Increased risk for CNS relapse in pre-B cell leukemia with the t(1;19)/TCF3-PBX1.

To evaluate the impact of contemporary therapy on the clinical outcome of children with pre-B acute lymphoblastic leukemia (ALL) and the t(1;19)/TCF3/PBX1, we analyzed 735 patients with B-cell precursor ALL treated in four successive protocols at St Jude Children's Research Hospital. The 41 patients with the t(1;19) had a comparable event-free survival to that of the 694 patients with other B-cell precursor ALL (P=0.63; 84.2+/-7.1% (s.e.) vs 84.0+/-1.8% at 5 years). However, patients with the t(1;19) had a lower cumulative incidence of any hematological relapse (P=0.06; 0 vs 8.3+/-1.2% at 5 years) but a significantly higher incidence of central nervous system (CNS) relapse (P<0.001; 9.0+/-5.1% vs 1.0+/-0.4% at 5 years). In a multivariate analysis, the t(1;19) was an independent risk factor for isolated CNS relapse. These data suggest that with contemporary treatment, patients with the t(1;19) and TCF3/PBX1 fusion have a favorable overall outcome but increased risk of CNS relapse.