CD200/BTLA deletions in pediatric precursor B-cell acute lymphoblastic leukemia treated according to the EORTC-CLG 58951 protocol

Ghazavi, F (2015) Haematologica                                            

Link to abstract: http://www.haematologica.org/content/100/10/1311

CD200 and BTLA recurrent deletions (on 3q13.2) were screened for in 1154 patients (<18 years old) with high-risk precursor B-ALL treated with the EORTC-CLG 58951 protocol and identified in 4.8%. They are strongly associated with ETV6-RUNX1 translocations. CD200/BTLA deletion was associated with higher proportion of positive MRD at end of induction and inferior event free survival (70.2% vs 83.5%) and poorer disease free survival (72.8% vs 84.4%), but not overall survival  (91% vs 87%) at 8 years compared to those without deletion. The highest number of patients with this mutation, were in the poor prognosis group (as per EORTC-CLG classification).  

*Multivariate analysis indicates the deletion of CD200/BTLA as an independent prognostic factor on EFS. This has an implication for disease stratification and therapeutic planning – contextualizes relapsed disease though no prospective testing of intensified therapy.