Faculty Bibliography

BACKGROUND: This prospective study describes the procedure-related anxiety, treatment-related anxiety, pain, and nausea experienced by children with standard-risk acute lymphoblastic leukemia (ALL) during the first year of treatment. METHODS: This study was undertaken at 31 Children's Oncology Group (COG) sites. Eligible children who were 2 to 9.99 years old were enrolled in a COG trial for patients with newly diagnosed standard-risk ALL from 2005 to 2009. Parents completed a demographic survey at the baseline and the Pediatric Quality of Life Inventory 3.0 Cancer Module (proxy version) and the General Functioning Scale of the Family Assessment Device 1, 6, and 12 months after the diagnosis. The association between patient-related (age, sex, ethnicity, and treatment), parent-related (marital status and education), and family-related factors (functioning, income, and size) and symptom scores was evaluated. RESULTS: The mean scores for procedure-related anxiety, treatment-related anxiety, and pain improved during the first year of treatment (P < .0389). The mean nausea score was poorer 6 months after the diagnosis in comparison with the other assessments (P = .0085). A younger age at diagnosis was associated with significantly worse procedure-related anxiety (P = .004). An older age (P = .0002) and assignment to the intensified consolidation study arm (P = .02) were associated with significantly worse nausea. CONCLUSIONS: Children with ALL experienced decreasing treatment-related anxiety, procedure-related anxiety, and pain during the first year of treatment. In comparison with scores at 1 and 12 months, nausea was worse 6 months after the diagnosis. Minimization of procedure-related anxiety in younger children and improved nausea control in older children and those receiving more intensified treatment should be prioritized. Cancer 2016. (c) 2016 American Cancer Society.

PURPOSE OF REVIEW: The prognosis for children with the most common childhood malignancy, acute lymphoblastic leukemia (ALL), has improved dramatically. However, the burden of therapy can be substantial, with long-term side-effects, and certain subgroups continue to have a poor outcome. RECENT FINDINGS: The recent discovery of new genetic alterations in high-risk subsets provides targets for precision medicine-based interventions using existing Food and Drug Administration approved agents. Novel immunotherapeutic approaches are being deployed in relapsed ALL, one of the leading causes of cancer cell death in children. Moreover, genomic analysis has charted the evolution of tumor subclones, and relapse-specific alterations now provide a mechanistic explanation for drug resistance, setting the stage for targeted therapy. There is greater recognition that host factors - genetic polymorphisms - influence cancer risk, response to therapy, and toxicity. In the future, it is anticipated that they will be integrated into clinical decision making to maximize cure and minimize side-effects. Recent efforts to limit prophylactic central nervous system irradiation have been successful, thereby sparing many children late neurocognitive impairments. SUMMARY: Integration of advances in precision medicine approaches and novel agents will continue to increase the cure rate and decrease the burden of therapy for childhood ALL.

Standard risk acute lymphoblastic leukemia (SR-ALL) has high cure rates, but requires 2-3 years of therapy. We aimed to (i) prospectively evaluate health-related quality of life (HRQOL) during and after SR-ALL therapy, and (ii) identify associated predictors. Parents of 160 SR-ALL patients enrolled on Children's Oncology Group (COG) therapeutic trial AALL0331 at 31 sites completed the Pediatric Quality of Life Inventory (PedsQL) 4.0 Generic Core Scales (physical, emotional and social functioning) and Family Assessment Device-General Functioning (FAD-GF) at 1, 6 and 12 months after diagnosis, and 3 months post-therapy. Mean PedsQL scores in physical, emotional and social functioning were impaired 1 month after diagnosis but steadily improved. Three months post-therapy, impaired physical and social functioning was observed in 27.8 and 25.8% of patients, respectively. In repeated-measures analysis, problematic family functioning predicted emotional (OR = 1.85, 95% CI 1.03-3.34) and social (OR = 1.99, 95% CI 1.21-3.27) impairment. Larger household size was associated with social impairment (OR = 1.21, 95% CI 1.02-1.45). Adverse neurological event(s) during therapy predicted post-therapy physical (OR = 5.17, 95% CI 1.61-16.63) and social (OR = 8.17, 95% CI 1.19-56.16) impairment. HRQOL 1 month after diagnosis was not predictive of HRQOL 3 months after therapy completion. In conclusion, children with SR-ALL experience considerable impairment in HRQOL at the end of induction, but rapidly improve. However, many still experience physical and social impairment 3 months post-therapy, suggesting a role for continued family and physical functioning support. Longer follow-up is needed to determine if post-therapy deficits change over time.

Primary neuroendocrine carcinomas (NEC) are rare tumors in children and young adults, resulting in a lack of standardized treatment approach. To refine the molecular taxonomy of these rare tumors, we performed whole exome sequencing in a pediatric patient with mediastinal NEC. We identified a somatic mutation in HRAS gene and LOH regions in NF2, MYO18B, and RUX3 genes. In addition, a germline heterozygous somatic variant in BRCA2 with LOH at that same position in the tumor tissue was also found. Our data provide valuable insight into the genomic landscape of this tumor, prompting further investigation of therapeutic targets.

The outcome for pediatric ALL patients that relapse is dismal. A hallmark of relapsed disease is acquired resistance to multiple chemotherapeutic agents, particularly glucocorticoids. In this study, we performed a genome-scale shRNA screen to identify mediators of prednisolone sensitivity in ALL cell lines. The incorporation of this data with an integrated analysis of relapse-specific genetic and epigenetic changes allowed us to identify the MAPK pathway as a mediator of prednisolone resistance in pediatric ALL. We show that knockdown of the specific MAPK pathway members MEK2 and MEK4 increased sensitivity to prednisolone through distinct mechanisms. MEK4 knockdown increased sensitivity specifically to prednisolone by increasing the levels of the glucocorticoid receptor. MEK2 knockdown increased sensitivity to all chemotherapy agents tested by increasing the levels of p53. Furthermore, we demonstrated that inhibition of MEK1/2 with trametinib increased sensitivity of ALL cells and primary samples to chemotherapy in vitro and in vivo. To confirm a role for MAPK signaling in patients with relapsed ALL, we measured the activation of MEK1/2 target ERK in matched diagnosis and relapse primary samples and observed increased pERK levels at relapse. Furthermore, relapse samples have an enhanced response to MEK inhibition compared to matched diagnosis samples in xenograft models. Altogether, our data indicate that inhibition of the MAPK pathway increases chemosensitivity to glucocorticoids and possibly other agents, and is an attractive target for prevention and/or treatment of relapsed disease.

Glucocorticoids are important therapy for acute lymphoblastic leukemia (ALL) and their major adverse effect is osteonecrosis. Our goal was to identify genetic and nongenetic risk factors for osteonecrosis. We performed a genome-wide association study of single nucleotide polymorphisms (SNPs) in a discovery cohort comprising 2285 children with ALL treated on the Children's Oncology Group AALL0232 protocol (NCT00075725 https://clinicaltrials.gov/ct2/show/NCT00075725), adjusting for covariates. The minor allele at SNP rs10989692 (near the glutamate receptor GRIN3A locus) was associated with osteonecrosis (hazard ratio = 2.03, P=3.59x10-7). The association was supported by two replication cohorts, including 361 children with ALL on St. Jude's Total XV protocol (NCT00137111 https://clinicaltrials.gov/ct2/show/NCT00137111) and 309 non-ALL patients from Vanderbilt University's BioVU repository treated with glucocorticoids (odds ratio = 1.87 and 2.26, P = 0.063 and 0.0074 respectively). In a meta-analysis, rs10989692 was also highest ranked (P = 2.68x10-8), and the glutamate pathway was the top ranked pathway (P = 9.8x10-4). Osteonecrosis-associated glutamate receptor variants were also associated with other vascular phenotypes including cerebral ischemia (OR = 1.64, P = 2.5x10-3) and arterial embolism and thrombosis (OR = 1.88, P = 4.2x10-3). In conclusion, osteonecrosis was associated with inherited variations near glutamate receptor genes. Further understanding this association may allow interventions to decrease osteonecrosis.

We previously showed that minimal residual disease (MRD) detection pre-hematopoietic cell transplant (HCT) and acute GvHD (aGvHD) independently predicted risk of relapse in pediatric ALL. In this study we further define risk by assessing timing of relapse and the effects of leukemia risk category and post-HCT MRD. By multivariate analysis, pre-HCT MRD <0.1% and aGvHD by day +55 were associated with decreased relapse and improved event-free survival (EFS). Intermediate leukemia risk status predicted decreased relapse, and improved EFS and overall survival (OS). Patients with pre-HCT MRD 0.1% who did not develop aGvHD compared with those with MRD <0.1% who did develop aGvHD had much worse survival (2 years EFS 18% vs 71%; P=0.001, 2 years OS 46 vs 74%; P=0.04). Patients with pre-HCT MRD <0.1% who did not experience aGvHD had higher rates of relapse than those who did develop aGvHD (40% vs 13%; P= 0.008). Post-HCT MRD led to a substantial increase in relapse risk (HR=4.5, P<0.01). Patients at high risk of relapse can be defined after transplant using leukemia risk category, presence of MRD pre or post HCT, and occurrence of aGvHD. An optimal window to initiate intervention to prevent relapse occurs between day +55 and +200 after HCT.

Minimal residual disease (MRD) is highly prognostic in pediatric B-precursor acute lymphoblastic leukemia (ALL). In COG High Risk B-ALL study AALL0232 we investigated MRD in subjects randomized in a 2X2 factorial design to receive either High-Dose (HD-MTX) or Capizzi Methotrexate (C-MTX) during interim maintenance (IM), or Prednisone or Dexamethasone during induction. Subjects with end induction MRD>=0.1% or those with morphologic slow early response were non-randomly assigned to receive a second IM and delayed intensification phase. MRD was measured by 6-color flow cytometry in one of two reference labs, with excellent agreement between the two. Subjects with end induction MRD<.01% had a 5y EFS of 87+/-1% vs 74+/-4% for those with MRD 0.01%-0.1%; increasing MRD amounts was associated with progressively worse outcome. Subjects converting from MRD positive to negative by end consolidation had a relatively favorable 79+/-5% 5 y DFS vs 39+/-7% for those with MRD>=0.01%. Although HD-MTX was superior to C-MTX, MRD retained prognostic significance in both groups (86+/-2% vs 58+/-4% for MRD negative vs positive C-MTX subjects; 88+/-2% vs 68+/-4% for HD-MTX subjects). Intensified therapy given to subjects with MRD>0.1% did not improve either 5y EFS or OS. However, these subjects showed an early relapse rate similar to that seen in MRD negative ones, with EFS/OS curves for patients with 0.1%-1% MRD crossing those with 0.01%-0.1% MRD at 3 and 4 years, thus suggesting that the intensified therapy altered the disease course of MRD positive subjects. Additional interventions targeted at the MRD positive group may further improve outcome. NCT00075725 at www.clinicaltrials.gov.

Asparaginase is used to treat acute lymphoblastic leukemia (ALL); however, hypersensitivity reactions can lead to suboptimal asparaginase exposure. Our objective was to use a genome-wide approach to identify loci associated with asparaginase hypersensitivity in children with ALL enrolled on St. Jude Children's Research Hospital (SJCRH) protocols Total XIIIA (n = 154), Total XV (n = 498) and Total XVI (n = 271) or Children's Oncology Group protocols POG 9906 (n = 222) and AALL0232 (n = 2,163). Germline DNA was genotyped using the Affymetrix 500K, Affymetrix 6.0, or the Illumina Exome Beadchip array. In multivariate logistic regression, the intronic rs6021191 variant in NFATC2 had the strongest association with hypersensitivity (P = 4.1x10-8, OR = 3.11). RNA-seq data available from 65 SJCRH ALL tumor samples and 52 Yoruban HapMap samples showed that samples carrying the rs6021191 variant had higher NFATC2 expression compared to non-carriers (P = 1.1x10-3 and 0.03, respectively). The top ranked non-synonymous polymorphism was rs17885382 in HLA-DRB1 (P = 3.2x10-6, OR = 1.63), which is in near complete linkage disequilibrium with the HLA-DRB1*07:01 allele we previously observed in a candidate gene study. The strongest risk factors for asparaginase allergy are variants within genes regulating the immune response.