Polymorphisms in DNA repair genes, hair dye use, and the risk of non-Hodgkin lymphoma

Genetic polymorphisms, methylation, and expression levels in the GSTP1 and MGMT genes in urothelial bladder tumors

BACKGROUND

Alteration in DNA repair and metabolism genes can affect the maintenance of DNA integrity or xenobiotics metabolism, potentially leading to DNA damage accumulation. The present study investigated the association between polymorphisms in Glutathione S-Transferase Pi 1 (GSTP1, rs1695) and O-6-Methylguanine-DNA Methyltransferase (MGMT, rs2308321) genes with urothelial bladder cancer (UBC) susceptibility and prognosis. Furthermore, the methylation patterns of the promoter region of these genes were analyzed in tumor and non-tumor bladder tissues, besides MGMT gene expression in tumor samples.

METHODS AND RESULTS

Blood samples of 295 patients and 295 healthy controls were genotyped using TaqMan probe assays. The DNA of 39 bladder tumors and 4 adjacent non-tumor samples were used in the Methylation-Sensitive High-Resolution Melting (MS-HRM) assay. Neither polymorphism conferred UBC susceptibility/protection or affected tumor grade, muscle invasion, and recurrence). GSTP1 did not show methylation in the promoter region, while in the MGMT gene, all samples presented heterogeneous methylation with no significant differences between tumor and non-tumor tissues. High MGMT expression was associated with low-grade (p = 0.0153) and trends related to non-invasive tumors (p = 0.070).

CONCLUSIONS

In our cohort, MGMT expression seems helpful as a biomarker of good prognosis (low-grade and absence of muscle invasion). A heterogeneous methylation pattern in the MGMT gene requires additional investigation to elucidate its potential implications.

Potential Pathogenic Impact of Cow’s Milk Consumption and Bovine Milk-Derived Exosomal MicroRNAs in Diffuse Large B-Cell Lymphoma

Epidemiological evidence supports an association between cow’s milk consumption and the risk of diffuse large B-cell lymphoma (DLBCL), the most common non-Hodgkin lymphoma worldwide. This narrative review intends to elucidate the potential impact of milk-related agents, predominantly milk-derived exosomes (MDEs) and their microRNAs (miRs) in lymphomagenesis. Upregulation of PI3K-AKT-mTORC1 signaling is a common feature of DLBCL. Increased expression of B cell lymphoma 6 (BCL6) and suppression of B lymphocyte-induced maturation protein 1 (BLIMP1)/PR domain-containing protein 1 (PRDM1) are crucial pathological deviations in DLBCL. Translational evidence indicates that during the breastfeeding period, human MDE miRs support B cell proliferation via epigenetic upregulation of BCL6 (via miR-148a-3p-mediated suppression of DNA methyltransferase 1 (DNMT1) and miR-155-5p/miR-29b-5p-mediated suppression of activation-induced cytidine deaminase (AICDA) and suppression of BLIMP1 (via MDE let-7-5p/miR-125b-5p-targeting of PRDM1). After weaning with the physiological termination of MDE miR signaling, the infant’s BCL6 expression and B cell proliferation declines, whereas BLIMP1-mediated B cell maturation for adequate own antibody production rises. Because human and bovine MDE miRs share identical nucleotide sequences, the consumption of pasteurized cow’s milk in adults with the continued transfer of bioactive bovine MDE miRs may de-differentiate B cells back to the neonatal “proliferation-dominated” B cell phenotype maintaining an increased BLC6/BLIMP1 ratio. Persistent milk-induced epigenetic dysregulation of BCL6 and BLIMP1 expression may thus represent a novel driving mechanism in B cell lymphomagenesis. Bovine MDEs and their miR cargo have to be considered potential pathogens that should be removed from the human food chain.

Hair Dye Ingredients and Potential Health Risks from Exposure to Hair Dyeing

Given the worldwide popularity of hair dyeing, there is an urgent need to understand the toxicities and risks associated with exposure to chemicals found in hair dye formulations. Hair dyes are categorized as oxidative and nonoxidative in terms of their chemical composition and ingredients. For several decades, the expert panel's Cosmetic Ingredient Review (CIR) has assessed the safety of many of the chemicals used in hair dyes; however, a comprehensive review of hair dye ingredients and the risk of exposure to hair dyeing has not been documented. Herein, we review the safety of the various chemicals in oxidative and nonoxidative hair dyes, toxicities associated with hair dyeing, and the carcinogenic risks related to hair dyeing. While many compounds are considered safe for users at the concentrations in hair dyes, there are conflicting data about a large number of hair dye formulations. The CIR expert panel has ratified a number of coloring ingredients for hair dyes and banned a series of chemicals as carcinogenic to animals and unsafe for this application. The use of these chemicals as raw materials for producing hair dyes may result in the synthesis of other contaminants with potential toxicities and increased risk of carcinogenesis. It is an open question whether personal or occupational hair dyeing increases the risk of cancer; however, in specific subpopulations, a positive association between hair dye use and cancer occurrence has been reported. To address this question, a better understanding of the chemical and mechanistic basis of the reported toxicities of hair dye mixtures and individual hair dye ingredients is needed. It is anticipated that in-depth chemical and systems toxicology studies harnessing modern and emerging techniques can shed light on this public health concern in the future.

Association between hair dye use and cancer in women: a systematic review and meta-analysis of case-control studies

Background

The use of hair dye for cosmetic purposes appears to be increasing worldwide. As 50-80% of women use hair dye throughout their lifetimes, the possible association between hair dye use and cancer is a public health concern.

Method

This systematic review was performed by retrieving studies from PubMed, Scopus, WOS, and ProQuest databases. The inclusion criteria were case-control studies evaluating the association between hair dye use and cancer in women. Women with cancer who have used any hair dye were the focus of our study.

Results

The present study combined 28 studies, to assess the association between hair dye use and cancer. The pooled odds ratio (OR) of hematopoietic system cancers among those who have generally ever used any type of hair dyes was 1.10 (95% CI:1.01-1.20) in 17 studies. In 11 studies investigating hair dye made before and after 1980 as a risk factor for cancer, the pooled OR for cancer was 1.31(95% CI:1.08-1.59). Likewise, in the 13 studies that evaluated the association of light and dark hair dye with cancer, the risk among those using dark hair dye increased by 9%, compared to non-users (OR=1.09; 95% CI:0.95-1.25).

Conclusion

The present study suggests that, although the use of hair dye may increase the risk of cancer among users, a more detailed evaluation is required to assess the type of hair dye use in terms of guidelines and metrics.

Modification Effect of PARP4 and ERCC1 Gene Polymorphisms on the Relationship between Particulate Matter Exposure and Fasting Glucose Level

Particulate matter (PM) has been linked to adverse health outcomes, including insulin resistance (IR). To evaluate the relationships between exposures to PM₁₀, PM_2.5–10, and PM_2.5; the serum level of fasting glucose, a key IR indicator; and effects of polymorphisms of two repair genes (PARP4 and ERCC1) on these relations, PMs exposure data and blood samples for glucose measurement and genotyping were collected from 527 Korean elders. Daily average levels of PMs during 8 days, from 7 days before examination to the health examination day (from lag day 7 to lag day 0), were used for association analyses, and mean concentrations of PM₁₀, PM_2.5–10, and PM_2.5 during the study period were 43.4 µg/m³, 19.9 µg/m³, and 23.6 µg/m³, respectively. All three PMs on lag day 4 (mean, 44.5 µg/m³ for PM₁₀, 19.9 µg/m³ for PM_2.5–10, and 24.3 µg/m³ for PM_2.5) were most strongly associated with an increase in glucose level (percent change by inter-quartile range-change of PM: (β) = 1.4 and p = 0.0023 for PM₁₀; β = 3.0 and p = 0.0010 for PM_2.5–10; and β = 2.0 and p = 0.0134 for PM_2.5). In particular, elders with PARP4 G-C-G or ERCC1 T-C haplotype were susceptible to PMs exposure in relation to glucose levels (PARP4 G-C-G: β = 2.6 and p = 0.0006 for PM₁₀, β = 3.5 and p = 0.0009 for PM_2.5–10, and β = 1.6 and p = 0.0020 for PM_2.5; ERCC1 T-C: β = 2.2 and p = 0.0016 for PM₁₀, β = 3.5 and p = 0.0003 for PM_2.5–10, and β = 1.2 and p = 0.0158 for PM_2.5). Our results indicated that genetic polymorphisms of PARP4 and ERCC1 could modify the relationship between PMs exposure and fasting glucose level in the elderly.

Assessment of biomarkers influencing treatment success on small intestinal lymphoma in dogs

This study aimed to determine a reliable therapeutic biomarker for localized small intestinal lymphoma (SIL) in dogs based on clinical and histopathological features. We retrospectively investigated 84 dogs with localized SIL, including 36 dogs receiving surgery and 48 dogs receiving chemotherapy. The dogs receiving surgery were divided into two subgroups: 18 dogs (group 1) with overall survival (OS) <120 days (median OS) and 18 dogs (group 2) with OS ≥120 days. Correspondingly, the dogs receiving chemotherapy were divided into 24 dogs (group 3) with OS <98 days (median OS) and 24 dogs (group 4) with OS ≥98 days. Clinical, haematological, histopathological and immunohistochemical analyses were comparatively evaluated among the four subgroups. There was no significant difference in OS between the surgery and chemotherapy groups. In dogs receiving surgery, the rate of Ki67-positive cells was significantly increased in group 1 compared to group 2 and showed no significant difference between groups 3 and 4. In dogs receiving chemotherapy, the rate of O6-methylguanine-DNA methyltransferase (MGMT) was significantly higher in group 3 than in group 4 and showed no significant difference between groups 1 and 2. Additionally, our data showed that OS in dogs with higher Ki67 expression might be significantly increased by chemotherapy than by surgery, that of those with higher MGMT expression might be significantly increased by surgery than by chemotherapy, and Ki67 and MGMT were independent of each other. Indices of Ki67 and MGMT are suggested therapeutic biomarkers to determine the optimal first-line treatment for localized SIL in dogs.

Linking Environmental Exposures to Molecular Pathogenesis in Non-Hodgkin Lymphoma Subtypes

Non-Hodgkin lymphoma comprises a heterogeneous group of hematologic malignancies, with about 60 subtypes that arise via various pathogenetic mechanisms. Although establishing etiology for specific NHL subtypes has been historically difficult given their relative rarity, environmental exposures have been repeatedly implicated as risk factors across many subtypes. Large-scale epidemiologic investigations have pinpointed chemical exposures in particular, but causality has not been established, and the exact biologic mechanisms underpinning these associations are unclear. Here we review chemical exposures that have been associated with development of NHL subtypes and discuss their biologic plausibility based on current research.

The Bio-Safety Concerns of Three Domestic Temporary Hair Dye Molecules: Fuchsin Basic, Victoria Blue B and Basic Red 2

Hair-coloring products include permanent, semi-permanent and temporary dyes that vary by chemical formulation and are distinguished mainly by how long they last. Domestic temporary hair dyes, such as fuchsin basic, basic red 2 and Victoria blue B, are especially popular because of their cheapness and facile applications. Despite numerous studies on the relationship between permanent hair dyes and disease, there are few studies addressing whether these domestic temporary hair dyes are associated with an increased cancer risk. Herein, to ascertain the bio-safety of these temporary hair dyes, we comparatively studied their percutaneous absorption, hemolytic effect and cytotoxic effects in this paper. Furthermore, to better understand the risk of these dyes after penetrating the skin, experimental and theoretical studies were carried out examining the interactions between the dyes and serum albumins as well as calf thymus (CT)-DNA. The results showed that these domestic temporary hair dyes are cytotoxic with regard to human red blood cells and NIH/3T3 cell lines, due to intense interactions with bovine serum albumin (BSA)/DNA. We conclude that the temporary hair dyes may have risk to human health, and those who use them should be aware of their potential toxic effects.

Impact of rs12917 MGMT Polymorphism on [18F]FDG-PET Response in Pediatric Hodgkin Lymphoma (PHL)

PURPOSE

The enzyme O6-methylguanine-DNA methyltransferase (MGMT) is an important component of the DNA repair machinery. MGMT removes O6-methylguanine from the DNA by transferring the methyl group to a cysteine residue in its active site. Recently, we detected the single nucleotide polymorphism (SNP) rs12917 (C/T) in the MGMT sequence adjacent to the active site in Hodgkin lymphoma (HL) cell line KM-H2. We now investigated whether this SNP is also present in other HL cell lines and patient samples. Furthermore, we asked whether this SNP might have an impact on metabolic response in 2-deoxy-2-[¹⁸F]fluoro-D-glucose positron emission tomography ([¹⁸F]FDG-PET), and on overall treatment outcome based on follow-up intervals of at least 34 months.

PROCEDURES

We determined the frequency of this MGMT polymorphism in 5 HL cell lines and in 29 pediatric HL (PHL) patients. The patient cohort included 17 female and 12 male patients aged between 4 and 18 years. After characterization of the sequence, we tested a possible association between rs12917 and age, gender, Ann Arbor stage, treatment group, metabolic response following two courses of OEPA (vincristine, etoposide, prednisone, and doxorubicin) chemotherapy, radiotherapy indication, and relapse status.

RESULTS

We detected the minor T allele in four of five HL cell lines. 11/29 patients carried the minor T allele whereas 18/29 patients showed homozygosity for the major C allele. Interestingly, we observed significantly better metabolic response in PHL patients carrying the rs12917 C allele resulting in a lower frequency of radiotherapy indication.

CONCLUSION

MGMT polymorphism rs12917 seems to affect chemotherapy response in PHL. The prognostic value of this polymorphism should be investigated in a larger patient cohort.

A Meta-Analysis on the Relationship Between Hair Dye and the Incidence of Non-Hodgkin's Lymphoma

BACKGROUND

Epidemiologic studies have suggested hair dye to be a risk factor for many cancers. However, previous studies on the association between the personal use of hair dye and risk of non-Hodgkin's lymphoma (NHL) have been inconclusive.

METHODS

The PubMed, Embase, Cochrane Library, and Web of Science databases, as well as the references cited in included studies, were searched for relevant studies up to February 10, 2015. Odds ratios (OR) with 95% confidence intervals (CI) were applied to assess the strength of the association. Publication bias was evaluated using a funnel plot by Egger's and Begg's tests.

RESULTS

A total of 16 studies were included in the analysis, including 13 case-control studies and 3 cohort studies. The present meta-analysis results revealed that the risk of NHL in a high population of hair dye users was 14% (OR 1.14, 95% CI 1.01-1.29). Furthermore, individuals who used more than 20 pack-years of hair dye had increased risk of NHL.

CONCLUSION

The outcomes indicate that hair dye use increases the risk of NHL, especially for females. Hence, people who frequently use hair dyes or have been using hair dyes for more than 20 years should minimize their exposure to hair dye products to prevent the risk of NHL.

Development and validation of an allele-specific PCR assay for genotyping a promoter and exonic single nucleotide polymorphisms of MGMT gene

DNA repair protein O⁶-methylguanine-DNA methyltransferase (MGMT) specifically remove the methyl/alkyl group from the O⁶-position of guanine and restore the guanine to its normal form without causing DNA strand breaks. Relationship between MGMT activity and resistance to alkylating therapeutic agents is well established. Non-availability of simple, cost-effective and efficient methods of genotyping may hinder investigations on genotype-phenotype associations. No simple genotyping procedures such as allele-discrimination Taqman Assays were available for two genetic variations in MGMT gene that had previously demonstrated to be affecting its function and expression. These two variants were included to genotype in a clinical study (Clinicaltrail.gov ID: NCT01257854). Hence, the present study is aimed at developing, validating a rapid and simple allele-specific PCR method that genotypes exonic variant rs2308321 (c.520A>G) and a promoter variant rs113813075 (c.-459C>A) with standard PCR instruments. Web-based allele-specific (AS) primer design application called web-based allele-specific primer was used to design primers. Genomic DNA of lymphoblastoid cell line obtained from the Coriell repository with known genotypes were used to standardize the genotyping procedure. The PCR products were analyzed by 3% Agarose gel electrophoresis and by DNA Screen Tape assay with the Agilent 4200 TapeStation. The allele-specific PCR assay described here is a suitable strategy for efficient and reliable genotyping for difficult variants. This method offers cost-effective strategy for genotyping in clinical cohort studies provided positive controls established by Sanger sequencing are available for the variant.

Expanding primary cells from mucoepidermoid and other salivary gland neoplasms for genetic and chemosensitivity testing

Restricted availability of cell and animal models is a rate-limiting step for investigation of salivary gland neoplasm pathophysiology and therapeutic response. Conditionally reprogrammed cell (CRC) technology enables establishment of primary epithelial cell cultures from patient material. This study tested a translational workflow for acquisition, expansion and testing of CRC-derived primary cultures of salivary gland neoplasms from patients presenting to an academic surgical practice. Results showed that cultured cells were sufficient for epithelial cell-specific transcriptome characterization to detect candidate therapeutic pathways and fusion genes, and for screening for cancer risk-associated single nucleotide polymorphisms (SNPs) and driver gene mutations through exome sequencing. Focused study of primary cultures of a low-grade mucoepidermoid carcinoma demonstrated amphiregulin-mechanistic target of rapamycin-protein kinase B (AKT; AKT1) pathway activation, identified through bioinformatics and subsequently confirmed as present in primary tissue and preserved through different secondary 2D and 3D culture media and xenografts. Candidate therapeutic testing showed that the allosteric AKT inhibitor MK2206 reproducibly inhibited cell survival across different culture formats. By contrast, the cells appeared resistant to the adenosine triphosphate competitive AKT inhibitor GSK690693. Procedures employed here illustrate an approach for reproducibly obtaining material for pathophysiological studies of salivary gland neoplasms, and other less common epithelial cancer types, that can be executed without compromising pathological examination of patient specimens. The approach permits combined genetic and cell-based physiological and therapeutic investigations in addition to more traditional pathologic studies, and can be used to build sustainable bio-banks for future inquiries.This article has an associated First Person interview with the first author of the paper.

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.

MGMT gene variants, temozolomide myelotoxicity and glioma risk. A concise literature survey including an illustrative case

Temozolomide may cause thrombocytopenia or neutropenia in 3-4% of glioblastoma patients, respectively. However, pancytopenia is rarely reported. MGMT (O6-methylguanine-DNA-methyltransferase) enzyme repairs temozolomide-induced DNA mutations and associates both with antitumour efficacy and myelosuppression. Many studies on the effects of MGMT gene-methylation on temozolomide's effects exist, but much fewer publications concerning MGMT variants were documented. A full sequencing of the MGMT gene was performed in a female glioblastoma patient, who developed pancytopenia following temozolomide treatment. Results indicated the presence of all the rs2308321 (I143 V), rs2308327 (K178R) and rs12917 (L84F) MGMT-variants, which were previously associated with temozolomide myelotoxicity. rs12917 (L84F) variant was reported as associating with lesser risk of gallbladder tumours, yet with higher risk of non-Hodgkin lymphomas related with exposure to chlorinated solvents or hair dyes. DNA repair proteins may exert diverging effects on DNA injuries caused by different chemicals and therefore exerting complex effects on myelotoxicity, antitumour activity and carcinogenesis.

Genetic Variations in XRCC4 (rs1805377) and ATF6 (rs2070150) are not Associated with Hepatocellular Carcinoma in Thai Patients with Hepatitis B Virus Infection

The liver is one of the most common sites of cancer in the world, hepatocellular carcinoma (HCC) predominating. Chronic hepatitis B virus infection (CHB) is considered as an important potential risk factors for HCC. Different people have diverse responses to HBV infection regarding the likelihood of HCC development, and host factors such as single nucleotide polymorphisms (SNPs) might account for this. The present study was conducted to evaluate any association between SNP frequencies in two genes, XRCC4 (rs1805377) and ATF6 (rs2070150), and the risk of CHB and HCC development in Thai patients. The study covered 369 subjects including 121 HCC patients, 141 with chronic hepatitis B virus infection (CHB) and 107 healthy controls. With TaqMan real-time PCR, the results showed that no significant association between XRCC4 (rs1805377) and ATF6 (rs2070150) and risk of HCC in the Thai population. From this first study of the 2 polymorphisms and HCC in Thailand it can concluded that rs1805377 and rs2070150 polymorphisms may not be applicable as genetic markers in the Thai population for HCC assessment.

Polymorphism rs144848 in BRCA2 may reduce lung cancer risk in women: a case-control study in southeast China

PURPOSE

Whereas lung cancer incidence among men has declined in recent years, the incidence rate among women has increased rapidly. Sex could affect DNA repair capacity. Although BRCA2 is important in DNA repair, few data are available on the association between BRCA2 polymorphisms and lung cancer in women. Therefore, we investigated this in a case-control study among Chinese women.

METHODS

We enrolled 226 women with lung cancer and 269 age-matched healthy controls in our study. Polymorphisms studied were genotyped by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.

RESULTS

Unconditional logistic regression showed no association between rs1799943 or rs1799944 and cancer risk. However, the AC and CC genotypes of rs144848 were significantly associated with reduced risk after adjustment for age and education, with adjusted odds ratios (ORs) of 0.66 (95% confidence interval [CI] 0.45-0.97) and 0.37 (95% CI 0.16-0.78), respectively. The adjusted OR of carriers with the C allele was 0.62 (95% CI 0.44-0.81) compared with the A allele.

CONCLUSIONS

The rs144848 mutation may have a protective effect against lung cancer among women.