EFS according to BCL-2 expression levels in primary leukemic cells. The cumulative proportions of patients surviving event-free are shown according to levels of BCL-2 expression on leukemic cells. Patients were divided into two groups: BCL-2 level ≥ median (ie, ≥65 U/cell) and BCL-2 level < median (ie, <65 U/cell). BCL-2 level showed no prognostic effect on EFS.