The Molecular Landscape of KMT2A-Rearranged Leukemia from Infancy to Adulthood Reveals Age and Leukemia-Specific Mutational Patterns

Vincristine is a key drug in the treatment of childhood and adult acute lymphoblastic leukemia (ALL), and many other childhood malignancies. Despite decades of wide clinical use, no data on the correlation between vincristine pharmacokinetics and long-term clinical outcome have been published. We here report clinical data (median follow-up time 10.5 years, range 7.3-12 years) for 86 children with B-cell precursor ALL, in whom vincristine kinetics were studied on treatment day 1. The median total plasma clearance was 429 and 331 ml/min per m(2) and the area under the plasma concentration-time curve (AUC) was 4.49 and 5.40 mg/l x min in relapse and non-relapse patients, respectively (not significant). In standard risk patients, where treatment depends more heavily on vincristine than in other subgroups, the relative risk (RR) of relapse was significantly increased for patients with clearance values above median (RR 5.2; P = 0.036), or AUC values below median (RR 5.8; P = 0.025). Our data suggest a relationship between the antileukemic effect and the systemic exposure of the drug, which warrants further studies.

Specific Promoter CpG Island Methylation Patterns Identify Different Subgroups of MLL - Rearranged Infant Acute Lymphoblastic Leukemia, and Define Clinical Outcome

10030 Background: Infant acute lymphoblastic leukemia (ALL) is the only subtype of childhood ALL whose outcome has not improved over the past two decades. The most important prognosticator is the presence of rearrangements in the Mixed Lineage Leukemia gene (MLL-r), however, many patients present with high-risk clinical features but without MLL-r. We recently identified two cases of infant ALL with high-risk clinical features resembling MLL-r, but were negative for MLL-r by conventional diagnostics. RNA sequencing revealed a partial tandem duplication in MLL (MLL-PTD). We thus aimed to determine if MLL-PTD, other MLL abnormalities, or other genetic or transcriptomic features were driving this subset of high-risk infant ALL without MLL-r. Methods: We obtained 19 banked patient samples from the Children’s Oncology Group (COG) infant ALL trial (AALL0631) from MLL wildtype patients as determined by FISH and cytogenetics. Utilizing deep RNA-sequencing, we manually inspected the MLL gene for MLL-PTD, while also performing automated fusion detection and gene expression profiling in search of defining features of these tumors. Results: 3 additional MLL-PTDs were identified, all in patients with infant T-cell ALL, whereas both index cases were in patients with infant B-cell ALL. Gene expression profiling analysis revealed that all five MLL-PTD infants clustered together. Eight infants (7 with B-cell ALL) were found to have Ph-like expression. Five of these 8 infants were also found to have an IKZF1/JAK2 expression profile; one of these five had a PAX5-JAK2 fusion detected. Two infants (including the one noted above) had novel PAX5 fusions, known drivers of B-cell leukemia. Additional detected fusions included TCF3-PBX1 and TCF4-ZNF384. Conclusions: MLL-PTDs were found in both B- and T-cell infant ALL. Though Ph-like ALL has been described in adolescents and young adults, we found a substantial frequency of Ph-like expression among MLL-WT infants. Further characterization of these infants is ongoing. If replicated in other infant cohorts, these two findings may help explain the poor prognosis of MLL-WT ALL when compared to children with standard risk ALL, and offer the possibility of targeted therapy for select infants.

Prognosis in childhood and adult acute lymphoblastic leukaemia: a question of maturation?

Homozygous Deletion of p16, p14 and p15 Is a Poor Prognostic Factor in Adult B-Lineage Acute Lymphoblastic Leukemia, Not in Childhood B-ALL: A Comparison through Deletion and Hypermethylation Study

Low Expression of IL-15 in Adult B-Lineage Acute Lymphoblastic Leukemia Is Associated with Central Nervous System Involvement at Initial Presentation.

Acute Lymphoblastic Leukemia

The incidence of childhood, adolescent, and young adult (AYA) cancers have been increasing since 1975.[1][1] In 2014, an estimated 10 450 and 5330 new cancers will be diagnosed among children aged birth–14 and adolescents aged 15 to 19 years old, respectively.[2][2] For young adults aged 20 to 34

Immunoglobulin heavy chain gene (IgH gene) rearrangements are found in the majority of cases of B-lineage acute lymphoblastic leukaemia (ALL). We have examined bone marrow samples taken at presentation or relapse from 109 patients (79 adults and 30 children) and have performed sequence analysis of the complementarity determining region 3 (CDR3) on 65 alleles from 54 patients. We aimed to define immunoglobulin heavy chain (IgH) variable segment family use and investigate biological and structural features of the B cell in adult and childhood ALL. Using the FR1 fingerprinting method, a rearranged band was identified in 70 (89%) of 79 adult ALL and in 29 (97%) of 30 childhood ALL. This study found no preferential use or selection of IgH VH genes and no statistically significant structural differences between normal and leukaemic B cells in either adult and childhood ALL. An equal proportion of amplifiable cases of adult and childhood ALL uses more than one VH family gene (24/70, 34%, and 8/29, 27.5%, respectively). There were no significant differences in the structure or size of the CDR3 region and the variable (V) or joining (J) segment use in ALL patients compared to normal B cells. We observed that the N2 region was shorter than N1 in children whereas the opposite was observed in adults (not statistically significant). The J4 segment was a more common rearrangement in children than in adults, and in both groups J4 was more frequently associated with multiple D segment VDJ rearrangements. An increase in VH6 use in leukaemic alleles compared to normal B lymphocytes (2%) was observed but it was not statistically significant in our group of patients. Amongst children and adults, in-frame CDR3 junctions occurred in 78% and 64% of rearranged alleles, respectively, compared to 75% of in-frame sequences reported by others to occur among normal B cells.

Distinct Methylation Patterns among Infants with MLL Rearranged Acute Lymphoblastic Leukemia.

Cytogenetics and Outcome Of Infants With Acute Lymphoblastic Leukemia and Absence Of MLL Rearrangements

Acute lymphoblastic leukemia (ALL) affects both children and adults. Survival in ALL has improved in recent decades due to recognition of its biological heterogeneity. Although children have higher remission and cure rates than adults, both populations have benefited from these improvements. Our aim in this study is to determine the association between HLA-DQB1 genes with childhood and adult ALL patients. To define this association, we compared HLA-DQB1 allele frequencies and allele carrier frequencies in a cohort of 135 adults and children with ALL with 150 controls, using polymerase chain reaction with sequence-specific primers. Allele carrier frequencies in childhood ALL show a deficiency in DQ2 (*0201) (P 0.049 and RR 0.75), but an increase in DQ5 (*0501-*0504) and DQ7 (*0301, *0304) compared to the control group (P 0.001 RR 1.89, P 0.003 RR 1.48, respectively). Allele carrier frequencies in adult ALL indicated an increase in DQ5 (*0501-*0504) (P0.045 RR 2.28). Allelic frequencies in childhood ALL revealed the same increase in DQ5 and DQ7, and a decrease in DQ2. In adult ALL it shows a decrease in DQ7. Therefore, our results in adult ALL were similar to childhood ALL addressing DQ5 allele carriers, which showed an increase in both age groups. We suggest that DQ5 could be more strongly considered as an ALL susceptibility allele, and that this allele may underlie a pathogenic phenotype with a major role in the immunologic process involved in both adults and children with ALL.

Mutations of the PTPN11 Gene in Childhood Hematological Malignancies.

The application of high-dose treatment elements has an increasing importance in the therapy of acute lymphoblastic leukemia (ALL). High-dose methotrexate (HDMTX) has been introduced in clinical trials more than 20 years ago, since it has several theoretical advantages compared to conventional dose methotrexate. These trials revealed that the efficacy and toxicity of HDMTX depends on features such as dose level, infusion time, combination regimen and schedule of leucovorin rescue. Particularly the application of controlled leucovorin rescue and improved supportive care enabled the application of increasing doses of HDMTX in the treatment of childhood and adult ALL within a variety of schedules and at dose levels mostly ranging between 0.5 g/m2 and 5.0 g/m2. In childhood ALL, first devised to replace CNS irradiation in the prophylaxis of CNS relapse HDMTX has contributed to the reduction of bone marrow relapses particularly in low risk B-lineage ALL. In addition it proved to be an effective therapy element for prophylaxis and treatment of CNS disease. At least in low risk ALL CNS irradiation could be safely replaced by repeated cycles of HDMTX with additional intrathecal therapy. In adult ALL only few of the successful treatment approaches with HDMTX have been investigated up to now. The results indicate that HDMTX has a beneficial effect with regard to overall outcome in adult B-lineage ALL. It provides effective CNS prophylaxis in combination with intrathecal therapy. In mature B-ALL HDMTX proved to be one of the most effective treatment elements and contributed to an impressive improvement of outcome in this subgroup. For T-ALL however sufficient data do not exist either in childhood or in adult ALL. Since HDMTX is an effective treatment element with manageable acute and long-term toxicity, its role in the management of adult ALL should be explored more intensively.

Optimizing antimetabolite-based chemotherapy for the treatment of childhood acute lymphoblastic leukaemia.