Polymorphisms In Folate Pathway Research Articles

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

Genetic factors may play an important role in susceptibility to childhood acute lymphoblastic leukemia (ALL). The aim of our study was to evaluate the associations of genetic polymorphisms in folate pathway and DNA repair genes with susceptibility to ALL. In total, 121 children with ALL and 184 unrelated healthy controls of Slovenian origin were genotyped for 14 polymorphisms in seven genes of folate pathway, base excision repair and homologous recombination repair (TYMS, MTHFR, OGG1, XRCC1, NBN, RAD51, and XRCC3). In addition, the exon 6 of NBN was screened for the presence of mutations using denaturing high performance liquid chromatography. Twelve polymorphisms were in Hardy–Weinberg equilibrium in controls and their genotype frequencies were in agreement with those reported in other Caucasian populations. Among the investigated polymorphisms and mutations, NBN Glu185Gln significantly decreased susceptibility to B-cell ALL (p=0.037), while TYMS 3R allele decreased susceptibility to T-cell ALL (p=0.011). Moreover, significantly decreased susceptibility to ALL was observed for MTHFR TA (p=0.030) and RAD51 GTT haplotypes (p=0.016). Susceptibility to ALL increased with the increasing number of risk alleles (ptrend=0.007). We also observed significant influence of hOGG–RAD51 and NBN–RAD51 interactions on susceptibility to ALL. Our results suggest that combination of several polymorphisms in DNA repair and folate pathways may significantly affect susceptibility to childhood ALL.

Folate pathway gene polymorphisms, maternal folic acid use, and risk of childhood acute lymphoblastic leukemia.

Several studies suggest that maternal folic acid supplementation before or during pregnancy protects against childhood acute lymphoblastic leukemia (ALL). We investigated associations between ALL risk and folate pathway gene polymorphisms, and their modification by maternal folic acid supplements, in a population-based case-control study (2003-2007). All Australian pediatric oncology centers provided cases; controls were recruited by national random digit dialing. Data from 392 cases and 535 controls were included. Seven folate pathway gene polymorphisms (MTHFR 677C>T, MTHFR 1298A>C, MTRR 66A>G, MTR 2756 A>G, MTR 5049 C>A, CBS 844 Ins68, and CBS 2199 T>C) were genotyped in children and their parents. Information on prepregnancy maternal folic acid supplement use was collected. ORs were estimated with unconditional logistic regression adjusted for frequency-matched variables and potential confounders. Case-parent trios were also analyzed. There was some evidence of a reduced risk of ALL among children who had, or whose father had, the MTRR 66GG genotype: ORs 0.60 [95% confidence interval (CI) 0.39-0.91] and 0.64 (95% CI, 0.40-1.03), respectively. The ORs for paternal MTHFR 677CT and TT genotypes were 1.41 (95% CI, 1.02-1.93) and 1.81 (95% CI, 1.06-3.07). ORs varied little by maternal folic acid supplementation. Some folate pathway gene polymorphisms in the child or a parent may influence ALL risk. While biologically plausible, underlying mechanisms for these associations need further elucidation. Folate pathway polymorphisms may be related to risk of childhood ALL, but larger studies are needed for conclusive results.

Highlights of This Issue

Bonn and colleagues investigated the effect of physical activity after a prostate cancer diagnosis in a large cohort. Statistically significantly lower overall mortality rates were found among men engaged in walking/bicycling ≥20 min/day, performing household work ≥1 h/day, or exercising ≥1 h/week, compared to less active men. Higher levels of physical activity were associated with reduced rates of overall and prostate cancer–specific mortality, further strengthening previous results indicating beneficial effects of physical activity on survival among men with prostate cancer.Fecal immunochemical testing (FIT) is one of the primary screening tests for colorectal cancer. Clarke and colleagues performed a meta-analysis to determine if uptake of FIT screening differs between men and women. Nineteen studies met the authors' inclusion criteria. Male FIT uptake was significantly lower than female uptake and this male/female difference persisted regardless of study design, screening organization, number of samples, age range, and setting. Further investigation is required to identify the factors that influence male nonparticipation in FIT screening.Milne and colleagues investigated associations between pediatric acute lymphoblastic leukemia (ALL) risk and folate pathway gene polymorphisms and their modification by maternal folic acid supplements. Seven folate pathway gene polymorphisms were genotyped in 392 pediatric ALL cases and pre-pregnancy maternal folic acid supplement use information was collected. The authors report some folate-pathway gene polymorphisms in the child or parent may influence ALL risk. Folate pathway polymorphisms may be related to risk of childhood ALL, but larger studies are needed for conclusive results.Schmit and colleagues searched for miRNA-related polymorphisms contributing to colorectal cancer etiology using the Axiom miRNA Target Site Genotyping Array containing 237,858 markers. The study included 596 cases from the Molecular Epidemiology of Colorectal Cancer study. The authors identified twenty-three markers with P values less than 5.0E–04 and replicated a previously published locus within the 3′-untranslated region of the insulin receptor gene INSR. This study demonstrates the potential for a miRNA-targeted genome-wide association study to identify candidate susceptibility loci and prioritize them for functional characterization.

A NOS3 Polymorphism Determines Endothelial Response to Folate in Children with Type 1 Diabetes or Obesity

To determine the effect of polymorphisms in NOS3 and folate pathway enzymes on vascular function and folate status and endothelial response to folate in children with diabetes or obesity. A total of 244 subjects (age 13.8 ± 2.8 years, 125 males) were studied for NOS3 and/or folate pathway polymorphisms using polymerase chain reaction/restriction fragment length polymorphism, including at baseline: 139 with type 1 diabetes; 58 with obesity; and 47 controls. The effect of NOS3 genotype on endothelial response to folate (5 mg) was assessed in 85 subjects with diabetes and 28 obese subjects who received active treatment during intervention trials. Vascular function (flow-mediated dilatation [FMD] and glyceryl trinitrate-mediated dilatation), clinical, and biochemical measurements were assessed at baseline and 8 weeks in folate intervention studies. Folate pathway enzyme and NOS3 polymorphisms did not significantly affect baseline vascular function. The polymorphism in intron 4 of endothelial nitric oxide synthase altered endothelial response to folate significantly: in subjects with diabetes FMD improved by 6.4 ± 5% (insertion carriers) vs 2.3 ± 6.6% (deletion carriers), P = .01; in obese subjects FMD improved by 1.8 ± 5.4% (insertion carriers) and deteriorated by -3.2 ± 7.2% (deletion carriers), P = .05. More subjects carrying the insertion normalized FMD after folate supplementation (insertion 64% vs deletion 28%, χ(2) = 10.14, P = .001). A NOS3 polymorphism predicts endothelial response to folate in children with diabetes or obesity, with implications for vascular risk and folate intervention studies.

The influence of folate pathway polymorphisms on high-dose methotrexate-related toxicity and survival in children with non-Hodgkin malignant lymphoma.

BackgroundWe evaluated the influence of folate pathway polymorphisms on high-dose methotrexate (HD-MTX) related toxicity in paediatric patients with T-cell non-Hodgkin lymphoma (NHL).Patients and methodsIn total, 30 NHL patients were genotyped for selected folate pathway polymorphisms.ResultsCarriers of at least one MTHFR 677T allele had significantly higher MTX area under the time-concentration curve levels at third MTX cycle (P = 0.003). These patients were also at higher odds of leucopoenia (P = 0.006) or thrombocytopenia (P = 0.041) and had higher number of different HD-MTX-related toxicity (P = 0.035) compared to patients with wild-type genotype.ConclusionsOur results suggest an important role of MTHFR 677C>T polymorphism in the development of HD-MTX-related toxicity in children with NHL.

Polymorphisms in folate pathway and pemetrexed treatment outcome in patients with malignant pleural mesothelioma.

IntroductionA combination of pemetrexed and cisplatin has been shown to improve the outcome in patients with malignant pleural mesothelioma (MPM), however, there is a great heterogeneity in treatment response among patients. The aim of our study was to evaluate the influence of polymorphisms in folate pathway and transporter genes on pemetrexed treatment outcome in Slovenian patients with MPM.MethodsMPM patients treated with pemetrexed in the course of a prospective randomized clinical trial were genotyped for nineteen polymorphisms in five genes of folate pathway and six transporter genes. Logistic regression was used to assess the influence of polymorphisms on treatment efficacy and toxicity, while Cox regression was used to determine their influence on progression-free and overall survival.ResultsPatients with at least one polymorphic MTHFD1 rs2236225 allele had a significantly lower response rate (p = 0.005; odds ratio [OR] = 0.12; 95% confidence interval [CI] = 0.03−0.54) and shorter progression-free survival (p = 0.032; hazard ratio [HR] = 3.10; 95% CI = 1.10−8.74) than non-carriers. Polymorphisms in transporter genes did not influence survival; however, several were associated with toxicity. Liver toxicity was significantly lower in carriers of polymorphic ABCC2 rs2273697 (p = 0.028; OR = 0.23; 95% CI = 0.06−0.85), SLCO1B1 rs4149056 (p = 0.028; OR = 0.23; 95% CI = 0.06−0.85) and rs11045879 (p = 0.014; OR = 0.18; 95% CI = 0.05−0.71) alleles compared to non-carriers, as well as in patients with SLCO1B1 GCAC haplotype (p = 0.048; OR = 0.17; 95% CI = 0.03−0.98). Gastrointestinal toxicity was much more common in patients with polymorphic ABCC2 rs717620 allele (p = 0.004; OR = 10.67; 95% CI = 2.15−52.85) and ABCC2 CAG haplotype (p = 0.006; OR = 5.67; 95% CI = 1.64−19.66).ConclusionsMTHFD1 polymorphism affected treatment response and survival, while polymorphisms in ABCC2 and SLCO1B1 transporter genes influenced the risk for toxicity. These polymorphisms could serve as potential markers of pemetrexed treatment outcome in patients with MPM.

AB0036 Analysis of genetic polymorphisms in folate pathway affecting the efficacy of methotrexate in japanese patients with rheumatoid arthritis

BackgroundLow-dose methotrexate (MTX) is an anchor drug in the medication of rheumatoid arthritis (RA). However, MTX exhibited large inter-individual and inter-ethnic differences in the dose required for its anti-inflammatory effect....

Association of genetic polymorphisms in the folate pathway with efficacy and toxicity of methotrexate in pediatric osteosarcoma.

10051 Background: Osteosarcoma is the most common childhood malignant bone tumor. Methotrexate (MTX), one of the main drugs used for osteosarcoma, is a representative folic acid antagonist. Genetic polymorphisms in folate pathway genes are expected to influence the response and toxicity of high-dose MTX therapy. However, there are scarce data available regarding associations between genetic polymorphisms and pediatric osteosarcoma. This study evaluated the effect of common genetic polymorphisms in the folate metabolic pathway on overall survival, event-free survival and histological response to neoadjuvant chemotherapy including high-dose MTX. In addition, whether these genetic polymorphisms affect the concentrations of MTX and toxicity after high-dose MTX therapy for osteosarcoma was investigated. Methods: Blood and tissue samples from 48 osteosarcoma patients who had completed chemotherapy were obtained, and the following polymorphisms were analyzed; RFC1 80G>A, DHFR 829C>T, MTHFR 677C>T, MTHFR 1298A>C, AMPD1 34C>T, ATIC 347C>G, and ITPA 94C>A. Associations between candidate polymorphisms and survival, histological response (tumor necrosis rate) and MTX level and toxicity after high-dose MTX therapy were analyzed. Results: Event-free survival significantly decreased in DHFR 829 CC homozygote (P=0.045). Variant carriers of MTHFR 677C>T had tendency towards poor histological response (P=0.078). MTX concentration was significantly associated with RFC1 80G>A polymorphism (P=0.027). Liver toxicity after high-dose MTX was associated with ATIC 347C>G (P=0.043) and tended to increase in carriers of MTHFR 677C>T (P=0.069). Severe stomatitis was associated with RFC1 80G>A (P=0.012). Conclusions: This study has demonstrated that several genetic polymorphisms in folate pathway can significantly influence therapeutic response, clinical outcome and MTX level and toxicity after high-dose MTX therapy in osteosarcoma patients. If these associations are independently validated, these variants could be used as genetic predictors of clinical outcome in the treatment of patients with osteosarcoma, aiding the development of tailored therapeutic approaches.

Influence of folate pathway polymorphisms on high-dose methotrexate-related toxicity and survival in childhood acute lymphoblastic leukemia

The prediction of high-dose methotrexate (HD-MTX) toxicity is a key issue in the individualization of treatment in childhood acute lymphoblastic leukemia (ALL). Our aim was to evaluate the influence of MTX pathway polymorphisms on HD-MTX treat- ment outcome in children with ALL. In total, 167 children with ALL were genotyped for methylenetetrahydrofolate dehydrogenase (MTHFD1) 1958G > A, methylenetetrahydrofolate reductase (MTHFR) 677C > T and 1298A > C and thymidylate synthase (TYMS) 2R > 3R polymorphisms. The MTHFD1 1958A allele significantly reduced the odds of hepatotoxicity (adjusted p = 0.009), while the TYMS 3R allele significantly reduced the odds of leukocytopenia and thrombocytopenia (adjusted p = 0.005 and adjusted p = 0.002, respectively). MTHFR polymorphisms did not influence HD-MTX-related toxicity, but a significant effect of MTHFR 677C > T–TYMS 2R > 3R and MTHFD1 1958G > A–MTHFR 677C > T interactions on HD-MTX-related toxicity was observed. None of the investigated polymorphisms influenced survival. Our study suggests an important role of polymorphisms and gene–gene interactions within the folate pathway in HD-MTX-related toxicity in childhood ALL.

Folate pathway polymorphisms predict deficits in attention and processing speed after childhood leukemia therapy

Neurocognitive impairment occurs in 20-40% of childhood acute lymphoblastic leukemia (ALL) survivors, possibly mediated by folate depletion and homocysteine elevation following methotrexate treatment. We evaluated the relationship between folate pathway polymorphisms and neurocognitive impairment after childhood ALL chemotherapy. Seventy-two childhood ALL survivors treated with chemotherapy alone underwent a neurocognitive battery consisting of: Trail Making Tests A (TMTA) and B (TMTB), Grooved Pegboard Test Dominant-Hand and Nondominant-Hand, Digit Span subtest, and Verbal Fluency Test. We performed genotyping for: 10-methylenetetrahydrofolate reductase (MTHFR 677C>T and MTHFR 1298A>C), serine hydroxymethyltransferase (SHMT 1420C>T), methionine synthase (MS 2756 A>G), methionine synthase reductase (MTRR 66A>G), and thymidylate synthase (TSER). Student's two sample t-test and analysis of covariance were used to compare test scores by genotype. General impairment on the neurocognitive battery was related to MTHFR 1298A>C (P = 0.03) and MS 2756A>G (P = 0.05). Specifically, survivors with MTHFR 1298AC/CC genotypes scored, on average, 13 points lower on TMTB than those with MTHFR 1298AA genotype (P = 0.001). The MS 2756AA genotype was associated with a 12.2 point lower mean TMTA score, compared to MS 2756 AG/GG genotypes (P = 0.01). The TSER 2R/3R and 3R/3R genotypes were associated with an 11.4 point lower mean score on TMTB, compared to the TSER 2R/2R genotype (P = 0.03). Survivors with ≥6 folate pathway risk alleles demonstrated a 9.5 point lower mean TMTA score (P = 0.06) and 14.5 point lower TMTB score (P = 0.002) than survivors with <6 risk alleles. Folate pathway polymorphisms are associated with deficits in attention and processing speed after childhood ALL therapy.

Association between selected folate pathway polymorphisms and nonsyndromic limb reduction defects: a case–parental analysis

Inadequate folate status resulting from either genetic variation or nutritional deficiencies has been associated with an increased risk of congenital malformations including orofacial clefting, limb, cardiac and neural tube defects. Few epidemiological studies have examined the association between limb reduction defects (LRDs) and folate-related genetic polymorphisms other than MTHFR 677C→T. We conducted a case-parental analysis of 148 families who participated in the National Birth Defects Prevention Study to examine the association between nonsyndromic transverse and longitudinal LRDs with five single nucleotide polymorphisms (SNPs) in genes encoding enzymes in folate and methionine pathways. Log-linear Poisson regression, adapted for analysis of case-parental data assuming an additive genetic model, was used to estimate genetic relative risks and 95% confidence intervals for the association between LRDs and each SNP. Among women who did not take multivitamin supplements, the MTHFR 677T variant acts via the offspring's genome to increase the risk of LRDs. No association between LRDs and any fetal SNP was found among women who used multivitamin supplements. These results suggest the possibility that initiating folic acid supplementation prior to pregnancy may reduce the risk of having a LRD-affected pregnancy, especially in women whose offspring inherit one or two copies of the MTHFR 677T variant.

Associations of Folate, Vitamin B12, Homocysteine, and Folate-Pathway Polymorphisms with Prostate-Specific Antigen Velocity in Men with Localized Prostate Cancer

Vitamin B(12), holo-haptocorrin, and the folate-pathway single-nucleotide polymorphisms MTR 2756A>G and SHMT1 1420C>T have been associated with an increased risk of prostate cancer. We investigated whether these and other elements of folate metabolism were associated with prostate-specific antigen (PSA) velocity (PSAV) as a proxy measure of prostate cancer progression in men with localized prostate cancer. We measured plasma folate, B(12), holo-haptocorrin, holo-transcobalamin, total transcobalamin, and total homocysteine at diagnosis in 424 men (ages 45-70 years) with localized prostate cancer in a U.K.-wide population-based cohort. Thirteen folate-pathway single-nucleotide polymorphisms were genotyped for 311 of these men. Postdiagnosis PSAV (continuous measure and with a threshold set a priori at 2 ng/mL/y) was estimated from repeat PSA measurements. Median follow-up time was 2.5 (range, 0.8-5.6) years. Vitamin B(12), holo-haptocorrin, holo-transcobalamin, total transcobalamin, and total homocysteine were not associated with postdiagnosis PSAV. Folate was associated with an increased risk of PSAV >2 ng/mL/y [odds ratio (OR) per unit increase in log(e) concentration, 1.57; 95% confidence interval (95% CI), 0.98-2.51; P = 0.06]. MTRR 66A>G (rs1801394) was associated with a reduced risk (recessive model OR, 0.33; 95% CI, 0.11-0.97; P = 0.04), and SHMT1 1420C>T (rs1979277) with an increased risk (per-allele OR, 1.49; 95% CI, 0.93-2.37; P = 0.09) of PSAV >2 ng/mL/y. We found weak evidence that higher folate levels may be associated with faster progression of localized prostate cancer. Long-term follow-up is needed to test associations with metastases and mortality, and the observed genetic effects require replication.

Variants in folate pathway genes as modulators of genetic instability and lung cancer risk

Genetic instability plays a crucial role in cancer development. The genetic stability of the cell as well as DNA methylation status could be modulated by folate levels. Several studies suggested associations between polymorphisms in folate genes and alterations in protein expression and variations in serum levels of the folate. The objective of this study was to investigate the effect of folate pathway polymorphisms on modulating genetic instability and lung cancer risk. Genotyping of 5 SNPs in folate pathway genes and cytokinesis-blocked micronucleus cytome assay analysis (to determine the genetic instability at baseline and following NNK treatment) was conducted on 180 lung cancer cases and 180 age-, gender-, and smoking-matched controls. Our results showed that individually, folate pathway SNPs were not associated with cytogenetic damage or lung cancer risk. However, in a polygenic disease such as lung cancer, gene-gene interactions are expected to play an important role in determining the phenotypic variability of the diseases. We observed that interactions between MTHFR677, MTHFR1298, and SHMT polymorphisms may have a significant impact on genetic instability in lung cancer patients. With regard to cytogenetic alterations, our results showed that lymphocytes from lung cancer patients exposed to the tobacco-specific carcinogen 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone [NNK] had considerably increased frequency of cytogenetic damage in presence of MTHFR 677, MTHFR 1298, and SHMT allelic variants. These findings support the notion that significant interactions may potentially modulate the lung cancer susceptibility and alter the overall the repair abilities of lung cancer patients when exposed to tobacco carcinogens such as NNK.

The impact of Folate Pathway Polymorphisms Combined to Nutritional Deficiency As a Maternal Predisposition Factor for Down Syndrome

Polymorphisms in genes encoding folate metabolizing enzymes have been linked to an increased risk of maternal chromosomal nondisjunction in several populations. With the purpose of evaluating this relationship, we compared the frequencies of 677C>T and 1298A>C polymorphisms in the methylenetetrahydrofolate reductase gene (MTHFR) and 66A>G in the methionine synthase reductase gene (MTRR) between 103 young mothers of Down syndrome (DS) individuals and 108 control mothers, whose offspring was karyotypically normal, correlating it with an estimative of folate and – related micronutrients levels intake. Maternal and paternal transmission frequencies of MTHFR 677T allele were also examined to access potential parent-of-origin effects. PCR-RFLP for genomic DNA was accomplished and allele/genotype frequencies differences were determined using the x2 test, whereas pattern of transmission of the MTHFR 677 allele was analyzed by transmission disequilibrium test. None of the polymorphisms seemed to be more frequent in case mothers than in controls, either individually or combined. The estimative of nutritional intake revealed that folate consumption median was inadequate in both groups, whereas methionine and zinc consumption medians were significantly greater in control mothers. It suggests that such interaction between genetic profile and environment could predispose this sub group of women to have a DS child. Additional studies focusing the interaction between nutritional intakes, biochemical data and folate pathway polymorphisms are needed to confirm the present results. The possibility of neutralize the biochemical negative effects of folate-related polymorphisms through oral supplementation could provide new targets for DS prevention.