The association of folate pathway and DNA repair polymorphisms with susceptibility to childhood acute lymphoblastic leukemia

Detecting Gene-Gene Interaction among DNA Repair Genes in Chinese non-Syndromic Cleft lip with or Without Palate Trios

OBJECTIVE

The objective of this study is to investigate the gene-gene interactions associated with NSCL/P among DNA repair genes.

DESIGN

This study included 806 NSCL/P case-parent trios from China. Quality control process was conducted for genotyped single nucleotide polymorphisms (SNPs) located in six DNA repair genes (ATR, ERCC4, RFC1, TYMS, XRCC1 and XRCC3). We tested gene-gene interactions with Cordell's method using statistical package TRIO in R software. Bonferroni corrected significance level was set as P = 4.24 × 10-4. We also test the robustness of the interactions by permutation tests.

SETTING

Not applicable.

PATIENTS/PARTICIPANTS

A total of 806 NSCL/P case-parent trios (complete trios: 682, incomplete trios: 124) with Chinese ancestry.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURE(S)

Not applicable.

RESULTS

A total of 118 SNPs were extracted for the interaction tests. Fourteen pairs of significant interactions were identified after Bonferroni correction, which were confirmed in permutation tests. Twelve pairs were between ATR and ERCC4 or XRCC3. The most significant interaction occurred between rs2244500 in TYMS and rs3213403 in XRCC1(P = 8.16 × 10-15).

CONCLUSIONS

The current study identified gene-gene interactions among DNA repair genes in 806 Chinese NSCL/P trios, providing additional evidence for the complicated genetic structure underlying NSCL/P. ATR, ERCC4, XRCC3, TYMS and RFC1 were suggested to be possible candidate genes for NSCL/P.

PARP Inhibitors and Haematological Malignancies-Friend or Foe?

Simple Summary

PARP inhibitors are a class of orally active drugs that kill a range of cancer types by inducing synthetic lethality. The usefulness of PARP inhibitors for the treatment of haematological malignancies has begun to be explored in a variety of both pre-clinical models and human clinical trials. Despite being largely considered safe and well tolerated, secondary haematological malignancies have arisen in patients following treatment with PARP inhibitors, raising concerns about their use. In this review, we discuss the potential benefits and risks for using PARP inhibitors as treatments for haematological malignancies.

Abstract

Since their introduction several years ago, poly (ADP-ribose) polymerase (PARP) inhibitors (PARPi) have become the standard of care for breast and gynaecological cancers with BRCA gene mutations. Given that PARPi act by exploiting defective DNA repair mechanisms within tumour cells, they should be ideally suited to combatting haematological malignancies where these pathways are notoriously defective, even though BRCA mutations are rare. To date, despite promising results in vitro, few clinical trials in humans for haematological malignancies have been performed, and additional investigation is required. Paradoxically, secondary haematological malignancies have arisen in patients after treatment with PARPi, raising concerns about their potential use as therapies for any blood or bone marrow-related disorders. Here, we provide a comprehensive review of the biological, pre-clinical, and clinical evidence for and against treating individual haematological malignancies with approved and experimental PARPi. We conclude that the promise of effective treatment still exists, but remains limited by the lack of investigation into useful biomarkers unique to these malignancies.

The association between XRCC3 rs1799794 polymorphism and cancer risk: a meta-analysis of 34 case-control studies

BACKGROUND

Studies on the XRCC3 rs1799794 polymorphism show that this polymorphism is involved in a variety of cancers, but its specific relationships or effects are not consistent. The purpose of this meta-analysis was to investigate the association between rs1799794 polymorphism and susceptibility to cancer.

METHODS

PubMed, Embase, the Cochrane Library, Web of Science, and Scopus were searched for eligible studies through June 11, 2019. All analyses were performed with Stata 14.0. Subgroup analyses were performed by cancer type, ethnicity, source of control, and detection method. A total of 37 studies with 23,537 cases and 30,649 controls were included in this meta-analysis.

RESULTS

XRCC3 rs1799794 increased cancer risk in the dominant model and heterozygous model (GG + AG vs. AA: odds ratio [OR] = 1.04, 95% confidence interval [CI] = 1.00-1.08, P = 0.051; AG vs. AA: OR = 1.05, 95% CI = 1.00-1.01, P = 0.015). The existence of rs1799794 increased the risk of breast cancer and thyroid cancer, but reduced the risk of ovarian cancer. In addition, rs1799794 increased the risk of cancer in the Caucasian population.

CONCLUSION

This meta-analysis confirms that XRCC3 rs1799794 is related to cancer risk, especially increased risk for breast cancer and thyroid cancer and reduced risk for ovarian cancer. However, well-designed large-scale studies are required to further evaluate the results.

Assessment of the relationship between methylenetetrahydrofolate reductase polymorphism and acute lymphoblastic leukemia: Evidence from an updated meta-analysis

OBJECTIVE

The methylenetetrahydrofolate reductase gene C677T polymorphism is closely related to the acute lymphoblastic leukemia. Several case-control studies have investigated this association; however, no conclusions could be drawn. A comprehensive updated meta-analysis is established to explain these contradictions and clarify the overall impact of this variant on the susceptibility to acute lymphoblastic leukemia.

METHODS

Electronic searches were conducted to select published studies prior to June 2018. Pooled odds ratios and stratification analysis were performed under different genetic comparison models, age, and ethnicity.

RESULTS

Totally, 66 case-control studies including 9619 acute lymphoblastic leukemia cases and 17,396 controls were selected. Our analyses showed that methylenetetrahydrofolate reductase C677T polymorphism was protective mainly in Asian and European countries, under all genetic models and regardless of age, but leukemogenic in mixed population.

CONCLUSION

Thus, C677T polymorphism may be a promising acute lymphoblastic leukemia biomarker, but they should be interpreted with caution considering other factors such as folic acid intake, gene-gene and gene-environment interactions.

The contribution of XRCC3 genotypes to childhood acute lymphoblastic leukemia

Purpose

A growing body of evidence shows an association between DNA repair protein genotypes and susceptibility to various cancers. However, few studies have assessed the contribution of the genotype of XRCC3, a homologous repair gene, to the occurrence or prognosis of childhood acute lymphoblastic leukemia (ALL). In this study, we investigated the contribution of seven XRCC3 polymorphisms to childhood ALL.

Patients and methods

We recruited 266 patients with childhood ALL and 266 healthy controls. Genomic DNA was isolated from peripheral blood samples. The XRCC3 rs1799794, rs45603942, rs1799796, rs861530, rs28903081, rs861539, and rs3212057 polymorphic genotypes of each subject were determined through conventional polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis.

Results

Genotypes with the rs861539 polymorphism were significantly associated with the risk of childhood ALL. The allelic distribution analyses suggested a significant association between the T allele at rs861539 with an increased risk of childhood ALL in the Taiwanese population. Polymorphic variants of XRCC3 at rs3212057 or rs28903081 did not exist in the study population. XRCC3 rs1799794, rs45603942, rs1799796, and rs861530 were not significantly associated with the risk of childhood ALL in the Taiwanese population.

Conclusion

Our findings suggest that XRCC3 genotypes with polymorphisms at rs861539 may play a role in determining individual susceptibility to childhood ALL in this Taiwanese population. The polymorphism may be a potential detector and predictor of childhood ALL.

C677T and A1298C polymorphisms of methylene tetrahydrofolate reductase in non-Hodgkin lymphoma: southeast Iran

PURPOSE

Polymorphisms of the methylene tetrahydrofolate reductase (MTHFR) gene have been reported as risk factors for non-Hodgkin lymphoma (NHL) in some populations. Our goal was to evaluate the potential role of A1298C and C677T polymorphisms of MTHFR in risk of NHL in southeast Iran.

METHODS

In the present case-control study, 127 patients with newly diagnosed NHL along with 150 ethnicity- and age-matched controls were examined. The A1298C and C677T polymorphisms were genotyped using the Tetra Amplification Refractory Mutation System polymerase chain reaction method.

RESULTS

There were no significant differences in genotype frequencies between cases and controls regarding either A1298C polymorphism. For this polymorphism, 53.8% of the controls and 54.3% of the patients with NHL showed homozygous wild-type (AA) genotype. Variant 1298C allele was recognized with overall frequency of 34.6% in both groups. Frequencies of CC, CT, and TT genotypes of C677T polymorphism were observed in 73.1%, 25.8%, and 1.3% of the controls, and 64.5%, 33.1%, and 2.4% of the patients with NHL (p>0.05). In combination, CT + TT conferred a significantly higher risk of NHL (odds ratio [OR] 1.5, 95% confidence interval [CI] 0.9-2.4, p = 0.03). Overall, variant 677T allele presented with higher frequency in the patients with NHL than the controls (26.7% versus 21.3%, respectively; OR 1.3, 95% CI 0.8-2.1, p>0.05). Although statistically insignificant, the highest risk of NHL was identified in patients with C677T; A1298C: CT; CC haplotype (OR 4.7, 95% CI 0.4-46.4, p = 0.1).

CONCLUSIONS

Combination of CT and TT genotypes of C677T polymorphism conferred a significantly higher risk for NHL. It is recommended to investigate further the potential role of this polymorphism in NHL development.

The thymidylate synthase enhancer region (TSER) polymorphism increases the risk of thymic lymphoid hyperplasia in patients with Myasthenia Gravis

BACKGROUND

Myasthenia Gravis (MG) is caused, in approximately 80% of the patients, by autoantibodies against the nicotinic acetylcholine receptor (AChR). The disease is often associated with pathological changes of the thymus: thymic epithelial tumours are present in about 10-20% of the patients, while up to 80% of the patients with early disease onset have thymic hyperplasia. Folate metabolism is required for the production of DNA precursors and for proper DNA methylation reactions, and impaired folate metabolism has been often associated with cellular growth and cancer.

METHODS

We investigated if major polymorphisms of folate-related genes, namely MTHFR c.677C>T, MTR c.2756A>G, MTRR c.66A>G and TYMS TSER (a 28-bp tandem repeat in the 5' promoter enhancer region of TYMS) increase the risk of pathological changes of the thymus in AChR+ MG patients. A total of 526 AChR+ MG patients, including 132 patients with normal (involuted) thymus, 146 patients with thymic hyperplasia, and 248 patients with a thymoma were included in the study. Allele and genotype comparisons were performed among the three study groups, after correcting for multiple testing.

RESULTS

The frequency of the TYMS TSER 3R allele was significantly higher in MG patients with thymic hyperplasia (P=0.004), and the TYMS TSER 3R3R genotype was significantly associated with increased risk of thymic hyperplasia [OR 2.71 (95% CI: 1.34-5.47)].

CONCLUSIONS

The 3R allele in the thymidylate synthase promoter enhancer region results in increased protein production, required for the synthesis of DNA precursors. The present study suggests that the TYMS TSER 3R allele increases the risk of thymic lymphoid hyperplasia in AChR+ MG patients.

The methylenetetrahydrofolate reductase 677T-1298C haplotype is a risk factor for acute lymphoblastic leukemia in children

The etiology of acute lymphoblastic leukemia (ALL) is complex, linked with both environmental exposures and genetic factors. Functional variants of the methylenetetrahydrofolate reductase (MTHFR) gene result in disturbance in folate metabolism and may affect susceptibility to cancer. The study was performed to evaluate whether MTHFR C677T and A1298C polymorphisms, analyzed separately and together, are associated with the development of ALL in a population under 18 years of age of Caucasian ancestry.The study included 117 pediatric patients (59% males, mean age at diagnosis 7.4 ± 5.2 years) with ALL, confirmed by conventional immunophenotyping surface-marker analysis and 404 healthy control subjects (48.5% men, mean age 37.7 ± 11.3 years). The MTHFR C677T and A1298C genotypes were analyzed using allele discrimination tests with Taq-Man fluorescent probes.The MTHFR 677TT genotype was related to a 2-fold increase in risk of ALL (P = .014). The 677T-1298C haplotype was found in ALL patients but not in controls (frequency 0.598%; P <.0001). The observed frequency of carriers of this rare haplotype was 12%, including 677CT/1298CC (1.7%), 677TT/1298AC (6.0%), and 677CT/1298AC (4.3%) genotypes.The MTHFR 677T allele alone or in combination with the MTHFR 1298C allele significantly increases the risk of development of ALL in Polish population under 18 years of age. Further studies of haplotype composition in subjects with the 677CT/1298AC genotype are necessary to assess the risk of childhood ALL.

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.