Polymorphisms in GSTT1, GSTZ1, and CYP2E1, Disinfection By-products, and Risk of Bladder Cancer in Spain

Background: Bladder cancer has been linked with long-term exposure to disinfection by-products (DBPs) in drinking water.Objectives: In this study we investigated the combined influence of DBP exposure and polymorphisms in glutathione S-transferase (GSTT1, GSTZ1) and cytochrome P450 (CYP2E1) genes in the metabolic pathways of selected by-products on bladder cancer in a hospital-based case–control study in Spain. Methods: Average exposures to trihalomethanes (THMs; a surrogate for DBPs) from 15 years of age were estimated for each subject based on residential history and information on municipal water sources among 680 cases and 714 controls. We estimated effects of THMs and GSTT1, GSTZ1, and CYP2E1 polymorphisms on bladder cancer using adjusted logistic regression models with and without interaction terms. Results: THM exposure was positively associated with bladder cancer: adjusted odds ratios (ORs) and 95% confidence intervals (CIs) were 1.2 (0.8–1.8), 1.8 (1.1–2.9), and 1.8 (0.9–3.5) for THM quartiles 2, 3, and 4, respectively, relative to quartile 1. Associations between THMs and bladder cancer were stronger among subjects who were GSTT1 +/+ or +/– versus GSTT1 null (pinteraction = 0.021), GSTZ1 rs1046428 CT/TT versus CC (pinteraction = 0.018), or CYP2E1 rs2031920 CC versus CT/TT (pinteraction = 0.035). Among the 195 cases and 192 controls with high-risk forms of GSTT1 and GSTZ1, the ORs for quartiles 2, 3, and 4 of THMs were 1.5 (0.7–3.5), 3.4 (1.4–8.2), and 5.9 (1.8–19.0), respectively. Conclusions: Polymorphisms in key metabolizing enzymes modified DBP-associated bladder cancer risk. The consistency of these findings with experimental observations of GSTT1, GSTZ1, and CYP2E1 activity strengthens the hypothesis that DBPs cause bladder cancer and suggests possible mechanisms as well as the classes of compounds likely to be implicated.This work was funded by the Intramural Research Program of the National Institutes of Health, National Cancer Institute (N02-CP-11015), the Fondo de Investigación Sanitaria (00/0745, G03/174, G03/160, C03/09, and C03/90), and the Instituto de Salud Carlos III, Spanish Health Ministry (CP06/00341

EPID-10. MITOCHONDRIAL DNA SEQUENCE VARIATION AND RISK OF GLIOMA

Abstract Malignant gliomas are the most common primary adult brain tumors, with poor prognosis and ill-defined etiology. Mitochondrial DNA (mtDNA) sequence variants and haplogroups have been linked with certain cancers, but research on glioma is lacking. We examined the association of germline mtDNA variants and haplogroups with glioma risk in 1,654 glioma cases and 1,065 controls from a US case-control study, and 427 glioma cases and 1,541 controls from the UK Biobank, all genotyped using the UKBiobank array with 276 tiled mtDNA variants. The analysis was restricted to participants of European ancestry, and risk of glioblastoma (GBM) and lower grade glioma (LGG) was examined separately. Distribution of mitochondrial haplogroups (H/HV,I,J,K,R,T,U,V,W,X) were similar in both study populations, with 46.4% and 48.1% of controls in the US and UK studies respectively, identified as H/HV, the most common haplogroup. In the US study there was an inverse association between haplogroup W and glioma (OR=0.43, 95%CI: 0.23–0.79) when compared with the H/HV haplogroup, which was not seen in the UK study (OR=1.10, 95%CI: 0.49–2.49). In the US study, a significant inverse association was observed with the previously reported mtDNA variant m.14798T > C (PMID: 31323957), resulting in the amino acid substitution F18L, for LGG (OR=0.73; 95%CI: 0.53–0.99) though not for GBM (OR=0.86; 95%CI: 0.66–1.11). In the UK study, the F18L substitution was associated with an increased risk of GBM (OR=1.48; 95%CI: 1.07–2.04), and no association was observed for LGG (OR=0.95; 95%CI: 0.53–1.68). Among cases in the US study with isocitrate dehydrogenase 1 (IDH1) status available (747 gliomas), a nonsignificant inverse association of the F18L substitution was observed in glioma cases with wild type (OR=0.72; 95%CI: 0.52–1.01) but not mutant (OR=1.08; 95%CI: 0.70–1.69) IDH1. No other common mtDNA variant (minor allele > 5%) was associated with glioma risk in either study. These associations merit further study

EPID-12. MITOCHONDRIAL DNA SEQUENCE VARIATION AND MENINGIOMA

Abstract Meningiomas are the most common primary central nervous system tumors. Risk factors include female sex, African American race, a higher body mass index, and exposure to ionizing radiation. Genome-wide association studies have identified two risk loci for meningioma in the nuclear genome (rs12770228 and rs2686876). Whereas mitochondrial DNA (mtDNA) sequence variants and haplogroups have been linked with certain cancers, research on meningioma is lacking. We examined the association of 42 common (minor allele frequency ≥ 5%) germline mtDNA variants, haplogroups, and genes with meningioma risk in 1,080 controls and 478 cases from a case-control study conducted at medical centers in the southeastern US. Participant DNA samples were genotyped using the UK Biobank array that included a set of common and rare mtDNA variants. Risk associations were examined separately for meningioma overall, WHO grade 1 (n=409) and WHO grade 2/3 (n=69) meningiomas. Overall, meningioma risk was significantly higher among women (OR=2.86; 95% CI:2.21-3.71) compared to men, higher among African Americans (OR=2.37, 95% CI:1.41-3.99) compared to Caucasians, and higher among those who were overweight (OR=1.48; 95% CI:1.11-1.98) or obese (OR= 1.73; 95% CI:1.26-2.38) compared to those of normal weight. The variant m.16362T >C (rs62581341) in the mitochondrial control region was positively associated with grade 2/3 meningiomas (OR=2.33; 95% CI: 1.14-4.79), but not with grade 1 tumors (OR=0.99; 95% CI:0.64-1.53). Haplogroup L, a marker for African ancestry, was identified among 3.6% of controls and 8.6% of cases and was associated with meningioma risk overall (OR=2.56; 95% CI:1.52-4.30). When stratifying by self-reported race, the association between haplogroup L and meningioma was only apparent among the small number of self-reported Caucasians with this haplogroup (OR=6.68; 95% CI=1.66-26.91) when compared to non-L haplogroups, combined. No other common mtDNA variant (minor allele >5%), haplogroup, or gene was associated with meningioma risk. These findings merit further study

Mitochondrial DNA sequence variation and risk of glioma & nbsp

Background: Malignant gliomas are the most common primary adult brain tumors, with a poor prognosis and illdefined etiology. Mitochondrial DNA (mtDNA) sequence variation has been linked with certain cancers; however, research on glioma is lacking.& nbsp;Methods: We examined the association of common (minor allele frequency >= 5%) germline mtDNA variants and haplogroups with glioma risk in 1,566 glioma cases and 1,017 controls from a US case-control study, and 425 glioma cases and 1,534 matched controls from the UK Biobank cohort (UKB). DNA samples were genotyped using the UK Biobank array that included a set of common and rare mtDNA variants. Risk associations were examined separately for glioblastoma (GBM) and lower grade tumors (non-GBM).& nbsp;Results: In the US study, haplogroup W was inversely associated with glioma when compared with haplogroup H (OR = 0.43, 95%CI: 0.23-0.79); this association was not demonstrated in the UKB (OR = 1.07, 95%CI: 0.47-2.43). In the UKB, the variant m.3010G > A was significantly associated with GBM (OR = 1.32; 95%CI: 1.01-1.73; p = 0.04), but not non-GBM (1.23; 95%CI: 0.78-1.95; p = 0.38); no similar association was observed in the US study. In the US study, the variant m.14798 T > C, was significantly associated with non-GBM (OR = 0.72; 95%CI: 0.53-0.99), but not GBM (OR = 0.86; 95%CI: 0.66-1.11), whereas in the UKB, a positive association was observed between this variant and GBM (OR = 1.46; 95%CI: 1.06-2.02) but not non-GBM (OR = 0.92; 95%CI: 0.52-1.63). None of these associations were significant after adjustment for multiple testing.& nbsp;Conclusion: The association of inherited mtDNA variation, including rare and singleton variants, with glioma risk merits further study

Mitochondrial DNA sequence variation and risk of meningioma

Background Risk factors for meningioma include female gender, African American race, high body mass index (BMI), and exposure to ionizing radiation. Although genome-wide association studies (GWAS) have identified two nuclear genome risk loci for meningioma (rs12770228 and rs2686876), the relation between mitochondrial DNA (mtDNA) sequence variants and meningioma is unknown. Methods We examined the association of 42 common germline mtDNA variants (minor allele frequency ≥ 5%), haplogroups, and genes with meningioma in 1080 controls and 478 meningioma cases from a case–control study conducted at medical centers in the southeastern United States. Associations were examined separately for meningioma overall and by WHO grade (n = 409 grade I and n = 69 grade II/III). Results Overall, meningioma was significantly associated with being female (OR 2.85; 95% CI 2.21–3.69), self-reported African American race (OR 2.38, 95% CI 1.41–3.99), and being overweight (OR 1.48; 95% CI 1.11–1.97) or obese (OR 1.70; 95% CI 1.25–2.31). The variant m.16362T > C (rs62581341) in the mitochondrial control region was positively associated with grade II/III meningiomas (OR 2.33; 95% CI 1.14–4.77), but not grade I tumors (OR 0.99; 95% CI 0.64–1.53). Haplogroup L, a marker for African ancestry, was associated with meningioma overall (OR 2.92; 95% CI 1.01–8.44). However, after stratifying by self-reported race, this association was only apparent among the few self-reported Caucasians with this haplogroup (OR 6.35; 95% CI 1.56–25.9). No other mtDNA variant, haplogroup, or gene was associated with meningioma. Conclusion Common mtDNA variants and major mtDNA haplogroups do not appear to have associations with the odds of developing meningioma

Urinary pH, cigarette smoking and bladder cancer risk

Glucuronide conjugates of 4-aminobiphenyl and its N-hydroxy metabolite can be rapidly hydrolyzed in acidic urine to undergo further metabolic activation and form DNA adducts in the urothelium. We conducted a large multicenter case–control study in Spain to explore the etiology of bladder cancer and evaluated the association between urine pH and bladder cancer risk, alone and in combination with cigarette smoking. In total, 712 incident urothelial cell carcinoma cases and 611 hospital controls directly measured their urine pH with dipsticks twice a day (first void in the morning and early in the evening) during four consecutive days 2 weeks after hospital discharge. We found that a consistently acidic urine pH ≤6.0 was associated with an increased risk of bladder cancer [odds ratio (OR) = 1.5, 95% confidence interval (CI): 1.2–1.9] compared with all other subjects. Furthermore, risk estimates for smoking intensity and risk of bladder cancer among current smokers tended to be higher for those with a consistently acidic urine (OR = 8.8, 11.5 and 23.8) compared with those without (OR = 4.3, 7.7 and 5.8, respectively, for 1–19, 20–29 and 30+ cigarettes per day; Pinteraction for 30+ cigarettes per day = 0.024). These results suggest that urine pH, which is determined primarily by diet and body surface area, may be an important modifier of smoking and risk of bladder cancer

Polymorphisms in GSTT1, GSTZ1, and CYP2E1, Disinfection By-products, and Risk of Bladder Cancer in Spain

BACKGROUND: Bladder cancer has been linked with long-term exposure to disinfection by-products (DBPs) in drinking water. OBJECTIVES: In this study we investigated the combined influence of DBP exposure and polymorphisms in glutathione S-transferase (GSTT1, GSTZ1) and cytochrome P450 (CYP2E1) genes in the metabolic pathways of selected by-products on bladder cancer in a hospital-based case-control study in Spain. METHODS: Average exposures to trihalomethanes (THMs; a surrogate for DBPs) from 15 years of age were estimated for each subject based on residential history and information on municipal water sources among 680 cases and 714 controls. We estimated effects of THMs and GSTT1, GSTZ1, and CYP2E1 polymorphisms on bladder cancer using adjusted logistic regression models with and without interaction terms. RESULTS: THM exposure was positively associated with bladder cancer: adjusted odds ratios (ORs) and 95% confidence intervals (CIs) were 1.2 (0.8-1.8), 1.8 (1.1-2.9), and 1.8 (0.9-3.5) for THM quartiles 2, 3, and 4, respectively, relative to quartile 1. Associations between THMs and bladder cancer were stronger among subjects who were GSTT1 +/+ or +/- versus GSTT1 null (pinteraction = 0.021), GSTZ1 rs1046428 CT/TT versus CC (p(interaction) = 0.018), or CYP2E1 rs2031920 CC versus CT/TT (p(interaction) = 0.035). Among the 195 cases and 192 controls with high-risk forms of GSTT1 and GSTZ1, the ORs for quartiles 2, 3, and 4 of THMs were 1.5 (0.7-3.5), 3.4 (1.4-8.2), and 5.9 (1.8-19.0), respectively. CONCLUSIONS: Polymorphisms in key metabolizing enzymes modified DBP-associated bladder cancer risk. The consistency of these findings with experimental observations of GSTT1, GSTZ1, and CYP2E1 activity strengthens the hypothesis that DBPs cause bladder cancer and suggests possible mechanisms as well as the classes of compounds likely to be implicated