Clinical features predict responsiveness to imatinib in platelet-derived growth factor receptor-alpha-negative hypereosinophilic syndrome.

BACKGROUND: With the exception of the presence of the FIP1L1-PDGFRA fusion gene, little is known about predictors of imatinib response in clinically-defined hypereosinophilic syndrome (HES). METHODS: Subjects with FIP1L1-PDGFRA-myeloid neoplasm (FP; n =12), PDGFRA-negative HES with ≥4 criteria suggestive of a myeloid neoplasm (MHES; n =10), or steroid-refractory PDGFRA-negative HES with <4 myeloid criteria (SR; n = 5) were enrolled in a prospective study of imatinib therapy (NCT00044304: registered at clinicaltrials.gov). The primary outcome was an eosinophil count <1.5 × 109/L at one month and improvement of clinical symptoms. Clinical, molecular, and bone marrow responses to imatinib were assessed. A retrospective cohort of 18 subjects with clinically-defined HES who received imatinib (300-400 mg daily ≥ 1 month) were classified according to the criteria used in the prospective study. RESULTS: Overall, imatinib response rates were 100% in the FP group (n = 16), 54% in the MHES group (n = 13) and 0% in the SR group (n = 16). The presence of ≥ 4 myeloid features was the sole predictor of response. After ≥ 18 months in complete remission, imatinib was tapered and discontinued in 8 FP and 1 MHES subjects. Seven subjects (6 FP, 1 MHES) remain in remission off therapy for a median of 29 months (range 14-36). CONCLUSIONS: Clinical features of MHES predict imatinib response in PDGFRA-negative HES.

Prognostic variables in newly diagnosed children and adolescents with acute myeloid leukemia: Children's Cancer Group Study 213.

The objective of this study was to identify biologic parameters that were associated with either exceptionally good or poor outcome in childhood acute myeloid leukemia (AML). Among the children with AML who entered Children's Cancer Group trial 213, 498 patients without Down syndrome or acute promyelocytic leukemia (APL) comprise the basis for this report. Univariate comparisons of the proportion of patients attaining complete remission after induction (CR) indicate that, at diagnosis, male gender, low platelet count (< or =20 000/microl), hepatomegaly, myelodysplastic syndrome (MDS), French-American- British (FAB) category M5, high (>15%) bone marrow (BM) blasts on day 14 of the first course of induction, and +8 are associated with lower CR rates, while abnormal 16 is associated with a higher CR rate. Multivariate analysis suggests high platelet count at diagnosis (>20 000/microl), absence of hepatomegaly, < or =15% day 14 BM blast percentage, and abnormal 16 are independent prognostic factors associated with better CR. Univariate analysis demonstrated a significant favorable relationship between platelet count at diagnosis (>20 000/microl), absence of hepatomegaly, low percentage of BM blasts (< or =15%), and abnormal 16 with overall survival. Absence of hepatomegaly, < or =15% day 14 BM blast percentage, and abnormal 16 were determined to be independent prognostic factors associated with better survival.

Rabaptin-5 is a novel fusion partner to platelet-derived growth factor beta receptor in chronic myelomonocytic leukemia.

Chromosomal translocations involving the platelet-derived growth factor beta receptor (PDGFbetaR) gene have been reported in some patients with chronic myelomonocytic leukemia (CMML). The resultant fusion proteins have constitutive PDGFbetaR tyrosine kinase activity, but the partner genes previously reported (tel, Huntingtin interacting protein 1 [HIP-1], H4/D10S170) have poorly understood roles in the oncogenic activity of the fusion proteins. A novel PDGFbetaR fusion protein has been characterized in a patient with CMML and an acquired t(5;17)(q33;p13). Southern blot analysis on patient leukemia cells demonstrated involvement of the PDGFbetaR gene. Using 5' rapid amplification of complementary DNA ends-polymerase chain reaction (RACE-PCR) on patient RNA, rabaptin-5 was identified as a novel partner fused in-frame to the PDGFbetaR gene. The new fusion protein includes more than 85% of the native Rabaptin-5 fused to the transmembrane and intracellular tyrosine kinase domains of the PDGFbetaR. Transduction with a retroviral vector expressing rabaptin-5/PDGFbetaR transformed the hematopoietic cell line Ba/F3 to growth factor independence and caused a fatal myeloproliferative disease in mice. Rabaptin-5 is a well-studied protein shown to be an essential and rate-limiting component of early endosomal fusion through interaction with the Ras family GTPases Rab5 and Rab4. The fusion protein includes 3 of 4 coiled-coil domains (involved in homodimerization of native rabaptin-5), 2 caspase-3 cleavage sites, and a binding site for the tumor suppressor gene tuberin (tuberous sclerosis complex-2). Early endosomal transport is critical in regulation of various growth factor receptors, through ligand-induced clathrin-mediated endocytosis, and thus this new fusion protein links together 2 important pathways of growth regulation.

Diagnostic utility of flow cytometric immunophenotyping in myelodysplastic syndrome.

The myelodysplastic syndromes (MDSs) are characterized by bilineage or trilineage dysplasia. Although diagnostic criteria are well established for MDS, a significant number of patients have blood and bone marrow findings that make diagnosis and classification difficult. Flow cytometric immunophenotyping is an accurate and highly sensitive method for detection of quantitative and qualitative abnormalities in hematopoietic cells. Flow cytometry was used to study hematopoietic cell populations in the bone marrow of 45 patients with straightforward MDS. The results were compared with those obtained in a series of patients with aplastic anemia, healthy donors, and patients with a history of nonmyeloid neoplasia in complete remission. The immunophenotypic abnormalities associated with MDS were defined, and the diagnostic utility of flow cytometry was compared, with morphologic and cytogenetic evaluations in 20 difficult cases. Although morphology and cytogenetics were adequate for diagnosis in most cases, flow cytometry could detect immunophenotypic abnormalities in cases when combined morphology and cytogenetics were nondiagnostic. It is concluded that flow cytometric immunophenotyping may help establish the diagnosis of MDS, especially when morphology and cytogenetics are indeterminate. (Blood. 2001;98:979-987)

A comparison of allogeneic bone marrow transplantation, autologous bone marrow transplantation, and aggressive chemotherapy in children with acute myeloid leukemia in remission.

Intensive, myelosuppressive therapy is necessary to maximize outcomes for patients with acute myeloid leukemia (AML). A comparison was made of 3 aggressive postremission approaches for children and adolescents with AML in a randomized trial, CCG-2891. A total of 652 children and adolescents with AML who achieved remission on 2 induction regimens using identical drugs and doses (standard and intensive timing) were eligible for allocation to allogeneic bone marrow transplantation (BMT) based on matched related donor status (n = 181) or randomization to autologous BMT (n = 177) or to aggressive high-dose cytarabine-based chemotherapy (n = 179). Only 115 patients (18%) refused to participate in the postremission phase of this study. Overall compliance with the 3 allocated regimens was 90%. At 8 years actuarial, 54% +/- 4% (95% confidence interval) of all remission patients remain alive. Survival by assigned regimen ("intent to treat") is as follows: allogeneic BMT, 60% +/- 9%; autologous BMT, 48% +/- 8%; and chemotherapy, 53% +/- 8%. Survival in the allogeneic BMT group is significantly superior to autologous BMT (P =.002) and chemotherapy (P =.05); differences between chemotherapy and autologous BMT are not significant (P =.21). No potential confounding factors affected results. Patients receiving intensive-timing induction therapy had superior long-term survival irrespective of postremission regimen received (allogeneic BMT, 70% +/- 9%; autologous BMT, 54% +/- 9%; chemotherapy, 57% +/- 10%). Allogeneic BMT remains the treatment of choice for children and adolescents with AML in remission, when a matched related donor is available. For all others, there is no advantage to autologous BMT; hence, aggressive nonablative chemotherapy should be used.

Association of chromosome arm 9p abnormalities with adverse risk in childhood acute lymphoblastic leukemia: A report from the Children's Cancer Group.

Cytogenetic abnormalities of chromosome arm 9p occur frequently in children with acute lymphoblastic leukemia (ALL). We analyzed 201 such cases (11%) in 1,839 children with newly diagnosed ALL treated between 1989 and 1995 on risk-adjusted protocols of the Children's Cancer Group (CCG). The majority of patients (131; 65%) with a 9p abnormality were classified as higher risk. Nearly all patients had complex karyotypes; most cases had deletions of 9p, add/der(9p), a dicentric involving chromosome arm 9p, and/or balanced translocations and inversions involving 9p. Event-free survival (EFS) estimates at 6 years for patients with and without a 9p aberration were 61% (standard deviation [SD] = 5%) and 76% (SD = 2%; P <.0001). In addition, patients with a 9p abnormality had an increased cumulative incidence of both marrow (P =.04) and central nervous system (P =.0001) relapses. Overall survival also was significantly worse for patients with an abnormal 9p (P <.0001). These effects were most pronounced in standard-risk patients (age 1 to 9 years with white blood cell count <50,000/microL): 6-year EFS of 61% (SD = 9%) versus 80% (SD = 2%; P <.0001). Also, a 9p aberration was an adverse risk factor for B-lineage, but not T-lineage patients. The effect of 9p status on EFS was attenuated, but maintained in a multivariate analysis of EFS after adjustment for Philadelphia chromosome status, age, white blood cell (WBC) count, sex, race, and ploidy group (P =.01). Thus, abnormalities of chromosome arm 9p identify a subgroup of standard-risk patients with increased risk of treatment failure.

Cytogenetic studies of infant acute lymphoblastic leukemia: poor prognosis of infants with t(4;11) - a report of the Children's Cancer Group.

Infants less than 1 year of age at diagnosis of acute lymphoblastic leukemia (ALL) have a poor prognosis, which has been attributed primarily to a breakpoint in chromosomal band 11q23 or the MLL gene. Most infants with an 11q23 breakpoint have a t(4;11)(q21 ;q23). We studied the cytogenetics of the leukemia cells of 56 infants on CCG-1883, a single-arm clinical treatment protocol for infant ALL. Twenty-one patients had t(4;11)(q21;q23), seven had other rearrangements with breakpoints in 11q23 (other 11q23), 16 had normal chromosomes, two had t(1;19)(q32;p13), one had >50 chromosomes, and nine had non-recurring structural abnormalities. To determine whether there is a difference in outcome for infants with t(4;11), other 11q23 and the remaining patients, we compared event-free survival (EFS) and other clinical and laboratory features of the above infants. Infants without t(4;11) and those with other 11q23 rearrangements had significantly better EFS than those with t(4;11) (P= 0.007 and P= 0.02, respectively). t(4;11) correlated with age less than 6 months and with CD10 negativity, both of which also were poor prognostic indicators. After adjustment for age, there was still a significant difference in EFS between patients with t(4;11) and those with other 1lq23 rearrangements (P=0.02), and between patients with t(4;11) and those without t(4;11) (P=0.04). Among CD10 negative patients, t(4;11) was associated with a worse EFS (P=0.01). Multivariate analysis showed that after adjusting for a variety of clinical and laboratory features, t(4;11) was the most important prognostic factor for poor outcome, and patients with other 11q23 rearrangements had as good an outcome as the remaining patients without t(4;11).

Chromosome abnormalities of eighty-one pediatric germ cell tumors: sex-, age-, site-, and histopathology-related differences--a Children's Cancer Group study.

The chromosomes of 81 pediatric germ cell tumors (GCTs) were analyzed as part of two clinical treatment trials, INT-0098 and INT-0097, conducted by the Children's Cancer Group. The analysis of chromosome results showed differences with respect to sex, age, tumor location, and histology. Sixteen of 17 benign teratomas of infants and children less than 4 years old and from gonadal and extragonadal locations were chromosomally normal. Twenty-three malignant GCTs from gonadal and extragonadal locations of the same age group were endodermal sinus tumors and varied in their karyotypic findings. The most common abnormalities were gains of 1q and chromosome 3. Of eight benign ovarian teratomas from older girls, five with normal G-banded karyotypes were determined to be homozygous for Q-band heteromorphisms, suggesting a meiosis II error. Among the 12 malignant ovarian GCTs from older girls, the common abnormalities were loss of 1p/gain of 1q, +3, +8, +14, and +21. Four of eight extragonadal tumors from older boys demonstrated +21; one had +X. Five of the eight had associated constitutional chromosome abnormalities, including one trisomy 21 and three with Klinefelter syndrome. The testicular GCTs of adolescents had abnormalities resembling those found in adult testicular GCT, including near-triploidy, loss of chromosomes 11, 13, and 18, and gain of chromosomes 7, 8, the X chromosome, and an isochromosome 12p. The gain of an isochromosome 12p was only frequent in the tumors from adolescent boys. Deletion of 1p/gain of 1q and +3 were the most common abnormalities among the malignant tumors from both sexes.

Frequency of prolonged remission duration after high-dose cytarabine intensification in acute myeloid leukemia varies by cytogenetic subtype.

Advances in the treatment of acute myeloid leukemia (AML) have occurred with the introduction of new therapies including high-dose cytarabine and the identification of powerful prognostic factors such as cytogenetics that predict for long-term outcome. To date, the prognostic impact of cytarabine dose escalation within various cytogenetic groups of AML has not been assessed. We describe 285 newly diagnosed patients with primary AML who had adequate karyotypes and were enrolled on a prospective Cancer and Leukemia Group B cytogenetic study. All patients were randomly assigned to postremission treatment with standard-, intermediate-, or high-dose cytarabine intensification. Patients were categorized to one of three cytogenetic groups: (a) core binding factor type [(CBF); ie., t(8;21) inv(16), t(16;16), and del(16)]; (b) normal; and (c) other abnormality karyotype. An evaluation of these patients after a median follow-up time of over 7 years was performed to determine the relationship of intensification to outcome by cytogenetic group. Patients included 57 patients with CBF AML, 140 patients with normal karyotype AML, and 88 patients with other cytogenetic abnormalities. The treatment outcome of CBF AML patients was superior, with an estimated 50% still in complete remission (CR) after 5 years as compared with 32 and 15% for patients with normal karyotype AML and other abnormality AML, respectively (P < 0.001). Univariate analysis showed the following nonkaryotype factors to predict a prolonged CR duration: (a) younger age (P < 0.008); (b) lower leukocyte count (P=0.01); (c) the presence of Auer rods (P=0.004); (d) a lower percentage of bone marrow blasts (P=0.001) at the time of diagnosis, (e) and a higher postremission cytarabine dose (P < 0.001). The impact of cytarabine dose on long-term remission was most marked (P < 0.001) in the CBF AML group (after 5 years, 78% of those with a dose of 3 g/m2 were still in CR, 57% of those with a dose of 400 mg/m2 were still in CR, and 16% of those with a dose of 100 mg/m2 were still in CR) followed by normal karyotype AML (P=0.01; after 5 years, 40% of those with a dose of 3 g/m2 were still in CR, 37% of those with a dose of 400 mg/m2 were still in CR, and 20% of those with a dose of 100 mg/m2 were still in CR). In contrast, cytarabine at all doses produced only a 21% or less chance of long-term continuous CR for patients with other cytogenetic abnormalities. A multivariate analysis of CR duration assessed the independent impact of each of these variables on cure. Significant factors entering this model in descending order of importance were cytogenetic group (CBF > normal > other abnormality; P=0.00001), cytarabine dose (3 g/m2 > 400 mg/m2 > 100 mg/m2; P=0.00001), logarithm of leukocyte count at the time of diagnosis (P=0.0005), and histological subtype of AML (P=0.005). This study demonstrates that the curative impact of cytarabine intensification varies significantly among cytogenetic groups and results in a substantial prolongation of CR among patients with CBF and normal karyotypes, but not in those with other karyotypic abnormalities. These findings support the use of pretreatment cytogenetics in risk stratification of postremission AML therapy.

Patients with isolated trisomy 8 in acute myeloid leukemia are not cured with cytarabine-based chemotherapy: results from Cancer and Leukemia Group B 8461.

To date, neither the clinical significance of isolated trisomy 8, the most frequent trisomy in acute myeloid leukemia (AML), nor the effect of age within a single cytogenetic group has been examined. We report a large cohort of adult trisomy 8 patients and examine whether increasing age within a homogeneous cytogenetic group alters clinical outcome. Characteristics and outcome of patients with isolated trisomy 8 enrolled in the prospective Cancer and Leukemia Group B (CALGB) cytogenetic study CALGB 8461 are described. Isolated trisomy 8 was identified in 42 (3.03%) of 1387 patients enrolled in five CALGB treatment protocols. These patients had a median age of 64 (range, 16-79) years, 50% female proportion, and a low frequency of hepatomegaly (10%) or splenomegaly (10%). Laboratory features included a median white blood count of 7.3 x 10(9)/L, nonspecific French-American-British distribution, with 36% of patients having Auer rods. Treatment outcome was unsatisfactory with a complete remission (CR) rate of 59%, median CR duration of 13.6 months, and median survival of 13.1 months. Older age adversely affected outcome; trisomy 8 patients > or =60 years had both an inferior CR rate (40% versus 88%; P = 0.004) and overall survival (median, 4.8 versus 17.5 months; P = 0.01), as compared with those <60 years of age. Of the patients <60 years of age, only four remain alive, and all received noncytarabine-based intensive chemotherapy, followed in three cases by autologous (n = 2) or allogeneic (n = 1) stem cell transplant in CR1. Adults with AML and isolated trisomy 8 have a poor outcome that is accentuated by increasing age and is rarely cured with cytarabine-based therapy. Alternative investigational treatments should be considered for individuals with this AML subset.

Clinical characteristics of patients with de novo acute myeloid leukaemia and isolated trisomy 11: a Cancer and Leukemia Group B study.

Isolated trisomy 11 is the third most common sole trisomy in de novo acute myeloid leukaemia (AML). However, only 49 cases have been published, and for only a fraction of these cases has full description of clinical and haematological features been provided. As a result, little is known about the clinical characteristics of de novo AML patients with solitary trisomy 11. We have identified 13 patients (0.9%) with isolated trisomy 11 among a total of 1496 consecutive adult patients successfully karyotyped as part of a prospective Cancer and Leukemia Group B (CALGB) cytogenetic study (CALGB 8461). Nine patients (69%) were over the age of 60 (range 29-73 years). Eight patients (62%) were diagnosed with AML of FAB M2 subtype, three patients (23%) had FAB M1 AML and one patient each had AML of FAB M0 and M7, respectively. Seven patients (54%) had high, >100 x 10(9)/l, platelet counts (median 102 x 10(9)/l; range 17-207 x 10(9)/l). All patients received CALGB induction therapy with standard doses of cytarabine and daunorubicin. Six patients (46%) achieved a complete remission (CR). The median CR duration was 17.5 months (range 8.7-49.8). Only one patient, who underwent bone marrow transplantation in first CR, continues in initial CR. The median survival was 14.3 months (range 0.5-50.7); only one patient survives. We conclude that de novo AML with isolated trisomy 11 is predominantly associated with older age, M2 and M1 FAB subtypes, high platelet count and few long-term disease-free survivals, although it is currently unknown whether isolated trisomy 11 constitutes an independent prognostic factor.

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

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

Acute myeloid leukemia with 11q23 translocations: myelomonocytic immunophenotype by multiparameter flow cytometry.

11q23 translocations (t(11q23)) are recurring cytogenetic abnormalities in both acute myeloid leukemia (AML) and acute lymphoblastic leukemia, involving the same gene, ALL1 (or MLL). Mixed lineage antigen expression has been reported in these leukemias, but its frequency and clinical significance are unknown. We immunophenotyped leukemia cells from 19 adult de novo AML patients with t(11q23) by multiparameter flow cytometry. Translocations included t(6;11)(q27;q23), t(9;11)(p22;q23), t(9;11;19)(p22;q23;q13.3), t(2;11)(11;17)(q37;q11q23;q11), t(11;17)(q23;q25), t(11;19)(q23;p13.1), t(11;19)(q23;p13.3) and t(11;22)(q23;q11). FAB types were M4 and M5. The committed stem cell and myeloid antigens HLADr, CD4dim, CD11b, CD13, CD15, CD32, CD33, CD38 and CD64 were each expressed in 80-100% of cases, and the early stem cell and lymphoid antigens CD34, CD56, CD3, CD2 and CD7 in 42, 39, 16, 5 and 5%, respectively. Antigen expression frequencies did not differ from those in 443 adequately karyotyped M4 and M5 cases without t(11q23). Fifteen patients (79%) attained complete remission (CR); median CR duration and survival were 10.0 and 15.1 months. CR duration and survival did not correlate with antigen expression. In particular, patients with t(9;11) survived longer than those with other t(11q23) (median not reached vs 7.6 months; P = 0.048), but antigen expression did not differ in the two groups. Thus frequencies of lymphoid antigen expression are similar in AML with t(11q23) and in other FAB M4 and M5 cases, treatment outcome does not differ in t(11q23) cases with and without lymphoid antigen expression, and better outcome of patients with t(9;11) compared to other t(11q23) does not correlate with differences in antigen expression. Mixed lineage antigen expression is not a distinctive feature of AML with t(11q23).

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

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

Rearrangement of ALL1 (MLL) in acute myeloid leukemia with normal cytogenetics.

Approximately 45% of adults with acute myeloid leukemia (AML) have normal cytogenetics and therefore lack structural abnormalities that can assist in the localization and characterization of molecular defects. The partial tandem duplication of the ALL1 (MLL) gene has been found in several such cases of AML, yet its frequency and clinical significance are unclear. We performed Southern analysis of the ALL1 gene in pretreatment samples from 98 AML patients with normal cytogenetics. Eleven of 98 such patients (11%; 95% confidence interval, 6-19%) showed rearrangement of ALL1 at diagnosis. The partial tandem duplication of ALL1 was responsible for ALL1 rearrangement in all such cases examined, making it a frequent molecular defect in adult AML patients with normal cytogenetics. Furthermore, patients with ALL1 rearrangement had a significantly shorter duration of complete remission when compared to patients without ALL1 rearrangement (P = 0.01; median, 7.1 versus 23.2 months). This defect defines for the first time a subset of AML patients with normal cytogenetics who have short durations of complete remission and thus require new therapeutic approaches.

Distinctive demography, biology, and outcome of acute myeloid leukemia and myelodysplastic syndrome in children with Down syndrome: Children's Cancer Group Studies 2861 and 2891.

In recent pediatric trials of acute myeloid leukemia (AML), children with Down syndrome (DS) have had significantly more megakaryoblastic leukemia and have experienced better outcome than other children. To further characterize AML in DS, Children's Cancer Group Studies 2861 and 2891 prospectively studied demography, biology, and response in AML and myelodysplastic syndrome (MDS) of children with and without DS. These studies evaluated timing of induction therapy and compared postremission chemotherapy with marrow transplantation in 1,206 children. One-hundred eighteen (9.8%) had DS, a fourfold increase in 20 years. DS patients were younger, had lower white blood cell and platelet counts, more antecedent MDS, acute megakaryoblastic leukemia or undifferentiated AML, and an under-representation of chromosomal translocations (P < .001 for each variable). Four-year event-free survival in DS was 69% versus 35% in others (P < .001). Intensively timed induction conferred significantly higher mortality in DS patients; bone marrow transplantation offered no advantage. Conventional induction followed by chemotherapy achieved an 88%, 4-year, disease-free survival in DS patients versus 42% in others (P < .001). Megakaryoblastic leukemia was unfavorable in others but prognostically neutral in DS. AML in DS is demographically and biologically distinct from AML in other children. It is singularly responsive to conventional chemotherapy and may warrant even less therapy. The increasing proportion of DS patients with AML most likely reflects changes in attitudes about entering DS patients on AML trials and possibly increasing ability to distinguish megakaryoblastic leukemia from lymphoid leukemia.

Expression of the neural cell adhesion molecule CD56 is associated with short remission duration and survival in acute myeloid leukemia with t(8;21)(q22;q22).

Although acute myeloid leukemia (AML) with t(8;21) (q22;q22) is associated with a high complete remission (CR) rate and prolonged disease-free survival, treatment outcome is not universally favorable. Identifying factors that predict for treatment outcome might allow therapy to be optimized based on risk. AML with t(8;21) has a distinctive immunophenotype, characterized by expression of the myeloid and stem cell antigens CD13, CD15, CD34, and HLADr, and frequent expression of the B-cell antigen CD19 and the neural cell adhesion molecule CD56, a natural killer cell/stem cell antigen. Because CD56 expression has been associated with both extramedullary leukemia and multidrug resistance, we sought to correlate CD56 expression with treatment outcome in AML with t(8;21). Pretreatment leukemia cells from 29 adult de novo AML patients with t(8;21) treated on Cancer and Leukemia Group B (CALGB) protocols were immunophenotyped by multiparameter flow cytometry as part of a prospective immunophenotyping study of adult AML (CALGB 8361). CD56 was expressed in 16 cases (55%). There was no correlation between CD56 expression and age, sex, white blood cell count, granulocyte count, the presence of additional cytogenetic abnormalities, or the presence of extramedullary disease at diagnosis. The CR rate to standard-dose cytarabine and daunorubicin was similar for cases with and without CD56 expression (88% v 92%; P = 1.0). Post-CR therapy included at least one course of high-dose cytarabine in 24 of 26 patients who achieved CR; numbers of courses administered were similar in cases with and without CD56 expression. Although post-CR therapy did not differ, CR duration was significantly shorter in cases with CD56 expression compared with those without (median, 8.7 months v not reached; P = .01), as was survival (median, 16.5 months v not reached; P = .008). We conclude that CD56 expression in AML with t(8;21) is associated with significantly shorter CR duration and survival. Our results suggest that CD56 expression may be useful in stratifying therapy for this subtype of AML.

Clinical features and treatment outcome of children with myeloid antigen positive acute lymphoblastic leukemia: a report from the Children's Cancer Group.

Leukemic cells from a significant number of children with acute lymphoblastic leukemia (ALL) express protein antigens characteristic of both lymphoid and myeloid cells, yet the clinical significance of this immunophenotype has remained controversial. In the current study, we have determined relationships between myeloid antigen expression and treatment outcome in a large cohort of children with newly diagnosed ALL. A total of 1,557 children enrolled on risk-adjusted Children's Cancer Group studies were classified as myeloid antigen positive (My+) or myeloid antigen negative (My-) B-lineage ALL (BL) or T-lineage ALL (TL), according to expression of CD7, CD19, CD13, and CD33 antigens on the surface of their leukemic cells. My+ patients in both BL and TL groups were more likely than My- patients to have favorable presenting features. Induction therapy outcome was similar for My+ and My- patients in both the BL and TL categories. Importantly, 4-year event-free survival (EFS) was similar for My+ BL (77.0%, standard deviation [SD] = 4.0%) versus My- BL (75.9%, SD = 1.8%) and for My+ TL (72.7%, SD = 7.1%) versus My- TL (70.1%, SD = 5.7%). An overall relative hazard rate (RHR) of 0.89 (P = .49) was determined by a cross strata analysis for My+ versus My- patients. Moreover, similar EFS and RHR also were found when My+ and My- BL patients were compared according to National Cancer Institute risk classification. Thus, patients with My+ ALL have similar treatment outcomes as My- ALL patients. In contrast to previous studies, this result was independent of treatment risk category, demonstrating that myeloid antigen expression was not an adverse prognostic factor for childhood ALL.

MLL gene rearrangement, cytogenetic 11q23 abnormalities, and expression of the NG2 molecule in infant acute myeloid leukemia.

To study prognostic factors in infant acute myeloid leukemia (AML), we analyzed 44 children treated on Childrens Cancer Group protocols for MLL gene rearrangement by Southern blot, cytogenetic 11q23 abnormalities, and reactivity with monoclonal antibody 7.1. This antibody detects the human homologue of the rat NG2 chondroitin sulfate proteoglycan molecule, which has previously been reported to be expressed on human melanoma. NG2 has been found to be expressed on human leukemic blasts but not on other hematopoietic cells. In childhood AML, NG2 cell surface expression correlated with poor outcome and with some but not all 11q23 rearrangements. In childhood acute lymphoblastic leukemia, NG2 expression correlated with poor outcome and with balanced 11q23 translocations. In this study, 29 of 44 (66%) of infants with AML showed MLL rearrangement and, as expected, this group had a high incidence of French-American-British M4/M5 morphology (22/29). Of the cases tested, 35.1% (13/37) were NG2 positive. All (13/13) NG2-positive cases were rearranged at MLL, whereas only 46% (11/24) of NG2-negative cases had MLL rearrangement. NG2 expression did not correlate with poor outcome (P = .31); there was a trend towards a worse outcome with MLL rearrangement (P = .13). Thus monoclonal antibody 7.1 does not detect all cases of MLL rearrangement in infant AML.