Table 1.

Characteristics of the test data. Contents of the Ross data set [26] of expression profiles of childhood acute lymphoblastic leukemias (ALL). The elements indicate the numbers of cases of each leukemic subtype, as defined by cytogenetic and molecular genetic criteria according to the World Health Organization (WHO) classification system [27]. Also outlined are the clinical characteristics and defining genetic change of each leukemic subtype.

Leukemic subtype	Number of cases	Clinical characteristics
B-cell ALL, Hyperdiploid (> 50 chromosomes)	17	Around 25% of childhood ALL cases, favor-able prognosis, gains of chromosomes X, 4, 6, 8, 10, 14, 17, 18 or 21.
B-cell ALL, TCF3/PBX1 gene fusion	18	Around 5% of cases, poor prognosis without intensive treatment, gene fusion corresponds to a balanced translocation between chromo- somes 1 and 19.
B-cell ALL, ETV6/RUNX1 gene fusion	20	Around 25% of cases, favorable prognosis, gene fusion corresponds to a balanced trans- location between chromosomes 12 and 21.
B-cell ALL, BCR/ABL1 gene fusion	15	Around 3% of cases, unfavorable prognosis, gene fusion corresponds to a balanced trans- location between chromosomes 9 and 22.
B-cell ALL, MLL fusions	20	Around 80% of cases in infants, about 5% of older children, unfavorable prognosis, gene fusions correspond to various structural re- arrangements of chromosome band 11q23.
T-cell ALL	14	Unfavorable prognosis.