novo AML (42%; P <.001). Treatment outcome is very poor for patients with AMKL in the absence of Down syndrome. Remission induction is the most important prognostic factor. Allogeneic transplantation during remission offers the best chance of cure; in the absence of remission, transplantation offers no advantage over chemotherapy alone. (Blood. 2001;97:3727-3732)

Parvovirus B19 infection in a child with acute lymphoblastic leukemia during induction therapy

Immunocompromised children, including those undergoing chemotherapy treatment of malignant disease, are at particular risk for infection with parvovirus B19. However, these patients' attenuated immune responses may obscure the serologic and clinical manifestations of the infection. The authors describe a patient undergoing induction therapy for acute lymphoblastic leukemia whose parvovirus B19 infection was identified by the incidental detection of giant pronormoblasts and absence of normal mature erythroid precursors, characteristic of parvovirus infection, on a routine bone marrow examination. Intravenous immunoglobulin was administered and the patient's aplastic anemia resolved completely within 3 weeks. This highlights the importance of alertness to the possibility of parvovirus infection in children with cancer.

Experience with 2-chlorodeoxyadenosine in previously untreated children with newly diagnosed acute myeloid leukemia and myelodysplastic diseases

PURPOSE

To develop more effective chemotherapy regimens for childhood acute myelogenous leukemia (AML).

PATIENTS AND METHODS

Between June 1991 and December 1996, we administered the nucleoside analog 2-chlorodeoxyadenosine (2-CDA) to 73 children with primary AML and 20 children with secondary AML or myelodysplastic syndrome (MDS). Patients received one or two 5-day courses of 2-CDA (8.9 mg/m(2)/d) given by continuous infusion. All patients then received one to three courses of daunomycin, cytarabine, and etoposide (DAV) remission induction therapy.

RESULTS

Seventy-two patients with primary AML were assessable for response. Their rate of complete remission (CR) was 24% after one course of 2-CDA, 40% after two courses of 2-CDA, and 78% after DAV therapy. Of the 57 patients who entered CR, 11 subsequently underwent allogeneic bone marrow transplantation (BMT), and 40 underwent autologous BMT. Twenty-nine patients remain in continuous CR after BMT. Two patients remain in CR after chemotherapy only. The 5-year event-free survival (EFS) estimate was 40% (SE = 0.080%). Patients with French-American-British (FAB) M5 AML had a higher rate of CR after treatment with 2-CDA (45% after one course and 70.6% after two courses) than did others (P =.002). In contrast, no patient with FAB M7 AML (n = 10) entered CR after treatment with 2-CDA. Similarly, no patient with primary MDS (n = 6) responded to 2-CDA. Seven patients with secondary AML or MDS (n = 14) had a partial response to one course of 2-CDA.

CONCLUSION

This agent was well tolerated, and its toxicity was acceptable. Future trials should examine the effectiveness of 2-CDA given in combination with other agents effective against AML.

Overexpression of the cell cycle inhibitor p16INK4A in high-grade prostatic intraepithelial neoplasia predicts early relapse in prostate cancer patients

Prostate cancer (PC) is the most commonly diagnosed male cancer in industrialized societies. No molecular markers of PC progression or outcome with proven clinical utility have been described. Because the loss of normal cell cycle control is an early event in the evolution of cancer, we sought to determine whether changes in expression of the cyclin-dependent kinase inhibitor, p16INK4A, predicted outcome in this disease. We screened a cohort of 206 patients with clinically localized PC treated with radical prostatectomy for overexpression of the INK4A gene, the product of which inactivates the G1-phase cyclin dependent kinases, Cdk4 and Cdk6. p16INK4A protein expression was evaluated by immunohistochemistry in areas of high-grade intraepithelial neoplasia (HGPIN), a precursor to invasive disease, and of cancer in the same specimen. Data were evaluated for disease relapse using the Kaplan-Meier method and in a Cox proportional hazards model by assessing p16INK4A status in areas of HGPIN and cancer with other variables of known clinical relevance. Overexpression of p16INK4A in HGPIN and cancer was correlated with, but independent of, pathological stage and was associated with early relapse in PC patients treated with radical prostatectomy (log-rank test, P < 0.001). In a multivariate model adjusted for Gleason grade, pretreatment prostate-specific antigen levels, pathological stage, and margin status, overexpression of p16INK4A in HGPIN was an independent predictor of disease relapse and increased the risk of recurrence 2.24-fold (95% confidence interval, 1.28-3.93). These data provide the first evidence for a prognostic marker in HGPIN. The clinical utility of p16INK4A status in stratifying patients for aggressive treatment very early in the disease process, potentially several years prior to the onset of invasive disease, requires further investigation.

Comparison of the L10M consolidation regimen to an alternative regimen including escalating methotrexate/L-asparaginase for adult acute lymphoblastic leukemia: a Southwest Oncology Group Study

The effectiveness of intensive post-remission chemotherapy regimens for adult patients with acute lymphoblastic leukemia (ALL) is limited by both a high rate of disease recurrence and a substantial incidence of treatment toxicity. To evaluate a potentially more effective and less toxic approach, we conducted a multicenter phase III trial of consolidation therapies comparing the standard L10M regimen with one combining the brief, intensive L17M regimen and escalating methotrexate (MTX) and L-asparaginase (L-asp). Patients over age 15 with previously untreated ALL were eligible. Induction therapy included vincristine, prednisone, doxorubicin, cyclophosphamide and intrathecal methotrexate administered over 36 days. Patients who achieved complete remission (CR) were randomized to receive consolidation with either the L10M regimen or with DAT (daunomycin, cytosine arabinoside, 6-thioguanine) and escalating MTX and L-asp. The randomization was stratified by age, WBC and Ph chromosome status. Maintenance therapy was the same in both arms. Of 353 eligible patients, 218 (62%) achieved CR and 195 were randomized. The treatment arms did not differ significantly with respect to disease-free survival (DFS; P= 0.46) or overall survival (P= 0.39). Estimated DFS at 5 years was 32% (95% confidence interval (CI) 23-42%) in the L10M arm and 25% (95% CI 16-33%) in the DAT/MTX/L-asp arm. In each arm, 4% of patients died of toxicities (infection in all but one case). Infections and nausea/vomiting were somewhat more common in the L10M arm (occurring in 68% and 53% of patients respectively) than the DAT/MTX/L-asp arm (56% and 33%). The DAT/MTX/L-asp consolidation regimen was associated with some reduction in nonfatal toxicities, but no significant improvement in DFS, overall survival or non-relapse mortality when compared to the standard L10M regimen.

Altered expression of androgen receptor in the malignant epithelium and adjacent stroma is associated with early relapse in prostate cancer

The molecular basis of androgen-independent prostate cancer is unknown; however, functional androgen receptor (AR) signaling is maintained after the acquisition of hormone-refractory disease. Because normal and malignant prostate epithelial cell proliferation is regulated by androgen stimulation via both the AR-positive stroma and epithelium, we sought to evaluate patterns of AR expression in these cells and to determine any relationships with prostate cancer progression. AR expression in the malignant epithelium and associated periepithelial and nonperiepithelial stroma was measured in a cohort of 96 patients with clinically localized prostate cancer treated with radical prostatectomy. Data were evaluated for disease relapse using the Kaplan-Meier method and in a Cox proportional hazards model with other variables of known clinical relevance, including Gleason score, pathological stage, clinical stage, and pretreatment prostate-specific antigen concentration. Concurrent overexpression of AR (> or = 70% positive nuclei) in the malignant epithelium and loss of AR immunoreactivity in the adjacent periepithelial stroma (< or = 30%) was associated with higher clinical stage (P = 0.01), higher pretreatment prostate-specific antigen level (P = 0.03), and earlier relapse after radical prostatectomy (log-rank P = 0.009). These data identify a pattern of AR expression in malignant epithelium and adjacent stroma that is associated with a poor clinical outcome in prostate cancer. Equally important, they identify the need to further investigate the mechanistic basis of loss of AR expression in the malignant stroma and its potential role in deregulation of prostate epithelial cell proliferation.

Karyotypic analysis predicts outcome of preremission and postremission therapy in adult acute myeloid leukemia: a Southwest Oncology Group/Eastern Cooperative Oncology Group Study

The associations of cytogenetics with complete remission (CR) rates, overall survival (OS), and outcomes after CR were studied in 609 previously untreated AML patients younger than 56 years old in a clinical trial comparing 3 intensive postremission therapies: intensive chemotherapy, autologous transplantation (ABMT), or allogeneic bone marrow transplantation (alloBMT) from matched related donors. Patients were categorized into favorable, intermediate, unfavorable, and unknown cytogenetic risk groups based on pretreatment karyotypes. CR rates varied significantly (P <.0001) among the 4 groups: favorable, 84% (95% confidence interval [CI], 77%-90%); intermediate, 76% (CI, 71%-81%); unfavorable, 55% (CI, 48%-63%); and unknown, 54% (CI, 33%-74%). There was similar significant heterogeneity of OS (P <.0001), with the estimated relative risk of death from any cause being 1.50 (CI, 1.10-2.05), 3. 33 (CI, 2.43-4.55), and 2.66 (CI, 1.59-4.45) for the intermediate, unfavorable, and unknown risk groups, respectively, compared with the favorable group. In multivariate analyses, the effects of cytogenetic risk status on CR rate and OS could not be explained by other patient or disease characteristics. Among postremission patients, survival from CR varied significantly among favorable, intermediate, and unfavorable groups (P =.0003), with significant evidence of interaction (P =.017) between the effects of treatment and cytogenetic risk status on survival. Patients with favorable cytogenetics did significantly better following ABMT and alloBMT than with chemotherapy alone, whereas patients with unfavorable cytogenetics did better with alloBMT. Cytogenetic risk status is a significant factor in predicting response of AML patients to therapy; however, to tighten treatment correlates within genetically defined AML subsets, a significantly larger leukemia cytogenetic database is warranted.

Hematologic abnormalities and acute myeloid leukemia in children and adolescents administered intensified chemotherapy for the Ewing sarcoma family of tumors

PURPOSE

Current treatment of the Ewing sarcoma family of tumors (ESFT) includes intensive multiagent chemotherapy with topoisomerase II inhibitors, alkylating agents, and granulocyte colony-stimulating factor (G-CSF). This treatment approach has been associated with myelodysplasia and acute myeloid leukemia. Because macrocytosis and thrombocytopenia are distinctive features of myelodysplasia, the authors evaluated a cohort of patients treated for ESFT to determine the degree and duration of macrocytosis and thrombocytopenia and their relation with the development of therapy-related hematologic malignancies.

PATIENTS AND METHODS

The study group consisted of 73 patients with ESFT treated on two consecutive protocols (EW92 and EW87). Both chemotherapy regimens incorporated the same agents but differed in cumulative drug dose, dose per course, and the use of G-CSF. Platelet counts and the mean corpuscular volume (MCV) of erythrocytes were determined at diagnosis and during follow-up visits after completion of treatment.

RESULTS

Patients in the EW92 group had significantly greater MCVs after treatment than did the less intensively treated EW87 group. These changes persisted throughout the 40-month observation period. Patients in the EW92 group also had lesser mean platelet counts after treatment than those in the EW87 group. MCV differences (from baseline) were inversely related to platelet counts. The cumulative incidence of treatment-related acute myeloid leukemia was 7.8%+/-4.7% at 4 years in the EW92 group and zero in the EW87 group.

CONCLUSION

Patients treated for ESFT with intensive chemotherapy that includes large doses of alkylators, topoisomerase II inhibitors, and G-CSF characteristically have persistently elevated MCVs and decreased platelet counts after completion of therapy. These hematologic abnormalities may represent stem cell damage, predisposing patients to myelodysplasia and acute myeloid leukemia, but further study is needed to establish this relation.

A phase I study of induction chemotherapy for older patients with newly diagnosed acute myeloid leukemia (AML) using mitoxantrone, etoposide, and the MDR modulator PSC 833: a southwest oncology group study 9617

Older patients with acute myelogenous leukemia (AML) have overexpression of P-glycoprotein (Pgp+), and this has been shown to correlate quantitatively with therapeutic outcome. Since Pgp-mediated efflux of cytotoxic drugs can be inhibited by the cyclosporine analogue, PSC 833, we investigated the use of this agent with a 5-day mitoxantrone/etoposide regimen in patients over age 55 with newly diagnosed AML. Previous studies suggested a 33% incidence of grade IV/V non-hematologic toxicity with the use of mitoxantrone 10 mg/M(2) and etoposide 100 mg/M(2), each for 5 days, in this patient population. Since PSC 833 alters the pharmacokinetic excretion of MDR-related cytotoxins, this phase I dose-finding study was performed to identify doses of mitoxantrone/etoposide associated with a similar 33% incidence of grade IV/V non-hematologic toxicity, when given with PSC 833. Mitoxantrone/etoposide (M/E) doses were escalated in fixed ratio from a starting dose of M: 4 mg/M(2) and E: 40 mg/M(2), to M: 7 mg/M(2) and E: 70 mg/M(2), in successive cohorts of eight patients each. PSC 833 was well tolerated and the MTD of this M/E regimen with PSC 833 in this population was M: 6 mg/M(2) and E: 60 mg/M(2). The complete response (CR) rate for all patients was 50% (15/30) and was considerably higher for de novo than for secondary AML. These data suggest that the addition of PSC 833 to an M/E regimen for older patients with untreated AML is well tolerated but requires a reduction in M/E dosing to avoid increased toxicity.

Long-term survival of infants with idiopathic myelofibrosis

Idiopathic myelofibrosis can develop in children as well as adults. However, the disease appears to be much more aggressive in adults, being characterized by poor survival rates and a high frequency of malignant transformation. Here, we describe three cases of idiopathic myelofibrosis in infants, two of whom were followed for 16 and 22 years after diagnosis. Neither of these patients required more than minimal supportive care, and both have had spontaneous erythropoietic recovery as early as 2-3 years after diagnosis. There have been no indications of malignant transformation or clinical deterioration. Thus, idiopathic myelofibrosis may have a different pathogenesis and clinical course in infants from adults, requiring a more conservative approach to management.

Prognostic significance of p53 nuclear accumulation in localized prostate cancer treated with radical prostatectomy

The role of p53 in the pathogenesis of, and as a predictive biomarker for, localized prostate cancer (PCa) is contested. Recent work has suggested that patterns of p53 nuclear accumulation determined by immunohistochemistry are prognostic, whereas studies using other methods question the role of p53 mutations in predicting outcome. We studied 263 men with localized PCa treated with radical prostatectomy to determine whether p53 nuclear accumulation predicts relapse and disease-specific mortality. We combined two p53 immunohistochemistry scoring systems: (a) percentage of p53-positive tumor nuclei in all major foci of cancer within the prostate; and (b) clustering, where the presence of 12 or more p53-positive cells within a x 200 power field was deemed "cluster positive." Analysis was undertaken using chi2, Kruskal-Wallis, and Mann-Whitney tests for clinicopathological variables and the Kaplan-Meier method, log-rank test, and univariate and multivariate Cox regression modeling for evaluation of contribution to relapse and disease-specific survival. At mean follow-up of 55.1 months (range, 4.9-123.0 months), 39% (102 of 263) of patients had relapsed and 2.3% (6 of 253) had died of PCa. Pretreatment serum prostate-specific antigen concentration, pathological tumor stage, lymph node involvement, Gleason score, and p53 nuclear accumulation, as determined by either percentage score or cluster status, were independent predictors of relapse in multivariate analysis. Clustering of p53-positive cells distinguished between favorable and poor prognosis patients within the lowest p53-positive stratum (>0 to <2%) and was the most discriminatory threshold for predicting relapse in the entire cohort. p53 status predicted outcome in patients with a Gleason score of 5 and above but not those with a score of 4 and below. In patients treated with neoadjuvant hormonal therapy, p53 cluster positivity carried a 90% (19 of 21) risk of relapse by 36 months. All six patients who died from PCa in the period of the study exhibited p53 nuclear accumulation in 20% or more tumor nuclei. This study demonstrates strong relationships between p53 nuclear accumulation and relapse and disease-specific mortality in a large series of localized PCas. Furthermore, the presence of clusters of p53-positive nuclei delineates a group of patients with poor prognosis not identified by traditional scoring methods and supports the hypothesis that p53 dysfunction within PCa may exist in foci of tumor cells that are clonally expanded in metastases.

A phase II study of high dose ARA-C and mitoxantrone for treatment of relapsed or refractory adult acute lymphoblastic leukemia

PURPOSE

The Southwest Oncology Group performed a Phase II study to investigate the effectiveness of an induction regimen of high dose cytosine arabinoside (ara-C) with high dose mitoxantrone for treatment of relapsed or refractory adult acute lymphoblastic leukemia (ALL).

PATIENTS AND METHODS

Patients at least 16-years-old with ALL that was in relapse after, or was refractory to, standard induction therapy including at least vincristine and prednisone were eligible, as long as they had no prior treatment with high dose ara-C. The induction regimen included high dose ara-C (3 g/m2 by 3-h i.v. days 1-5) and mitoxantrone (80 mg/m2 by 15-30 min i.v. 12-20 h after the first dose of ara-C). The study design called for a maximum of 55 patients, with early termination if less than nine of the first 30 achieved complete remission.

RESULTS

Thirty-three patients entered the study, and 31 were included in the analysis. All 31 completed one course of induction therapy. Four patients died of infection and a fifth of cardiomyopathy with possible sepsis. Seven patients achieved complete remission (23%; 95% confidence interval 10-41%). One of the seven received syngeneic bone marrow transplantation while in remission, and the other six all relapsed within 10 months. All 31 patients died within 25 months after entering the study.

CONCLUSIONS

The regimen of high dose ara-C and mitoxantrone was found to be insufficiently effective to warrant further investigation.

Refractory anemia with ringed sideroblasts in children: two diseases with a similar phenotype?

Three pediatric patients with refractory anemia with ringed sideroblasts (RARS) are presented. Bone marrow aspirates were examined using Romanowsky and Prussian blue iron stains in all three patients, and electron microscopic analysis was performed in one patient. All three patients had cytogenetic analysis of the bone marrow. Other studies included analysis of serum iron, total iron-binding capacity, ferritin, copper, vitamins B6 and B12, and folate levels. Antibody titers to Parvovirus, HIV, and other viruses were measured. The patients had contrasting clinical courses. Patients 1 and 2 had dysplastic hematopoietic features and cytogenetic findings (with either partial or one allele loss of chromosome 7), suggestive of myelodysplastic syndrome. Patient 1 experienced acute myeloid leukemia (AML) and had a good response to AML-directed therapy. Patient 2 had prolonged cytopenias and underwent bone marrow transplantation (BMT). Patient 3 had features suggestive of refractory anemia associated with mitochondrial cytopathy, including normal cytogenetics with pronounced vacuolization of marrow precursors. His anemia regressed spontaneously a few months after diagnosis. These patients represent two subgroups of pediatric RARS. Patients with the myelodysplastic syndrome (MDS) type may progress to cytopenias or leukemia and may require aggressive therapy; the type is characterized by clonal cytogenetic findings. The non-MDS type, which may relate to mitochondrial cytopathy, often shows spontaneous regression and requires only supportive treatment; it has normal cytogenetic findings.

A phase III comparison of high dose ARA-C (HIDAC) versus HIDAC plus mitoxantrone in the treatment of first relapsed or refractory acute myeloid leukemia Southwest Oncology Group Study

The aim of this study is to determine whether the addition of mitoxantrone to high dose cytarabine improves the outcome of treatment in patients with relapsed or refractory acute myeloid leukemia (AML). One hundred and sixty-two eligible patients, 14-76 years of age, with AML either in first relapse or that failed to respond to initial remission induction therapy, with no CNS involvement were randomized to receive therapy with cytarabine 3 gm/M2 i.v. over 2 h every 12 h for 12 doses on days 1-6 (Arm I) (HIDAC); or HIDAC plus mitoxantrone 10 mg/M2 i.v. daily on days 7 9 (Arm II) (HIDAC + M). Patients achieving complete remission were treated with three courses of consolidation including HIDAC (Ara-C 3 gm/M2 i.v. 12 h days 1 3; 2 gm/M2 over age 50) alone (ARM I) or with mitoxantrone (10 mg/M2 i.v. day 1) (ARM II). Among 162 patients (81 HIDAC, 81 HIDAC + M) evaluated for induction toxicity, there were 10 (12%) induction deaths with HIDAC and 13 (17%) with HIDAC + M (2-tailed P = 0.65). Most early deaths were due to infection and/or hemorrhage. Among 162 patients evaluated for responses to induction therapy, 26/81 (32%) HIDAC and 36/81 (44%) HIDAC + M patients achieved complete remission (two-tailed P = 0.15). Although this difference was not statistically significant in univariate analysis, it was after adjusting for the effects of WBC and PMN percentage in multivariate analysis (P=0.013). Median survivals from study entry were 8 months (HIDAC) and 6 months (HIDAC + M); 2-tailed logrank P = 0.58. Among 48 patients registered for consolidation, the median disease-free survivals from that registration were 8 months with HIDAC and 11 months with HIDAC + M (P = 0.60). There were three treatment-related deaths during consolidation (1 HIDAC, 2 HIDAC + M), all due to infections. In this randomized trial, the addition of mitoxantrone to high-dose cytarabine was associated with a trend toward a higher CR rate. There was less evidence for an advantage in disease-free or overall survival, although any such conclusion is limited by the size of the study.

Frequency and clinical significance of the expression of the multidrug resistance proteins MDR1/P-glycoprotein, MRP1, and LRP in acute myeloid leukemia: a Southwest Oncology Group Study

Therapeutic resistance is a major obstacle in the treatment of acute myeloid leukemia (AML). Such resistance has been associated with rapid drug efflux mediated by the multidrug resistance gene 1 (MDR1; encoding P-glycoprotein) and more recently with expression of other novel proteins conferring multidrug resistance such as MRP1 (multidrug resistance-associated protein 1) and LRP (lung resistance protein). To determine the frequency and clinical significance of MDR1, MRP1, and LRP in younger AML patients, we developed multiparameter flow cytometric assays to quantify expression of these proteins in pretreatment leukemic blasts from 352 newly diagnosed AML patients (median age, 44 years) registered to a single clinical trial (SWOG 8600). Protein expression was further correlated with functional efflux by leukemic blasts [assessed using two substrates: Di(OC)(2) and Rhodamine 123] and with the ability of MDR-reversing agents to inhibit efflux in vitro. MDR1/P-glycoprotein expression, which was highly correlated with cyclosporine-inhibited efflux, was noted in only 35% of these younger AML patients, distinctly lower than the frequency of 71% we previously reported in AML in the elderly (Blood 89:3323, 1997). Interestingly, MDR1 expression and functional drug efflux increased with patient age, from a frequency of only 17% in patients less than 35 years old to 39% in patients aged 50 years (P =.010). In contrast, MRP1 was expressed in only 10% of cases and decreased with patient age (P =. 024). LRP was detected in 43% of cases and increased significantly with increasing white blood cell counts (P =.0015). LRP was also marginally associated with favorable cytogenetics (P =.012) and French-American-British (FAB) AML FAB subtypes (P =.013), being particularly frequent in M4/M5 cases. Only MDR1/P-glycoprotein expression and cyclosporine-inhibited efflux were significantly associated with complete remission (CR) rate (P(MDR1) =.012; P(efflux) =.039) and resistant disease (RD; P(MDR1) =.0007; P(efflux) =.0092). No such correlations were observed for MRP1 (P(CR) =.93; P(RD) =.55) or LRP (P(CR) =.50; P(RD) =.53). None of these parameters were associated with overall or relapse-free survival. Unexpectedly, a distinct and nonoverlapping phenotype was detected in 18% of these cases: cyclosporine-resistant efflux not associated with MDR1, MRP1, or LRP expression, implying the existence of other as yet undefined efflux mechanisms in AML. In summary, MDR1 is less frequent in younger AML patients, which may in part explain their better response to therapy. Neither MRP1 nor LRP are significant predictors of outcome in this patient group. Thus, inclusion of MDR1-modulators alone may benefit younger AML patients with MDR1(+) disease.

Human herpesvirus-8 (HHV-8) associated with small non-cleaved cell lymphoma in a child with AIDS

The association of human herpesvirus-8 (HHV-8) with a small non-cleaved cell lymphoma is described in a child with the acquired immunodeficiency syndrome (AIDS) who developed a malignant pleural effusion and radiologic evidence of multiple solid tumors. HHV-8 DNA and Epstein-Barr virus DNA were identified in pleural fluid cells by polymerase chain reaction (PCR) amplification. The serum antibody titer against lytic HHV-8 proteins was 1:640; antibodies to latent HHV-8 proteins were not detected. Cytogenetic analysis of malignant cells revealed three abnormal karyotypes sharing the common finding of a t(8;14) translocation. Rearrangement of c-myc was demonstrated by PCR analysis. Oligoclonal JH immunoglobulin bands were found. Insufficient pleural fluid cells were available to permit localization of HHV-8 to malignant cells by in situ hybridization. This malignancy contrasts with HHV-8-associated lymphomas reported in adult patients with AIDS with respect to cell morphology, c-myc translocation, and oligoclonal immunoglobulin gene rearrangement. HHV-8 is associated with a wider spectrum of malignancies than recognized previously.

Acute lymphoblastic leukemia with the (8;14)(q24;q32) translocation and FAB L3 morphology associated with a B-precursor immunophenotype: the Pediatric Oncology Group experience

Five pediatric patients are described with acute lymphoblastic leukemia (ALL) who at presentation had clinical findings suggestive of B cell ALL and lymphoblasts with FAB L3 morphology and the characteristic t(8;14)(q24;q32). However, the leukemia cells of all five patients failed to express surface immunoglobulin (sIg) and kappa or lambda light chains. Based on initial immunophenotyping results consistent with B-precursor ALL, four of these cases were initially treated with conventional ALL chemotherapy. These four patients were switched to B cell ALL treatment protocols once cytogenetic results became available revealing the 8;14 translocation. The fifth case was treated with B cell ALL therapy from the outset. Four of the five patients are in complete remission at 64, 36, 29 and 13 months from diagnosis. One patient relapsed and died 6 months after initial presentation. These five unusual cases with clinical B cell ALL, the t(8;14), and FAB L3 morphology, but negative sIg, demonstrate the importance of careful and multidisciplinary evaluation of leukemic cells with morphology, cytochemistry, immunophenotyping and cytogenetic analysis. Future identification of patients with this profile will allow us to expand our knowledge regarding prognostic significance and optimal treatment for this rare subgroup of patients.

Chemotherapy compared with autologous or allogeneic bone marrow transplantation in the management of acute myeloid leukemia in first remission

BACKGROUND

In young adults with acute myeloid leukemia, intensive chemotherapy during the initial remission improves the long-term outcome, but the role of bone marrow transplantation is uncertain. We compared high-dose cytarabine with autologous or allogeneic marrow transplantation during the first remission of acute myeloid leukemia.

METHODS

Previously untreated adolescents and adults 16 to 55 years of age who had acute myeloid leukemia received standard induction chemotherapy. After complete remission had been achieved, idarubicin (two days) and cytarabine (five days) were administered. Patients with histocompatible siblings were offered allogeneic marrow transplantation, whereas the remaining patients were randomly assigned to receive a single course of high-dose cytarabine or transplantation of autologous marrow treated with perfosfamide (4-hydroperoxycyclophosphamide). Oral busulfan and intravenous cyclophosphamide were used as preparative regimens for both allogeneic and autologous marrow transplantation. The end points were survival from the time of complete remission and disease-free survival.

RESULTS

In an intention-to-treat analysis, we found no significant differences in disease-free survival among patients receiving high-dose chemotherapy, those undergoing autologous bone marrow transplantation, and those undergoing allogeneic marrow transplantation. The median follow-up was four years. Survival after complete remission was somewhat better after chemotherapy than after autologous marrow transplantation (P=0.05). There was a marginal advantage in terms of overall survival with chemotherapy as compared with allogeneic marrow transplantation (P=0.04).

CONCLUSIONS

A postinduction course of high-dose cytarabine can provide equivalent disease-free survival and somewhat better overall survival than autologous marrow transplantation in adults with acute myeloid leukemia.

Reappraisal of the clinical and biologic significance of myeloid-associated antigen expression in childhood acute lymphoblastic leukemia

PURPOSE

To reassess the clinical and biologic significance of myeloid-associated antigen expression in childhood acute lymphoblastic leukemia (ALL).

PATIENTS AND METHODS

We prospectively studied 334 newly diagnosed cases of this disease, using a comprehensive panel of antibodies that represented five myeloid cluster groups (CD13, CD14, CD15, CD33, and CD65). Blast cells were tested for ETV6 and MLL rearrangement using Southern blot analysis.

RESULTS

CD13 was expressed in 13.7% of cases, CD14 in 1%, CD15 in 6.6%, CD33 in 16%, and CD65 in 9.7%. Approximately one third of cases (31.4%) expressed one or more of these antigens (B-cell precursor, 31.9%; T-cell, 28.8%), while 10.5% expressed two or more (B-cell precursor, 11.3%; T-cell, 6.1%). Among the B-cell precursor leukemias, myeloid-associated antigen expression was significantly associated with a lack of hyperdiploidy and rearrangements of ETV6 or MLL gene. Most of the cases with MLL rearrangements (82%) expressed CD65, CD15, and CD33, either alone or in combination, whereas 48% of those with a rearranged ETV6 gene expressed CD13, CD33, or both. Myeloid-associated antigen expression did not correlate with event-free survival, whether the analysis was based on any of the five antigens in our panel or on the three more commonly tested antigens (CD13, CD33, and CD65). Importantly, this finding was not affected by exclusion of patients with ETV6 or MLL gene rearrangements.

CONCLUSION

Even though blast cell expression of myeloid-associated antigen expression shows significant associations with specific genetic abnormalities, it lacks prognostic value in childhood ALL.

Trisomy 6 as a primary karyotypic aberration in hematologic disorders

We identified seven patients with hematologic disorders and trisomy 6 as the sole karyotypic aberration in bone marrow aspirates or unstimulated peripheral blood. Five patients were male and two were female; all were adults with ages ranging from 22 to 74 years. Three of the seven patients presented with manifestations of peripheral cytopenia. Their bone marrows were hypocellular with slight or no dysplastic changes and without an increase in blasts. One of these patients subsequently developed acute myeloid leukemia (AML-M1). The four remaining patients were initially diagnosed with AML--three consistent with French-American-British classification of M1 and M4 in the fourth patient. These results suggest that trisomy 6 is a nonrandom primary numerical anomaly of myeloid disorders. The association of cytopenia and hypoplastic bone marrow with trisomy 6 may constitute a new, distinctive variant among myelodysplastic syndromes.

Early intensification of intrathecal chemotherapy virtually eliminates central nervous system relapse in children with acute lymphoblastic leukemia

Central nervous system (CNS) relapse has been an obstacle to uniformly successful treatment of childhood acute lymphoblastic leukemia (ALL) for many years. We therefore intensified intrathecal chemotherapy (simultaneously administered methotrexate, hydrocortisone, and cytarabine) for 165 consecutive children with newly diagnosed ALL enrolled in Total Therapy Study XIIIA from December 1991 to August 1994. The 64 patients (39%) who had 1 or more blast cells in cytocentrifuged preparations of cerebrospinal fluid at diagnosis, with or without associated higher-risk features, received additional doses of intrathecal chemotherapy during remission induction and the first year of continuation treatment. Patients with higher-risk leukemia, regardless of cerebrospinal fluid findings, also received additional doses of intrathecal chemotherapy during the first year of continuation treatment. Cranial irradiation was reserved for patients with higher-risk leukemia (22% of the total). The 5-year cumulative risk of an isolated CNS relapse among all 165 patients was 1.2% (95% confidence interval, 0% to 2.9%), whereas that of any CNS relapse was 3.2% (0. 4% to 6.0%). The probability of surviving for 5 years without an adverse event of any type was 80.2% +/- 9.2% (SE). Our results suggest that early intensification of intrathecal chemotherapy will reduce the risk of CNS relapse to a very low level in children with ALL, securing a higher event-free survival rate overall.

A double-blind placebo-controlled trial of granulocyte colony-stimulating factor in elderly patients with previously untreated acute myeloid leukemia: a Southwest oncology group study (9031)

Older age is a poor prognosis factor in acute myeloid leukemia (AML). This double-blind trial was designed to test the hypothesis that granulocyte colony-stimulating factor (G-CSF) used as supportive care could improve the treatment of elderly AML patients. Two hundred thirty-four patients 55 or more years of age with a morphologic diagnosis of de novo or secondary AML, French-American-British (FAB) M0-M7, excluding M3, were randomly assigned to a standard induction regimen (daunorubicin at 45 mg/m2 intravenously [IV] on days 1 through 3 and Ara-C at 200 mg/m2 IV continuous infusion on days 1 through 7) plus either placebo or G-CSF (400 microg/m2 IV over 30 minutes once daily). Results are reported here for 211 centrally confirmed cases of non-M3 AML. The two groups were well balanced in demographic, clinical, and hematological parameters, with median ages of 68 years in the G-CSF and 67 years in the placebo groups. The complete response (CR) rate was not significantly better in the G-CSF group: 50% in the placebo and 41% in the G-CSF group (one-tailed P = .89). Median overall survival was also similar, 9 months (95% confidence interval [CI], 7 to 10 months) in the placebo and 6 months (95% CI, 3 to 8 months) in the G-CSF arms (P = .71). We found a significant 15% reduction in the time to neutrophil recovery in the G-CSF group (P = .014). G-CSF had no impact on recovery from thrombocytopenia (P = .80) or duration of first hospitalization (P = .27). When infection complications were evaluated, G-CSF had a beneficial effect on the duration but not on incidence of infection. G-CSF patients had fewer days with fever and shorter duration of antibiotic use. However, there was no difference in the frequency of total documented infections or in the number of fatal infections (19% placebo v 20% G-CSF). In this study of elderly AML patients, G-CSF improved clinical parameters of duration of neutropenia and antibiotic use, but did not change CR rate or survival or shorten hospitalization.

Characterization and use of an antibody detecting the CBFbeta-SMMHC fusion protein in inv(16)/t(16;16)-associated acute myeloid leukemias

The inv(16)(p13q22) and t(16;16)(p13;q22) cytogenetic abnormalities occur commonly in acute myeloid leukemia (AML), typically associated with French-American-British (FAB) AML-M4Eo subtype. Reverse transcriptase-polymerase chain reaction (RT-PCR) techniques have been recently developed to detect the presence of several variants of the resultant CBFB-MYH11 fusion gene that encodes a CBFbeta-smooth muscle myosin heavy chain (SMMHC) fusion protein. We have now determined the clinical use of a polyclonal antibody [anti-inv(16) Ab] directed against a junctional epitope of the most common type of CBFbeta-SMMHC fusion protein (type A), which is present in 90% of inv(16)/t(16;16) AML cases. Using flow cytometry, reproducible methods were developed for detection of CBFbeta-SMMHC proteins in permeabilized cells; flow cytometric results were then correlated with cytogenetics and RT-PCR detection methods. In an analysis of 42 leukemia cases with various cytogenetic abnormalities and several normal controls, the anti-inv(16) Ab specifically detected all 23 cases that were cytogenetically positive for inv(16) or t(16;16), including a single AML case that was RT-PCR-negative. In addition to detecting all type A fusions, the anti-inv(16) Ab also unexpectedly identified the type C and type D CBFbeta-SMMHC fusion proteins. Molecular characterization of one RT-PCR-positive and Ab-positive t(16;16) case with a non-type A product showed a novel previously unreported CBFB-MYH11 fusion (CBFB nt 455-MYH11 nt 1893). Flow cytometric results were analyzed using the Kolmogorov-Smirnov statistic D-value and the median value for positive samples was 0.65 (range, 0.35 to 0.77) versus 0.07 (range, -0.21 to 0.18) in the negative group (P < .0001). The overall concordance between cytogenetics and RT-PCR was 97%, whereas the concordance between flow cytometry and cytogenetics was 100%. Thus, using the anti-inv(16) Ab, all cytogenetically positive and RT-PCR-positive AML cases with inv(16) or t(16;16) could be rapidly identified. This study demonstrates the use of this antibody as an investigational tool in inv(16)/t(16;16) AML and suggests that the development of such reagents may have potential clinical diagnostic use.

Thrombopoietin level in young patients is related to megakaryocyte frequency and platelet count

PURPOSE

To examine the relationships among platelet counts, bone marrow megakaryocyte frequency, and circulating thrombopoietin (TPO) levels.

PATIENTS AND METHODS

TPO levels in 17 children and one young adult with chronic or recurrent thrombocytopenia were measured by ELISA and megakaryocyte frequency was analyzed by light microscopy. Three groups of patients were studied: Group I patients had aplastic anemia and absent or decreased megakaryocytes; Group II patients had intermittent periods of chemotherapy-induced thrombocytopenia; and Group III patients had normal or increased megakaryocytes. Controls consisted of 77 healthy adults.

RESULTS

Patients in Group I had markedly increased TPO levels compared to normal controls. Their levels were significantly different (p = 0.03) from those of patients in Group III. The latter had normal or only mildly increased TPO levels except for one patient with myelodysplastic syndrome. Patients in Group II had markedly elevated TPO levels. After their bone marrow and platelet counts recovered from chemotherapy, their TPO levels decreased. In all three groups, a transient increase in platelet count (e.g., after platelet transfusion or anti-D immune globulin therapy) was associated with a moderate decrease in TPO.

CONCLUSIONS

From this study, three conclusions can be made: 1) TPO levels are inversely related to megakaryocyte frequency; 2) platelet counts have a modest influence on TPO level; and 3) TPO levels may have clinical utility in diagnosis and management and further our understanding of the pathobiology of the disorders that cause thrombocytopenia.

Myelodysplastic syndrome in children: differentiation from acute myeloid leukemia with a low blast count

To evaluate diagnostic criteria, disease characteristics, and the clinical course of pediatric myelodysplastic syndrome (MDS), we reviewed 327 consecutive cases diagnosed with de novo acute myeloid leukemia (AML) or MDS at St Jude Children's Research Hospital between February 1980 and January 1993. Among 49 cases with <30% marrow blasts (consistent with FAB criteria and common diagnostic practice for MDS), eight had karyotypes associated with de novo AML (four with t(8;21)(q22;q22) and one each with inv(16)(p13q22), t(11;17)(q23;q21), t(9;11)(p22;q13), and i(1)(ql0)). We termed these cases AML with a low blast count (AML-LBC) and compared their clinical and morphologic features with those of the remaining 41 cases. AML-LBC cases had little or no hematopoietic dysplasia. MDS cases consisted of refractory anemia (RA, n=6), RA with ring sideroblasts (n=2), RA with excess blasts (RAEB, n=4), RAEB in transformation (n=14), and chronic myelomonocytic leukemia (n=15). Most had moderate/severe or multilineage hematopoietic dysplasia, with significantly higher dysplasia scores than AML-LBC cases (P=0.007). Only 30% of patients with MDS achieved complete remission (CR) after two cycles of AML-directed therapy, compared with 88% of patients with AML-LBC (P=0.0001); MDS patients tended to experience prolonged severe cytopenias with chemotherapy. The 4-year survival for MDS patients was 23% +/- 7% (s.e.), vs 50% +/- 18% (s.e.) for AML-LBC (P=0.048). AML-LBC patients frequently had chloromas; none were seen in MDS patients. We conclude that the 30% blast threshold is ineffective for separation of AML and MDS in pediatric patients, and that genetic data should be included in this decision process. AML-LBC, defined by <30% blasts in bone marrow and cyto- (or molecular) genetic abnormalities associated with de novo AML, and characterized by absent or mild marrow dysplasia, is biologically and clinically distinct from MDS and should be treated as de novo AML. Outcome in pediatric MDS remains poor, and new treatment strategies are needed for these patients.

Acute myeloid leukemia in the elderly: assessment of multidrug resistance (MDR1) and cytogenetics distinguishes biologic subgroups with remarkably distinct responses to standard chemotherapy. A Southwest Oncology Group study

Compared with younger patients, elderly patients with acute myeloid leukemia (AML) respond poorly to conventional chemotherapy. To determine if this poor response is due to differences in the biologic characteristics of AML in the elderly, we studied 211 patients (161 de novo, 50 secondary AML) over 55 years of age (median, 68 years) registered to a single clinical trial for previously untreated AML (SWOG 9031, Phase III randomized trial of standard dose cytosine arabinoside and daunomycin + rhG-CSF). Pretreatment leukemic blasts were karyotyped and were also analyzed for intrinsic drug resistance by quantitating expression of the multidrug resistance glycoprotein MDR1 and functional drug efflux using sensitive flow cytometric techniques. Results were correlated with clinical variables and outcome. These elderly AML patients had a high frequency of unfavorable cytogenetics (32%), MDR1 protein expression (71%), and functional drug efflux (58%); each of these factors occurred at high frequencies in both de novo and secondary AML patients and was associated with a significantly poorer complete remission (CR) rate. In multivariate analysis, secondary AML (P = .0035), unfavorable cytogenetics (P = .0031), and MDR1 (P = .0041) were each significantly and independently associated with lower CR rates. Resistant disease was associated with unfavorable cytogenetics (P = .017) and MDR1 expression (P = .0007). Strikingly, elderly MDR1(-) de novo AML patients with favorable/intermediate cytogenetics had a CR rate of 81%; with increasing MDR1 expression, CR rate decreased in this cytogenetic group. MDR1(+) secondary AML patients with unfavorable cytogenetics had a CR rate of only 12%. Thus, AML in the elderly is associated with an increased frequency of unfavorable cytogenetics and MDR1 expression, both of which independently contribute to poor outcomes. The high frequencies of these features in both de novo and secondary elderly AML patients suggest a common biologic mechanism for these leukemias distinct from that in younger patients. Investigation of biologic parameters at diagnosis in AML in the elderly may help identify patients with a high likelihood of achieving CR with conventional regimens, as well as those who may require alternate regimens designed to overcome therapy resistance.

TEL gene rearrangement in acute lymphoblastic leukemia: a new genetic marker with prognostic significance

PURPOSE

TEL gene rearrangements due to the 12;21 chromosomal translocation are the most common molecular genetic abnormality in childhood acute lymphoblastic leukemia (ALL), occurring in approximately 25% of cases with a B-precursor immunophenotype. The limited number of clinically useful genetic markers in this leukemia subtype prompted us to assess TEL status as a predictor of treatment outcome.

PATIENTS AND METHODS

We determined the status of the TEL gene (rearranged or germline) in 188 cases of B-precursor acute leukemia using Southern blot analysis and related the findings to event-free survival. All comparisons of outcome were stratified by treatment regimen, risk classification, age, and leukocyte count.

RESULTS

Forty-eight patients (26%) had a rearranged TEL gene. At 5 years of follow-up, an estimated 91% +/- 5% (SE) of this group were event-free survivors, compared with only 65% +/- 5% of the group with germline TEL (stratified log-rank P = .011). For nonhyperdiploid patients, the odds ratio of an adverse event in the germline TEL group to that for the rearranged TEL group was 4.06 (95% confidence interval, 1.86 to 8.84). The relationship of TEL rearrangement to a favorable prognosis was independent of recognized good-risk features in B-precursor leukemia, including age, initial leukocyte count, and hyperdiploidy.

CONCLUSION

Rearrangement of the TEL gene distinguishes a large subset of children with favorable-prognosis B-precursor leukemia who cannot be identified by standard prognostic features. It may be possible to treat these patients less aggressively without loss of therapeutic efficacy.