CD200/BTLA deletions were identified in 56 of the patients (4.8%) and were associated with an inferior 8-year event free survival in this treatment protocol [70.2% ? 1.2% for patients with deletions versus 83.5% ? 6.4% for non-deleted cases (hazard ratio 2.02.     ///    CD200/BTLA deletions in pediatric precursor B-cell acute lymphoblastic leukemia treated according to the EORTC-CLG 58951 protocol..     ///    "Genetically, CD200/BTLA deletions were strongly associated with ETV6-RUNX1-positive leukemias (P<0.0001), but were also identified in patients who did not have any genetic abnormality that is currently used for risk stratification. "    ///    "Within the latter population of patients, the presence of CD200/BTLA deletions was associated with inferior event-free survival and overall survival. "