Opposing effects of KDM6A and JDP2 on glucocorticoid sensitivity in T-ALL

Glucocorticoids (GCs) are the cornerstone of acute lymphoblastic leukemia (ALL) therapy. Although mutations in NR3C1, which encodes the GC receptor (GR), and other genes involved in GC signaling occur at relapse, additional mechanisms of adaptive GC resistance are uncertain. We transplanted and treated 10 primary mouse T-lineage acute lymphoblastic leukemias (T-ALLs) initiated by retroviral insertional mutagenesis with GC dexamethasone (DEX). Multiple distinct relapsed clones from 1 such leukemia (T-ALL 8633) exhibited discrete retroviral integrations that upregulated Jdp2 expression. This leukemia harbored a Kdm6a mutation. In the human T-ALL cell line CCRF-CEM, enforced JDP2 overexpression conferred GC resistance, whereas KDM6A inactivation unexpectedly enhanced GC sensitivity. In the context of KDM6A knockout, JDP2 overexpression induced profound GC resistance, counteracting the sensitization conferred by KDM6A loss. These resistant "double mutant" cells with combined KDM6A loss and JDP2 overexpression exhibited decreased NR3C1 mRNA and GR protein upregulation upon DEX exposure. Analysis of paired samples from 2 patients with KDM6A-mutant T-ALL in a relapsed pediatric ALL cohort revealed a somatic NR3C1 mutation at relapse in 1 patient and a markedly elevated JDP2 expression in the other. Together, these data implicate JDP2 overexpression as a mechanism of adaptive GC resistance in T-ALL, which functionally interacts with KDM6A inactivation.

Concurrent Subcutaneous Panniculitis-like T-Cell Lymphoma and B-Cell Acute Lymphoblastic Leukemia in 2 Pediatric Patients

Subcutaneous panniculitis-like T-cell lymphoma is a cutaneous lymphoma characterized by CD8+ T-cell infiltrate in the subcutis that is rare in children. Acute lymphoblastic lymphoma is the most common pediatric malignancy and often presents with fevers and pancytopenia. Herein, we report 2 pediatric patients presenting with subcutaneous panniculitis-like T-cell lymphoma and B-cell acute lymphoblastic lymphoma, distinct hematologic malignancies arising from different lymphoid lineages, with no identifiable germline cancer predisposition.

Survival Impact of Early Post-Transplant Toxicities in Pediatric and Adolescent Patients Undergoing Allogeneic Hematopoietic Cell Transplantation for Malignant and Nonmalignant Diseases: Recognizing Risks and Optimizing Outcomes

In pediatric and adolescent patients undergoing allogeneic hematopoietic cell transplantation, treatment-related toxicities remain a clinical challenge. A paucity of data investigates the risks for and survival impact of treatment-related toxicities in this population. Here the authors assess the relative toxicity of myeloablative, reduced-toxicity, and reduced-intensity conditioning regimens; identify patient-related predictors of post-transplant toxicities; and investigate the impact of early post-transplant toxicities on transplant-related mortality (TRM). In this retrospective study, 164 patients (aged 1 to 22 years) underwent allogeneic stem cell transplantation after busulfan-based conditioning for malignant and nonmalignant diseases between 2000 and 2014. The number of grades III to IV toxicities between days 0 and +30 was calculated for each patient. TRM was calculated to 2 years. Median patient age was 9 years, and median number of toxicities was 3 (range, 0 to 17). The 100-person day incidence of post-transplant toxicities in myeloablative conditioning was not different from the incidence in reduced-toxicity conditioning (13.88 versus 13.59, P = .812). Reduced intensity was less toxic than both myeloablative and reduced toxicity (13.75 versus 8.41, P < .001). Age ≥ 12 years (.276 with SE = .138, P = .045) and unrelated donor transplant (.318 with SE = 0.113, P = .005) were risk factors for ≥3 toxicities. Having ≥3 toxicities or a performance score < 90 conferred higher risk of TRM (P = .021). In pediatric and adolescent patients undergoing hematopoietic cell transplantation, reduced-toxicity conditioning was not significantly less toxic than myeloablative conditioning. Additionally, the number of post-transplant toxicities correlated with the risk of mortality. Further investigations to confirm our findings are warranted.