Polymorphisms in DNA repair pathway genes, body mass index, and risk of non-Hodgkin lymphoma

Screening of BRCA1 variants c.190T>C, 1307delT, g.5331G>A and c.2612C>T in breast cancer patients from North India

The polymorphic variants of BRCA1, which lead to amino acid substitutions, have a known pathogenic role in breast cancer. The present study investigated in North Indian breast cancer patients the association of risk with four reported pathogenic variants of BRCA1: c.190T>C (p.Cys64Arg), 1307delT, g.5331G>A (p.G1738R) and c.2612C>T (p.Pro871Leu). Genotyping was done by PCR-RFLP method in 255 clinically confirmed breast cancer patients and 255 age and gender matched healthy individuals. For c.190T>C, 1307delT and g.5331G>A, all the patients and controls had the wild-type genotype indicating no association with breast cancer risk. For c.2612C>T polymorphism, the frequency of the CC, CT, and TT genotypes was 14.5 vs 15.7%, 59.6 vs 53.7% and 25.9 vs 30.6% in breast cancer patients and controls respectively. The frequency of heterozygotes (CT genotype) was higher in cases than controls but the difference was not statistically significant. Genetic model analysis showed no association of the four analyzed BRCA1 variants with breast cancer risk with any model. The studied variants were not associated with the risk of breast cancer in Punjab, North west India, suggesting a need for further screening of other BRCA1 variants. It is the first reported study on these 4 variants from India.

Novel Associations between BRCA1 Variants C.181 T>G (Rs28897672) and Ovarian Crisk in Saudi Females

BACKGROUND

Mutations in BRCA1 gene have been implicated in ovarian cancers, and BRCA testing may be conducted in high-risk women. This study was designed to determine the frequency of three single nucleotide polymorphisms (SNPs) variants in BRCA1 gene and BRCA1 expression in Saudi females with ovarian cancer.

METHODS

Expression levels of mRNA of BRCA1 gene were studied in 10 ovarian cancer and 10 normal ovarian tissues, by quantitative real time polymerase chain reaction (qPCR). The study also included 28 females who had suffered from ovarian cancer and had been successfully operated upon and 90 healthy females with no history of cancer. Blood was drawn in EDTA tubes and used for extraction of DNA. The genotyping was carried out using Taqman® SNP Genotyping kit by RT-PCR. The variants investigated included c.871 T>C (rs799917), c.1040 G>A (rs4986852), c.181 T>G (rs28897672) in BRCA1 gene.

RESULTS

The c.181 T>G (rs28897672) showed significantly different genotype and allele frequencies between the patients and the control subjects (p value = 0.002 and 0.02, respectively). The genotype TG was significantly protective (OR = 0.36, p value = 0.024). The mRNA expression of BRCA1 gene was found to be low in the ovarian cancer tissues.

CONCLUSIONS

This study showed that c.181 T>G in BRCA1 genes is associated with the development of ovarian cancer in Saudis. More studies are needed to unveil other SNPs that may be associated with ovarian cancer and to understand the mechanism(s) involved in reducing the expression of BRCA1 gene in ovarian cancer tissues.

Association of ERCC2 Gene Polymorphisms with Susceptibility to Diffuse Large B-Cell Lymphoma

BACKGROUND The objective of this study was to detect the association between ERCC excision repair 2, TFIIH core complex helicase subunit (ERCC2) gene polymorphisms and diffuse large B-cell lymphoma (DLBCL) susceptibility. MATERIAL AND METHODS This study used a case-control design. ERCC2 gene rs1799793 (Asp312Asn) and rs13181 (Lys751Gln) polymorphisms were genotyped by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) both in DLBCL patients and healthy controls. The association between ERCC2 gene polymorphisms and DLBCL risk was assessed by χ² test. Odds ratios (ORs) with corresponding 95% confidence intervals (95% CIs) were used to address the association strength. Subgroup analyses were also performed to investigate the genetic effects of ERCC2 polymorphisms on clinical characteristics of DLBCL patients. RESULTS A significant association was discovered between the rs1799793 A allele and increased DLBCL risk (P=0.031, OR=1.928, 95% CI=1.052-3.534). The C allele of rs13181 was obviously associated with elevated DLBCL susceptibility (P=0.047, OR=1.820, 95% CI=1.002-3.305). The subgroup analysis demonstrated that rs1799793 and rs13181 polymorphisms had no relationship with serum lactate dehydrogenase level, nidus number, B-symptoms, Ann Arbor stages, or immunological types in DLBCL cases (P>0.05 for all). CONCLUSIONS Minor allele carriers of ERCC2 gene rs1799793 (Asp312Asn) and rs13181 (Lys751Gln) polymorphisms had higher susceptibility to DLBCL.

Werner syndrome (WRN) gene variants and their association with altered function and age-associated diseases

Werner syndrome (WS) is a heritable autosomal recessive human disorder characterized by the premature onset of several age-associated pathologies including cancer. The protein defective in WS patients, WRN, is encoded by a member of the human RECQ gene family that contains both a DNA exonuclease and a helicase domain. WRN has been shown to participate in several DNA metabolic pathways including DNA replication, recombination and repair, as well as telomere maintenance and transcription modulation. Here we review base pair-level genetic variation that has been documented in WRN, with an emphasis on non-synonymous coding single nucleotide polymorphisms (SNPs) and their associations with anthropomorphic features, longevity and disease risk. These associations have been challenging to identify, as many reported WRN SNP associations appear to be further conditioned upon ethnic, age, gender or other environmental co-variables. The WRN variant phenotypic associations identified to date are intriguing, and several are of clear clinical import. Consequently, it will be important to extend these initial associations and to identify the mechanisms and conditions under which specific WRN variants may compromise WRN function to drive cellular and organismal phenotypes as well as disease risk.

Association between BRCA1 P871L polymorphism and cancer risk: evidence from a meta-analysis

Breast cancer 1 (BRCA1) gene makes great contributions to the repair of DNA. The association between BRCA1 P871L polymorphism and cancer risk has been investigated in a growing number of studies, but the conclusions are not conclusive. To obtain a comprehensive conclusion, we performed a meta-analysis of 24 studies with 13762 cases and 22388 controls. The pooled results indicated that BRCA1 gene P871L variant decreased risk of overall cancer (homozygous model: odds ratio (OR) = 0.89, 95%confidence interval (CI) = 0.79-1.00; recessive model: OR = 0.89, 95% CI = 0.80-0.99). The stratified analysis observed decreased risk associated with BRCA1 P871L in subgroups among Asians and high score studies, but not Caucasians or low score studies. In conclusion, despite several limitations, this meta-analysis suggested that BRCA1 P871L genetic variation may be associated with decreased susceptibility to cancer.

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.

Association of the Asp312Asn and Lys751Gln polymorphisms in the XPD gene with the risk of non-Hodgkin's lymphoma: evidence from a meta-analysis

Polymorphisms in DNA repair genes may alter DNA repair capacity and, consequently, lead to genetic instability and carcinogenesis. Several studies have investigated the association of the Asp312Asn and Lys751Gln polymorphisms in the xeroderma pigmentosum complementation group D (XPD) gene with the risk of non-Hodgkin's lymphoma (NHL), but the conclusions have been inconsistent. Therefore, we performed this meta-analysis to more precisely estimate these relationships. A systematic literature search was performed using the PubMed, Embase, and Chinese Biomedical (CBM) databases. Ultimately, 6 studies of Asp312Asn, comprising 3,095 cases and 3,306 controls, and 7 studies of Lys751Gln, consisting of 3,249 cases and 3,676 controls, were included. Pooled odds ratios (ORs) and 95% confidence intervals (CIs) were calculated to assess the strength of each association. Overall, no association was observed between the Asp312Asn polymorphism and NHL risk (homozygous: OR = 1.11, 95% CI = 0.94-1.32; heterozygous: OR = 1.00, 95% CI = 0.89-1.11; recessive: OR = 1.12, 95% CI = 0.95-1.31; dominant: OR = 1.02, 95% CI = 0.92-1.13; and allele comparison: OR = 1.04, 95% CI = 0.96-1.12) or between the Lys751Gln polymorphism and NHL risk (homozygous: OR = 0.97, 95% CI = 0.83-1.15; heterozygous: OR = 0.96, 95% CI = 0.86-1.06; recessive: OR = 1.00, 95% CI = 0.86-1.16; dominant: OR = 0.96, 95% CI = 0.87-1.06; and allele comparison: OR = 0.98, 95% CI = 0.91-1.05). Furthermore, subgroup analyses did not reveal any association between these polymorphisms and ethnicity, the source of the controls, or the NHL subtype. These results indicated that neither the Asp312Asn nor Lys751Gln XPD polymorphism was related to NHL risk. Large and well-designed prospective studies are required to confirm this finding.

Body mass index and other anthropometric parameters in patients with diffuse large B-cell lymphoma: physiopathological significance and predictive value in the immunochemotherapy era

Diffuse large B-cell lymphoma (DLBCL) is the most common form of aggressive non-Hodgkin lymphoma, accounting for 30-40% of newly diagnosed cases. Obesity is a well-defined risk factor for DLBCL. However, the impact of body mass index (BMI) on DLBCL prognosis is controversial. Recent studies suggest that skeletal muscle wasting (sarcopenia) or loss of fat mass can be detected by computed tomography (CT) images and is useful for predicting the clinical outcome in several types of cancer including DLBCL. Several hypotheses have been proposed to explain the differences in DLBCL outcome according to BMI or weight that include tolerance to treatment, inflammatory background and chemotherapy or rituximab metabolism. In this review, we summarize the available literature, addressing the impact and physiopathological relevance of simple anthropometric tools including BMI and tissue distribution measurements. We also discuss their relationship with other nutritional parameters and their potential role in the management of patients with DLBCL.

Novel Germline Mutation of BRCA1 Gene in a 56-Year-Old Woman with Breast Cancer, Ovarian Cancer, and Diffuse Large B-Cell Lymphoma

We report a case of a 56-year-old woman with breast cancer, ovarian cancer, and diffuse large B-cell lymphoma with a BRCA1 gene mutation. Evidence is mounting that there is a large increase in the risk for hematologic malignancies among patients with genetic changes in the BRCA pathways. The genomic analysis demonstrated a frameshift mutation in the BRCA1 gene: 277_279delinsCC (Phe93fs). It is a novel BRCA1 mutation that has never been reported, and caused malignant lymphoma as well as breast and ovarian cancer.

Association between BRCA1 rs799917 polymorphism and breast cancer risk: A meta-analysis of 19,878 subjects

Studies investigating the association between the BRCA1 rs799917 polymorphism and breast cancer risk have reported controversial results. In order to derive a more precise estimation of the relationship, we performed a comprehensive meta-analysis. A total of 8 articles comprising 19,878 subjects were included in this meta-analysis. Odds ratios (ORs) and corresponding 95% confidence intervals (CIs) were calculated by Stata 11 software. Heterogeneity tests were conducted by Q test with I(2) value, and publication bias assessment was performed by Begg's funnel plot and Egger's test. The pooled results did not show any sufficient evidence approving the association between the BRCA1 rs799917 polymorphism and breast cancer risk in total population (T vs C: OR=1.01, 95% CI=0.97-1.06; TT vs CC: OR=1.03, 95% CI=0.93-1.13; CT vs CC: OR=1.04, 95% CI=0.92-1.16; TT+CT vs CC: OR=1.04, 95% CI=0.94-1.15; TT vs CT+CC: OR=1.03, 95% CI=0.94-1.12). In the further subgroup analyses, no significant associations were found in any comparison models according to ethnicity and source of controls. No publication bias was observed in this meta-analysis. In summary, based on the overall results, this meta-analysis strongly suggests that the BRCA1 rs799917 polymorphism is not associated with breast cancer risk.