Table 1.
Clinical information for the acute lymphoblastic leukemia patients included in the study
| Clinical feature a | BCP ALL (%) | T-ALL (%) |
|---|---|---|
| Number of patients |
663 |
101 |
| Male:female ratio |
1.2 |
2.9 |
| Median age (years) |
4.8 |
9.4 |
| High hyperdiploid (HeH)b |
187 (30%) |
3 (3%) |
| t(12;21)ETV6/RUNX1c |
163 (26%) |
0 (0%) |
| Undefinedd |
105 (17%) |
54 (54%) |
| Non-recurrente |
100 (16%) |
37 (37%) |
| 11q23/MLLc |
28 (4.5%) |
4 (4%) |
| t(1;19)TCF3/PBX1c |
23 (3.5%) |
0 (0%) |
| dic(9;20)c |
20 (3%) |
0 (0%) |
| t(9;22)BCR/ABL1 |
19 (3%) |
1 (<1%) |
| iAMP21c |
10 (1.5%) |
0 (0%) |
| <45 chromosomes |
5 (<1%) |
0 (0%) |
| >67 chromosomes |
3 (<1%) |
2 (2%) |
| First relapsef |
24 |
3 |
| Second relapsef | 5 | 0 |
aThe diagnosis was established at a pediatric oncology center by analysis of bone marrow aspirates with respect to morphology, immunophenotype, and cytogenetics of the leukemic cells. Immunophenotypes (BCP ALL or T-ALL) were defined according to the European Group for the Immunological Characterization of Leukemias. Chromosome banding of bone marrow and/or peripheral blood samples was performed using standard methods. The definition and description of clonal abnormalities followed the recommendations of International System for Human Cytogenetic Nomenclature. Karyotypes were centrally reviewed.
bHigh hyperdiploidy (HeH) was defined as a modal number more than 50 chromosomes.
cFluorescence in situ hybridization and/or reverse-transcriptase polymerase chain reaction were applied to identify t(12;21), t(1;19), 11q23, dic(9;20)(p11-13;q11), and iAMP(21q22).
dUndefined includes patients with no karyotype information available.
eNon-recurrent includes patients with chromosomal abnormalities other than those defined in the recurrent groups.
fDetailed information on relapse samples is available in Additional file 2: Table S15.