XRCC3 Thr241Met polymorphism and risk of acute myeloid leukemia in a Romanian population

RAD51 and RAD50 genetic polymorphisms from homologous recombination repair pathway are associated with disease outcomes and organ toxicities in AML

BACKGROUND

Acute myeloid leukemia (AML) is a heterogeneous malignancy that responds to various therapies. The sensitivity of leukemia cells to chemotherapy is affected by the DNA damage response (DDR). In this study, we examined the association between RAD51 rs1801320, XRCC3 rs861539, NBS1 rs1805794, MRE11 rs569143, and RAD50 rs2299014 variants of the homologous recombination repair (HRR) pathway and AML outcomes.

MATERIAL AND METHODS

PCR-RFLP was applied for the genotyping of 67 newly diagnosed cases. We performed Sanger sequencing to confirm the results of RFLP genotyping. Outcomes and organ toxicities were collected and χ2 testing was performed for association analysis.

RESULTS

RAD50 variant allele carriers were protected from renal and hepatic toxicities (p = 0.024 and p = 0.045, respectively), and were associated with resistant disease (p = 0.001). RAD51 variant alleles were protected from liver toxicity (p = 0.031) and correlated with disease resistance (p = 0.012).

CONCLUSION

RAD50 rs2299014 and RAD51 rs1801320 polymorphisms may be useful for drug adjustment in AML.

Molecular Profiling of Kenyan Acute Myeloid Leukemia Patients

Acute myeloid leukemia (AML) is an infrequent disease, and it is associated with high morbidity and mortality. It harbors a unique configuration of cytogenetic abnormalities and molecular mutations that can be detected using microscopic and molecular methods respectively. These genetic tests are core elements of diagnosis and prognostication in high-income countries. They are routinely incorporated in clinical decision making, allowing for the individualization of therapy. However, these tests are largely inaccessible to most patients in Kenya and therefore no data has been reported on this group of patients. The main purpose of this study is to describe the cytogenetic and molecular abnormalities of acute myeloid leukemia patients seen at the hemato-oncology unit of Kenyatta National Hospital. A cross-sectional descriptive study was carried out over a 3-month period on ten patients with a diagnosis of AML. Social demographics and clinical data were collected through a study proforma. A peripheral blood sample was collected for conventional metaphase G-banding technique and next generation sequencing. Particularly, targeted DNA sequencing (Illumina myeloid panel) and whole exome sequencing (WES) were performed. Cytogenetic analysis failed in 10/10 cases. Targeted sequencing was successfully obtained in 8 cases, whereas WES in 7. Cytogenetic studies yielded no results. There were 20 mutations detected across 10 commonly mutated genes. All patients had at least one clinically relevant mutation. Based on ELN criteria, NGS identified three patients with high-risk mutations, affecting TP53 (n = 2) and RUNX1 (n = 1). One patient was classified as favorable (PML-RARA) while 4 were standard risk. However, WT1 mutations associated with unfavorable prognosis were recorded in additional 2 cases. WES showed concordant results with targeted sequencing while unveiling more mutations that warrant further attention. In conclusion, we provide the first molecular profiling study of AML patients in Kenya including application of advanced next generation sequencing technologies, highlighting current limitations of AML diagnostics and treatment while confirming the relevance of NGS in AML characterization.

Ethnicity-stratified analysis of the association between XRCC3 Thr241Met polymorphism and leukemia: an updated meta-analysis

BACKGROUND

Presently, whether X-ray repair cross complementing group 3 (XRCC3) Thr241Met polymorphism is correlated to leukemia risk remains controversial. Because of this reason, the objective of current study is to explore whether XRCC3 Thr241Met polymorphism confers risk to leukemia.

METHODS

Two independent authors systematically and comprehensively searched Pubmed, Embase, the Cochrane library, Google academic, China National Knowledge Infrastructure (CNKI). Search time is from database foundation to March 2021.

RESULTS

Overall, significant associations between leukemia risk and XRCC3 Thr241Met polymorphism were found in Caucasian population by allele contrast (T vs. C: OR 1.20, 95% CI 1.02-1.40), homozygote comparison (TT vs. CC: OR 1.35, 95% CI 1.05-1.73), and recessive genetic model (TT vs. TC/CC: OR 1.31, 95% CI 1.04-1.64).

CONCLUSIONS

The present meta-analysis suggests that the XRCC3 Thr241Met polymorphism may be a risk factor for leukemia in Caucasian population.

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.

Co-occurrence of PML-RARA gene fusion, chromosome 8 trisomy, and FLT3 ITD mutation in a young female patient with de novo acute myeloid leukemia and early death: A CARE case report

RATIONALE

Co-occurrence of cytogenetic and molecular abnormalities is frequently seen in patients with acute myeloid leukemia (AML). The clinical outcome and genetic abnormalities of AML may vary; therefore, genetic investigation must be complex, using several techniques, to have an appropriate characterization of the AML genome and its clinical impact. The available molecular markers can predict prognosis only partially. Acute promyelocytic leukemia subtype M3 (AML M3) is a subtype of AML characterized by the presence of promyelocytic leukemia-retinoic acid receptor alpha (PML-RARA) genes fusion. Targeted treatment with all-trans-retinoic acid (ATRA) and ATRA combined with arsenic trioxide significantly improved the survival of AML M3 patients. Unknown prognostic factors could contribute to the early death of these patients.

PATIENT CONCERNS

We present the case of a young female (20 years old) patient, who presented at the emergency department 5 months after giving birth to her first child, complaining of asthenia, fatigue, general musculoskeletal pain, and fever (38°C), symptoms having been present for the previous 6 days. The patient denied any chronic diseases in her medical and family history.

DIAGNOSIS

Laboratory analysis revealed severe pancytopenia. Cytogenetic and molecular analyzes revealed chromosomal abnormalities (trisomy 8), PML-RARA gene fusion, and fms-like tyrosine kinase 3 (FLT3) gene mutation. The immunophenotypic analysis was also suggestive for AML M3 according to the FAB classification.

INTERVENTIONS

Specific treatment was initiated for AML M3 and for secondary conditions. Molecular and cytogenetic analyzes were performed to have a more detailed characterization of the patient's genome.

OUTCOME

Seventy-two hours after admission, she developed psychomotor agitation, confusion, coma, and convulsion. Subsequent deterioration and early death were caused by intracerebral hemorrhage with multiple localization and diffuse cerebral edema.

LESSONS

The presence of FLT3 internal tandem duplication (ITD) mutation may explain the rapid and progressive degradation of this AML M3 case and it may be used as a prognostic marker even when co-occuring with other markers such as PML-RARA gene fusion and trisomy 8. We consider that FLT3 ITD mutation analysis in young patients with AML should be performed as soon as possible. New strategies for patients' education, AML (or cancers in general) prevention, and treatment are needed.

A literature review and systematic meta-analysis on XRCC3 Thr241Met polymorphism associating with susceptibility of oral cancer

Oral cancer is very common, occurring on head as well as neck region with poor prognosis. The X-ray repair cross-complementing group 3 (XRCC3) gene contained in DNA repairing pathway has been investigated for its functional role in oral cancer. Nevertheless, the corresponding results are inconclusive. This study investigated the association of XRCC3 Thr241Met polymorphism regarding oral cancer risk. Article and literature searches were performed using Embase, Medline, PubMed, Wanfang and China National Knowledge Infrastructure (CNKI) databases with a manual search. The keywords of ‘XRCC3 or X-ray repair cross complementing protein 3’, ‘polymorphism or SNP’, ‘oral cancer or oral squamous cell carcinoma’ and their combinations were used to search literature. In accordance with the criteria of inclusion, we focused on only case-and-control studies with the distribution of genotypes and alleles being available to be extracted. Systematic meta-analysis was conducted via the STATA software (version 11.0). After a comprehensive literature collection and review, 1,615 oral cancer cases and 1,897 matched controls extracted from 7 articles were included for this meta-analysis. Our results show that only Met/Met (TT) genotype with the recessive model was associated with high risk of oral cancer (CC + CT vs. TT, OR=1.81, P=0.001, 95% CI=1.28–2.567). A significant relationship was identified under both homozygous and recessive model in Asians (CC vs. TT: OR=2.15, 95% CI=1.107–4.170, P=0.024; CT + CC vs. TT: OR=2.140, 95% CI=1.105–4.144, P=0.024), but not among Caucasians (P>0.05). The results indicate that XRCC3 241Met allele might be a potential factor for oral cancer risk, particularly among Asian population. A further study using a larger population and more ethnicities should be performed to confirm the findings.

Genetic variants involved in oxidative stress, base excision repair, DNA methylation, and folate metabolism pathways influence myeloid neoplasias susceptibility and prognosis

Myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML) share common features: elevated oxidative stress, DNA repair deficiency, and aberrant DNA methylation. We performed a hospital-based case-control study to evaluate the association in variants of genes involved in oxidative stress, folate metabolism, DNA repair, and DNA methylation with susceptibility and prognosis of these malignancies. To that end, 16 SNPs (one per gene: CAT, CYBA, DNMT1, DNMT3A, DNMT3B, GPX1, KEAP1, MPO, MTRR, NEIL1, NFE2F2, OGG1, SLC19A1, SOD1, SOD2, and XRCC1) were genotyped in 191 patients (101 MDS and 90 AML) and 261 controls. We also measured oxidative stress (reactive oxygen species/total antioxidant status ratio), DNA damage (8-hydroxy-2'-deoxyguanosine), and DNA methylation (5-methylcytosine) in 50 subjects (40 MDS and 10 controls). Results showed that five genes (GPX1, NEIL1, NFE2L2, OGG1, and SOD2) were associated with MDS, two (DNMT3B and SLC19A1) with AML, and two (CYBA and DNMT1) with both diseases. We observed a correlation of CYBA TT, GPX1 TT, and SOD2 CC genotypes with increased oxidative stress levels, as well as NEIL1 TT and OGG1 GG genotypes with higher DNA damage. The 5-methylcytosine levels were negatively associated with DNMT1 CC, DNMT3A CC, and MTRR AA genotypes, and positively with DNMT3B CC genotype. Furthermore, DNMT3A, MTRR, NEIL1, and OGG1 variants modulated AML transformation in MDS patients. Additionally, DNMT3A, OGG1, GPX1, and KEAP1 variants influenced survival of MDS and AML patients. Altogether, data suggest that genetic variability influence predisposition and prognosis of MDS and AML patients, as well AML transformation rate in MDS patients. © 2016 Wiley Periodicals, Inc.

Susceptibility to Breast Cancer and Intron 3 Ins/Del Genetic Polymorphism of DNA Double-Strand Break Repair Gene XRCC4

BACKGROUND

Since genetic variations in X-ray cross-complementing group 4 (XRCC4; OMIM: 194363) repair gene might be associated with a reduction in cellular DNA repair capacity, it is hypothesized that XRCC4 Ins/Del (I/D) polymorphism (in intron 3 of the gene; rs28360071) may be a risk factor for breast cancer. Therefore, the present case-control study was carried out.

METHODS

The present case-control study included 407 females with breast cancer and a total of 394 healthy females from the general population matched with patients according to age. Genotypic analysis for the XRCC4 I/D polymorphism was performed by PCR. In order to investigate the effect of XRCC4 I/D polymorphism on age at diagnosis of breast cancer, the Kaplan-Meier survival analysis and the Cox proportional hazards regression model were used.

RESULTS

Based on the present case-control study, the ID (OR=0.95, 95% CI: 0.69-1.31, P=0.781) and DD (OR=1.24, 95% CI: 0.84-1.83, P=0.274) genotypes were not associated with breast cancer risk compared with the II genotype. Based on the Cox regression model, there was significant association between genotypes of I/D polymorphism and age at diagnosis of breast cancer (ID+DD vs II; HR=0.79, 95% CI: 0.64-0.98, P=0.036).

CONCLUSION

Although there was no significant association between XRCC4 I/D polymorphism and risk of breast cancer, patients having the II genotype have lower age at diagnosis in comparison with patients having ID+DD genotypes.

The hMLH1 -93G>A Polymorphism and Risk of Ovarian Cancer in the Chinese Population

Background

As a mismatch repair (MMR) gene, hMLH1 plays an important role in the maintenance of chromosomal integrity. Several studies have investigated the associations of hMLH1 -93G>A (rs1800734) and Ile219Val (rs1799977) in diverse tumor types with discordant results, but their roles in ovarian cancer in the Chinese population remains to be elucidated.

Methods

In a case-control analysis, we assessed the association between these two polymorphisms and ovarian cancer risk in 421 ovarian cancer patients and 689 control subjects in the Chinese population using logistic regression.

Results

We found that the variant hMLH1 genotypes (-93AA and AG) are associated with risk of ovarian cancer (adjusted odds ratio [OR] = 2.02, 95% confidence interval [CI] = 1.42–2.89) compared with the -93GG genotype. The A allele increases the risk of ovarian cancer in a dose-dependent manner (P<10⁻⁴). Functional test showed that -93A allele increased hMLH1 promoter transcriptional activity and the luciferase activity. However, no significant difference was found in the genotype frequencies at the Ile219Val site between the cases and controls.

Conclusions

These findings indicate that the -93G>A polymorphism in hMLH1 may affect ovarian cancer susceptibility in the Chinese population.

Identification of XRCC1 Arg399Gln and XRCC3 Thr241Met Polymorphisms in a Turkish Population and Their Association with the Risk of Chronic Lymphocytic Leukemia

DNA repair systems are essential for cellular functions. Defects due to sequence variations in DNA repair genes can lead severe failure of cell functions and causing many cancer types including leukemia. The aim of this study was to investigate the relationship between XRCC1 Arg399Gln and XRCC3 Thr241Met polymorphisms and susceptibility to chronic lymphocytic leukemia (CLL) in Turkish patients. In addition, genotype distribution of these polymorphisms was compared with other populations. The frequencies of Arg399Gln and Thr241Met single nucleotide polymorphisms were studied in 25 CLL patients and 30 healthy individuals. Single nucleotide polymorphisms were genotyped by PCR-RFLP method. The genotype and allele frequencies of Arg399Gln and Thr241Met polymorphisms were not statistically different between the CLL patients and control group. The allelic frequency similarities were found between Turkish and Brazilian populations for Arg399Gln polymorphism. On the other hand, similarities were found between Turkish and other Caucasian populations for Thr241Met polymorphism. Marked differences were observed between American African versus Turkish and Chinese versus Turkish populations for Arg399Gln and Thr241Met polymorphisms respectively. These results indicate that Arg399Gln and Thr241Met polymorphisms were not associated with the development of CLL in Turkish population and ethnic differences is one of the most important factor for allele frequency differences.

Association of XRCC3 Thr241Met polymorphism and leukemia risk: evidence from a meta-analysis

The relationship between the X-ray repair cross-complementing group 3 (XRCC3) Thr241Met (rs861539) polymorphism and the risk of leukemia remains inclusive or controversial. For a better understanding of the effect of XRCC3 Thr241Met (rs861539) polymorphism on leukemia risk, we performed a meta-analysis. All eligible studies were identified through a search of PubMed, Excerpta Medica Database (Embase) and the Chinese Biomedical Literature Database (CBM) up to August 2013. The association between the XRCC3 Thr241Met (rs861539) polymorphism and leukemia risk was analyzed by means of odds ratios (ORs) and 95% confidence intervals (CI). Ultimately, seven studies with 1070 cases and 1850 controls were included in the meta-analysis. There was no association between Thr241Met polymorphism and leukemia risk in any of the five models in the overall populations (T vs. C: OR = 1.43, 95% CI = 0.95-2.13, p = 0.086; TT vs. CC: OR = 1.71, 95% CI = 0.88-3.33, p = 0.112; TC vs. CC: OR = 1.35, 95% CI = 0.96-1.91, p = 0.089; TT vs.

TC/CC

OR = 1.59, 95% CI = 0.87-2.89, p = 0.132; TT/TC vs. CC: OR = 1.37, 95% CI = 0.98-1.94, p = 0.070). In subgroup analysis according to ethnicity, a significant association was found between XRCC3 Thr241Met (rs861539) polymorphism and leukemia risk in Asian but not in Caucasian or mixed populations. In conclusion, the results suggest no association between XRCC3 Thr241Met (rs861539) polymorphism and leukemia risk in the overall populations but a significant association between XRCC3 Thr241Met (rs861539) polymorphism and leukemia risk in the Asian population. Considering the limited sample size and ethnicities included in the meta-analysis, further large-scale, well-designed studies are needed to confirm our results.

Comprehensive assessment of the association between DNA repair gene XRCC3 Thr241Met polymorphism and leukemia risk

The XRCC3 gene has been suggested to play an important role in the pathogenesis of leukemia risk. But the findings of publications are contradictory. To derive a more precise estimation of the association, we performed a meta-analysis. The PubMed, Embase, and China National Knowledge Infrastructure (CNKI) databases were searched for case-control studies published up to August 2013. The pooled odds ratio (OR) and its corresponding 95% confidence interval (CI) were calculated by using a fixed- or random-effect model. A total of 15 case-control studies met the inclusion criteria and were selected. The pooled OR showed that there was no statistically significant association between XRCC3 Thr241Met polymorphism and leukemia risk in overall including studies, while a risky association was observed for acute myeloid leukemia (AML) (dominant model TT/TC vs. CC: OR = 1.240, 95% CI = 1.018-1.511, P = 0.032). The XRCC3 Thr241Met polymorphism might be associated with risk of leukemia in AML. More studies with larger sample sizes are needed to validate this result.