Genetic Polymorphisms of Cytochrome P450 and Matrix Metalloproteinase in Chronic Obstructive Pulmonary Disease

We investigated whether polymorphisms of cytochrome P450 (CYP) and matrix metalloproteinase (MMP) are associated with the development and severity of chronic obstructive pulmonary disease (COPD). Genotypes of 184 patients with COPD and 212 controls were determined by polymerase chain reaction, followed by restriction fragment length polymorphism. The homozygous T allele of MMP-9 was significantly higher in patients with COPD than in controls (14.7% vs. 7.5%). The odds ratio was 2.4 (95% CI 1.1–5.9). No differences were observed in the frequency of polymorphic genotypes in CYP1A1, 1A2, MMP-1 and -3. During combined analysis of these candidate genes, we found strong indicators for susceptibility to COPD (combined with homozygotes *2A for CYP1A1 and T alleles of MMP-9 versus others = 3.3, 95% CI 1.2–8.6). The frequency of the homozygous *2A allele of CYP1A1 was significantly higher in very severe COPD (P < 0.01). Combinations of genetic variants including *2A homozygotes of CYP1A1 and T alleles in MMP-9 are significant indicators for susceptibility to COPD. The homozygous *2A allele of CYP1A1 is an independent risk factor for very severe COPD.     

Association of CYP3A5*3 polymorphism with development of acute leukemia

BACKGROUND:

CYP3A5 was observed to be an important genetic contributor to inter individual differences in CYP3A-dependent drug metabolism in acute leukemic patients. Loss of CYP3A5 expression was mainly conferred by a single nucleotide polymorphism at 6986A>G (CYP3A5*3). We investigated the association between CYP3A5*3 polymorphism and acute leukemia.

MATERIALS AND METHODS:

Two hundred and eighty nine acute leukemia cases comprising of 145 acute lymphocytic leukemia (ALL), 144 acute myeloid leukemia and 241 control samples were analyzed for CYP3A5*3 polymorphism using PCR-RFLP method. Statistical analysis was performed with SPSS version (15.0) to detect the association between CYP3A5*3 polymorphism and acute leukemia.

RESULTS:

The CYP3A5*3 polymorphism 3/3 genotype was significantly associated with acute leukemia development (χ²- 133.53; df-2, P 0.000). When the data was analyzed with respect to clinical variables, mean WBC, blast % and LDH levels were increased in both ALL and AML cases with 3/3 genotype. The epidemiological variables did not contribute to the genotype risk to develop either AML or ALL.

CONCLUSION:

The results suggest that the CYP3A5*3 polymorphism might confer the risk to develop ALL or AML emphasizing the significance of effective phase I detoxification in carcinogenesis. Association of the polymorphism with clinical variables indicate that the 3/3 genotype might also contribute to poorer survival of the patients.     

Allele and genotype frequencies of CYP2B6 in a Turkish population

Increasing interest in cytochrome P450 2B6 (CYP2B6) genetic polymorphism was stimulated by revelations of a specific CYP2B6 genotype significantly affecting the metabolism of various drugs in common clinical use in terms of increasing drug efficacy and avoiding adverse drug reactions. The present study aimed to determine the frequencies of CYP2B6*4 CYP2B6*5, CYP2B6*6, CYP2B6*7 and CYP2B6*9 alleles in healthy Turkish individuals (n = 172). Frequencies of three single nucleotide polymorphisms were 516G>T (28 %), 785A>G (33 %), and 1459C>T (12 %). The frequencies of CYP2B6*1, *4, *5, *6, *7, and *9 alleles were 54.3 (95 % CI 49.04–59.56), 6.4 % (95 % CI 3.81–8.99), 11 % (95 % CI 7.69–14.31), 25.3 % (95 % CI 20.71–29.89), 0.87 % (95 % CI ?0.11–1.85) and 2.0 % (95 % CI 0.52–3.48), respectively. Allele *6 was more frequent (25.3 %) than the other variant alleles in Turkish subjects. The frequencies of CYP2B6*4, *5, *6, *7, and *9 alleles were similar to European populations but significantly different from that reported for Asian populations. This is the first study to document the frequencies of the CYP2B6*4, *5, *6, *7, *9 alleles in the healthy Turkish individuals and our results could provide clinically useful information on drug metabolism by CYP2B6 in Turkish population.     

Polymorphism in environment responsive genes and association with Parkinson disease

Attempts were made in the present case-control study to investigate the association of polymorphism in the genes encoding proteins involved in toxication–detoxication and dopaminergic pathways and susceptibility to Parkinson’s disease (PD). Seventy patients suffering from PD and one hundred healthy controls belonging to the same geographical location and same ethnicity were included in the study. PCR-RFLP and allele-specific PCR-based methodology were used to identify the genotypes. Multivariate logistic regression analysis revealed that heterozygous genotypes of cytochrome P4502D6*4(CYP2D6*4), CYP2E1*5B (RsaI) polymorphism and homozygous mutant genotypes of CYP2E1*6 (Dra1) were found to be overrepresented in PD cases when compared to the controls. Risk was also found to be increased in patients carrying glutathione S-transferase T1 (GSTT1) null or homozygous variant genotypes of GSTP1. Significant association was observed for monoamine oxidase-B(MAO-B) variant allele G and PD, whereas no difference in genotype and allele frequencies was observed for manganese-superoxide dismutase (MnSOD), dopamine receptor-D2(DRD2), and dopamine transporter (DAT) genes between controls and PD cases. Genotype combinations characterized by the presence of two variant genotypes on their corresponding loci revealed that four combinations of GSTT1 null and MnSOD(-9Val) or GST null and MAOB-G or CYP2E1*5B and MAO-B-AG or CYP2E1*5B and DRD2 (Taq1A-het) genotypes in the patients exhibited severalfold higher and significant association with risk to PD. Our data suggest that polymorphism in the genes involved in detoxification and dopamine regulation may modulate the susceptibility to PD and could be important risk factors in the pathogenesis of PD.     

Single nucleotide polymorphism of CYP3A5*3 contributes to clopidogrel resistance in coronary artery disease patients among Tamilian population

Clopidogrel is an antiplatelet drug. It is used for the treatment as well as for the prophylaxis of coronary artery disease. Clopidogrel resistance is an emerging problem in clinical settings. The aim of the present study was to evaluate the effect of CYP3A5*3 genetic polymorphism on clopidogrel resistance. One hundred and forty-seven patients from outpatient Department of Cardiology on 75 mg/day of clopidogrel as maintenance dose were recruited from April 2010 to July 2011. All subjects gave written informed consent to participate in the study. DNA extraction was performed using phenol chloroform extraction procedure and genotyping by standard Taqman based RT-PCR method. Platelet aggregation was done at the end of 7th and 14th day by using chronolog lumi Aggregometer which is expressed as impedance in ohms. Impedance values of >5 ohms at the end of 6 min were considered as clopidogrel resistance. Subjects (N = 147) were analysed for CYP3A5*3 polymorphism, of which 49 (33 %) were found to be clopidogrel resistant. Homomutants of CYP3A5*3 gene had 2.78 (0.97–7.98; p < 0.05) fold risk and heteromutants had 2.4 (0.93–6.46; p < 0.05) fold risk of developing clopidogrel resistance. Carriers of defective allele G of CYP3A5*3 had higher propensity to cause clopidogrel resistance with an odds ratio of 1.63. Variant alleles and genotypes of CYP3A5*3 polymorphism contributed significantly to clopidogrel resistance with a higher odds ratio. Thus, pharmacogenomics paves way for the emergence of stratified medicine in clopidogrel therapy and personalised pharmacotherapy in ischaemic heart disease.     

Pyrosequencing to Identify Homogeneous Phenomenon When Using Recipients/Donors with Different CYP3A5*3 Genotypes in Living Donor Liver Transplantation

This study used pyrosequencing to determine the proportional distribution of CYP3A5*3 genotypes to further confirm the homogeneous phenomenon that is observed when recipients and donors in living donor liver transplantation (LDLT) have a different single nucleotide polymorphism (SNP) genotype. We enrolled 42 recipient/living donor pairs and the SNPs of CYP3A5*3 were identified by polymerase chain reaction-restriction fragment length polymorphism. We performed 120 liver graft biopsies as part of clinical investigations after LDLT. Pyrosequencing of the CYP3A5*3 SNPs revealed that among the 16 recipients with the G/G genotype, 94.68% had the G and 5.32% the A allele. Among the 14 recipients with the A/G genotype, 78.08% had the G and 21.92% the A allele, and among the 12 recipients with the A/A genotype, 18.45% had the G and 81.55% the A allele. Among the 12 donors with the G/G genotype, 93.85% had the G and 6.14% the A allele. Among the 26 donors with the A/G genotype, 75.73% had the G and 24.27% the A allele, and among the 4 donors with the A/A genotype, 11.09% had the G and 88.91% the A allele. There were a total of 120 liver graft biopsy samples; among the 37 recipients with the G/G genotype, 89.74% had the G and 10.26% the A allele, among the 70 recipients with the A/G genotype, 71.57% had the G and 28.43% the A allele, and among the 13 recipients with the A/A genotype, 48.25% had the G and 51.75% the A allele. The proportional distribution of G and A alleles of the CYP3A5*3 SNP between recipients/donors and liver grafts after LDLT was significantly different (p<0.001). Pyrosequencing was useful in identifying detailed proportional changes of the CYP3A5*3 SNP allele distribution, and to confirm the homogeneous phenomenon when recipients and donors in LDLT have a different genotype.     

Study the polymorphism of CYP3A5 and CYP3A4 loci in Iranian population with laryngeal squamous cell carcinoma

Cancer reflects a complicated network of interactions between genes and environmental factors. Cytochrome P450 (CYP) is a multi-gene superfamily participating in the metabolism of xenobiotics. The aim of our study was to examine whether polymorphisms in the CYP enzyme genes affect the risk of developing larynx squamous cell carcinoma (SCC). Polymorphism of CYP3A5 and CYP3A4 genes were investigated in 50 patients with laryngeal SCC and 100 control subjects by polymerase chain reaction- restriction fragment length polymorphism (PCR-RFLP). In patients the CYP3A5 3*/3* and 1*/3*genotypes were detected in 92% and 8% respectively. There was no relation between genotype, allele frequency and grade/stage of tumor. In control group, the frequency of CYP3A5 3*/3* and CYP3A5 1*/3* genotype were 98% and 2% respectively. There was no significant difference in genotype and allele frequency of this gene between patient and control group. In respect of CYP3A41A*/B*, people in both patient and control groups had the same genotype of CYP3A41A*/1A*. In this study, the CYP gene variants were not associated with increased risk of laryngeal SCC. Study on the other genetic factors which are involved in activation/detoxication of procarcinogenes, such as CYP1A1, CYP1B1, CYP2E1 and gluthation S transferase is recommended.     

A Novel Simple Method for Determining CYP2D6 Gene Copy Number and Identifying Allele(s) with Duplication/Multiplication

Background

Cytochrome P450 2D6 (CYP2D6) gene duplication and multiplication can result in ultrarapid drug metabolism and therapeutic failure or excessive response in patients. Long range polymerase chain reaction (PCR), restriction fragment length polymorphism (RFLP) and sequencing are usually used for genotyping CYP2D6 duplication/multiplications and identification, but are labor intensive, time consuming, and costly.

Methods

We developed a simple allele quantification-based Pyrosequencing genotyping method that facilitates CYP2D6 copy number variation (CNV) genotyping while also identifying allele-specific CYP2D6 CNV in heterozygous samples. Most routine assays do not identify the allele containing a CNV. A total of 237 clinical and Coriell DNA samples with different known CYP2D6 gene copy numbers were genotyped for CYP2D6 *2, *3, *4, *6, *10, *17, *41 polymorphisms and CNV determination.

Results

The CYP2D6 gene allele quantification/identification were determined simultaneously with CYP2D6*2, *3, *4, *6, *10, *17, *41 genotyping. We determined the exact CYP2D6 gene copy number, identified which allele had the duplication or multiplication, and assigned the correct phenotype and activity score for all samples.

Conclusions

Our method can efficiently identify the duplicated CYP2D6 allele in heterozygous samples, determine its copy number in a fraction of time compared to conventional methods and prevent incorrect ultrarapid phenotype calls. It also greatly reduces the cost, effort and time associated with CYP2D6 CNV genotyping.     

Molecular basis for subtypic differences of the “a” subunit of coagulation factor XIII with description of the genesis of the subtypes

The “a” subunit of human coagulation factor XIII (F13A) exhibits genetic polymorphism defined by four common alleles, F13A*1A, *1B, *2A, and *2B. We have previously suggested on the basis of the isoelectric focusing patterns of the four allele products that point mutations at two separate sites and one intragenic crossing over might be involved in the genes of F13A polymorphism. Here, we report nucleotide substitutions associated with F13A polymorphism. A C/T transition of the second nucelotide of codon 564 in exon 12 is responsible for the difference between F13A*1A and *1B and that between F13A*2A and *2B, and a set of two base changes in codons 650 and 651 in exon 14 leads to the differences between F13A*1A and *2A and those between F13A*1B and *2B. The four combinations of the point mutations at the two exons thus correspond to the four alleles, two of which were generated by the point mutations from ancestral monomorphic gene. The results suggest strongly that intragenic crossing over must be involved in the genesis of the fourth allele. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) methods discriminating these base changes in exons 12 and 14 are also presented.     

Quantitative Assessment of the Influence of Cytochrome P450 1A2 Gene Polymorphism and Colorectal Cancer Risk

Cytochrome P450 1A2 (CYP1A2) encodes a member of the cytochrome P450 superfamily of enzymes, which play a central role in activating and detoxifying many carcinogens and endogenous compounds thought to be involved in the development of colorectal cancer (CRC). The CYP1A2*C (rs2069514) and CYP1A2*F (rs762551) polymorphism are two of the most commonly studied polymorphisms of the gene for their association with risk of CRC, but the results are conflicting. To derive a more precise estimation of the relationship between CYP1A2 and genetic risk of CRC, we performed a comprehensive meta-analysis which included 7088 cases and 7568 controls from 12 published case-control studies. In a combined analysis, the summary per-allele odds ratio for CRC was 0.91 (95% CI: 0.83–1.00, P = 0.04), and 0.91 (95% CI: 0.68–1.22, P = 0.53), for CYP1A2 *F and *C allele, respectively. In the subgroup analysis by ethnicity, significant associations were found in Asians for CYP1A2*F and CYP1A2*C, while no significant associations were detected among Caucasian populations. Similar results were also observed using dominant genetic model. Potential sources of heterogeneity were explored by subgroup analysis and meta-regression. No significant heterogeneity was detected in most of comparisons. This meta-analysis suggests that the CYP1A2 *F and *C polymorphism is a protective factor against CRC among Asians.     

Polymorphisms in the CYP2E1 and GSTM1 Genes as Possible Protection Factors for Leprosy Patients

Background

The CYP2E1 and GSTM1 genes encode metabolic enzymes that have key functions in drug modification and elimination.

Methodology/Principal Findings

We investigated the possible effects of CYP2E1 and GSTM1 polymorphisms in 71 leprosy patients and in 110 individuals from the general population. The GSTM1*0 null allele and INDEL CYP2E1*1D mutant genotypes were analyzed by conventional PCR, while CYP2E1 SNPs (1053C>T, 1293G>C and 7632T>A) were determined by RT-PCR. In leprosy patients, the GSTM1*0 and CYP2E1*5 alleles and the combined alleles GSTM1*0/CYP2E1*6 and GSTM1*0/CYP2E1*5 were significantly related to a baciloscopic index (BI) (BI<3), while the CYP2E1*6 allele was related to a better clinical evolution in the leprosy spectrum.

Conclusions/Significance

Therefore, GSTM1*0, CYP2E1*5 and CYP2E1*6 may be possible protection factors for leprosy patients.     

Assessment of clinical outcomes in breast cancer patients treated with taxanes: multi-analytical approach

Polymorphisms in genes encoding CYPs (Phase I) and ABCB1 (Phase III) enzymes may attribute to variability of efficacy of taxanes. The present study aims to find the influence of CYP and ABCB1 gene polymorphisms on taxanes based clinical outcomes. 132 breast cancer patients treated with taxanes based chemotherapy were genotyped for CYP3A4*1B, CYP3A5*3, CYP1B1*3, CYP2C8*3, ABCB1 1236C>T, 2677G>T/A and 3435C>T polymorphisms using PCR-RFLP. Associations of genetic variants with clinical outcomes in terms of response in 58 patients receiving neo-adjuvant chemotherapy (NACT), and chemo-toxicity in 132 patients were studied. Multifactor dimensionality reduction (MDR) analysis was performed to evaluate higher order gene–gene interactions with clinical outcomes. Pathological response to taxane based NACT was associated with GA genotype as well as A allele of CYP3A5*3 polymorphism (P_corr = 0.0465, P_corr = 0.0465). Similarly, association was found in dominant model of CYP3A5*3 polymorphism with responders (P_corr = 0.0465). Haplotype analysis further revealed A_CYP3A4–A_CYP3A5 haplotype to be significantly associated with responders (P_corr = 0.048). In assessing toxicity, significant association of variant (TT) genotype and T allele of ABCB1 2677G>T/A polymorphism, was found with ‘grade 1 or no leucopenia’ (P_corr = 0.0465, P_corr = 0.048). On evaluating higher order gene–gene interaction models by MDR analysis, CYP3A5*3; ABCB11236C>T and ABCB1 2677G>T/A; ABCB1 3435C>T and CYP1B1*3 showed significant association with treatment response, grade 2–4 anemia and dose delay/reduction due to neutropenia (P = 0.024, P = 0.004, P = 0.026), respectively. Multi-analytical approaches may provide a better assessment of pharmacogenetic based treatment outcomes in breast cancer patients treated with taxanes.     

High prevalence of CYP2C19*2 allele in Roma samples: study on Roma and Hungarian population samples with review of the literature

The purpose of our study was to characterise the CYP2C19*2 and CYP2C19*3 alleles in healthy Roma and Hungarian populations. DNA of 500 Roma and 370 Hungarian subjects were genotyped for CYP2C19*2 (G681A, rs4244285) and CYP2C19*3 (G636A, rs4986893) by PCR–RFLP assay and direct sequencing. Significant differences were found comparing the Roma and Hungarian populations in CYP2C19 681 GG (63.6 vs. 75.9 %), GA (31.8 vs. 23.0 %), AA (4.6 vs. 1.1 %), GA+AA (36.4 vs. 24.1 %) and A allele frequencies (0.205 vs. 0.125) (p < 0.004). Striking differences were found between Roma and Hungarian samples in CYP2C19*1 (79.5 vs. 87.4 %) and CYP2C19*2 (20.5 vs. 12.6 %) alleles, respectively (p < 0.001). None of the subjects was found to carry the CYP2C19*3 allele. Frequencies of the intermedier metabolizer phenotype defined by the *1/*2 genotype (0.318 vs. 0.230, p < 0.005) and poor metabolizer predicted by the *2/*2 genotype (0.046 vs. 0.011, p < 0.005) was significantly higher in Roma than in Hungarians, respectively. Genotype distribution of the Roma population was similar to those of the population of North India, however, a major difference was found in the frequency of the CYP2C19*2 allele, which is likely a result of admixture with European lineages. In conclusion, the frequencies of the CYP2C19 alleles, genotypes and corresponding extensive, intermediate and poor metabolizer phenotypes studied here in the Hungarian population are similar to those of other European Caucasian populations, but display clear differences when compared to the Roma population.     

Sex Differences in the Blood Concentration of Tacrolimus in Systemic Lupus Erythematosus and Rheumatoid Arthritis Patients with <Emphasis Type="Italic">CYP3A5</Emphasis>*3/*3

The purpose of this study was to describe the impact of sex and cytochrome P450 3A5 (CYP3A5) variant on the blood concentration of tacrolimus in patients with systemic lupus erythematosus or rheumatoid arthritis. The blood concentration of tacrolimus (ng/mL) divided by the daily dose of tacrolimus (mg/day) and the patient’s weight (kg) (C/D) was obtained from 55 patients. The C/D value was analysed according to genetic variation in CYP3A5 or ATP binding cassette subfamily B member 1 (ABCB1), sex, and age. The C/D value in the CYP3A5*3/*3 group was significantly higher than in the CYP3A5*1/*1 and *1/*3 groups (p < 0.05, effect size: d = 1.40). In the CYP3A5*3/*3 group, the concentration of tacrolimus was significantly higher in men than in women (p < 0.05, effect size: d = 1.78). Furthermore, in the CYP3A5*3/*3 group, the concentration of tacrolimus was significantly higher in women aged over 50 years than in women aged under 50 years (p < 0.05, effect size: d = 1.18). In contrast, ABCB1 genetic variations did not show any significant effect on the C/D value. Since the blood concentration of tacrolimus in patients with CYP3A5*3/*3 varies depending on sex and age, these factors should be considered when studying the difference of sex in CYP3A.     

Polymorphisms and phenotypic analysis of cytochrome P450 2D6 in the Tibetan population

The cytochrome P450 2D6 enzyme (CYP2D6) metabolizes about 25% of prescribed drugs in the endoplasmic reticulum, and genetic polymorphisms in CYP2D6 can greatly affect its activity and lead to differences among individuals in drug efficacy and adverse drug reactions. To investigate genetic polymorphisms in CYP2D6 among Tibetan Chinese, we directly sequenced the whole gene in 96 unrelated, healthy Tibetans from The Tibet Autonomous Region of China and screened for genetic variants in the promoter, exons, introns, and 3′UTR. We detected fifty-one genetic polymorphisms in CYP2D6, and 16 of them are novel. The allele frequencies of CYP2D6*1, *2, *5, *10, *41, and *49 were 0.25, 0.43, 0.02, 0.29, 0.02, and 0.01, respectively. The frequency of CYP2D6*10, a putative poor-metabolizer allele, was lower in our sample population compared with that in the Han Chinese population (p < 0.001). In addition, haplotype analysis allowed 15 CYP2D6 haplotypes to be classified into three groups. In conclusion, our results provide basic information about CPY2D6 alleles in Tibetans and suggest that the enzymatic activities of CYP2D6 may differ among the diverse ethnic populations of China. Our results provide a basis for safer drug administration and better therapeutic treatment among Tibetans.     

CYP2C9 Genotype vs. Metabolic Phenotype for Individual Drug Dosing—A Correlation Analysis Using Flurbiprofen as Probe Drug

Currently, genotyping of patients for polymorphic enzymes responsible for metabolic elimination is considered a possibility to adjust drug dose levels. For a patient to profit from this procedure, the interindividual differences in drug metabolism within one genotype should be smaller than those between different genotypes. We studied a large cohort of healthy young adults (283 subjects), correlating their CYP2C9 genotype to a simple phenotyping metric, using flurbiprofen as probe drug. Genotyping was conducted for CYP2C9*1, *2, *3. The urinary metabolic ratio MR (concentration of CYP2C9-dependent metabolite divided by concentration of flurbiprofen) determined two hours after flurbiprofen (8.75 mg) administration served as phenotyping metric. Linear statistical models correlating genotype and phenotype provided highly significant allele-specific MR estimates of 0.596 for the wild type allele CYP2C9*1, 0.405 for CYP2C9*2 (68 % of wild type), and 0.113 for CYP2C9*3 (19 % of wild type). If these estimates were used for flurbiprofen dose adjustment, taking 100 % for genotype *1/*1, an average reduction to 84 %, 60 %, 68 %, 43 %, and 19 % would result for genotype *1/*2, *1/*3, *2/*2, *2/*3, and *3/*3, respectively. Due to the large individual variation within genotypes with coefficients of variation ≥ 20 % and supposing the normal distribution, one in three individuals would be out of the average optimum dose by more than 20 %, one in 20 would be 40 % off. Whether this problem also applies to other CYPs and other drugs has to be investigated case by case. Our data for the given example, however, puts the benefit of individual drug dosing to question, if it is exclusively based on genotype.     

Gene–gene interactions of drug metabolizing enzymes and transporter protein in the risk of upper aerodigestive tract cancers among Indians

Background: The combined genetic effects of single nucleotide polymorphisms may additively or synergistically contribute to the increased cancer risk. The interactions associated with xenobiotic metabolizing enzymes and transporter protein involved in the biotransformation and transport of xenobiotics could determine the functional outcomes over the independent effects of a single susceptibility gene in the risk of upper aerodigestive tract cancers. Methods: The hospital-based case–control study evaluated CYP1A1 (*2A and *2C), CYP2E1 (*1B, *5B, and *6), GST (M1, T1, and P1) and ABCB1 3435C>T polymorphisms among 408 histopathologically confirmed cases and 220 controls using polymerase chain reaction based methods in an Indian population. Results: The multivariate logistic regression analyses demonstrated potentially high risk gene–gene interactions with the concurrent deletions of the GSTT1 and GSTM1 genes and GSTP1 variant genotypes (OR 5.81; 95% CI 1.01–40.28), the deletions of GSTT1 and GSTM1 genotypes with variant genotypes of CYP1A1*2A (OR 8.21; 95% CI 1.91–49.48), GSTT1 and GSTM1 deficient genotypes along with CYP2E1*1B variant genotypes (OR 6.73; 95% CI 1.32–22.81), the polymorphic genotypes of ABCB1 and deficient GSTT1 (OR 6.08; 95% CI 2.21–16.76) and an enhanced risk with the combined variant genotypes of CYP1A1*2A, GSTT1 and ABCB1 (OR 11.14; 95% CI 2.70–46.02). Conclusion: The findings indicate that the interactions associated with various drug metabolizing enzymes and transporter protein exhibit high risk for UADT cancers than that ascribed to a single susceptible gene. This was particularly established among the polymorphic carriers of CYP1A1*2A, GSTT1 and ABCB1 genes in the population investigated.     

Polymorphisms of arylamine N-acetyltransferase2 and risk of lung and colorectal cancer

The arylamine N-acetyltransferase 2 (NAT2) enzymes detoxify a wide range of naturally occurring xenobiotics including carcinogens and drugs. Point mutations in the NAT2 gene result in the variant alleles M1 (NAT2 *5A), M2 (NAT2*6A), M3 (NAT2*7) and M4 (NAT2 *14A) from the wild-type WT (NAT2 *4) allele. The current study was aimed at screening genetic polymorphisms of NAT2 gene in 49 lung cancer patients, 54 colorectal cancer patients and 99 cancer-free controls, using PCR-RFLP. There were significant differences in allele frequencies between lung cancer patients and controls in the WT, M2 and M3 alleles (p < 0.05). However, only M2 and M3 allele frequencies were different between colorectal cancer patients and controls (p < 0.05). There was a marginal significant difference in the distribution of rapid and slow acetylator genotypes between lung cancer patients and controls (p = 0.06 and p = 0.05, respectively), but not between colorectal cancer patients and controls (p = 1.0 and p = 0.95, respectively). Risk of lung cancer development was found to be lower in slow acetylators [odds ratio (OR): 0.51, 95% confidence interval (95% CI): 0.25, 1.02, p-value = 0.07]. No effect was observed in case of colorectal cancer. Our results showed that NAT2 genotypes and phenotypes might be involved in lung cancer but not colorectal cancer susceptibility in Jordan.     

Genetic polymorphisms of glutathione S-transferases and cytochrome P450 enzymes as susceptibility factors to systemic lupus erythematosus in southern Brazilian patients

Systemic lupus erythematosus (SLE) is an autoimmune chronic inflammatory disease that presents several clinical manifestations, affecting multiple organs and systems. Immunological, environmental, hormonal and genetic factors may contribute to disease. Genes and proteins involved in metabolism and detoxification of xenobiotics are often used as susceptibility markers to diseases with environmental risk factors. Cytochrome P450 (CYP) enzymes activate the xenobiotic making it more reactive, while the Glutathione S-transferases (GST) enzymes conjugate the reduced glutathione with electrophilic compounds, facilitating the toxic products excretion. CYP and GST polymorphisms can alter the expression and catalytic activity of enzymes. This study aimed to investigate the role of genetic variants of CYP and GST in susceptibility and clinical expression of SLE, through the analysis of GSTM1 null, GSTT1 null, GSTP1*Ile105Val, CYP1A1*2C and CYP2E1*5B polymorphisms. 371 SLE patients from Hospital de Clínicas de Porto Alegre and 522 healthy blood donors from southern Brazil were evaluated. GSTP1 and CYP variants were genotyped using PCR–RFLP and GSTT1 and GSTM1 variants were analyzed by multiplex PCR. Among European-derived individuals, a lower frequency of GSTP1*Val heterozygous genotypes was found in SLE patients when compared to controls (p = 0.005). In African-derived SLE patients, the CYP2E1*5B allelic frequency was higher in relation to controls (p = 0.054). We did not observe any clinical implication of the CYP and GST polymorphisms in patients with SLE. Our data suggest a protective role of the GSTP1*Ile/Val heterozygous genotype against the SLE in European-derived and a possible influence of the CYP2E1*5B allele in SLE susceptibility among African-derived individuals.     

CYP3A5 and NAT2 gene polymorphisms: role in childhood acute lymphoblastic leukemia risk and treatment outcome

Susceptibility to acute lymphoblastic leukemia can be highly influenced by genetic polymorphisms in metabolizing enzyme genes of environmental carcinogens. This study aimed to evaluate the impact of the CYP3A5 and NAT2 metabolizing enzyme polymorphisms on the risk of childhood acute lymphoblastic leukemia. The analysis was conducted on 204 ALL patients and in 364 controls from a Brazilian population, using PCR-RFLP. The CYP3A5 3 polymorphic homozygous genotype was more frequent among ALL patients and the 3 allele variant was significantly associated with increased risk of childhood ALL (OR = 0.29; 95% CI, 0.14-0.60). The homozygous polymorphic genotype for the 6 allele variant was extremely rare and found in only two individuals. The heterozygous frequencies were similar for the ALL group and the control group. No significant differences were observed between the groups analyzed regarding NAT2 variant polymorphisms. None of the polymorphisms analyzed was related to treatment outcome. The results suggest that CYP3A5 3 polymorphism may play an important role in the risk of childhood ALL.