DNA repair gene XPD and XRCC1 polymorphisms and the risk of febrile neutropenia and mucositis in children with leukemia and lymphoma

Immune signatures, testing, and management of febrile neutropenia in pediatric cancer patients

INTRODUCTION

Infectious complications, particularly invasive bacterial and fungal infections, are still a major cause of morbidity in pediatric cancer patients and are associated with significant mortality. Over the last few years, there has been much effort in defining risk groups to tailor antimicrobial therapy, and in establishing pediatric-specific guidelines for antimicrobial strategies.

AREAS COVERED

This review provides a critical overview of defining risk groups for infection, diagnostic work-up, antimicrobial prophylaxis, empirical therapy, and treatment of established infections.

EXPERT OPINION

To date, no generalizable risk prediction model has been established for pediatric cancer patients. There is growing interest in defining the impact of the individual genetic background on infectious complications. New diagnostic tools have been developed over the last few years, but they need to be validated in pediatric cancer patients. International, pediatric-specific guidelines for antimicrobial prophylaxis, empirical therapy, and treatment of established infections have recently been published and will harmonize antimicrobial strategies in the future.

Risk factors associated with the development of oral mucositis in pediatric oncology patients: Systematic review and meta-analysis

OBJECTIVES

Oral mucositis (OM) is an acute toxicity related to cancer treatment. This systematic review aimed to identify potential risk factors associated with the development of OM in pediatric cancer patients.

METHODS

A search was performed in four electronic databases to identify studies that analyzed risk factors for OM in pediatric cancer patients.

RESULTS

Nineteen articles were included. The incidence of OM ranged from 20% to 80.4%. Chemotherapeutic agents were potential risk factors for OM in eight (42%) studies. Hematological, hepatic, and renal parameters were also considered in eight (42%) studies, while specific individual factors were reported in five (26.3%) studies. Baseline disease, oral microbiota, genetic profile, and biomarkers were reported in four (21.5%) studies each. Meta-analysis showed that groups submitted to high-risk chemotherapy for OM had a 2.79-fold increased risk of OM.

CONCLUSIONS

Identifying risk factors for OM is essential in order to allow individualized and early prevention treatment.

DNA repair pathways as guardians of the genome: Therapeutic potential and possible prognostic role in hematologic neoplasms

DNA repair pathways, which are also identified as guardians of the genome, protect cells from frequent damage that can lead to DNA breaks. The most deleterious types of damage are double-strand breaks (DSBs), which are repaired by homologous recombination (HR) and non-homologous end joining (NHEJ). Single strand breaks (SSBs) can be corrected through base excision repair (BER), nucleotide excision repair (NER), and mismatch repair (MMR). Failure to restore DNA lesions or inappropriately repaired DNA damage culminates in genomic instability and changes in the regulation of cellular functions. Intriguingly, particular mutations and translocations are accompanied by special types of leukemia. Besides, expression patterns of certain repair genes are altered in different hematologic malignancies. Moreover, analysis of mutations in key mediators of DNA damage repair (DDR) pathways, as well as investigation of their expression and function, may provide us with emerging biomarkers of response/resistance to treatment. Therefore, defective DDR pathways can offer a rational starting point for developing DNA repair-targeted drugs. In this review, we address genetic alterations and gene/protein expression changes, as well as provide an overview of DNA repair pathways.

Predicting mucositis risk associated with cytotoxic cancer treatment regimens: rationale, complexity, and challenges

PURPOSE OF REVIEW

The goals of this review are to describe the complexity of factors influencing the risk of cancer regimen-related mucosal injury (CRRMI), to evaluate the contribution of the innate immune response to CRRMI risk, to compare the concordance of genome analytics in describing mechanism and risk, and to determine if common biological pathways are noted when CRRMI is compared to a disease with a similar phenotype.

RECENT FINDINGS

The pathogenesis of and risk for CRRMI are complex and influenced by multiple intrinsic and extrinsic factors. It is incumbent on analyses to recognize the likelihood that the interplay and cross-talk of synergistically expressed factors is critical and that the contributing weights of these factors is not uniform from patient to patient. Genomically derived analyses imply final common pathways are implicit in phenotype expression.

SUMMARY

The identification of specific factors (both genomic and otherwise) which contribute to CRRMI risk represents an important opportunity to apply principles of precision medicine to the management of regimen-related toxicities.

Associations Between XPD Lys751Gln Polymorphism and Leukemia: A Meta-Analysis

Objectives: The aim of the present study was to define the potential relationship between xeroderma pigmentosum group D (XPD) Lys751Gln polymorphisms and the risk of leukemia.

Methods: A comprehensive search of Pubmed, Web of Science, EBSCO, the Cochrane Library and China National Knowledge Infrastructure was conducted to identify original articles published before March 2017 concerning the association between XPD Lys751Gln polymorphisms and leukemia risk. A literature quality assessment was performed using the Newcastle-Ottawa Scale. Heterogeneity across studies was assessed using I² statistics. Random- or fixed-effects models were used to calculate pooled odds ratios (ORs) in the presence or absence of heterogeneity, respectively. Sensitivity analysis was used to assess the influence of individual studies on the pooled estimate. Publication bias was investigated using funnel plots and Egger’s regression test. All data analyses were performed using Stata 14.0 and Revman 5.3.

Results: Fourteen studies with a total of 7525 participants (2,757 patients; 4,768 controls) were included in this meta-analysis. We found that XPD Lys751Gln polymorphisms significantly increased the risk of developing leukemia in both dominant OR = 1.21, 95%CI [1.10–1.35], P ≤ 0.001) and heterozygote (OR = 1.22, 95%CI [1.09–1.36], P ≤ 0.001) model. An allele model showed a borderline significant increase in leukemia risk (OR = 1.13, 95%CI [1.00–1.27], P = 0.05). A subgroup analysis revealed a consistent association between XPD Lys751Gln polymorphisms and leukemia risk for some genetic models in Caucasian populations, adult or chronic groups, and in almost all models of childhood or acute groups.

Conclusion: Our results indicate that XPD Lys751Gln polymorphism increases the risk of leukemia, especially in childhood and acute cases.

Identifying novel genes and biological processes relevant to the development of cancer therapy-induced mucositis: An informative gene network analysis

Mucositis is a complex, dose-limiting toxicity of chemotherapy or radiotherapy that leads to painful mouth ulcers, difficulty eating or swallowing, gastrointestinal distress, and reduced quality of life for patients with cancer. Mucositis is most common for those undergoing high-dose chemotherapy and hematopoietic stem cell transplantation and for those being treated for malignancies of the head and neck. Treatment and management of mucositis remain challenging. It is expected that multiple genes are involved in the formation, severity, and persistence of mucositis. We used Ingenuity Pathway Analysis (IPA), a novel network-based approach that integrates complex intracellular and intercellular interactions involved in diseases, to systematically explore the molecular complexity of mucositis. As a first step, we searched the literature to identify genes that harbor or are close to the genetic variants significantly associated with mucositis. Our literature review identified 27 candidate genes, of which ERCC1, XRCC1, and MTHFR were the most frequently studied for mucositis. On the basis of this 27-gene list, we used IPA to generate gene networks for mucositis. The most biologically significant novel molecules identified through IPA analyses included TP53, CTNNB1, MYC, RB1, P38 MAPK, and EP300. Additionally, uracil degradation II (reductive) and thymine degradation pathways (p = 1.06-08) were most significant. Finally, utilizing 66 SNPs within the 8 most connected IPA-derived candidate molecules, we conducted a genetic association study for oral mucositis in the head and neck cancer patients who were treated using chemotherapy and/or radiation therapy (186 head and neck cancer patients with oral mucositis vs. 699 head and neck cancer patients without oral mucositis). The top ranked gene identified through this association analysis was RB1 (rs2227311, p-value = 0.034, odds ratio = 0.67). In conclusion, gene network analysis identified novel molecules and biological processes, including pathways related to inflammation and oxidative stress, that are relevant to mucositis development, thus providing the basis for future studies to improve the management and treatment of mucositis in patients with cancer.

Non-infectious chemotherapy-associated acute toxicities during childhood acute lymphoblastic leukemia therapy

During chemotherapy for childhood acute lymphoblastic leukemia, all organs can be affected by severe acute side effects, the most common being opportunistic infections, mucositis, central or peripheral neuropathy (or both), bone toxicities (including osteonecrosis), thromboembolism, sinusoidal obstruction syndrome, endocrinopathies (especially steroid-induced adrenal insufficiency and hyperglycemia), high-dose methotrexate-induced nephrotoxicity, asparaginase-associated hypersensitivity, pancreatitis, and hyperlipidemia. Few of the non-infectious acute toxicities are associated with clinically useful risk factors, and across study groups there has been wide diversity in toxicity definitions, capture strategies, and reporting, thus hampering meaningful comparisons of toxicity incidences for different leukemia protocols. Since treatment of acute lymphoblastic leukemia now yields 5-year overall survival rates above 90%, there is a need for strategies for assessing the burden of toxicities in the overall evaluation of anti-leukemic therapy programs.

The association between XRCC1 Arg399Gln polymorphism and risk of leukemia in different populations: a meta-analysis of case-control studies

Background

Associations between Arg399Gln single-nucleotide polymorphism (SNP) in the XRCC1 gene and leukemia susceptibility have been studied extensively, however, the results are inconsistent. The aim of this study was to determine these associations using meta-analytical methods.

Methods

A meta-analysis was performed to examine the associations between XRCC1 Arg399-Gln SNP and leukemia risk. A literature search of PubMed and Web of Science databases was conducted to identify relevant studies published up to March 10, 2015. The references of the retrieved articles were also screened. All the statistical analyses were conducted using Review Manager software.

Results

The XRCC1 Arg399Gln SNP was found to be associated with increased childhood risk of acute lymphoblastic leukemia among Asians under the dominant (odds ratio [OR] 2.11, 95% confidence interval [CI] 1.50–2.97, P<0.0001), allele contrast (OR 1.72, 95% CI 1.33–2.23, P<0.0001), and homozygote contrast (OR 2.34, 95% CI 1.25–4.36, P=0.008) models. However, no association was found in Caucasians between the SNP and risk of either chronic myeloid leukemia or chronic lymphocytic leukemia under any contrast model.

Conclusion

The findings of the current meta-analysis indicate that the XRCC1 Arg399Gln SNP is a risk factor for childhood lymphoblastic leukemia in Asians.

Risk analysis, diagnosis and management of gastrointestinal mucositis in pediatric cancer patients

Mucositis is a complex inflammatory reaction of the mucous membranes of the alimentary tract upon chemotherapy and radiotherapy treatment in oncology patients. Mucositis can be subdivided in oral and gastrointestinal mucositis (GI mucositis). The damage to the gastrointestinal tract compromises the intestinal function and thereby the nutritional status and the quality of life, and eventually affects survival. The literature on GI mucositis focuses mainly on adults. This review focuses on data available on GI mucositis in pediatric cancer patients. An evaluation of the clinical presentation and consequences of GI mucositis in children is outlined. The review summarizes key issues for clinicians with respect to risk analysis for developing mucositis and the diagnosis of this condition in children. Information on these issues is obtained from clinical trials in children and adults, and from animal models. Diagnostic tools and assessment of severity of GI mucositis in children is elaborated on. Furthermore, the clinical management of the symptoms and consequences of GI mucositis in children, with specific focus on nutritional support, are discussed.

The effect of XPD/ERCC2 Lys751Gln polymorphism on acute leukemia risk: a systematic review and meta-analysis

AIMS

Epidemiological studies have assessed the association between xeroderma pigmentosum group D (XPD) Lys751Gln and acute leukemia risk with conflicting results. We performed this meta-analysis to derive a more precise estimation of the relationship. Pooled odds ratio (OR) with 95% confidence interval (95% CI) was used to assess the strength of the association.

RESULTS

Ten published case-control studies including a total of 1494 cases and 2259 controls were identified. Overall, significant risk effects of Lys751Gln genotype was found under the dominant model (OR=1.16; 95% CI=1.01-1.34; P=0.032). When stratified by clinical types, the variant genotype was associated with the acute myeloid leukemia (AML) risk under the heterozygote comparison (OR=1.20; 95% CI=1.00-1.43; P=0.048), the homozygote comparison (OR=1.35; 95% CI=1.05-1.74; P=0.019) and the dominant model (OR=1.23; 95% CI=1.04-1.45; P=0.015), respectively. Furthermore, significantly increased risks were also pronounced in Caucasian AML patients (the homozygote comparison: OR=1.38; 95% CI=1.07-1.78; P=0.013; the dominant model: OR=1.23; 95% CI=1.03-1.46; P=0.020; and the recessive model: OR=1.26; 95% CI=1.00-1.60; P=0.050). No evident heterogeneities were observed for the overall data under all genetic models. In addition, no statistical evidence for publication bias was found using the method of Begg's and Egger's tests.

CONCLUSION

This meta-analysis suggested that XPD Lys751Gln polymorphism might be a risk factor for AML and Caucasian acute leukemia patients.

Excision repair cross-complementing group 2/Xeroderma pigmentousm complementation group D (ERCC2/XPD) genetic variations and susceptibility to diffuse large B cell lymphoma in Egypt

Diffuse large B-cell lymphoma (DLBCL) is a genetically heterogeneous neoplasm. Although several genetic and environmental factors have been postulated, no obvious risk factors have been emerged for DLBCL in the general population. DNA repair systems are responsible for maintaining the integrity of the genome and protecting it against genetic alterations that can lead to malignant transformation. The current study aimed at investigating the possible role of ERCC2/XPD Arg156Arg, Asp312Asn and Lys751Gln genetic polymorphisms as risk factors for DLBCL in Egypt. The study included 81 DLBCL patients and 100 healthy controls. Genotyping of the studied genetic polymorphisms was performed by polymerase chain reaction-restriction fragment length polymorphism technique. Our results revealed that there was no statistical difference encountered in the distribution of -Asp312Asn and -Lys751Gln polymorphic genotypes between DLBCL cases and controls, thus it could not considered as molecular risk factors for DLBCL in Egyptians. However, Arg156Arg polymorphism at exon-6 conferred twofold increased risk of DLBCL (OR 2.034, 95 %CI 1.015-4.35, p = 0.43), and the risk increased when co-inherited with Lys751Gln at exon-23 (OR 3.304, 95 %CI 1.113-9.812, p = 0.038). In conclusion, ERCC2/XPD Arg156Arg polymorphism might be considered as a genetic risk factor for DLBCL in Egyptians, whether alone or conjoined with Lys751Gln.

XRCC1 Arg399Gln variation and leukemia susceptibility: evidence from 2,647 cases and 5,518 controls

Previous reports implicate XRCC1 Arg399Gln polymorphism as a possible risk factor for several cancers. Increasing studies have been conducted on the association of XRCC1 Arg399Gln polymorphisms with susceptibility to leukemia. However, conflicting results have been generated. The goal of the present study was to derive a more precise estimation of the relationship. Meta-analyses assessing the association of XRCC1 Arg399Gln variation with leukemia were conducted, and subgroup analyses on ethnicity and clinical types were further performed. Eligible studies were identified for the period up to February 2013. Consequently, 16 publications including 17 case-control studies with 2,647 cases and 5,518 controls were selected for analysis. The overall data indicated a significant association of XRCC1 Arg399Gln polymorphism with leukemia risk (Gln/Gln versus Arg/Arg: OR = 1.37, 95% confidence interval (CI) = 1.08-1.74; dominant model: OR = 1.23, 95%CI = 1.03-1.46; recessive model: OR = 1.23, 95%CI = 1.06-1.44). In the subgroup analysis by ethnicity, Gln allele may increase leukemia susceptibility among Asians (Gln/Gln versus Arg/Arg: OR = 1.82, 95%CI = 1.19-2.78; dominant model: OR = 1.53, 95%CI = 1.00-2.33; recessive model: OR = 1.51, 95%CI = 1.11-2.06), but not Caucasians or mixed ethnicities. In the subgroup analysis by clinical types, increased risk was observed in acute lymphocytic leukemia (ALL) subgroup (Gln/Gln versus Arg/Arg: OR = 1.45, 95%CI = 1.09-1.93; recessive model: OR = 1.30, 95%CI = 1.00-1.69), but not in acute myeloid leukemia, chronic lymphocytic leukemia, or chronic myeloid leukemia subgroups, respectively. Collectively, the results of the present study suggest that XRCC1 Arg399Gln polymorphism might be a low-penetrant risk factor for leukemia, particularly among Asians. Homozygous Gln/Gln alleles might have a correlation with increased ALL susceptibility.