Variation in N-acetyltransferase 2 (NAT2), smoking and risk of prostate cancer in the Slovak population

Genetic variants in xenobiotic detoxification enzymes, antioxidant defenses and hormonal pathways as biomarkers of susceptibility to prostate cancer

Cancer is considered a complex disease that in many cases results from the interaction between chemical exposures, either from environmental or dietary sources, and genetic polymorphisms of xenobiotic-metabolizing enzymes (XME) or antioxidant enzymatic defenses. This study explored associations and interactions between genetic and environmental risk factors on the risk of prostate cancer (PCa) in 323 subjects that underwent prostate biopsy due to prostate specific antigen (PSA) levels above 4 ng/ml (161 PCa and 162 non-PCa). Eleven genes involved directly or indirectly in xenobiotic detoxification, oxidative stress and estrogen signaling were studied (GSTM1, GPX1 (rs1050450 and rs17650792), NAT2 (rs1801280), TXNRD1 (rs7310505), PRDX3 (rs3740562), CYP17A1 (rs743572), PON1 (rs662), SOD1 (rs10432782), SOD2 (rs4880), CAT (rs1001179), and ESR1 (rs746432)). A structured questionnaire was administered to all individuals to assess environmental and dietary chemical exposures. Medical data was collected by urologists. GPX1 rs17650792 polymorphism was the only one showing a significant inverse association with PCa risk. PRDX3 and GPX1 (rs17650792) genetic polymorphisms were significantly associated with Gleason score and PSA levels, respectively. The intake of nuts and soya products was associated with a reduced risk of PCa, as well as the performance of physical activity. Moreover, a number of gene-environmental interactions were found to increase the risk of PCa, particularly exposure to pesticides and rs1801280 (NAT2) and tobacco smoking and rs1050450 (GPX1). These findings suggest that the association of genetic and environmental risk factors with PCa risk should be assessed jointly for a better understanding of this complex disease.

Isoniazid acetylation phenotypes in the Sudanese population; findings and implications

Background

Isoniazid (INH) is the mainstay antimicrobial in the treatment of tuberculosis (TB). It is acetlylated in the liver to acetyl-INH. However, there is variation in rate of acetylation of INH among TB patients (i.e. fast, intermediate or slow acetylators) which impacts on the treatment outcomes.

Aim

The isoniazid acetylation phenotypes in the expatriate Sudanese population were determined to provide future guidance since TB is prevalent in Sudan.

Methods

A community-based trial among Sudanese expatriates in Saudi Arabia was undertaken to identify INH-acetylation phenotypes. After overnight fasting, a single dose of 200 mg of INH was given to the volunteers. Three hours later, 5 ml of blood were drawn from each volunteer and prepared for High-Performance Liquid Chromatography (HPLC) analysis. The main outcomes were INH and Acetyl-INH concentrations in plasma and the subsequent Acetyl-INH/INH metabolic ratio (MR).

Results

The findings suggest that slow acetylation is highly prevalent among the study participants (n = 43; 84.31%). Moreover, there was no statistically significant correlation between age and the MR (r = −0.18, P = 0.20). Further, there was no significant association between gender and the MR (P = 0.124). Similarly, no significant association was found between smoking habits and MR (P = 0.24).

Conclusion

Isoniazid phenotyping suggests predominantly slow acetylation among the Sudanese in this sample. The study found no statistically significant associations between the MR and age or gender or smoking.

Lack of association between NAT2 polymorphism and prostate cancer risk: a meta-analysis and trial sequential analysis

Previous studies have investigated the association between NAT2 polymorphism and the risk of prostate cancer (PCa). However, the findings from these studies remained inconsistent. Hence, we performed a meta-analysis to provide a more reliable conclusion about such associations. In the present meta-analysis, 13 independent case-control studies were included with a total of 14,469 PCa patients and 10,689 controls. All relevant studies published were searched in the databates PubMed, EMBASE, and Web of Science, till March 1st, 2017. We used the pooled odds ratios (ORs) with 95% confidence intervals (CIs) to evaluate the strength of the association between NAT2*4 allele and susceptibility to PCa. Subgroup analysis was carried out by ethnicity, source of controls and genotyping method. What's more, we also performed trial sequential analysis (TSA) to reduce the risk of type I error and evaluate whether the evidence of the results was firm. Firstly, our results indicated that NAT2*4 allele was not associated with PCa susceptibility (OR = 1.00, 95% CI= 0.95–1.05; P = 0.100). However, after excluding two studies for its heterogeneity and publication bias, no significant relationship was also detected between NAT2*4 allele and the increased risk of PCa, in fixed-effect model (OR = 0.99, 95% CI= 0.94–1.04; P = 0.451). Meanwhile, no significant increased risk of PCa was found in the subgroup analyses by ethnicity, source of controls and genotyping method. Moreover, TSA demonstrated that such association was confirmed in the present study. Therefore, this meta-analysis suggested that no significant association between NAT2 polymorphism and the risk of PCa was found.

Associations of polymorphisms in NAT2 gene with risk and metastasis of osteosarcoma in young Chinese population

Osteosarcoma is the most common primary malignancy of bone in young individuals. Genetic factors may play an important role in the tumorigenesis of osteosarcoma. Here we carried out a case-control study to investigate seven NAT2 single-nucleotide polymorphisms (rs1799929, rs120, rs1041983, rs1801280, rs1799930, rs1799931, and rs1801279) on the risk and prognosis of osteosarcoma. This study included 260 young osteosarcoma cases and 286 controls. The TaqMan method was used to determine genotypes. We found that rs1799931 G>A polymorphisms were associated with a decreased risk of osteosarcoma in young Chinese population, and rs1041983 CT genotype seemed to play a protective role in the risk of osteosarcoma. However, further analysis showed that rs1041983 polymorphisms were associated with an elevated risk of tumor metastasis, predicting poor prognosis. This study provided the first evidence for the associations between NAT2 polymorphisms and osteosarcoma risk and metastasis in Chinese population.