Association of genotypes of carcinogen-activating enzymes, phenol sulfotransferase SULT1A1 (ST1A3) and arylamine N-acetyltransferase NAT2, with urothelial cancer in a Japanese population

Copy number variants as modifiers of breast cancer risk for BRCA1/BRCA2 pathogenic variant carriers

The contribution of germline copy number variants (CNVs) to risk of developing cancer in individuals with pathogenic BRCA1 or BRCA2 variants remains relatively unknown. We conducted the largest genome-wide analysis of CNVs in 15,342 BRCA1 and 10,740 BRCA2 pathogenic variant carriers. We used these results to prioritise a candidate breast cancer risk-modifier gene for laboratory analysis and biological validation. Notably, the HR for deletions in BRCA1 suggested an elevated breast cancer risk estimate (hazard ratio (HR) = 1.21), 95% confidence interval (95% CI = 1.09-1.35) compared with non-CNV pathogenic variants. In contrast, deletions overlapping SULT1A1 suggested a decreased breast cancer risk (HR = 0.73, 95% CI 0.59-0.91) in BRCA1 pathogenic variant carriers. Functional analyses of SULT1A1 showed that reduced mRNA expression in pathogenic BRCA1 variant cells was associated with reduced cellular proliferation and reduced DNA damage after treatment with DNA damaging agents. These data provide evidence that deleterious variants in BRCA1 plus SULT1A1 deletions contribute to variable breast cancer risk in BRCA1 carriers.

SULT genetic polymorphisms: physiological, pharmacological and clinical implications

INTRODUCTION

Cytosolic sulfotransferases (SULTs)-mediated sulfation is critically involved in the metabolism of key endogenous compounds, such as catecholamines and thyroid/steroid hormones, as well as a variety of drugs and other xenobiotics. Studies performed in the past three decades have yielded a good understanding about the enzymology of the SULTs and their structural biology, phylogenetic relationships, tissue/organ-specific/developmental expression, as well as the regulation of the SULT gene expression. An emerging area is related to the functional impact of the SULT genetic polymorphisms.

AREAS COVERED

The current review aims to summarize our current knowledge about the above-mentioned aspects of the SULT research. An emphasis is on the information concerning the effects of the polymorphisms of the SULT genes on the functional activity of the SULT allozymes and the associated physiological, pharmacological, and clinical implications.

EXPERT OPINION

Elucidation of how SULT SNPs may influence the drug-sulfating activity of SULT allozymes will help understand the differential drug metabolism and eventually aid in formulating personalized drug regimens. Moreover, the information concerning the differential sulfating activities of SULT allozymes toward endogenous compounds may allow for the development of strategies for mitigating anomalies in the metabolism of these endogenous compounds in individuals with certain SULT genotypes.

N-acetyltransferase 2 polymorphism is associated with bladder cancer risk: An updated meta-analysis based on 54 case-control studies

OBJECTIVE

N-acetyltransferase 2 (NAT2) polymorphism could participate in the metabolism of carcinogens through regulating the activity of a series of critical enzymes. However, the effects of NAT2 polymorphism on bladder cancer (BCa) risk were still inconclusive. In order to illustrate whether NAT2 polymorphism may influence the susceptibility to BCa, we conducted this updated meta-analysis.

MATERIALS AND METHODS

Databases including PubMed, Medline, Embase, Web of Science, Cochrane Library, and China National Knowledge Infrastructure(CNKI) were systematically retrieved and we applied MetaGenyo to perform final meta-analysis. Odds ratios (ORs) as well as 95% confidence intervals (CIs) were calculated and Bonferroni method was applied to correct the P-value for multiple comparisons. The registration of this study protocol is at PROSPERO and ID is CRD42019133957.

RESULTS

Ultimately, 54 case-control studies were identified for final meta-analysis (13343 BCa cases and 18,586 controls). Overall analysis indicated that the slow genotype in NAT2 polymorphism was obviously associated with BCa risk (P_Bonferroni < 0.001). Subgroup analyses demonstrated that significant risk with the slow genotype was observed in Caucasians, Asians, smokers, non-exposed individuals, high grade bladder cancer (HGBC) patients and muscle-invasive bladder cancer (MIBC) patients. In addition, the intermediate NAT2 genotype was revealed to increase the BCa risk of Asians and transitional cell carcinoma (TCC) patients. However, no correlation was identified in Africans with the NAT2 polymorphism.

CONCLUSIONS

The slow NAT2 genotype was identified to be the risk genotype for BCa. The intermediate genotype could serve as the candidate risk genotype. The gene-smoking interaction with NAT2 polymorphism might accelerate the tumor progression.

Genetic variants of SULT1A1 and XRCC1 genes and risk of lung cancer in Bangladeshi population

Lung cancer is one of the most frequently occurring cancers throughout the world as well as in Bangladesh. This study aimed to correlate the prognostic and/or predictive value of functional polymorphisms in SULT1A1 (rs9282861) and XRCC1 (rs25487) genes and lung cancer risk in Bangladeshi population. A case-control study was conducted which comprises 202 lung cancer patients and 242 healthy volunteers taking into account the age, sex, and smoking status. After isolation of genomic DNA, genotyping was done by polymerase chain reaction-restriction fragment length polymorphism method and the lung cancer risk was evaluated as odds ratio that was adjusted for age, sex, and smoking status. A significant association was found between SULT1A1 rs9282861 and XRCC1 rs25487 polymorphisms and lung cancer risk. In case of rs9282861 polymorphism, Arg/His (adjusted odds ratio = 5.06, 95% confidence interval = 3.05-8.41, p < 0.05) and His/His (adjusted odds ratio = 3.88, 95% confidence interval = 2.20-6.82, p < 0.05) genotypes were strongly associated with increased risk of lung cancer in comparison to the Arg/Arg genotype. In case of rs25487 polymorphism, Arg/Gln heterozygote (adjusted odds ratio = 4.57, 95% confidence interval = 2.79-7.46, p < 0.05) and Gln/Gln mutant homozygote (adjusted odds ratio = 4.99, 95% confidence interval = 2.66-9.36, p < 0.05) were also found to be significantly associated with increased risk of lung cancer. This study demonstrates that the presence of His allele and Gln allele in case of SULT1A1 rs9282861 and XRCC1 rs25487, respectively, involve in lung cancer prognosis in Bangladeshi population.

Relationship of SULT1A1 copy number variation with estrogen metabolism and human health

Human cytosolic sulfotransferase 1A1 (SULT1A1) is considered to be one of the most important SULT isoforms for metabolism, detoxification, and carcinogenesis. This theory is driven by observations that SULT1A1 is widely expressed in multiple tissues and acts on a wide range of phenolic substrates. SULT1A1 is subject to functional common copy number variation (CNV) including deletions or duplications. However, it is less clear how SULT1A1 CNV impacts health and disease. To better understand the biological role of SULT1A1 in human health, we genotyped CNV in 14,275 Marshfield Clinic patients linked to an extensive electronic health record. Since SULT1A1 is linked to steroid metabolism, select serum steroid hormones were measured in 100 individuals with a wide spectrum of SULT1A1 CNV genotypes. Furthermore, comprehensive phenome-wide association studies (PheWAS) were conducted using diagnostic codes and clinical text data. For the first time, individuals homozygous null for SULT1A1 were identified in a human population. Thirty-six percent of the population carried >2 copies of SULT1A1 whereas 4% had ≤1 copy. Results indicate SULT1A1 CNV was negatively correlated with estrone-sulfate to estrone ratio predominantly in males (E1S/E1; p=0.03, r=-0.21) and may be associated with increased risk for common allergies. The effect of SULT1A1 CNV on circulating estrogen metabolites was opposite to the predicted CNV-metabolite trend based on enzymatic function. This finding, and the potential association with common allergies reported herein, warrants future studies.

Sulfotransferase SULT1A1 Arg213His polymorphism with cancer risk: a meta-analysis of 53 case-control studies

Background

The SULT1A1 Arg213His (rs9282861) polymorphism is reported to be associated with many kinds of cancer risk. However, the findings are conflicting. For better understanding this SNP site and cancer risk, we summarized available data and performed this meta-analysis.

Methods

Data were collected from the following electronic databases: PubMed, Web of Knowledge and CNKI. The association was assessed by odd ratio (OR) and the corresponding 95% confidence interval (95% CI).

Results

A total of 53 studies including 16733 cancer patients and 23334 controls based on the search criteria were analyzed. Overall, we found SULT1A1 Arg213His polymorphism can increase cancer risk under heterozygous (OR = 1.09, 95% CI = 1.01–1.18, P = 0.040), dominant (OR = 1.10, 95% CI = 1.01–1.19, P = 0.021) and allelic (OR = 1.08, 95% CI = 1.02–1.16, P = 0.015) models. In subgroup analyses, significant associations were observed in upper aero digestive tract (UADT) cancer (heterozygous model: OR = 1.62, 95% CI = 1.11–2.35, P = 0.012; dominant model: OR = 1.63, 95% CI = 1.13–2.35, P = 0.009; allelic model: OR = 1.52, 95% CI = 1.10–2.11, P = 0.012) and Indians (recessive model: OR = 1.93, 95% CI = 1.22–3.07, P = 0.005) subgroups. Hospital based study also showed marginally significant association. In the breast cancer subgroup, ethnicity and publication year revealed by meta-regression analysis and one study found by sensitivity analysis were the main sources of heterogeneity. The association between SULT1A1 Arg213His and breast cancer risk was not significant. No publication bias was detected.

Conclusions

The present meta-analysis suggests that SULT1A1 Arg213His polymorphism plays an important role in carcinogenesis, which may be a genetic factor affecting individual susceptibility to UADT cancer. SULT1A1 Arg213His didn't show any association with breast cancer, but the possible risk in Asian population needs further investigation.

Quantitative analysis of the association between sulfotransferase isoform 1A1 polymorphism and risk of urothelial carcinoma

Sulfotransferase isoform 1A1 (SULT1A1) is a member of the sulfotransferase family that plays an important role in the biotransformation of numerous carcinogenic and mutagenic compounds through sulfation. A number of case-control studies were conducted to investigate the association between the Arg213His polymorphism in SULT1A1 and the risk of urothelial carcinoma (UC) in humans. However, the results were inconsistent. A meta-analysis based on 10 case-control studies was performed to address this issue. Crude odds ratios (ORs) with 95% confidence intervals (CIs) were calculated to estimate the strength of this association. Between-study heterogeneity was assessed with the Chi-square-based Q test. Overall, a possibly decreased risk of UC was associated with the SULT1A1 A/A polymorphism for the heterozygote model (OR=0.86, 95% CI: 0.76-0.98, P=0.471). In the subgroup analysis by cancer type, the results indicated that individuals with the G/G genotype had a significantly higher bladder cancer (BC) risk (GA vs. GG: OR=0.88, 95% CI: 0.74-0.99, P=0.626; GA/AA vs. GG: OR=0.85, 95% CI: 0.74-0.97, P=0.504), which was contrary to the results of the upper urinary tract urothelial carcinoma (UTUC) group (AA vs. GG: OR=2.18, 95% CI: 1.28-3.69; AA vs.

GA/GG

OR=2.05, 95% CI: 1.24-3.38). In addition, stratification by smoking status demonstrated that the Arg213His polymorphism was associated with a decreased risk of UC in non-smokers (OR=0.70, 95% CI: 0.53-0.92) but not in smokers (OR=0.85, 95% CI: 0.70-1.03) under the dominant model. In conclusion, this meta-analysis demonstrated a significant association between the SULT1A1 Arg213His polymorphism and BC. However, there was insufficient evidence to support a consistent association between this polymorphism and UC, partly due to the differences between BC and UTUC.

Combined effects of GSTO1 and SULT1A1 polymorphisms and cigarette smoking on urothelial carcinoma risk in a Taiwanese population

BACKGROUND/PURPOSE

Cigarette smoking is the main risk factor for urothelial carcinoma of the bladder (UCB). Glutathione S-transferase omega 1 (GSTO1) and sulfotransferase 1A1 (SULT1A1) have been reported to be associated with the metabolism of polycyclic aromatic hydrocarbons (PAHs) and aromatic amines. The aim of the present study was to investigate the combined effects of polymorphisms in GSTO1 and SULT1A1 genes and cigarette smoking on UCB risk in a Taiwanese population.

METHODS

A total of 300 patients with histopathologically confirmed UCB and 233 cancer-free controls were recruited from the Department of Urology of Tung's Taichung Metro Harbor Hospital and Taipei Medical University Hospital. A comprehensive interview was conducted to collect personal information, including demographic characteristics and cigarette smoking status. A multivariate-adjusted logistic regression was performed to estimate the risk of UCB.

RESULTS

A significantly increased risk of UCB was observed in ever smokers [odds ratio (OR) = 2.3]. The Ala/Ala genotype of the GSTO1 gene and the Arg/Arg genotype of the SULT1A1 gene were associated with a significantly increased risk of UCB, with ORs of 1.8 [95% confidence interval (CI) = 1.2-2.6] and 2.1 (95% CI = 1.6-4.5), respectively. Significantly increased UCB risks were found in heavy smokers with the Ala/Ala genotype of the GSTO1 gene (OR = 4.2) and the Arg/Arg genotype of the SULT1A1 gene (OR = 6.8). Furthermore, a significant synergistic effect in an additive model (OR = 3.5) between the GSTO1 Ala/Ala genotype and the SULT1A1 Arg/Arg genotype on UCB risk was observed.

CONCLUSION

The present study provided epidemiological evidence for a significantly increased risk of UCB in ever smokers with the Ala/Ala genotype of the GSTO1 gene and the Arg/Arg genotype of the SULT1A1 gene.

Association between the SULT1A1 Arg213His polymorphism and the risk of bladder cancer: a meta-analysis

Several previous studies have investigated the association between the SULT1A1 Arg213His polymorphism and the risk of bladder cancer in various populations. However, these results remain inconsistent. Therefore, we performed this meta-analysis to evaluate the relationship between the SULT1A1 Arg213His polymorphism and the risk of bladder cancer. An extensive literature search was performed to identify all eligible studies regarding this association. The odds ratios (ORs) with 95 % confidence intervals (CIs) were used to estimate the strength of risk under fixed and random effects models. We identified and included eight case-control studies including 2,036 cases and 2,273 controls. No significant association was found between the SULT1A1 Arg213His polymorphism and the risk of bladder cancer under the dominant model; however, those with the SULT1A1 Arg/Arg genotype had a significantly increased risk (OR = 1.218, 95 % CI = 1.067-1.392, P = 0.0044) under the recessive model. In the subgroup analysis of ethnicity, a significant association was observed in Caucasians under the recessive model (OR = 1.269, 95 % CI = 1.069-1.506, P = 0.007). Furthermore, an increased risk of bladder cancer was observed between the Arg213His polymorphism and never smokers in the recessive model (OR = 1.428, 95 % CI = 1.079-1.890, P = 0.013). The results of this meta-analysis indicate that the SULT1A1 Arg213His polymorphism is associated with the risk bladder cancer under a recessive model; however, a possibly higher risk for Caucasians with the Arg/Arg genotype and never smokers needs further investigation.

Copy number variation in sulfotransferase isoform 1A1 (SULT1A1) is significantly associated with enzymatic activity in Japanese subjects

Sulfotransferase isoform 1A1 (SULT1A1) plays a key role in the metabolism of a variety of endo- and xenobiotics and it’s activity could influence response to drugs. Our previous studies have focused on the impact of genetic variants of SULT1A1 on enzymatic activity in Caucasians and African-Americans. However, the contribution of genetic variants to SULT1A1 activity in Asians has not been explored. In this study, we investigated the collective effects of both SULT1A1 copy number variants (CNVs) and single nucleotide polymorphisms (SNPs) in the promoter region, coding region, and 3′ untranslated region on SULT1A1 activity in Japanese subjects. SNPs in the SULT1A1 promoter and 3′ untranslated region were not associated with SULT1A1 activity (P > 0.05). SULT1A1*1/2 (Arg213His) was marginally associated with SULT1A1 activity (P = 0.037). However, SULT1A1 CNVs were strongly associated with SULT1A1 activity (trend test P = 0.008) and accounted for 10% of the observed variability in activity for Japanese subjects. In conclusion, SULT1A1 CNVs play a pivotal role in determination of SULT1A1 activity in Japanese subjects, highlighting the influence of ethnic differences in SULT1A1 genetic variants on drug metabolism and therapeutic efficacy.

Association of genotypes of carcinogen-metabolizing enzymes and smoking status with bladder cancer in a Japanese population

OBJECTIVES

Arylamines are considered to be the primary causative agent of bladder cancer in tobacco smokers. To test the hypothesis that variation in the genes that metabolize tobacco carcinogens contribute to bladder cancer, we examined the effects of single nucleotide polymorphisms in the genes of four key enzymes: cytochrome P450 1A2, N-acetyltransferase (NAT) 2, sulfotransferase 1A1, and UDP-glucuronosyltransferase (UGT) 2B7.

METHODS

In this study, 282 Japanese patients with transitional cell carcinoma, the most common bladder cancer, and 257 healthy controls were surveyed and compared for frequencies of the genotypes of the four enzymes. Genotypes were determined using PCR-restriction fragment length polymorphism and TaqMan assays. Smoking information was collected by personal interview. Logistic regression analysis and the chi-square test were employed as statistical methods.

RESULTS

The NAT2 slow genotype was significantly associated with the risk of bladder cancer [odds ratio (OR) 3.41, 95 % confidence interval (95 % CI) 1.68-6.87; p < 0.05). The NAT2 slow genotype also significantly increased the risk of bladder cancer in heavy smokers (OR 8.57, 95 % CI 1.82-40.25; p < 0.05). Among the different combinations of the four enzyme genotypes, the highest OR (4.20; 95 % CI 1.34-13.14; p < 0.05) was obtained with the NAT2 slow genotype when present in combination with the UGT2B7 *2/*2 or *1/*2 genotype.

CONCLUSIONS

Our results suggest that individuals with different genotypes for the enzymes involved in metabolizing carcinogenic arylamines have a different risk of developing bladder cancer. In particularly, the combination of the NAT2 slow genotype with UGT2B7 *1/*2 or *2/*2 genotype is a high risk factor for bladder cancer.

Genetic polymorphism of sulfotransferase 1A1, cigarette smoking, hazardous chemical exposure and urothelial cancer risk in a Taiwanese population

OBJECTIVES

To investigate the association between genetic polymorphism of sulfotransferase1A1 (SULT1A1), cigarette smoking, hazardous chemical exposure and urothelial cancer risk in a Taiwanese population.

METHODS

In a hospital-based case-control study, a total of 300 urothelial cancer (UC) cases and 300 cancer-free controls frequency-matched by age and gender were recruited from September 1998 to December 2005. The SULT1A1 arginine213histidine (Arg213His) polymorphism was genotyped using a polymerase chain reaction-restriction fragment length polymorphism method.

RESULTS

We found that the significantly increased UC risks of ever smokers and heavy smokers (> or =28 pack-years) were 2.1 (95% confidence interval [CI] = 1.4-3.3) and 2.2 (95% CI = 1.3-3.6), respectively. An increased UC risk of 1.8 (95% CI = 0.8-3.8) was observed among individuals with more than one item of hazardous chemical exposure, but it was not statistically significant. Compared with study subjects carrying the SULT1A1 Arg/Arg genotype, those with SULT1A1 Arg/His or His/His genotypes have a significantly decreased UC risk (Odds ratio [OR] = 0.5, 95% CI = 0.3-0.8). Heavy smokers carrying the SULT1A1 Arg/Arg genotype have a significantly increased UC risk (OR = 5.2, 95% CI = 2.3-11.6). Individuals who had been exposed to more than one item of hazardous chemicals and who carried the SULT1A1 Arg/Arg genotype have a significantly increased UC risk (OR = 3.7, 95% CI = 1.4-9.7). The highest significant increased UC risk (OR = 16.1, 95% CI = 2.9-87.2) was observed among ever smokers with hazardous chemical exposure and the SULT1A1 Arg/Arg genotype.

CONCLUSIONS

SULT1A1 Arg213His polymorphism is associated with the development of UC, especially among cigarette smokers exposed to hazardous chemicals.

Case-control study and meta-analysis of SULT1A1 Arg213His polymorphism for gene, ethnicity and environment interaction for cancer risk

Cytosolic sulphotransferase SULT1A1 plays a dual role in the activation of some carcinogens and inactivation of others. A functional polymorphism leading to Arg²¹³His substitution (SULT1A1*2) affects its catalytic activity and thermostability. To study the association of SULT1A1*2 polymorphism with tobacco-related cancers (TRCs), a case–control study comprising 132 patients with multiple primary neoplasm (MPN) involving TRC and 198 cancer-free controls was carried out. One hundred and thirteen MPN patients had at least one cancer in upper aerodigestive tract including lung (UADT-MPN). SULT1A1*2 showed significant risk association with UADT-MPN (odds ratio (OR)=5.50, 95% confidence interval (CI): 1.09, 27.7). Meta-analysis was conducted combining the data with 34 published studies that included 11 962 cancer cases and 14 673 controls in diverse cancers. The SULT1A1*2 revealed contrasting risk association for UADT cancers (OR=1.62, 95% CI: 1.12, 2.34) and genitourinary cancers (OR=0.73, 95% CI: 0.58, 0.92). Furthermore, although SULT1A1*2 conferred significant increased risk of breast cancer to Asian women (OR=1.91, 95% CI: 1.08, 3.40), it did not confer increased risk to Caucasian women (OR=0.92, 95% CI: 0.71, 1.18). Thus risk for different cancers in distinct ethnic groups could be modulated by interaction between genetic variants and different endogenous and exogenous carcinogens.

Human NAD(P)H:quinone oxidoreductase 1 (NQO1) and sulfotransferase 1A1 (SULT1A1) polymorphisms and urothelial cancer risk in Taiwan

PURPOSE

To investigate whether the NAD(P)H:quinone oxidoreductase 1 (NQO1) and sulfotransferase 1A1 (SULT1A1) polymorphisms are associated with urothelial cancer (UC) risk in Taiwan.

METHODS

In this study, 600 study subjects (including 300 UC patients and 300 cancer-free controls) were recruited from September 1998 to December 2005. We analyzed the NQO1 and SULT1A1 polymorphisms by the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. A comprehensive interview was conducted to collect information, including baseline characteristics and cigarette smoking status. We used an unconditional multivariate logistic regression to calculate the odds ratio (OR) and 95% confidence interval (CI).

RESULTS

We found a significantly increased UC risk in study subjects with the NQO1 C/T and T/T genotypes (OR = 1.5; 95% CI: 1.03-2.1). A significantly increased UC risk was found in those with the SULT1A1 G/G genotype (OR = 2.0; 95% CI: 1.3-3.2). Subjects who had ever smoked with either the NQO1 C/T and T/T genotypes or the SULT1A1 G/G genotype had significantly increased UC risks, showing ORs of 3.0 and 5.3, respectively. Subjects carrying both the NQO1 C/T and T/T genotypes and the SULT1A1 G/G genotype had a significantly increased UC risk (OR = 3.7; 95% CI, 1.4-9.7). Moreover, those who had ever smoked with both the NQO1 C/T and T/T genotypes and the SULT1A1 G/G genotype had the highest UC risk (OR = 8.6; 95% CI: 2.5-29.7).

CONCLUSIONS

These findings suggest that NQO1 and SULT1A1 polymorphisms are associated with the risk of UC, particularly among those who have ever smoked.

Dose-escalation study of isoniazid in healthy volunteers with the rapid acetylator genotype of arylamine N-acetyltransferase 2

OBJECTIVE

Genetic polymorphisms of arylamine N-acetyltransferase 2 (NAT2) result in large interindividual differences in the plasma concentration of isoniazid (INH). We hypothesized that the internationally recommended dosage should be increased for patients with two active NAT2 alleles (RA type) in order to achieve appropriate antituberculous efficiency; however, the pharmacokinetic effects of the dose increase have not been fully addressed. To estimate an optimal dosage for RA-type patients, we conducted a dose escalation study in healthy male volunteers carrying NAT2*4/*4.

METHODS

Oral doses of 300 mg, 600 mg, and 900 mg of INH were administered to eight RA-type subjects, whereas 300 mg was administered to eight IA-type subjects with one active allele (NAT2*4). The pharmacokinetic parameters were estimated from plasma INH concentrations for 24 h postdose.

RESULTS

The ratio of the mean area under the plasma-concentration time curve (AUC) was not proportional to the doses (1:2.6:5.0 for 300:600:900-mg dose) in parallel to the plasma concentration at 1 h (C(1)) and 2 h (C(2)) after administration. Compared with the IA-type group given 300 mg, the RA-type group had lower pharmacokinetic parameters at 300 mg (AUC, 66%; C(1), 72%; C(2), 61%), but higher parameters at 600 mg (AUC, 175%; C(1), 196%; C(2), 170%). Plasma concentrations of the IA-type group were within the therapeutic range. An optimal INH dose was calculated as 430 mg (7.2 mg/kg) for RA-type subjects to obtain an AUC comparable with that in IA-type subjects dosed with 300 mg.

CONCLUSION

In RA-type subjects, the pharmacokinetic parameters appeared to lack linearity with the increased dose of INH. We propose that the proper daily dose for RA-type patients is 1.5-times higher than that currently recommended.

Impact of polymorphism in sulfotransferase gene on the risk of lung cancer

Sulfotransferases (SULTs) are very important multifunctional enzymes that catalyze sulfonate conjugation, which is an important pathway in the phase II metabolism of numerous endogenous and exogenous compounds. Sulfotransferase 1A1 (SULT1A1) is active toward a wide range of substrates, including environmental and tobacco carcinogens. This case-control study involved collection of peripheral blood samples (2-5 mL) of 103 lung cancer patients and 122 controls from North Indian subjects. The SULT1A1 polymorphism was determined by using a polymerase chain reaction-restriction fragment length polymorphism method. The association between polymorphisms in the SULT1A1 gene with the risk of lung cancer was estimated by computing odds ratios (OR) and 95% confidence intervals (95% CI), using a multivariate logistic regression analysis. We observed marginally increased risk for mutant genotype (AA) of SULT1A1 for lung cancer (OR = 1.4, 95% CI = 0.48-4.06). A statistically significant association was found for smokers between either of two SULT1A1 genotypes, GA (OR = 10.3, 95% CI = 3.48-31.78, P = 0.000002) or AA (OR = 3.9, 95% CI = 1.99-7.81, P = 0.0002), and lung cancer. The present study indicates that the SULT1A1 genotype may play an important role in the risk of developing lung cancer, especially in cigarette smokers.

Phase I and Phase II Enzyme Polymorphisms and Childhood Cancer

Childhood cancers continue to be challenging clinical entities whose etiology, demographic characteristics, clinical progression, treatment efficacy, and outcomes remain incompletely understood. Research suggests that multiple environmental and genetic factors may play crucial roles in the pathophysiology of many of these malignancies. Recent attention has been directed to the role of carcinogen metabolizing enzymes in the etiology and progression of cancer in both adults and children due to their multitude of polymorphic variants and their intimate interaction with environmental factors. In particular, xenobiotic metabolizing enzymes (XME), which are intimately involved in the activation and deactivation of many environmental carcinogens, have become an area of significant interest. Traditionally, these enzymes have been classified into either phase I or phase II enzymes depending on their substrates, activity, and occasionally based on their sequence in the metabolic pathways, and have been demonstrated to have numerous polymorphic variants. Phase I enzymes predominantly consist of cytochrome enzymes responsible for mixed function oxidase activity, whereas phase II enzymes are frequently conjugation reactions necessary for drug metabolism or the further metabolism of phase I enzyme products. Current research has discovered numerous interactions between polymorphisms in these enzymes and changes in cancer susceptibility, treatment efficacy, and clinical outcomes in childhood cancer. Furthermore, studies of polymorphisms in these enzymes have demonstrated to have synergistic/antagonistic interactions with other XME polymorphisms and demonstrate variable influences on disease pathophysiology depending on the patient's ethnic background and environmental milieu. Continuing research on the role of polymorphisms in phase I and phase II enzymes will likely further elucidate the intimate role of these polymorphisms with environmental factors in the etiology of childhood cancer.

Genetic Polymorphisms of SULT1A1 and SULT1E1 and the Risk and Survival of Breast Cancer

We examined whether common single nucleotide polymorphisms (SNP) in SULT1A1 (c.779G>A, *14A>G, and *85C>T) and SULT1E1 (IVS1-447C>A, IVS4-1653T>C, and *959G>A) genes influenced the risk and survival of breast cancer. Our study population consisted of 989 histologically confirmed sporadic breast cancer patients and 1,054 controls without history of cancer recruited from three teaching hospitals in Seoul. Odds ratios (OR) and 95% confidence intervals (95% CI) were estimated by logistic regression model. In the survival analysis for 529 breast cancer patients with completed treatments, the hazard ratios (HR) were calculated with Cox proportional hazard model. Women with the SULT1E1 *959 GA/AA genotype had a moderately decreased breast cancer risk compared with those with the GG genotypes (OR, 0.8; 95% CI, 0.70-1.00). When the haplotypes were considered, the homozygous *959 AA genotype together with the IVS4-1653 T>C base change (CTA-CCA haplotype) was associated with halved breast cancer risk (OR, 0.5; 95% CI, 0.24-0.88) compared with the wild type CTG-CTG haplotype. No other significant overall association was observed between the SULT1A1 and SULT1E1 SNPs nor haplotypes and breast cancer risk. When stratified by survival, patients with the SULT1E1 IVS4-1653 TC/CC genotypes showed a >3-fold risk of recurrence (HR, 3.2; 95% CI, 1.39-7.48) compared with those with the TT genotype. Moreover, when the haplotypes were considered, the SULT1E1 *959 G>A base change together with the IVS4-1653 T>C base change (CTG-CCA haplotype) was associated with a >4-fold risk of breast cancer (OR, 4.2; 95% CI, 1.15-15.15). These findings suggest that genetic polymorphisms of SULT1E1 are associated with increased risk and a disease free survival of breast cancer in Korean women.

SULT1A1 genotype, active and passive smoking, and breast cancer risk by age 50 years in a German case-control study

INTRODUCTION

Sulfotransferase 1A1 (encoded by SULT1A1) is involved in the metabolism of procarcinogens such as heterocyclic amines and polycyclic aromatic hydrocarbons, both of which are present in tobacco smoke. We recently reported a differential effect of N-acetyltransferase (NAT) 2 genotype on the association between active and passive smoking and breast cancer. Additional investigation of a common SULT1A1 genetic polymorphism associated with reduced enzyme activity and stability might therefore provide deeper insight into the modification of breast cancer susceptibility.

METHODS

We conducted a population-based case-control study in Germany. A total of 419 patients who had developed breast cancer by age 50 years and 884 age-matched control individuals, for whom risk factor information and detailed smoking history were available, were included in the analysis. Genotyping was performed using a fluorescence-based melting curve analysis method. Multivariate logistic regression analysis was used to estimate breast cancer risk associated with the SULT1A1 Arg213His polymorphism alone and in combination with NAT2 genotype in relation to smoking.

RESULTS

The overall risk for breast cancer in women who were carriers of at least one SULT1A1*2 allele was not significantly different from that for women with the SULT1A1*1/*1 genotype (adjusted odds ratio 0.83, 95% confidence interval 0.66-1.06). Risk for breast cancer with respect to several smoking variables did not differ substantially between carriers of the *2 allele and noncarriers. However, among NAT2 fast acetylators, the odds ratio associated with passive smoking only (3.23, 95% confidence interval 1.05-9.92) was elevated in homozygous carriers of the SULT1A1*1 allele but not in carriers of the SULT1A1*2 allele (odds ratio 1.28, 95% confidence interval 0.50-3.31).

CONCLUSION

We found no evidence that the SULT1A1 genotype in itself modifies breast cancer risk associated with smoking in women up to age 50 years. In combination with NAT2 fast acetylator status, however, the SULT1A1*1/*1 genotype might increase breast cancer risk in women exposed to tobacco smoke.

Sulfotransferase 1A1 (SULT1A1) polymorphism and bladder cancer risk: a case-control study

Sulfotransferases (SULT) catalyze both the bioactivation and detoxification of a wide range of promutagens and procarcinogens. SULT1A1 appears to be an important phenol SULT because of its abundance and distribution in many tissues and wide substrate specificity. The SULT1A1 gene possesses a G-->A polymorphism that results in an Arg to His amino acid substitution, and the His(213) allele has been shown to have low activity and low thermal stability. Because of its functional role and published data showing the influence of Arg213His polymorphism on the risk of some cancers, we hypothesized that the His(213) allele of the SULT1A1 gene may modify bladder cancer risk. To test this hypothesis, we determined the SULT1A1 Arg213His genotypes in 384 incident bladder cancer patients and 386 healthy frequency-matched controls. A comprehensive epidemiologic interview was conducted on all participants to collect personal information, such as demographics and smoking status. The Arg/His and His/His genotypes were more common in the controls than the cases (P=0.035), resulting in a His(213) allele frequency of 35.0% in controls and 28.8% in cases. When individuals with the His(213) allele genotypes (Arg/His+His/His) were combined and compared to individuals with the Arg/Arg genotype, we observed a statistically significant reduced risk of bladder cancer (OR=0.72; 95% CI 0.54-0.97). When we examined the data by gender, there was a statistically significant reduced risk of bladder cancer only in women (OR=0.42; 95% CI 0.23-0.78) and not in men (OR=0.84; 95% CI 0.60-1.19) with the His(213) genotypes. In addition, there was a reduced bladder cancer risk in never smokers (OR=0.59; 95% CI 0.36-0.98) with the His(213) allele genotypes, but not in former (OR=0.82; 95% CI 0.54-1.25) or current smokers (OR=0.68; 95% CI 0.29-1.58). The His(213) allele genotypes also appeared to provide some protective benefit for current and former smokers, as compared to those with the Arg/Arg genotype. In conclusion, this study provides epidemiologic evidence of a reduced bladder cancer risk associated with the SULT1A1 His(213) polymorphism. Further studies are warranted to elucidate the function of this SULT1A1 polymorphism with regard to organ specificity, gene-environment interactions, and the gender-related difference we observed.

4-aminobiphenyl-induced liver and urinary bladder DNA adduct formation in Cyp1a2(-/-) and Cyp1a2(+/+) mice

BACKGROUND

Metabolites of the potent human carcinogen 4-aminobiphenyl (ABP) induce oxidative stress and form DNA adducts that are associated with hepatic and urinary bladder toxicity and bladder tumorigenesis. Results of in vitro and cell culture studies have suggested that cytochrome P450 1A2 (CYP1A2) is the major metabolic activator of ABP. We used Cyp1a2(-/-) knockout mice to examine the role of CYP1A2 in ABP-DNA adduct formation in the liver and the bladder.

METHODS

Cyp1a2(+/+) wild-type and Cyp1a2(-/-) mice (total of four mice per group) were treated topically with 10 mg/kg ABP for various times, with or without pretreatment with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), an inducer of CYP1A2 activity. We evaluated ABP-induced toxicity by carrying out quantitative histology (of the liver, skin, and bladder), oxidative stress by measuring hepatic thiol levels, and liver and bladder DNA adduct formation by using 32P-postlabeling. Data were analyzed by general linear models and analysis of variance. All statistical tests were two-sided.

RESULTS

At the experimental times selected, we observed no histologic evidence of toxicity in the liver, skin, or bladder. Overall, Cyp1a2(+/+) mice had fewer DNA adducts 24 hours after ABP treatment than similarly treated Cyp1a2(-/-) mice. Compared with male mice, female mice had more DNA adducts in the liver but fewer adducts in the bladder, regardless of Cyp1a2 genotype. TCDD pretreatment was associated with a decrease in ABP-DNA adduct levels overall. After 2 hours of ABP treatment, hepatic thiol levels underwent statistically significant declines of severalfold in Cyp1a2(+/+) and Cyp1a2(-/-) males and in Cyp1a2(-/-) females.

CONCLUSIONS

Contrary to our expectations, CYP1A2 expression was not associated with ABP-induced hepatic oxidative stress or with ABP-DNA adduct formation. Either CYP1A2 is not the major metabolic activator of ABP or other enzymes metabolically activate ABP in mice in the absence of CYP1A2.