Andishe Attarbaschi

The MLL recombinome of acute leukemias

Chromosomal rearrangements of the human MLL gene are a hallmark for aggressive (high-risk) pediatric, adult and therapy-associated acute leukemias. These patients need to be identified in order to subject these patients to appropriate therapy regimen. A recently developed long-distance inverse PCR method was applied to genomic DNA isolated from individual acute leukemia patients in order to identify chromosomal rearrangements of the human MLL gene. We present data of the molecular characterization of 414 samples obtained from 272 pediatric and 142 adult leukemia patients. The precise localization of genomic breakpoints within the MLL gene and the involved translocation partner genes (TPGs) was determined and several new TPGs were identified. The combined data of our study and published data revealed a total of 87 different MLL rearrangements of which 51 TPGs are now characterized at the molecular level. Interestingly, the four most frequently found TPGs (AF4, AF9, ENL and AF10) encode nuclear proteins that are part of a protein network involved in histone H3K79 methylation. Thus, translocations of the MLL gene, by itself coding for a histone H3K4 methyltransferase, are presumably not randomly chosen, rather functionally selected.

Mixed-phenotype acute leukemia: clinical and laboratory features and outcome in 100 patients defined according to the WHO 2008 classification

The features of 100 mixed-phenotype acute leukemias (MPALs), fulfilling WHO 2008 criteria, are documented. Myeloid and T-lineage features were demonstrated by cytoplasmic myeloperoxidase and CD3; B-lineage features were demonstrated by at least 2 B-lymphoid markers. There were 62 men and 38 women; 68% were adults. Morphology was consistent with acute lymphoblastic leukemia (ALL; 43%), acute myeloid leukemia (AML; 42%), or inconclusive (15%). Immunophenotyping disclosed B + myeloid (59%), T + myeloid (35%), B + T (4%), or trilineage (2%) combinations. Cytogenetics evidenced t(9;22)/(Ph(+)) (20%), 11q23/MLL rearrangements (8%), complex (32%), aberrant (27%), or normal (13%) karyotypes. There was no correlation between age, morphology, immunophenotype, or cytogenetics. Response to treatment and outcome were available for 67 and 70 patients, respectively; 27 received ALL, 34 AML, 5 a combination of ALL + AML therapy, and 1 imatinib. ALL treatment induced a response in 85%, AML therapy in 41%; 3 of 5 patients responded to the combination therapy. Forty (58%) patients died, 33 of resistant disease. Overall median survival was 18 months and 37% of patients are alive at 5 years. Age, Ph(+), and AML therapy were predictors for poor outcome (P < .001; P = .002; P = .003). MPAL is confirmed to be a poor-risk disease. Adults and Ph(+) patients should be considered for transplantation in first remission.

Phase II Window Study on Rituximab in Newly Diagnosed Pediatric Mature B-Cell Non-Hodgkin's Lymphoma and Burkitt Leukemia

PURPOSE The activity of rituximab in pediatric B-cell non-Hodgkins lymphoma (B-NHL) has not yet been determined. We conducted a phase II window study to examine activity and tolerability of rituximab in newly diagnosed pediatric B-NHL. PATIENTS AND METHODS Patients younger than age 19 years with CD20(+) B-NHL with at least one measurable site were eligible. Treatment consisted of rituximab at 375 mg/m(2) administered intravenously on day 1; concomitant therapy consisted of rasburicase, intrathecally (IT) triple drug (methotrexate, cytarabine, and prednisolone) on days 1 and 3 for CNS-positive patients and steroids only for anaphylaxis. Response criterion was the product of the two largest perpendicular diameters of one to three lesions and/or the percentage of blasts in bone marrow (BM) or peripheral blood (PB) within 24 hours before rituximab and on day 5. Responders had > or = 25% decrease of at least one lesion or BM or PB blasts and no disease progress at other sites. Response rate (RR) was set at 45% for unfavorable activity or at 65% for favorable activity. RESULTS From April 2004 to August 2008, 136 patients were enrolled. National Cancer Institute Common Toxicity Criteria 3/4 toxicities attributable to rituximab were general condition, 15%; fatigue, 13%; anaphylaxis, 7%; infection, 3%; glutamic-oxaloacetic transaminase/glutamic-pyruvic transaminase, 8%; no capillary leakage; and no toxic death. Forty-nine patients were not evaluable for response because of withdrawal from the study (n = 16), IT therapy in CNS-negative patients (n = 8), corticosteroid treatment (n = 3), technical inadequacy of response evaluation (n = 21), or no evaluable lesion (n = 1). Of 87 evaluable patients, 36 were responders (RR, 41.4%; 95% CI, 31% to 52%); among them, 27 of 67 with Burkitt lymphoma and seven of 15 with diffuse large B-cell lymphoma. A response was more frequently observed in BM (12 of 18) compared with solid tumor lesions (36 of 108; P = .007). CONCLUSION Rituximab is active as a single-agent in pediatric B-NHL even though the RR was lower than requested in the phase II plan.

CD20 up-regulation in pediatric B-cell precursor acute lymphoblastic leukemia during induction treatment: setting the stage for anti-CD20 directed immunotherapy

CD20 is expressed in approximately one- half of pediatric acute lymphoblastic leukemia (ALL) cases with B-cell precursor (BCP) origin. We observed that it is occasionally up-regulated during treatment. To understand the impact of this on the potential effectiveness of anti-CD20 immunotherapy, we studied 237 CD10(+) pediatric BCP-ALL patients with Berlin-Frankfurt-Munster (BFM)-type therapy. We analyzed CD20 expression changes from diagnosis to end-induction, focusing on sample pairs with more than or equal to 0.1% residual leukemic blasts, and assessed complement-induced cytotoxicity by CD20-targeting with rituximab in vitro. CD20-positivity significantly increased from 45% in initial samples to 81% at end-induction (day 15, 71%). The levels of expression also increased; 52% of cases at end-induction had at least 90% CD20(pos) leukemic cells, as opposed to 5% at diagnosis (day 15, 20%). CD20 up-regulation was frequent in high-risk patients, patients with high minimal residual disease at end-induction, and patients who suffered later from relapse, but not in TEL/AML1 cases. Notably, up-regulation occurred in viable cells sustaining chemotherapy. In vitro, CD20 up-regulation significantly enhanced rituximab cytotoxicity and could be elicited on prednisolone incubation. In conclusion, CD20 up-regulation is frequently induced in BCP-ALL during induction, and this translates into an acquired state of higher sensitivity to rituximab. This study was registered at http://www.clinicaltrials.gov as #NCT00430118.

Minimal Residual Disease Values Discriminate Between Low and High Relapse Risk in Children With B-Cell Precursor Acute Lymphoblastic Leukemia and an Intrachromosomal Amplification of Chromosome 21: The Austrian and German Acute Lymphoblastic Leukemia Berlin-Frankfurt- Munster (ALL-BFM) Trials

PURPOSE We aimed to identify relapse predictors in children with a B-cell precursor acute lymphoblastic leukemia (ALL) and an intrachromosomal amplification of chromosome 21 (iAMP21), a novel genetic entity associated with poor outcome. PATIENTS AND METHODS We screened 1,625 patients who were enrolled onto the Austrian and German ALL-Berlin-Frankfurt-Münster (ALL-BFM) trials 86, 90, 95, and 2000 with ETV6/RUNX1-specific fluorescent in situ hybridization probes, and we identified 29 patient cases (2%) who had an iAMP21. Minimal residual disease (MRD) was quantified with clone-specific immunoglobulin and T-cell receptor gene rearrangements. RESULTS Twenty-five patients were good responders to prednisone, and all achieved remission after induction therapy. Eleven patients experienced relapse, which included eight who experienced relapse after cessation of front-line therapy. Six-year event-free and overall survival rates were 37% +/- 14% and 66% +/- 11%, respectively. Results of MRD analysis were available in 24 (83%) of 29 patients: nine (37.5%) belonged to the low-risk, 14 (58.5%) to the intermediate-risk, and one (4%) to the high-risk group. MRD results were available in 8 of 11 patients who experienced a relapse. Seven occurred among the 14 intermediate-risk patients, and one occurred in the high-risk patient. CONCLUSION The overall and early relapse rates in the BFM study were lower than that in a previous United Kingdom Medical Research Council/Childhood Leukemia Working Party study (38% v 61% and 27% v 47%, respectively), which might result from more intensive induction and early reintensification therapy in the ALL-BFM protocols. MRD values were the only reliable parameter to discriminate between a low and high risk of relapse (P = .02).

An international study of intrachromosomal amplification of chromosome 21 (iAMP21): cytogenetic characterization and outcome

Intrachromosomal amplification of chromosome 21 (iAMP21) defines a distinct cytogenetic subgroup of childhood B-cell precursor acute lymphoblastic leukaemia (BCP-ALL). To date, fluorescence in situ hybridisation (FISH), with probes specific for the RUNX1 gene, provides the only reliable detection method (five or more RUNX1 signals per cell). Patients with iAMP21 are older (median age 9 years) with a low white cell count. Previously, we demonstrated a high relapse risk when these patients were treated as standard risk. Recent studies have shown improved outcome on intensive therapy. In view of these treatment implications, accurate identification is essential. Here we have studied the cytogenetics and outcome of 530 iAMP21 patients that highlighted the association of specific secondary chromosomal and genetic changes with iAMP21 to assist in diagnosis, including the gain of chromosome X, loss or deletion of chromosome 7, ETV6 and RB1 deletions. These iAMP21 patients when treated as high risk showed the same improved outcome as those in trial-based studies regardless of the backbone chemotherapy regimen given. This study reinforces the importance of intensified treatment to reduce the risk of relapse in iAMP21 patients. This now well-defined patient subgroup should be recognised by World Health Organisation (WHO) as a distinct entity of BCP-ALL.

Incidence and relevance of secondary chromosome abnormalities in childhood TEL / AML1 + acute lymphoblastic leukemia: an interphase FISH analysis

The aim of the present study was to determine the frequency and clinical relevance of the most common secondary karyotype abnormalities in TEL/AML1+ B-cell precursor acute lymphoblastic leukemia (ALL) as assessed with fluorescence in situ hybridization (FISH) analyses. Screening of 372 patients who were enrolled in two consecutive Austrian childhood ALL multicenter trials identified 94 (25%) TEL/AML1+ cases. TEL deletions, trisomy 21 and an additional der(21)t(12;21) were detected in 52 (55%), 13 (14%) and 14 (15%) TEL/AML1+ patients, respectively. The 12p aberrations (P=0.001) and near tetraploidy (P=0.045) were more common in TEL/AML1+ patients, whereas the incidence of diploidy, pseudodiploidy, hypodiploidy, low hyperdiploidy, near triploidy, del(6q), chromosome 9 and 11q23 abnormalities was similar among TEL/AML1+ and TEL/AML1− patients. None of the TEL/AML1+ patients had a high hyperdiploid karyotype. Univariate analysis indicated that among TEL/AML1+ patients those with a deletion of the nontranslocated TEL allele had a worse prognosis than those without this abnormality (P=0.034). We concluded that the type and incidence of the most common secondary aberrations in TEL/AML1+ ALL can be conveniently identified with little additional effort during interphase screening with appropriate TEL and AML1 FISH probes. We also provided preliminary evidence that the deletion of the nontranslocated TEL allele may adversely influence the clinical course of TEL/AML1+ ALL.

Improved outcome with hematopoietic stem cell transplantation in a poor prognostic subgroup of infants with mixed-lineage-leukemia (MLL)-rearranged acute lymphoblastic leukemia: results from the Interfant-99 Study.

To define a role for hematopoietic stem cell transplantation (HSCT) in infants with acute lymphoblastic leukemia and rearrangements of the mixed-lineage-leukemia gene (MLL(+)), we compared the outcome of MLL(+) patients from trial Interfant-99 who either received chemotherapy only or HSCT. Of 376 patients with a known MLL status in the trial, 297 (79%) were MLL(+). Among the 277 of 297 MLL(+) patients (93%) in first remission (CR), there appeared to be a significant difference in disease-free survival (adjusted by waiting time to HSCT) between the 37 (13%) who received HSCT and the 240 (87%) who received chemotherapy only (P = .03). However, the advantage was restricted to a subgroup with 2 additional unfavorable prognostic features: age less than 6 months and either poor response to steroids at day 8 or leukocytes more than or equal to 300 g/L. Ninety-seven of 297 MLL(+) patients (33%) had such high-risk criteria, with 87 achieving CR. In this group, HSCT was associated with a 64% reduction in the risk of failure resulting from relapse or death in CR (hazard ratio = 0.36, 95% confidence interval, 0.15-0.86). In the remaining patients, there was no advantage for HSCT over chemotherapy only. In summary, HSCT seems to be a valuable option for a subgroup of infant MLL(+) acute lymphoblastic leukemia carrying further poor prognostic factors. The trial was registered at www.clinicaltrials.gov as #NCT00015873 and at www.controlled-trials.com as #ISRCTN24251487.

Second Malignant Neoplasms After Treatment of Childhood Acute Lymphoblastic Leukemia

PURPOSE Second malignant neoplasms (SMNs) after diagnosis of childhood acute lymphoblastic leukemia (ALL) are rare events. PATIENTS AND METHODS We analyzed data on risk factors and outcomes of 642 children with SMNs occurring after treatment for ALL from 18 collaborative study groups between 1980 and 2007. RESULTS Acute myeloid leukemia (AML; n = 186), myelodysplastic syndrome (MDS; n = 69), and nonmeningioma brain tumor (n = 116) were the most common types of SMNs and had the poorest outcome (5-year survival rate, 18.1% ± 2.9%, 31.1% ± 6.2%, and 18.3% ± 3.8%, respectively). Five-year survival estimates for AML were 11.2% ± 2.9% for 125 patients diagnosed before 2000 and 34.1% ± 6.3% for 61 patients diagnosed after 2000 (P < .001); 5-year survival estimates for MDS were 17.1% ± 6.4% (n = 36) and 48.2% ± 10.6% (n = 33; P = .005). Allogeneic stem-cell transplantation failed to improve outcome of secondary myeloid malignancies after adjusting for waiting time to transplantation. Five-year survival rates were above 90% for patients with meningioma, Hodgkin lymphoma, thyroid carcinoma, basal cell carcinoma, and parotid gland tumor, and 68.5% ± 6.4% for those with non-Hodgkin lymphoma. Eighty-nine percent of patients with brain tumors had received cranial irradiation. Solid tumors were associated with cyclophosphamide exposure, and myeloid malignancy was associated with topoisomerase II inhibitors and starting doses of methotrexate of at least 25 mg/m(2) per week and mercaptopurine of at least 75 mg/m(2) per day. Myeloid malignancies with monosomy 7/5q- were associated with high hyperdiploid ALL karyotypes, whereas 11q23/MLL-rearranged AML or MDS was associated with ALL harboring translocations of t(9;22), t(4;11), t(1;19), and t(12;21) (P = .03). CONCLUSION SMNs, except for brain tumors, AML, and MDS, have outcomes similar to their primary counterparts.

qPET – a quantitative extension of the Deauville scale to assess response in interim FDG-PET scans in lymphoma

BackgroundInterim FDG-PET is used for treatment tailoring in lymphoma. Deauville response criteria consist of five ordinal categories based on visual comparison of residual tumor uptake to physiological reference uptakes. However, PET-response is a continuum and visual assessments can be distorted by optical illusions.ObjectivesWith a novel semi-automatic quantification tool we eliminate optical illusions and extend the Deauville score to a continuous scale.Patients and methodsSUVpeak of residual tumors and average uptake of the liver is measured with standardized volumes of interest. The qPET value is the quotient of these measurements. Deauville scores and qPET-values were determined in 898 pediatric Hodgkin’s lymphoma patients after two OEPA chemotherapy cycles.ResultsDeauville categories translate to thresholds on the qPET scale: Categories 3, 4, 5 correspond to qPET values of 0.95, 1.3 and 2.0, respectively. The distribution of qPET values is unimodal with a peak representing metabolically normal responses and a tail of clearly abnormal outliers. In our patients, the peak is at qPET = 0.95 coinciding with the border between Deauville 2 and 3. qPET cut values of 1.3 or 2 (determined by fitting mixture models) select abnormal metabolic responses with high sensitivity, respectively, specificity.ConclusionsqPET methodology provides semi-automatic quantification for interim FDG-PET response in lymphoma extending ordinal Deauville scoring to a continuous scale. Deauville categories correspond to certain qPET cut values. Thresholds between normal and abnormal response can be derived from the qPET-distribution without need for follow-up data. In our patients, qPET < 1.3 excludes abnormal response with high sensitivity.