PROGNOSTIC-SIGNIFICANCE OF THE CD10(-PROGENITOR IMMUNOPHENOTYPE IN CHILDREN WITH ACUTE LYMPHOBLASTIC-LEUKEMIA - A REPORT FROM THE CHILDRENSCANCER GROUP()CD19(+)CD34(+) B)

Leukemic cells from most patients with B-lineage acute lymphoblastic l eukemia (ALL) appear to originate from normal B-lymphocyte precursors. The earliest B-cell progenitors coexpress the antigens CD10, CD19, or CD34 on their cell surfaces. In a large cohort of 2028 children with ALL, we compared treatment outcomes of a subset of B-lineage ALL patie nts with CD10(+)CD19(+)CD34(+) immature B-progenitor leukemia (BPL) to the treatment outcomes of the remaining CD19(+) B-lineage ALL patient s. Pediatric B-Lineage ALL cases enrolled on risk-adjusted ALL treatme nt protocols of the Children's Cancer Group were immunophenotypically classified as BPL or non-BPL. Patients were stratified further into ag e groups of greater than or equal to 1 year and < 12 months. Event-fre e survival (EFS) outcomes were calculated by standard life table metho ds. BPL patients in both age groups generally had more favorable prese nting characteristics than non-BPL controls. Within the age group of g reater than or equal to 1 year, BPL patients had a slightly better EFS outcome than non-BPL patients, with 3-year estimates of 83.9% (SD = 1 .1%) vs. 78.8% (SD = 1.8%), respectively (P = 0.10). Infants with BPL, representing one-fifth of the total infant patient population, had a significantly better EFS outcome than infants with non-BPL (three-year EFS: 82.4%, SD = 9.2% vs. 34.4%, SD = 5.9%, P = 0.006). In univariate analyses, the relative hazard rate (RHR) was 3.73 for non-BPL vs BPL and this marked difference in EFS outcome was maintained at 5 years of follow-up. The favorable prognostic influence of the BPL immunophenot ype for infants remained significant in multivariate analyses with an RHR of 2.72 for non-BPL vs BPL (P = 0.05). CD10(+)CD19(+)CD34(+) immat ure B-progenitor immunophenotype is associated with favorable characte ristics for children with ALL and identifies a subset of infants who a chieve favorable EFS outcomes.