Role of NOS3 DNA variants in externalizing behavioral problems observed in childhood leukemia survivors

A Systematic Review of Host Genomic Variation and Neuropsychological Outcomes for Pediatric Cancer Survivors

Pediatric survivors of brain tumors and acute lymphoblastic leukemia (ALL) are at risk for long-term deficits in their neuropsychological functioning. Researchers have begun examining associations between germline single nucleotide polymorphisms (SNPs), which interact with cancer treatment, and neuropsychological outcomes. This review synthesizes the impact of treatment-related toxicity from germline SNPs by neuropsychological domain (i.e., working memory, processing speed, psychological functioning) in pediatric survivors. By focusing on specific neuropsychological domains, this review will examine outcome measurement and critique methodology. Fourteen studies were identified and included in this review using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). All studies were published in peer-reviewed journals in English by November 24^th, 2021. Reviewed studies were not of sufficient quality for a meta-analysis due to varying measurement strategies, gaps in reported descriptive variables, and low power. All neuropsychological domains evaluated in this review had associations with SNPs, except fine motor and visual integration abilities. Only five SNPs had consistent neuropsychological findings in more than one study or cohort. Future research and replication studies should use validated measures of discrete skills that are central to empirically validated models of survivors' long-term outcomes (i.e., attention, working memory, processing speed). Researchers should examine SNPs across pathophysiological pathways to investigate additive genetic risk in pediatric cancer survivors. Two SNPs were identified that confer resiliency in neuropsychological functioning, and future work should investigate resiliency genotypes and their underlying biological mechanisms.

Current and coming challenges in the management of the survivorship population

With the widespread adoption of multimodality treatment, 5-year survival of children diagnosed with cancer has improved dramatically in the past several decades from approximately 60% in 1970 to greater than 85% currently. As a result, there are an estimated nearly half a million long-term survivors of childhood cancer living in the United States today. However, survivors have, on average, significantly greater serious medical and psychosocial late effects compared with the general population. In this review, we will discuss the current epidemiology of childhood cancer survivorship, including new methods to estimate the burden of late effects and genetic susceptibility toward late effects. We will also review the development of surveillance guidelines for childhood cancer survivors and early toxicity signals from novel agents now being tested and used increasingly to treat pediatric and adult cancers. We conclude with an overview of current models of survivorship care and areas for future research.

Evidence for Genetic Risk Contributing to Long-Term Adverse Treatment Effects in Childhood Cancer Survivors

Survivors of childhood cancer are at increased risk for therapy-related morbidities and mortality. Although the demographic and clinical factors predicting the risk for long-term effects of cancer therapy are well known, the impact of genetic risk for specific late effects is less clearly defined. Here, we review the extant literature and recent research describing genetic modifiers to risk for the more common late effects of childhood cancer therapy. Results of this research support the need for clinical trials that attempt to further refine risk prediction by incorporating genetic testing into existing algorithms that are primarily based on clinical and demographic factors. Confirmation of genetic predisposition, as defined by reproducibility and prospective validation, would permit therapeutic modification and discussion of individualized survivor care plans even at initial cancer diagnosis.

Adverse neuropsychological effects associated with cumulative doses of corticosteroids to treat childhood acute lymphoblastic leukemia: A literature review

Corticosteroids (CS) are an essential component of childhood acute lymphoblastic leukemia treatments (cALL). Although there is evidence that daily doses of CS can have neuropsychological effects, few studies have investigated the role of cumulative doses of CS in short- and long-term neuropsychological effects in cALL. The aims of this review were to identify the measures used for documenting adverse neuropsychological effects (ANEs) of CS treatment and to study the association between cumulative doses of CS and the presence of ANEs. Twenty-two articles met the inclusion criteria. A variety of measures were used to evaluate outcomes in the domains of emotion, behaviour, neurocognition, and fatigue/sleep. The results suggest that we cannot conclude in favour of an association between the cumulative dosage of CS and ANEs. Yet, several factors including the heterogeneity of measures used to evaluate outcomes and reporting biases may limit the scope of the results. We offer several recommendations that could help improve the future published evidence on ANEs in relation to CS treatment in cALL.

A 2-year dyadic longitudinal study of mothers' and fathers' marital adjustment when caring for a child with cancer

OBJECTIVE

Studies examining interrelationships within parental couples confronted with pediatric cancer are scarce. This study explored dyadic longitudinal associations between both partners' family functioning and mood at diagnosis, and marital adjustment 2 years later.

METHOD

Parents of children (n = 47 couples) with acute lymphoblastic leukemia (ALL) completed the Family Well-Being Assessment and Profile of Mood States-Bipolar Form at diagnosis, and the Locke-Wallace Marital Adjustment Test 2 years post diagnosis. Multilevel linear models using the actor-partner interdependence model (APIM) and controlling for baseline marital adjustment were conducted to evaluate within subject and dyadic longitudinal effects.

RESULTS

For mothers, better marital adjustment 2 years post diagnosis was associated with perception of greater family support and less role conflict and role overload at diagnosis. For fathers, better marital adjustment 2 years post-diagnosis was associated with perception of less role conflict, greater role ambiguity, and being more tired at diagnosis, as well as their partner's perception of less role conflict at diagnosis.

CONCLUSIONS

These findings highlight the importance of considering both partners' perspectives in understanding marital adjustment across treatment phases in parents of children with ALL. Early interventions for couples should be tailored to meet each partner's needs in order to foster resilience within the couple.

Neurocognitive outcomes in long-term survivors of childhood acute lymphoblastic leukemia treated on contemporary treatment protocols: A systematic review

The intensified administration of chemotherapeutic drugs has gradually replaced cranial radiation therapy (CRT) for the treatment of childhood acute lymphoblastic leukemia (ALL). While CRT is often implicated in neurocognitive impairment in ALL survivors, there is a paucity of the literature that evaluates the persistence of neurocognitive deficits in long-term survivors of pediatric ALL who were treated with contemporary chemotherapy-only protocols. Results from this systematic review concurred to the probable cognitive-sparing effect of chemotherapy-based protocols over CRT in long-term survivors. However, coupled with multiple intrinsic and extrinsic factors, survivors who received chemotherapy treatment still suffered from apparent cognitive impairment, particularly in the attention and executive function domains. Notably, there is evidence to suggest that the late neurotoxic effect of methotrexate on survivors' neurocognitive performance may be dose-related. This review also recommends future pharmacokinetic, neuroimaging and genetic studies to illuminate the multifactorial nature of this subject matter and discusses the potential value of neurochemical, physiological, inflammatory and genetic markers for the prediction of susceptibility to neurocognitive impairment in long-term survivors of childhood ALL.

Pharmacogenetic considerations for acute lymphoblastic leukemia therapies

INTRODUCTION

Advances in our understanding of the pathobiology of childhood acute lymphoblastic leukemia (ALL) have led to risk-targeted treatment regimens and remarkable improvement in survival rates. Still, up to 20% of patients experience treatment failure due to drug resistance. Treatment-related toxicities are often life-threatening and are the primary cause of treatment interruption, while ALL survivors may develop complications due to exposure to chemotherapy and/or irradiation during a vulnerable period of development. Different factors may contribute to variable treatment outcomes including patient genetics that has been shown to play important role.

AREAS COVERED

This review summarizes candidate gene and genome-wide association studies that identified common polymorphisms underlying variability in treatment responses including a few studies addressing late effects of the treatment. Genetic variants influencing antileukemic drug effects or leukemic cell biology have been identified, including for example variants in folate-dependent enzymes, influx and efflux transporters, metabolizing enzymes, drug receptor or apoptotic proteins.

EXPERT OPINION

Many pharmacogenetic studies have been conducted in ALL and a variety of potential markers have been identified. Yet more comprehensive insight into genome variations influencing drug responses is needed. Whole exome/genome sequencing, careful study design, mechanistic explanation of association found and collaborative studies will ultimately lead to personalized treatment and improved therapeutic and health outcomes.