L Lo Nigro

New insights to the MLL recombinome of acute leukemias

Chromosomal rearrangements of the human MLL gene are associated with high-risk pediatric, adult and therapy-associated acute leukemias. These patients need to be identified, treated appropriately and minimal residual disease was monitored by quantitative PCR techniques. Genomic DNA was isolated from individual acute leukemia patients to identify and characterize chromosomal rearrangements involving the human MLL gene. A total of 760 MLL-rearranged biopsy samples obtained from 384 pediatric and 376 adult leukemia patients were characterized at the molecular level. The distribution of MLL breakpoints for clinical subtypes (acute lymphoblastic leukemia, acute myeloid leukemia, pediatric and adult) and fused translocation partner genes (TPGs) will be presented, including novel MLL fusion genes. Combined data of our study and recently published data revealed 104 different MLL rearrangements of which 64 TPGs are now characterized on the molecular level. Nine TPGs seem to be predominantly involved in genetic recombinations of MLL: AFF1/AF4, MLLT3/AF9, MLLT1/ENL, MLLT10/AF10, MLLT4/AF6, ELL, EPS15/AF1P, MLLT6/AF17 and SEPT6, respectively. Moreover, we describe for the first time the genetic network of reciprocal MLL gene fusions deriving from complex rearrangements.

Long-term results of the Italian Association of Pediatric Hematology and Oncology (AIEOP) Studies 82, 87, 88, 91 and 95 for childhood acute lymphoblastic leukemia.

We analyzed the long-term outcome of 4865 patients treated in Studies 82, 87, 88, 91 and 95 for childhood acute lymphoblastic leukemia (ALL) of the Italian Association of Pediatric Hematology and Oncology (AIEOP). Treatment was characterized by progressive intensification of systemic therapy and reduction of cranial radiotherapy. A progressive improvement of results with reduction of isolated central nervous system relapse rate was obtained. Ten-year event-free survival increased from 53% in Study 82 to 72% in Study 95, whereas survival improved from 64 to 82%. Since 1991, all patients were treated according to Berlin-Frankfurt-Muenster (BFM) ALL treatment strategy. In Study 91, reduced treatment intensity (25%) yielded inferior results, but intensification of maintenance with high-dose (HD)-L-asparaginase (randomized) allowed to compensate for this disadvantage; in high-risk patients (HR, 15%), substitution of intensive polychemotherapy blocks for conventional BFM backbone failed to improve results. A marked improvement of results was obtained in HR patients when conventional BFM therapy was intensified with three polychemotherapy blocks and double delayed intensification (Study 95). The introduction of minimal residual disease monitoring and evaluation of common randomized questions by AIEOP and BFM groups in the protocol AIEOP-BFM-ALL 2000 are expected to further ameliorate treatment of children with ALL.

Genetic polymorphism of NAD(P)H:quinone oxidoreductase is associated with an increased risk of infant acute lymphoblastic leukemia without MLL gene rearrangements.

NAD(P)H:quinone oxidoreductase 1 (NQO1) is a detoxification enzyme that protects cells against oxidative stress and toxic quinones. A polymorphism (C609T) in the gene produces in the heterozygous individuals (C/T) a reduction and in those homozygous for the variant allele (T/T) the abolishment of NQO1 protein activity. To assess whether NQO1 inactivating polymorphism (CT/TT) was a possible risk factor for infant acute lymphoblastic leukemia (iALL), we investigated the distribution of NQO1 genotype in 50 iALL patients, 32 with MLL gene rearrangements (MLL+) and 18 without (MLL−). As controls, 106 cases of pediatric ALL (pALL), and 147 healthy subjects were also studied. Compared to normal controls, the frequency of the low/null activity NQO1 genotypes was significantly higher in the iALL MLL− (72 vs 38%, P=0.006; odds ratio (OR) 4.22, 95% confidence interval (CI) 1.43–12.49), while no differences were observed in iALL MLL+ (44 vs 38%, P=0.553; OR 1.26, 95% CI 0.58–2.74). Similar results were observed when pALL were used as control. Our results indicate that only the iALL patients without MLL rearrangements had a significantly higher frequency of NQO1 genotypes associated with low/null activity enzyme, suggesting a possible role for NQO1 gene as an MLL-independent risk factor, in the leukemogenic process of this subtype of iALL.

Effect of Protracted High-Dose l-Asparaginase Given as a Second Exposure in a Berlin-Frankfurt-Münster–Based Treatment: Results of the Randomized 9102 Intermediate-Risk Childhood Acute Lymphoblastic Leukemia Study—A Report From the Associazione Italiana Ematologia Oncologia Pediatrica

PURPOSEnTo assess in a randomized study the therapeutic effect of the addition of high-dose L-asparaginase (HD ASP) in the context of a Berlin-Frankfurt-Münster (BFM)-based chemotherapy regimen for intermediate risk (IR) childhood acute lymphoblastic leukemia (ALL).nnnPATIENTS AND METHODSnFrom March 1991 to April 1995, a total of 705 patients, with 59% of the cohort of patients fewer than 15 years old, with newly diagnosed non-B ALL, enrolled onto the Associazione Italiana Ematologia Oncologia Pediatrica (AIEOP) ALL-91 study, were assigned to the IR group. Patients in remission at the beginning of the reinduction phase were randomized either to the standard treatment (SD ASP arm) or the experimental treatment (HD ASP arm; weekly intramuscular administration of HD ASP 25,000 IU/m(2) repeated for a total of 20 weeks). Most of the patients (90%) were treated with Erwinia chrysanthemi L-asparaginase product.nnnRESULTSnAmong the 610 patients randomized to the SD ASP arm (n = 322) or to the HD ASP arm (n = 288), relapse occurred at a median time of 24 months after randomization in 76 (24%) and in 64 children (22%), respectively. Most of the relapses occurred in the marrow (100 isolated, 21 combined). There was no significant difference between the disease-free survival in the two treatment arms (P =.64), with estimated values at 7 years from randomization of 72.4% (SE 3.1) v 75.7% (SE 2.6) in the SD ASP and HD ASP arms, respectively.nnnCONCLUSIONnNo advantage was observed for IR ALL children treated with BFM-based intensive chemotherapy who received protracted E chrysanthemi HD ASP during reinduction and the early continuation phase.

Clonal stability in children with acute lymphoblastic leukemia (ALL) who relapsed five or more years after diagnosis

Although most relapses of childhood acute lymphoblastic leukemia (ALL) occur 24–36 months after first CR has been achieved, few patients relapse 5 or more years after CR achievement. The assessment of clonality has proved to be useful in determining whether even those very late events represent the reoccurrence of the original clone or alternatively a secondary leukemia. To gain further information on clonal stability in such late relapse, we performed detailed comparative Southern blotting and PCR analyses of TcRδ and TcRγ gene rearrangements in five ALL at presentation and subsequent relapse which occurred more than 5 years after diagnosis. At least one stable rearranged allele of the TcRδ and TcRγ loci was traced in all cases at presentation and clinical relapse despite a wide heterogeneity of the pattern of rearrangements. Our study extends to a larger series of patients previous findings which have sought to analyze the phenomenon of clonal evolution in children relapsed after more than 5 years of CCR. With respect to the potential pitfalls in monitoring minimal residual disease in childhood ALL for the presence of clonal evolution, our results highlight the combination of two target genes (such as TcRγ and TcRδ) as a tool to reduce false negative MRD results.

Levels of L-asparagine in CSF after intramuscular administration of asparaginase from Erwinia in children with acute lymphoblastic leukemia.

PURPOSEnAs part of a study on the pharmacokinetics associated with the administration of asparaginase (ASNase) from Erwinia to the CNS, we determined the levels of asparagine in the CSF of children with acute lymphoblastic leukemia (ALL).nnnPATIENTS AND METHODSnTwenty children received eight standard doses of intramuscular ASNase (10,000 IU/m2) every 3 days as part of induction therapy. In the postremission phase of therapy, the children were randomized to receive either 20 courses of high-dose intramuscular ASNase (25,000 IU/m2) weekly (n = 8) or four courses of standard-dose intramuscular ASNase (10,000 IU/m2) every 3 days (n = 12).nnnRESULTSnAll patients had detectable levels of L-asparagine in the CSF at the time of diagnosis. The levels of L-asparagine in CSF were undetectable in 15 of 20 (75%) and in seven of 19 (36.8%) children 3 and 5 days, respectively, after administration of standard-dose ASNase. After administration of high-dose ASNase, the levels of L-asparagine in the CSF were undetectable in five (62.5%) and two (25%) of eight children after 3 and 5 days, respectively.nnnCONCLUSIONnIn this study 60% to 70% and 25% to 35% of children had complete depletion of L-asparagine from the CSF after 3 and 5 days, respectively, after administration of both schedules of ASNase from Erwinia. In the remaining patients, administration of ASNase may have resulted in a suboptimal antileukemic effect at the CNS level.

Incidence and morbidity of infection by hepatitis C virus in children with acute lymphoblastic leukaemia.

A group of 90 patients with acute lymphoblastic leukaemia (ALL) in first continuous complete remission (CCR), admitted in our hospital between January 1986 and September 1992, were tested for the presence of antibodies against hepatitis C virus (HCV), antibodies against hepatitis B virus and antibodies against HIV-1 during maintenance therapy or thereafter. They were compared with a group of 71 children with other malignancies in first CCR who had been diagnosed consecutively from January 1986 to September 1992. No patient with ALL or any other malignancy was found to be positive for hepatitis B surface antigen or HIV-1. HCV-specific antibodies were detected in 28 out of 87 children (32.1%) with ALL and in 4 out of 44 patients (9%) with malignancies other than ALL who had received at least one transfusion of blood or platelets (P<0.01). HCV-specific antibodies were also detected in one out of three untransfused children with ALL but in none of the untransfused children with malignancies other than ALL. HCV-specific seropositivity influenced the management of children with ALL during maintenance therapy. In fact, as a result of abnormal liver function tests, maintenance therapy had to be suspended significantly more often in the case of HCV-seropositive patients with ALL than in HCV-seronegative ones. Despite the high morbidity during maintenance therapy, chronic liver disease (CLD) was uncommon in both groups: five children with ALL (17.2% of HCV-seropositive children) and one child with a malignancy other than ALL (25%) had CLD. If a follow up for a longer period confirms these observations the impact of HCV-related CLD on the quality of life and survival of patients with ALL or other malignancies will probably be minimal.

Clonal variegation and dynamic competition of leukemia-initiating cells in infant acute lymphoblastic leukemia with MLL rearrangement.

Distinct from other forms of acute lymphoblastic leukemia (ALL), infant ALL with mixed lineage leukemia (MLL) gene rearrangement, the most common leukemia occurring within the first year of life, might arise without the need for cooperating genetic lesions. Through Ig/TCR rearrangement analysis of MLL-AF4+ infant ALL at diagnosis and xenograft leukemias from mice transplanted with the same diagnostic samples, we established that MLL-AF4+ infant ALL is composed of a branching subclonal architecture already at diagnosis, frequently driven by an Ig/TCR-rearranged founder clone. Some MLL-AF4+ clones appear to be largely quiescent at diagnosis but can reactivate and dominate when serially transplanted into immunodeficient mice, whereas other dominant clones at diagnosis can become more quiescent, suggesting a dynamic competition between actively proliferating and quiescent subclones. Investigation of paired diagnostic and relapse samples suggested that relapses often occur from subclones already present but more quiescent at diagnosis. Copy-number alterations identified at relapse might contribute to the activation and expansion of previously quiescent subclones. Finally, each of the identified subclones is able to contribute to the diverse phenotypic pool of MLL-AF4+ leukemia-propagating cells. Unraveling of the subclonal architecture and dynamics in MLL+ infant ALL may provide possible explanations for the therapy resistance and frequent relapses observed in this group of poor prognosis ALL.

Clinical, Hematological, and Molecular Features in Sicilians with Sickle Cell Disease

We report the clinical, hematological, and molecular findings observed in 32 Sicilian patients with sickle cell disease. None of our patients received regular blood transfusions and careful infectious disease prophylaxis was carried out for all. Haplotyping of beta S chromosomes was performed in all patients; all were homozygous for haplotype #19 (Benin). Gene mapping excluded the presence of an alpha-thalassemia in 13 of our patients; none of the relatives showed any evidence of the presence of alpha-thalassemia. Hb F levels were 11.8 +/- 5.9% with G gamma representing 39.6 +/- 3.6% of total gamma chain. Hb F levels were higher in females than in males (12.5 +/- 5.9% versus 9.7 +/- 6.5%) but the difference was not statistically significant. All patients, regardless of age and sex, were anemic with normal mean corpuscular hemoglobin concentration, high mean corpuscular volume and mean corpuscular hemoglobin, and mild reticulocytosis. Analysis of clinical manifestations suggests that our patients have a disease of moderate severity.

Gene expression profile unravels significant differences between childhood and adult Ph+ acute lymphoblastic leukemia

Gene expression profile unravels significant differences between childhood and adult Ph+ acute lymphoblastic leukemia