A novel somatic JAK2 kinase-domain mutation in pediatric acute lymphoblastic leukemia with rapid on-treatment development of LOH

作者：Sadras Teresa; Heatley Susan L; Kok Chung H; McClure Barbara J; Yeung David; Hughes Timothy P; Sutton Rosemary; Ziegler David S; White Deborah L^*

来源：Cancer Genetics, 2017, 216: 86-90.

DOI：10.1016/j.cancergen.2017.07.008

• JAK2
• kinase-domain
• lymphoblastic leukemia

We report a novel somatic mutation in the kinase domain of JAK2 (R938Q) in a high-risk pediatric case of B-cell acute lymphoblastic leukemia (ALL). The patient developed on-therapy relapse at 12 months, and interestingly, the JAK2 locus acquired loss of heterozygosity during treatment resulting in 100% mutation load. Furthermore, we show that primary ALL mononuclear cells harboring the JAK2 R938Q mutation display reduced sensitivity to the JAK1/2 ATP-competitive inhibitor ruxolitinib in vitro, compared to ALL cells that carry a more common JAK2 pseudokinase domain mutation. Our findings are in line with previous reports that demonstrate that mutations within the kinase domain of JAK2 are associated with resistance to type I JAK inhibitors. Importantly, given the recent inclusion of ruxolitinib in trial protocols for children with JAK pathway alterations, we predict that inter-patient genetic variability may result in suboptimal responses to JAK inhibitor therapy in a subset of cases. The need for alternate targeted and/or combination therapies for patients who display inherent or developed resistance to JAK inhibitor therapy will be warranted, and we propose that kinase-mutants less sensitive to type I JAK inhibitors may present a currently unexplored platform for investigation of improved therapies.

• 出版日期2017-10