Genotyping NAT2 with only two SNPs (rs1041983 and rs1801280) outperforms the tagging SNP rs1495741 and is equivalent to the conventional 7-SNP NAT2 genotype.

Genotyping N-acetyltransferase 2 (NAT2) is of high relevance for individualized dosing of antituberculosis drugs and bladder cancer epidemiology. In this study we compared a recently published tagging single nucleotide polymorphism (SNP) (rs1495741) to the conventional 7-SNP genotype (G191A, C282T, T341C, C481T, G590A, A803G and G857A haplotype pairs) and systematically analysed if novel SNP combinations outperform the latter. For this purpose, we studied 3177 individuals by PCR and phenotyped 344 individuals by the caffeine test. Although the tagSNP and the 7-SNP genotype showed a high degree of correlation (R=0.933, P<0.0001) the 7-SNP genotype nevertheless outperformed the tagging SNP with respect to specificity (1.0 vs. 0.9444, P=0.0065). Considering all possible SNP combinations in a receiver operating characteristic analysis we identified a 2-SNP genotype (C282T, T341C) that outperformed the tagging SNP and was equivalent to the 7-SNP genotype. The 2-SNP genotype predicted the correct phenotype with a sensitivity of 0.8643 and a specificity of 1.0. In addition, it predicted the 7-SNP genotype with sensitivity and specificity of 0.9993 and 0.9880, respectively. The prediction of the NAT2 genotype by the 2-SNP genotype performed similar in populations of Caucasian, Venezuelan and Pakistani background. A 2-SNP genotype predicts NAT2 phenotypes with similar sensitivity and specificity as the conventional 7-SNP genotype. This procedure represents a facilitation in individualized dosing of NAT2 substrates without losing sensitivity or specificity.

Rs710521[A] on chromosome 3q28 close to TP63 is associated with increased urinary bladder cancer risk.

Single nucleotide polymorphism (SNP) rs710521[A], located near TP63 on chromosome 3q28, was identified to be significantly associated with increased bladder cancer risk. To investigate the association of rs710521[A] and bladder cancer by new data and by meta-analysis including all published data, rs710521 was studied in 1,425 bladder cancer cases and 1,740 controls that had not been included in previous studies. Blood samples were collected from 1995 to 2010 in Germany (n = 948/1,258), Hungary (n = 262/65), Venezuela (n = 112/190) and Pakistan (n = 103/227) supplemented by a meta-analysis of 5,695 cases and 40,187 controls. Detection of a A/G substitution (rs710521) on chromosome 3q28, position 191128627 was done via fast real-time polymerase chain reaction (rt-PCR). Rs710521[A] is associated with increased risk in the unadjusted analysis (OR = 1.21; 95% Cl = 1.04-1.40; P = 0.011) and in the recessive model adjusted for age, gender, smoking habits and ethnicity (OR = 1.23; 95% Cl = 1.05-1.44; P = 0.010). No difference between individuals occupationally exposed versus not occupationally exposed to urinary bladder carcinogens was observed concerning the relevance of rs710521[A]. Similarly, rs710521[A] did not confer different susceptibility in smokers and non-smokers. Performing a meta-analysis of 5,695 cases and 40,187 controls including all published studies on rs710521, a convincing association with bladder cancer risk was obtained (OR = 1.18; 95% Cl = 1.12-1.25; P < 0.0001). However, the odds ratio is relatively small.

The influence of polymorphisms of glutathione S-transferases M1 and M3 on the development of human urothelial cancer.

Cigarette smoking is the most important risk factor for development of transitional cell carcinoma of the urinary bladder. The effect of polymorphisms of glutathione S-transferases M1 (GSTM1) and M3 (GSTM3) on the influence of cigarette smoking on urinary bladder carcinogenesis was investigated. In total, 293 bladder cancer patients from hospitals in Dortmund and Wittenberg as well as 176 patients without any malignancy from a Department of Surgery from Dortmund were genotyped for GSTM1 and GSTM3 according to standard PCR/RFLP methods. Smoking habits were quantified by a standardized interview. The proportion of GSTM1 negative cases was 63% in the entire bladder cancer cases group compared to 50% in controls. The GSTM3*A/*A genotype was 76% in cancer cases versus 74% in controls. Smokers and ex-smokers were overrepresented in bladder cancer cases. A significant association between smoking status and GSTM1 or GSTM3 genotype was not detected. The elevated proportion of GSTM1 negative bladder cancer cases shows an effect of this polymorphic enzyme on development of bladder cancer. In contrast to other studies, an influence of GSTM1 on the risk due to cigarette smoking was not observed.

Glutathione S-transferase P1 ILE105Val polymorphism in occupationally exposed bladder cancer cases.

The genotype glutathione S-transferase P1 (GSTP1) influences the risk for bladder cancer among Chinese workers occupationally exposed to benzidine. Studies of Caucasian bladder cancer cases without known occupational exposures showed conflicting results. Research was thus conducted to define the role of GSTP1 genotypes in Caucasian bladder cancer cases with an occupational history of exposure to aromatic amines. DNA from 143 cases reported to the Industrial Professional Associations (Berufsgenossenschaften) in Germany from 1996 to 2004, who had contracted urothelial cancer due to occupational exposure, and 196 patients from one Department of Surgery in Dortmund, without known malignancy in their medical history, were genotyped using real-time polymerase chain reaction (PCR) (LightCycler) in relation to GSTP1 A1578G (Ile105Val) polymorphism. Among the subjects with bladder cancer, 46% presented the AA genotype, 39% the AG genotype, and 15% the GG genotype. In the surgical (noncancer) control group analyzed, 42% presented the AA genotype, 42% the AG genotype, and 16% the GG genotype. A subgroup of bladder cancer cases, represented by 46 painters, showed a distribution of 41% of the AA genotype, 48% of the AG genotype, and 11% of the GG genotype. Data indicated that in Caucasians exposed to aromatic amines the GSTP1 A1578G polymorphism did not appear to play a significant role as a predisposing factor for bladder cancer incidence.

N-acetyltransferase 1 in colon and rectal cancer cases from an industrialized area.

Colon and rectal cancers are both associated with genetic as well as nutritional, occupational, and environmental factors. Aromatic amines and heterocyclic amines are established colorectal carcinogens. The polymorphic enzyme N-acetyltransferase 1 (NAT1) contributes to heterocyclic amine metabolism in the human colon. Thereby, NAT1 may influence the risk for development of colorectal cancer. The distribution of NAT1 genotypes was determined in 107 colon cancer cases, 77 rectal cancer cases, and 185 controls (suffering from nonmalignant diseases) by standard methods. In addition, possible occupational and nonoccupational risk factors were determined by a personal interview. Cancer cases and controls were derived from an area of former coal, iron, and steel industries, which is known for elevated colon cancer mortality. The proportions of NAT1*4/*4 genotype were 72% in controls, 75% in rectal cancer cases, and 72% in colon cancer cases. The proportions of the NAT1*4/*10 genotype were 17.8% in controls, 12.9% in rectal cancer cases, and 14% in colon cancer cases. Combinations of the determined NAT1 alleles *3/*3, *3/*10, *4/*3, *4/*11, *10/*10 and *11/*11 contributed to 10.2% of the genotypes in controls, 12.1% in rectal cancer cases, and 14% in colon cancer cases. In contrast to another study on healthy German volunteers, the NAT1*4/*4 genotype (wild type) is overrepresented. This might be due to the variation in the proportion of NAT1 alleles in the general population. The present study does not support a relevant impact of the NAT1 genotype on colorectal cancer risk development in the study area.