Replication and Meta-analysis of the Association between BDNF Val66Met Polymorphism and Cognitive Impairment in Patients Receiving Chemotherapy (original) (raw)
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Genetic risk factors for cancer-related cognitive impairment: a systematic review
Acta Oncologica
Background: Cancer-related cognitive impairment (CRCI) is a commonly reported complaint among non-CNS cancer patients. Even subtle CRCI may have detrimental effects on quality of life and identifying patients at increased risk for CRCI to improve survivorship care is important. In the present paper, we systematically reviewed available studies of possible genetic risk factors for developing CRCI. Methods: Keyword-based systematic searches were undertaken on 24 July 2018 in PubMed, Web of Science, The Cochrane Library, and CINAHL. Three authors independently evaluated full-texts of identified papers and excluded studies with registration of reasons. Seventeen studies reporting results from 14 independent samples were included for review. Two authors independently quality assessed the included studies. The review was preregistered with PROSPERO (CRD42018107689). Results: Ten studies investigated apolipoprotein E (APOE), with four studies reporting that carrying at least one risk allele (APOE4 (e4)) was associated with CRCI, while six studies found no association. The remaining identified genetic risk variants associated with CRCI located in: COMT, four DNA repair genes, five oxidative stress genes, 22 genes related to breast cancer phenotype, and GNB3. No associations were found between CRCI and genes coding for interleukin-6 (IL6), tumor necrosis factor alpha (TNF), interleukin 1 beta (IL1B), and brain-derived neurotropic factor (BDNF). With the exception of APOE, the genetic risk factors had only been investigated in one or two studies each. Conclusions: Overall, the available evidence of possible genetic risk factors for CRCI is limited. While some research suggests a role for the e4 allele, the literature is generally inconsistent, and the currently available evidence does not allow clear-cut conclusions regarding the role of genetic factors in the development of CRCI. Larger genetic studies and studies investigating additional genetic variants are needed to uncover genetic risk factors for CRCI.
medRxiv (Cold Spring Harbor Laboratory), 2022
Background: There have been no published genome-wide studies of the genetics of cancerand treatment-related cognitive decline (CRCD); the purpose of this study is to identify genetic variants associated with CRCD in older female breast cancer survivors. Methods: Analyses included white non-Hispanic breast cancer women with non-metastatic breast cancer aged 60+ (N=325) and age-, racial/ethnic group, and education-matched controls (N=340) with pre-systemic treatment and one-year follow-up cognitive outcomes. CRCD was assessed using longitudinal domain scores on neurocognitive tests of Attention, Processing speed, and Executive function (APE), and Learning and Memory (LM). Linear regression models of one-year cognition included an interaction term for SNP or gene SNP enrichment*cancer case/control status, controlling for demographic variables and baseline cognition. Results: Cancer patients carrying minor alleles for two SNPs, rs76859653 (chromosome 1) in the hemicentin 1 (HMCN1) gene (p=1.624x10-8), and rs78786199 (chromosome 2, p=1.925x10-8) in an intergenic region had lower one-year APE scores than non-carriers and controls. Genelevel analyses showed the POC5 centriolar protein gene was enriched for SNPs associated with differences in longitudinal LM performance between patients and controls. Conclusion: The SNPs associated with cognition in survivors, but not controls, were members of the cyclic nucleotide phosphodiesterase family, which play important roles in cell signaling, cancer risk, and neurodegeneration. These findings provide preliminary evidence that novel genetic loci may drive susceptibility to CRCD.
The brain derived neurotrophic factor (BDNF) is a neurotrophin that plays an important role in the cell survival, axonal and dendritic growth, and synaptic plasticity. BDNF gene polymorphisms, functional Val66Met mainly, were shown to influence human brain structure and cognition. The aim of the study was to assess the relationship between twelve BDNF gene variants and their haplotypes and cognitive performance measured using the Wisconsin Card Sorting Test (WCST), the Trail Making Test (TMT), the Stroop Test which are to a large extent connected with prefrontal cortex activity. Our sample consisted of 460 healthy participants from Polish population. We detected possible association between five BDNF polymorphisms (rs11030101, rs10835210, rs2049046, rs2030324, rs2883187) and TMT_A. Additionally, one haplotype block made from eleven BDNF variants (rs2883187, rs1401635, rs2049046, rs2030324, rs11030101, rs10835210, rs1013402, rs1401635, rs1013402), as significant linkage disequilibrium appeared. We discovered possible relationships of CACCGCGTACG and CACCGCGTACG haplotypes with TMT_A and TMT_B performance respectively. Our results confirmed the involvement of BDNF in the regulation of psychomotor speed, working memory and executive function in healthy subjects measured by a task engaging visuoperceptual abilities.
Additive effect of BDNF and REST polymorphisms is associated with improved general cognitive ability
Genes, Brain and Behavior, 2008
Brain-derived neurotrophic factor (BDNF) is a pleiotropic protein involved in neuronal proliferation, differentiation, synaptic plasticity and survival. Independent studies investigating association between the functional BDNF Val66Met polymorphism and cognitive abilities have reported some conflicting findings, which may reflect inadequate sample size, variation in testing methods, population stratification or the confounding effects of other genes. To test the latter hypothesis, we screened and genotyped polymorphisms in the RE1-silencing transcription factor (REST) gene whose function includes the downregulation of BDNF expression. We identified an exon 4 hexadecapeptide variable number tandem repeat (VNTR) with either four or five copies that was located within a proline-rich domain and investigated a further five single nucleotide polymorphisms (SNPs). Using a cohort of 746 community-dwelling older volunteers, we analysed REST genotype data both independently and in combination with the BDNF Val66Met polymorphism. A haplotype within the REST gene containing the four copy VNTR and a non-synonymous SNP showed a weak but significant association with a higher score of general intelligence (P 5 0.05). Analysis of this haplotype and the BDNF Val66Met polymorphism in combination showed a significant interaction (global P-value 5 0.0003) with an additive increase in cognitive performance for those possessing the BDNF Val66 allele and the REST haplotype containing the four copy repeat (P 5 0.004). The REST haplotypes in combination with the BDNF Met66 polymorphism did not reduce cognitive performance more than the independent influence of the Met66 allele. Our results suggest that investigation of a common REST polymorphism may be necessary to help reduce contrasting reports based around BDNF Val66Met and cognition.
Polymorphisms of genes controlling homocysteine/folate metabolism and cognitive function
NeuroReport, 2000
Introduction: One of the causes of long-term morbidity associated with the treatment of acute lymphoblastic leukemia (ALL) is late neurotoxicity manifesting as impairment of higher cognitive functions. Cranial radiation therapy (CRT) and chemotherapeutic agents, particularly methotrexate (MTX), are often suggested to be major contributing factors for its development. Homocysteinemia that arises as a result of MTX-induced folate depletion was proposed to play a role in MTX-related neurotoxicity. Several enzymes are essential to maintain the homocysteine levels. Their different functional forms, associated with common genetic polymorphisms, may modulate homocysteine levels and thereby influence MTX-associated neurotoxicity. Objectives: To test this hypothesis we assessed whether the variants of the methylene tetrahydrofolate reductase (MTHFR), methionine synthase (MTR), methionine synthase reductase (MTRR), cystathionine β-synthase (CBS) and endothelial nitric acid synthase (eNOS, NOS3) genes, acting either independently or in conjunction with other risk factors, influenced the cognitive functioning in ALL patients. The influence of the genes was measured by estimating the change in IQ scores over a period of 4 years post ALL diagnosis. Results: Two variants, the CBS 844ins68 polymorphism and NOS3 894T homozygosity, were associated with a change in IQ scores (p = 0.01 and 0.007, respectively). A multivariate model obtained through step-wise selection pointed to the importance of the NOS3 894TT genotype only. This effect appears to be dependent on CRT; IQ decline was apparent among individuals with the 894TT genotype who received radiation therapy (p = 0.03). Furthermore, additional factors affecting IQ were identified, including the treatment administered (i.e., CRT; p = 0.02) and a younger age at diagnosis (p = 0.003), and the modifying effect of the treatment protocols was also noted (p = 0.04). Conclusion: The results suggest that NOS3 genotyping might identify individuals that are susceptible to intellectual impairment following ALL treatment. Highlights
European Neuropsychopharmacology
The complex nature of human cognition has resulted in cognitive genomics lagging behind many other fields in terms of gene discovery using genome-wide association study (GWAS) methods. In an attempt to overcome these barriers, the current study utilized GWAS meta-analysis to examine the association of common genetic variation (~8M single-nucleotide polymorphisms (SNP) with minor allele frequency ⩾ 1%) to general cognitive function in a sample of 35 298 healthy individuals of European ancestry across 24 cohorts in the Cognitive Genomics Consortium (COGENT). In addition, we utilized individual SNP lookups and polygenic score analyses to identify genetic overlap with other relevant neurobehavioral phenotypes. Our primary GWAS meta-analysis identified two novel SNP loci (top SNPs: rs76114856 in the CENPO gene on chromosome 2 and rs6669072 near LOC105378853 on chromosome 1) associated with cognitive performance at the genome-wide significance level (P o 5 × 10 − 8). Gene-based analysis identified an additional three Bonferroni-corrected significant loci at chromosomes 17q21.31, 17p13.1 and 1p13.3. Altogether, common variation across the genome resulted in a conservatively estimated SNP heritability of 21.5% (s.e. = 0.01%) for general cognitive function.
Effect of BDNF val66met polymorphism on declarative memory and its neural substrate: A meta-analysis
Neuroscience & Biobehavioral Reviews, 2012
Brain derived neurotrophic factor (BDNF) is a critical component of the molecular mechanism of memory formation. Variation in the BDNF gene, particularly the rs6265 (val 66 met) single nucleotide polymorphism (SNP), has been linked to variability in human memory performance and to both the structure and physiological response of the hippocampus, which plays a central role in memory processing. However, these effects have not been consistently reported, which may reflect the modest size of the samples studied to date. Employing a meta-analytic approach, we examined the effect of the BDNF val 66 met polymorphism on human memory (5922 subjects) and hippocampal structure (2985 subjects) and physiology (362 subjects). Our results suggest that variations in the rs6265 SNP of the BDNF gene have a significant effect on memory performance, and on both the structure and physiology of the hippocampus, with carriers of the met allele being adversely affected. These results underscore the role of BDNF in moderating variability between individuals in human memory performance and in mediating some of the neurocognitive impairments underlying neuropsychiatric disorders.