Clinical features, molecular diagnosis, and treatment outcome of infants with leukemia in Taiwan

Infant leukemia is rare and quite distinct from other childhood leukemias. Differentiating between leukemia and transient myeloproliferative disorder (TMD) in phenotypically normal infants is sometimes difficult. The clinical features and molecular analyses for the fusion transcripts of mixed lineage leukemia (MLL) gene rearrangement in infant leukemia have not been well documented in the Chinese population.

Forty-five consecutive infants diagnosed with leukemia between 1995 and 2007 in a tertiary medical center in Taiwan were studied. Acute lymphoblastic leukemia (ALL) was diagnosed in 23 infants, acute myeloid leukemia (AML) in 21 (including TMD in 4), and juvenile myelomonocytic leukemia (JMML) in 1.

The median white count at diagnosis was higher in ALL than in AML (154.4 × 10(9)/l vs. 58.3 × 10(9)/l, P = 0.05). Chromosome 11q23/MLL abnormalities were present in 77% of ALL and 31% of AML. The 5-year event-free survival (EFS) in infant ALL and AML showed no difference (18% vs. 12%, respectively). The only independent predictor of an adverse prognosis among infants diagnosed with ALL was high presenting white count ≥ 100 × 10(9)/l (P = 0.05). However, no factor was associated with an adverse outcome for infants with AML.

The molecular assessments and prognostic factors of infant leukemia in Taiwan mirror those in developed Western countries. Continued molecular investigations and development of more effective therapies are needed.