Polymorphisms of CYP1A1, GSTM1, GSTT1, and prostate cancer risk in Turkish population

CYP1A1 gene polymorphism and heavy metal analyses in benign prostatic hyperplasia and prostate cancer: An explorative case-control study

INTRODUCTION

The prostatic disorder is associated with benign prostatic hyperplasia (BPH) and prostate cancer (CaP). Evidently, prevalent transcription factors and signaling pathways define their relationship. The etiology of the prostatic disorder is multifactorial including heavy metal toxicity like lead (Pb), Cadmium (Cd), and genetic factors. This study elucidates the association between heavy metal toxicity Pb, Cd, and CYP1A1 gene polymorphism with BPH and CaP.

METHODS

a case-control study with (BPH, n = 104), (CaP, n = 58) and (controls, n =107) patients. Heavy metal Pb and Cd estimation by atomic absorption spectrophotometer. The polymorphism of the CYP1A1 T>C (rs4646903) gene was analyzed byPCR-RFLP.

RESULT

Higher levels of Pb and Cd were found in BPH and CaP followed by the control group (P-value: < 0.05). Pb and Cd show a significant correlation among prostate volume in CaP. Additionally, PSA, IPSS score, and pre void volume were positively co-related with Pb in BPH patients. The posthoc test defines the level of Pb and Cd as significantly elevated in the mutant genotype, highest among homozygous mutant genotype of CYP1A1gene among BPH. In CaP, Pb is significantly higher among the homozygous mutant type of CYP1A1 gene. The risk is also influenced by smoking, tobacco, and alcohol.

CONCLUSION

The heavy metal toxicity Pb and Cd were reported to raise the risk of BPH and CaP. However, a person with heavy metal toxicity especially in BPH has a high-risk genetic susceptibility to the CYP1A1 gene in the north Indian population.

Association of CYP1A1, GSTM1 and GSTT1 gene polymorphisms with risk of prostate cancer in Algerian population

Background

Prostate cancer is the most common cancer in the world, and its etiology involves the interaction of genetic and environmental factors. Interindividual differences observed in the metabolism of xenobiotics may be due to polymorphisms of genes encoding the detoxification enzymes. This genetic variability seems to be associated with differences in susceptibility to certain types of cancers, including prostate cancer. Our study has been made in order to investigate a possible genetic predisposition to prostate cancer in an Algerian population, through the analysis of genetic polymorphisms of three enzymes metabolizing xenobiotics namely cytochrome P450 (CYP) 1A1, glutathione S-transferase mu 1 (GSTM1) and GST theta 1 (GSTT1).

Methods

The current case–control study included 101 prostate cancer patients and 101 healthy controls. Genotyping of CYP1A1 T3801C polymorphisms and GSTM1/GSTT-null was made, respectively, by PCR-RFLP and multiplex PCR.

Results

No significantly positive associations were found for the CYP1A1 T3801C [p = 0.71, OR = 1.23 (0.56–2.72)] and GSTM1-null [p = 0.26, OR = 1.37 (0.76–2.4)] polymorphisms and prostate cancer susceptibility. However, we detect a highly significant association between GSTT1-null genotype [p = 0.03, OR = 2.03 (1.06–3.99)], GSTM1/GSTT1-double null genotype [p = 0.027, OR = 2.6; CI (1.07–6.5)] and prostate cancer risk. Furthermore, no statistically significant differences between the studied polymorphisms and tumor parameters (the Gleason score and clinical stages of aggressiveness) at diagnosis of PCa.

Conclusions

The risk of developing prostate cancer in Algeria does not appear to be associated with CYP1A1 T3801C genotypes and GSTM1-null, but GSTT1-null and GSTM1/GSTT1-double null genotypes increased the risk of prostate cancer.

Untangling the association between environmental endocrine disruptive chemicals and the etiology of male genitourinary cancers

Endocrine disrupting chemicals disrupt normal physiological function of endogenous hormones, their receptors, and signaling pathways of the endocrine system. Most endocrine disrupting chemicals exhibit estrogen/androgen agonistic and antagonistic activities that impinge upon hormone receptors and related pathways. Humans are exposed to endocrine disrupting chemicals through food, water and air, affecting the synthesis, release, transport, metabolism, binding, function and elimination of naturally occurring hormones. The urogenital organs function as sources of steroid hormones, are targeted end organs, and participate within systemic feedback loops within the endocrine system. The effects of endocrine disruptors can ultimately alter cellular homeostasis leading to a broad range of health effects, including malignancy. Human cancer is characterized by uncontrolled cell proliferation, mechanisms opposing cell-death, development of immortality, induction of angiogenesis, and promotion of invasion/metastasis. While hormonal malignancies of the male genitourinary organs are the second most common types of cancer, the molecular effects of endocrine disrupting chemicals in hormone-driven cancers has yet to be fully explored. In this commentary, we examine the molecular evidence for the involvement of endocrine disrupting chemicals in the genesis and progression of hormone-driven cancers in the prostate, testes, and bladder. We also report on challenges that have to be overcome to drive our understanding of these chemicals and explore the potential avenues of discovery that could ultimately allow the development of tools to prevent cancer in populations where exposure is inevitable.

GSTM1 and GSTT1 Polymorphisms and Susceptibility to Prostate Cancer: A Case-Control Study of the Algerian Population

Objective: Prostate cancer (PCa) is a major public health problem worldwide, with high morbidity and mortality levels. Advanced age, androgen stimulation, and ethnicity have been reported to be possible risk factors. It has been suggested that particular genetic polymorphisms in glutathione S-transferases (GST), xenobiotic-metabolising enzymes, could predispose to prostate cancer through heritable deficiency in detoxification of environmental carcinogens. Conflicts in the published results and the absence of similar in depth studies in Algeria prompted us to perform the present case-control study of GSTM1 and GSTT1 polymorphisms and their possible association with PCa in an Algerian population. Methods: We determined GSTM1 and GSTT1 genotypes for 49 histologically verified prostate cancer patients and in 41 age-matched healthy controls by multiplex polymerase chain reaction (PCR) using peripheral blood DNA samples. Result: While an association between the GSTM1 null genotype and PCa risk (OR= 3.69, 95% CI= 1.30-10.44; P = 0.01) was evident, the GSTT1 null genotype (OR= 0.92, 95% IC= 0.32-2.62; P = 0.49) appeared without influence. Furthermore, no statistically significant differences between the double null genotype and PCa is detected, also no statistically significant differences between smoking status and PCa is detected. Conclusion: The GSTM1 null genotype may increase individual susceptibility to prostate cancer. On the other hand, the null-activity genotype of GSTT1 did not appear to contribute to the risk of prostate cancer in our population.

GSTT1 Null Genotype Significantly Increases the Susceptibility to Urinary System Cancer: Evidences from 63,876 Subjects

GSTT1 gene plays an important role in detoxification and clearance of reactive oxygen species(ROS). A null variant in this gene has been demonstrated to confer cancer susceptibility. Although many studies have demonstrated the association between GSTT1 null polymorphism and urinary system cancer susceptibility, several publications reported opposite conclusions. For better understanding the effects of this polymorphism on the risk of urinary system cancer, a updated meta-analysis was performed with a total of 26,666 cases and 37,210 controls extracted from 117 studies, by following the latest meta-analysis guidelines (PRISMA). The results suggested that the GSTT1 null genotype was significantly associated with an increased risk of urinary system cancer (OR=1.13, 95%CI=1.05-1.22). Furthermore, stratified analyses by the type of cancer, ethnicity, source of control and quality score presented a significantly increased risk associated with GSTT1 null genotype in bladder and prostate cancer subgroup, Caucasians and Indians subgroup, population-based(PB) subgroup, medium quality and low quality subgroup. Overall, our meta-analysis suggested that GSTT1 null genotype is a potential cancer susceptibility variant. Well-designed and large-cohort studies are needed to confirm the association between GSTT1 null genotype and urinary system cancer risk.

GSTM1 Gene Polymorphism is Implicated in Increased Susceptibility to Prostate Cancer in Caucasians and Asians

Published reports on the relationship between GSTM1 gene polymorphisms and prostate cancer risk are heterogeneous in their conclusions, and the significance of these polymorphisms is still debated. This meta-analysis was performed to attempt to combine comparable studies, thereby increasing sample size and statistical significance in order to obtain a better evaluation of the association between GSTM1 polymorphisms and prostate cancer risk. The association investigations were identified from PubMed, Cochrane Library, and China Biological Medicine Database on March 1, 2014. Forty-three reports were recruited into this meta-analysis that contained data from 6741 patients and 9053 controls. There was a marked association between the GSTM1 null genotype and prostate cancer risk in the overall population (odds ratio = 1.39, 95% confidence interval: 1.21-1.60, P <00001), caucasians (odds ratio = 1.48, 95% confidence interval: 1.23-1.79, P <0001) and Asians (odds ratio = 1.62, 95% confidence interval: 1.16-2.27, P = .005). However, the GSTM1 null genotype was not associated with prostate cancer risk in Africans (odds ratio = 0.77, 95% confidence interval: 0.53-1.13, P = 0.19) and African Americans (odds ratio = 1.00, 95% confidence interval: 0.69-1.45, P = 0.99). In conclusion, GSTM1 null genotype was a risk factor to predict the prostate cancer risk in the overall population, Caucasians, and Asians. Although compelling, limitations inherent to meta-analysis, study design of the individual studies, and most importantly, possible gene-gene and gene-environment interactions, as well as the potential involvement of glutathione S-transferases in multiple cellular processes make drawing definite conclusions difficult.

Prostate cancer and glutathione S-transferase deletions

GSTM1 and GSTT1 gene polymorphisms have been studied in many populations to evaluate their association with prostate cancer risk with contrasting results. The current study was aimed to find out the association of GSTM1 and GSTT1 gene polymorphisms with prostate cancer in Pakistani men. This case control study included pathologically confirmed prostate cancer patients and age matched male controls. Epidemiological data was collected by a standard questionnaire and presence or absence of GSTM1 and GSTT1 gene was observed by multiplex PCR using CYP1A1 as housekeeping gene. Prostate cancer was more prevalent in age of >60 years and most of the patients were at stage IV (70 %) and have undergone surgery. Family history of cancer, smoking, metastasis and surgery were found to be significant (P<0.05) risk factors in prostate cancer development. Gleason score 7 was most prevalent (40.5 %) in prostate cancer patients. Source of drinking water, residential area, occupation, eating habits and number of family members had no association (P>0.05) with prostate cancer risk. No significant association was found when comparing GSTM1 (OR=0.78) and GSTT1 (OR=0.89) gene deletions with prostate cancer risk. Smoking and TNM staging were also not associated with deletion of GSTM1 and GSTT1 genes. Comparison of dual null deletion of both genes with prostate cancer also showed non-significant associations. Deletion of GSTM1 gene at stage IV prostate cancer patients was significantly higher compared with other stages of cancer while no significance was shown by GSTT1 gene deletion. GSTM1, GSTT1 and deletion of both GSTM1 and GSTT1 genes do not contribute towards increased risk of prostate cancer in Pakistani population.

Topologically inferring pathway activity toward precise cancer classification via integrating genomic and metabolomic data: prostate cancer as a case

Precise cancer classification is a central challenge in clinical cancer research such as diagnosis, prognosis and metastasis prediction. Most existing cancer classification methods based on gene or metabolite biomarkers were limited to single genomics or metabolomics, and lacked integration and utilization of multiple ‘omics’ data. The accuracy and robustness of these methods when applied to independent cohorts of patients must be improved. In this study, we propose a directed random walk-based method to evaluate the topological importance of each gene in a reconstructed gene–metabolite graph by integrating information from matched gene expression profiles and metabolomic profiles. The joint use of gene and metabolite information contributes to accurate evaluation of the topological importance of genes and reproducible pathway activities. We constructed classifiers using reproducible pathway activities for precise cancer classification and risk metabolic pathway identification. We applied the proposed method to the classification of prostate cancer. Within-dataset experiments and cross-dataset experiments on three independent datasets demonstrated that the proposed method achieved a more accurate and robust overall performance compared to several existing classification methods. The resulting risk pathways and topologically important differential genes and metabolites provide biologically informative models for prostate cancer prognosis and therapeutic strategies development.

GSTT1 polymorphism and the risk of developing prostate cancer

A possible association between glutathione S-transferase theta 1 gene (GSTT1) polymorphism and the risk of developing prostate cancer is currently hotly debated, but evidence from various epidemiologic studies remains unclear. This investigation was performed to assess whether an association between GSTT1 polymorphism and prostate cancer risk exists by using meta-analysis to combine comparable studies, thereby increasing sample size and statistical significance, as well as to identify patterns in various studies. The association reports were identified from the PubMed database and the Cochrane Library on March 1, 2013, and data from eligible studies (from 1999-2012) were synthesized. Thirty-eight reports were included in this meta-analysis on the association of the null genotype of GSTT1 with prostate cancer risk. No solid association between the GSTT1 null genotype and prostate cancer risk could be established for the overall population (odds ratio = 1.11, 95% confidence interval: 0.97, 1.27; P = 0.13). However, the GSTT1 null genotype was distinctly associated with prostate cancer risk in Caucasians (odds ratio = 1.24, 95% confidence interval: 1.03, 1.48, P = 0.02). In conclusion, the GSTT1 null genotype is associated with prostate cancer risk in Caucasians, but not in the overall population.

Genetic polymorphisms of CYP2E1, GST, and NAT2 enzymes are not associated with risk of breast cancer in a sample of Lebanese women

Changes in the activity of drug metabolizing enzymes (DMEs) are potentially associated with cancer risk. This relationship is attributed to their involvement in the bioactivation of multiple procarcinogens or the metabolism of multiple substrates including an array of xenobiotics and environmental carcinogens. 326 Lebanese women of whom 99 were cancer free (controls) and 227 were diagnosed with breast cancer (cases) were included. Blood for DNA was collected and medical charts were reviewed. Three genotyping methods were employed including: (1) restriction fragment length polymorphism (RFLP) for CYP2E1*5B, CYP2E1*6, NAT2*5 and NAT2*6; (2) gel electrophoresis for GSTM1 and GSTT1; and (3) real-time PCR for GSTP1 Ile/Val polymorphism. We analyzed the relationship between genetic susceptibilities in selected xenobiotic metabolizing genes and breast cancer risk. Allele frequencies were fairly similar to previously reported values from neighboring populations with relevant migration routes. There were no statistically significant differences in the distribution of variant carcinogen metabolizing genes between cases and controls even after adjusting for age at diagnosis, menopausal status, smoking, and alcohol intake. Despite its limitations, this is the first study that assesses the role of genetic polymorphisms in DMEs with breast cancer in a sample of Lebanese women. Further studies are needed to determine the genetic predisposition and gene-environment interactions of breast cancer in this population.

Association of GSTT1 gene polymorphisms with the risk of prostate cancer: an updating meta-analysis

It has been demonstrated that the glutathione S-transferase (GST) superfamily helps remove carcinogens from the body and thus might be associated with prostate cancer risk. In recent years, GSTT1 polymorphism has been extensively studied as a potential prostate cancer risk factor; however, the results are inconsistent. To investigate the association between GSTT1 and prostate cancer, we conducted a meta-analysis of 33 studies with 6,697 prostate patients and 7,643 controls. For GSTM1 null versus present genotype, the random effects odds ratio was 0.98 (95 % confidence interval (CI) 0.83-1.16) based on a wide population. Subgroup analyses in the different ethnic groups and different controls were performed. The OR was 1.01 (95 % CI 0.86-1.19) in Caucasians, 1.01 (95 % CI 0.70-1.47) in Asians, and 0.77 (95 % CI 0.42-1.42) in Africans. The OR was 0.98 (95 % CI 0.82-1.16) in non-benign prostate hyperplasia (BPH) controls and 1.09 (95 % CI 0.66-1.79) in BPH controls. In conclusion, our present meta-analysis demonstrates that there is no association between GSTT1 polymorphism and prostate cancer, even in the sub-analysis concerning different races and control sources. The direction of further research should focus not only on the simple relationship of GSTT1 and prostate cancer but also on gene-environment interaction and distinctions of different GSTs.

Quantitative synthesis of the association between the cytochrome P450 1A1 Ile462Val polymorphism and prostate cancer risk

The association between the cytochrome P450 1A1 (CYP1A1) Ile462Val polymorphism and prostate cancer risk remains inconclusive owing to the conflicting findings from previous studies. To get a more precise estimate of the possible association, we performed the present meta-analysis. We searched the PUBMED, EMBASE, and Wanfang databases for the studies which met the inclusion criteria. The pooled odds ratio (OR) with corresponding 95 % confidence interval (95 % CI) was used to estimate the association between CYP1A1 Ile462Val polymorphism and prostate cancer risk. A total of 13 studies with 2,350 cases and 2,992 controls were included in the meta-analysis. The results indicated that there was an obvious association between CYP1A1 Ile462Val polymorphism and increased risk of prostate cancer (for Val versus Ile: OR=1.27, 95 % CI 1.13-1.43, P<0.001; for ValVal versus IleIle: OR=1.51, 95 % CI 1.14-2.01, P=0.004; for ValVal + ValIle versus IleIle: OR=1.31, 95 % CI 1.14-1.51, P<0.001; for ValVal versus IleIle + ValIle: OR=1.38, 95 % CI 1.05-1.81, P=0.020). Subgroup analyses by ethnicity suggested that CYP1A1 Ile462Val polymorphism was associated with prostate cancer risk in Asians but not in Caucasians. This meta-analysis suggests that there is an association between CYP1A1 Ile462Val polymorphism and increased risk of prostate cancer. More studies with large sample are needed to further assess the association in Caucasians.

GSTT1 null genotype is associated with an increased risk of prostate cancer in caucasians: a meta-analysis

BACKGROUND

Many studies have investigated the association between glutathione S-transferase T1 (GSTT1) null genotype and the risk of prostate cancer (PCa), but the impact of GSTT1 null genotype on PCa risk in Caucasians is still unclear owing to the inconsistency of such studies. The present study aimed to quantify the strength of association between GSTT1 null genotype and the risk of PCa in Caucasians.

METHODS

We searched the PubMed, Embase and Web of Science databases for studies assessing the association between GSTT1 null genotype and the risk of PCa in Caucasians. We estimated the summary odds ratio (OR) with the corresponding 95% confidence interval (95% CI) to assess the association.

RESULTS

16 case-control studies with 11,648 subjects were included in this meta-analysis. Meta-analysis of a total of 16 studies showed GSTT1 null genotype was significantly associated with an increased risk of PCa in Caucasians (random-effects OR 1.30, 95% CI 1.10-1.53, p = 0.002). After adjustment for heterogeneity, GSTT1 null genotype was still associated with an increased risk of PCa in Caucasians (fixed-effects OR 1.33, 95% CI 1.17-1.52, p < 0.001). The cumulative meta-analyses of all 16 studies showed a trend of more obvious association as information accumulated by year.

CONCLUSIONS

Meta-analysis of available data suggests the GSTT1 null genotype is significantly associated with an increased risk of PCa in Caucasians.

Significant association of Glutathione S-transferase T1 null genotype with prostate cancer risk: a meta-analysis of 26,393 subjects

Background

Recent studies on the association between Glutathione S-transferase T1 (GSTT1) polymorphism and risk of prostate cancer showed inconclusive results. To clarify this possible association, we conducted a meta-analysis of published studies.

Methods

Data were collected from the following electronic databases: Pubmed, Embase, and Chinese Biomedical Database (CBM). The odds ratio (OR) and its 95% confidence interval (95%CI) was used to assess the strength of the association. We summarized the data on the association between GSTT1 null genotype and risk of prostate cancer in the overall population, and performed subgroup analyses by ethnicity, adjusted ORs, and types of controls.

Results

Ultimately, a total of 43 studies with a total of 26,393 subjects (9,934 cases and 16,459 controls) were eligible for meta-analysis. Overall, there was a significant association between GSTT1 null genotype and increased risk of prostate cancer (OR = 1.14, 95%CI 1.01–1.29, P = 0.034). Meta-analysis of adjusted ORs also showed a significant association between GSTT1 null genotype and increased risk of prostate cancer (OR = 1.34, 95%CI 1.09–1.64, P = 0.006). Similar results were found in the subgroup analyses by ethnicity and types of controls.

Conclusion

This meta-analysis demonstrates that GSTT1 null genotype is associated with prostate cancer susceptibility, and GSTT1 null genotype contributes to increased risk of prostate cancer.

Genetic polymorphisms of GSTM1, GSTT1, and GSTP1 with prostate cancer risk: a meta-analysis of 57 studies

Background and Objectives

The GSTM1, GSTT1 and GSTP1 polymorphisms might be involved in inactivation of procarcinogens that contribute to the genesis and progression of cancers. However, studies investigating the association between GSTM1, GSTT1 or GSTP1 polymorphisms and prostate cancer (PCa) risk report conflicting results, therefore, we conducted a meta-analysis to re-examine the controversy.

Methods

Published literature from PubMed, Embase, Google Scholar and China National Knowledge Infrastructure (CNKI) were searched (updated to June 2, 2012). According to our inclusion criteria, studies that observed the association between GSTM1, GSTT1 or GSTP1 polymorphisms and PCa risk were included. The principal outcome measure was the odds ratio (OR) with 95% confidence interval (CI) for the risk of PCa associated with GSTM1, GSTT1 and GSTP1 polymorphisms.

Results

Fifty-seven studies involving 11313 cases and 12934 controls were recruited. The overall OR, which was 1.2854 (95% CI = 1.1405–1.4487), revealed a significant risk of PCa and GSTM1 null genotype, and the similar results were observed when stratified by ethnicity and control source. Further, the more important is that the present study first reported the high risks of PCa for people who with dual null genotype of GSTM1 and GSTT1 (OR = 1.4353, 95% CI = 1.0345–1.9913), or who with GSTT1 null genotype and GSTP1 A131G polymorphism (OR = 1.7335, 95% CI = 1.1067–2.7152). But no association was determined between GSTT1 null genotype (OR = 1.102, 95% CI = 0.9596–1.2655) or GSTP1 A131G polymorphism (OR = 1.0845, 95% CI = 0.96–1.2251) and the PCa risk.

Conclusions

Our meta-analysis suggested that the people with GSTM1 null genotype, with dual null genotype of GSTM1 and GSTT1, or with GSTT1 null genotype and GSTP1 A131G polymorphism are associated with high risks of PCa, but no association was found between GSTT1 null genotype or GSTP1 A131G polymorphism and the risk of PCa. Further rigorous analytical studies are highly expected to confirm our conclusions and assess gene-environment interactions with PCa risk.

Association of GSTM1 null allele with prostate cancer risk: evidence from 36 case-control studies

BACKGROUND

Glutathione S-transferase M1 (GSTM1) is thought to be involved in detoxifying several carcinogens and may play a vital role in tumorigenesis. Numerous studies have evaluated the association between GSTM1 null/present polymorphism and risk of prostate cancer (PCa). However, the results remain inconsistent. To derive a more precise estimation, we performed a meta-analysis.

METHODOLOGY/PRINCIPAL FINDINGS

A comprehensive search was conducted to identify all eligible case-control studies. We used odds ratios (ORs) with 95% confidence intervals (CIs) to assess the strength of the association. The overall association was significant (OR = 1.28, 95% CI: 1.11-1.48, P = 0.001). Moreover, subgroup analyses showed GSTM1 null genotype significantly associated with PCa risk among Asians (OR = 1.35, 95% CI: 1.03-1.78, P = 0.03) but not among Caucasians (OR = 1.12, 95% CI: 0.96-1.31, P = 0.16). In addition, we did not find that smoking modified the genotype effect on the risk of PCa.

CONCLUSIONS/SIGNIFICANCE

The present meta-analysis suggested that GSTM1 null allele was a low-penetrant risk factor for PCa among Asians.

Estrogens and prostate cancer: etiology, mediators, prevention, and management

The mainstay targets for hormonal prostate cancer (PCa) therapies are based on negating androgen action. Recent epidemiologic and experimental data have pinpointed the key roles of estrogens in PCa development and progression. Racial and geographic differences, as well as age-associated changes, in estrogen synthesis and metabolism contribute significantly to the etiology. This article summarizes how different estrogens/antiestrogens/estrogen mimics contribute to prostate carcinogenesis, the roles of the different mediators of estrogen in the process, and the potentials of new estrogenic/antiestrogenic compounds for prevention and treatment of PCa.

Sulfotransferase 1A1 Arg(213)His polymorphism and prostate cancer risk

Sulfotransferase 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 transition, G to A at position 638, in the SULT1A1 gene, results in the Arg(213)His change. This single nucleotide polymorphism reduces the activity and thermostability of the SULT1A1 enzyme. In the present study, the relationship between the SULT1A1 Arg(213)His polymorphism and prostate cancer was investigated using PCR-RFLP. No significant difference in genotype and allele distribution was noted between the prostate cancer and control populations (P=0.072; P=0.099, respectively). The risk of prostate cancer in individuals carrying the SULT1A1(*)2 allele (His(213) allele) was determined by combining the SULT1A1(*)1/SULT1A1(*)2 (Arg/His(213)) and SULT1A1(*)2/SULT1A1(*)2 (His/His(213)) genotypes. No association was observed between SULT1A1 Arg(213)His polymorphism and prostate cancer incidence (P=0.24; OR, 1.36; 95% CI, 0.84-2.25). However, the His(213) allele was found to increase the risk of prostate cancer by 1.36-fold. In smoker and non-smoker populations, no significant relationship was determined between the prostate cancer and control population (P=0.45; P=0.34, respectively).

Are GSTM1, GSTT1 and CAG repeat length of androgen receptor gene polymorphisms associated with risk of prostate cancer in Iranian patients?

We conducted this study to investigate whether CAG repeat length in androgen receptor gene and GSTM1 and GSTT1 polymorphisms influence prostate cancer risk in Iranian newly diagnosed cancer patients compared to age-matched BPH group and healthy individuals. DNA from 110 pathologically-confirmed prostate cancer patients, 99 age-matched men with Benign Prostatic Hyperplasia (BPH) and 100 healthy individuals were extracted and amplified by polymerase chain reaction (PCR). PCR products were examined by electrophoresis and sequencing. The mean number of CAG repeat in prostate cancer patients was significantly smaller than normal (19.9 vs 22.8; p < 0.0001) and BPH groups (19.9 vs 21.9; P < 0.0001) The mean difference between normal individuals and BPH group was also significant (21.9 vs. 22.8; P = 0.003). Presence of GSTM1 null genotype were significantly higher in cancer and BPH group vs. normal individuals (both P values < 0.0001). there was not seen association between GSTT1 null or positive genotype with cancer risk, but analysis of GSTM1 null and GSTT1 positive in combination was statistically associated with Prostate cancer risk (OR = 8.4, 95% CI 1.53-46.73). Our results showed that CAG repeat polymorphism in AR gene may act as a risk modifier and GSTM1 null genotypes also may be contributed to prostate cancer susceptibility in Iranian patients.

Evaluation of the influence of polymorphic variants CYP1A1 2B, CYP1B1 2, CYP3A4 1B, GSTM1 0, and GSTT1 0 in prostate cancer

BACKGROUND/OBJECTIVE

Genetic polymorphisms in cytochrome P-450 (CYPs) and glutathione S-transferase (GSTs) genes can influence the appearance of tumors by the formation of new enzymes with altered activities. In the present study, 5 polymorphic variants were examined in 154 patients with prostate carcinoma and in 154 controls.

MATERIALS AND METHODS

DNA analysis was carried out through PCR-based methods. The statistical methods used were odds ratio and confidence interval (95% CI), χ(2), Fisher, and Mann-Whitney.

RESULTS

The study showed absence of association for CYP1A1 2B, CYP1B1 2, GSTM1 0, and GSTT1 0. The statistical analysis implied a positive association of variant CYP3A4 1B for prostate cancer. The combined analysis of CYP1A1 2B, CYP1B1 2, and CYP3A4 1B genotypes showed positive association. The analysis of histopathologic parameters detected statistically significant differences for Gleason score and biochemistry recurrence risk. The presence of the GSTT1 0 genotype in red meat consumers increased the risk for this disease.

CONCLUSION

Some polymorphic variants analyzed can influence the development and the progression of prostate cancer.

Association of GSTM1T1 genes with COPD and prostate cancer in north Indian population

The glutathione S-transferase (GST) family of enzymes is known to play a pivotal role in phase II of biotransformation of xenobiotics, environmental carcinogens and pharmacological drugs. The objective of the present study was to investigate the role of GSTM1 and GSTT1 null genotypes as risk factors for chronic obstructive pulmonary disease (COPD) and prostate cancer. The subjects appraised were 200 COPD cases, 150 prostate cancer cases, 150 benign prostatic hyperplasia (BPH) cases, 200 age matched controls for COPD and 172 age matched controls for prostate cancer. GSTM1 and GSTT1 null genotype was found to confer 2.5 (OR 2.45; 95% CI 1.56-3.82; P value = 0.00008) and 2.4-fold (OR 2.39; 95% CI 1.36-4.20; P value = 0.002) significant higher risk for prostate cancer. Smoking imparted a 2.2-fold significant risk of prostate cancer cases (OR 2.23; 95% CI 1.36-3.65 P value = 0.001) and twofold risk in BPH (OR 2.09; 95% CI 1.26-3.46; P value = 0.005). In case of COPD only null genotype of GSTT1 has shown 2.1-fold (OR 2.11; 95% CI 1.22-3.62; P value = 0.007) significant increased risk.

CYP 1A1 polymorphism and organochlorine pesticides levels in the etiology of prostate cancer

Organochlorine pesticides (OCPs) and polymorphisms of xenobiotic metabolizing enzymes are reported to be associated with the possible risk of prostate cancer. OCPs are endocrine disruptors (EDs) which may act by disrupting the physiologic function of endogenous hormones and therefore possibly increase prostate cancer risk. CYP1A1 metabolizes several carcinogens and estrogens, etc. and hence polymorphism of this gene has been reported to be associated with prostate cancer risk. We studied 70 newly diagnosed prostate cancer patients and 61 age-matched healthy male controls. OCP levels in blood were determined by using gas chromatography-mass spectrometry (GC-MS) and CYP1A1 polymorphisms were analyzed by allele-specific PCR and RFLP-PCR methods. Significantly higher levels of β-HCH, γ-HCH and p,p'-DDE were found in cases as compared to controls (p-values=0.04, 0.008, and 0.01, respectively). Higher levels of γ-HCH were observed in advanced stages of prostate cancer cases (<or=T(2) vs. >or=T(3)), (p-value=0.04). Dieldrin was found significantly higher in cases with initial stages (p-value=0.03). We did not observe any correlation between prostate cancer and CYP1A1 polymorphisms. Hence, higher level of OCPs, especially β-HCH, γ-HCH and p,p'-DDE might be associated with prostate cancer risk.

Polymorphisms of glutathione-S-transferase M1 and T1 and prostate cancer risk in a Tunisian population

Several genes involved in the metabolism of carcinogenesis have been found to be polymorphic in the human population, and specific alleles are associated with increase risk of cancer of various sites. This study is focused on the polymorphic enzymes glutathione-S-transferase M1 (GSTM1) and T1 (GSTT1) that involved in the detoxification of many xenobiotics involved in the etiology of prostate cancer.

OBJECTIVE

To evaluate whether GSTM1 and/or GSTT1 contribute to prostate cancer (CaP) etiology, we studied 110 incident CaP cases and 122 controls.

RESULTS

The probability of having CaP was increased in men who had homozygous deleted (non-functional) genotypes at GSTT1 (OR=2.17; 95% CI=1-3.79) but not GSTM1 (OR=0.89; 95% CI=0.66-1.88). Hence, individuals lacking the GSTT1 gene are at approximately twofold higher risk of developing prostate cancer in comparison with individuals with at least one active allele in the GSTT1 locus.

CONCLUSION

These results suggest that GSTT1 is associated with CaP risk. The effect of smoking associated with the GSTT10/0 genotype was not found to affect the risk of prostate cancer.

Polymorphism of human cytochrome P450 enzymes and its clinical impact

Pharmacogenetics is the study of how interindividual variations in the DNA sequence of specific genes affect drug response. This article highlights current pharmacogenetic knowledge on important human drug-metabolizing cytochrome P450s (CYPs) to understand the large interindividual variability in drug clearance and responses in clinical practice. The human CYP superfamily contains 57 functional genes and 58 pseudogenes, with members of the 1, 2, and 3 families playing an important role in the metabolism of therapeutic drugs, other xenobiotics, and some endogenous compounds. Polymorphisms in the CYP family may have had the most impact on the fate of therapeutic drugs. CYP2D6, 2C19, and 2C9 polymorphisms account for the most frequent variations in phase I metabolism of drugs, since almost 80% of drugs in use today are metabolized by these enzymes. Approximately 5-14% of Caucasians, 0-5% Africans, and 0-1% of Asians lack CYP2D6 activity, and these individuals are known as poor metabolizers. CYP2C9 is another clinically significant enzyme that demonstrates multiple genetic variants with a potentially functional impact on the efficacy and adverse effects of drugs that are mainly eliminated by this enzyme. Studies into the CYP2C9 polymorphism have highlighted the importance of the CYP2C9*2 and *3 alleles. Extensive polymorphism also occurs in other CYP genes, such as CYP1A1, 2A6, 2A13, 2C8, 3A4, and 3A5. Since several of these CYPs (e.g., CYP1A1 and 1A2) play a role in the bioactivation of many procarcinogens, polymorphisms of these enzymes may contribute to the variable susceptibility to carcinogenesis. The distribution of the common variant alleles of CYP genes varies among different ethnic populations. Pharmacogenetics has the potential to achieve optimal quality use of medicines, and to improve the efficacy and safety of both prospective and currently available drugs. Further studies are warranted to explore the gene-dose, gene-concentration, and gene-response relationships for these important drug-metabolizing CYPs.

An updating meta-analysis of the GSTM1, GSTT1, and GSTP1 polymorphisms and prostate cancer: a HuGE review

It has been postulated that individuals with GSTM1, GSTT1 deficiency and, GSTP1 (105Ile/Val transition) have increased susceptibility to carcinogens and are more likely to develop prostate cancer. In recent years, GST status has been extensively studied as a prostate cancer risk factor; however, the results are inconsistent. To re-examine this controversy, we have undertaken an updating meta-analysis of 29 studies with GSTM1 genotyping (4,564 prostate cancer cases and 5,464 controls), 22 studies with GSTT1 genotyping (3,837 cases and 4,552 controls), and 24 studies with GSTP1 genotyping (5,301 cases and 5,621 controls). The random effects odds ratio was 1.33 [95% confidence interval (95% CI): 1.15, 1.55; I(2) = 68.9%, P for heterogeneity = 0.00] for the GSTM1 null versus present genotype and 1.05 (95% CI: 0.86, 1.27; I(2) = 68.2%, P for heterogeneity = 0.00) for the GSTT1 null versus present genotype, and 1.06 (95% CI: 0.91, 1.24; I(2) = 71.5%, P for heterogeneity = 0.00) for the GSTP1-Val versus GSTP1-Ile allele. For GSTM1 polymorphism, similar results reached in Caucasians and Asians, with exception for Africans. No association between GSTT1 or GSTP1 polymorphisms and prostate cancer risk was detected in different racial. In conclusion, the major finding of our study suggested that GSTM1 polymorphism conferred an increasing risk of prostate cancer on a wide population basis, however, no relationship was found between GSTT1 and GSTP1 status and the risk of prostate cancer.

Cytochrome P450 1A1, glutathione S-transferases M1 and T1 polymorphisms in Ovambos and Mongolians

Cytochrome P450 (CYP) 1A1, glutathione S-transferase (GST) M1, and GSTT1 gene polymorphisms have been shown to be associated with several diseases. In this study, CYP1A1 MspI, GSTM1 and GSTT1 gene polymorphisms were investigated in 134 Ovambo and 207 Mongolians, and the results were compared with those from previous studies. Using polymerase chain reaction/restriction fragment length polymorphism (PCR-RFLP) the frequency of CYP1A1 MspI mutation was determined. The multiplex PCR was used to determine the GSTM1 and GSTT1 polymorphism. The frequencies of wild-type, heterozygous variant and homozygous variant of the CYP1A1 MspI genotypes were 72.4%, 25.4% and 2.2%, and 22.7%, 55.6% and 21.7% in the Ovambos and Mongolians, respectively. The frequencies of GSTM1 (null) and GSTT1 (null) genotypes were 11.2% and 35.8%, and 46.4% and 25.6% in the Ovambos and Mongolians, respectively. The CYP1A1 MspI and GSTT1 (null) genotype distribution of the Ovambos was similar to that of African-Americans and some Caucasians. In contrast, the GSTM1 (null) genotype distribution was different from that of all other populations. Among Mongolians, the CYP1A1 MspI polymorphism showed the highest mutation frequencies, GSTM1 (null) was similar to that of East Asians, and GSTT1 (null) was different from that of almost all the Asians examined.

Meat and meat mutagens and risk of prostate cancer in the Agricultural Health Study

Meats cooked at high temperatures, such as pan-frying or grilling, are a source of carcinogenic heterocyclic amines and polycyclic aromatic hydrocarbons. We prospectively examined the association between meat types, meat cooking methods, meat doneness, and meat mutagens and the risk for prostate cancer in the Agricultural Health Study. We estimated relative risks and 95% confidence intervals (95% CI) for prostate cancer using Cox proportional hazards regression using age as the underlying time metric and adjusting for state of residence, race, smoking status, and family history of prostate cancer. During 197,017 person-years of follow-up, we observed 668 incident prostate cancer cases (613 of these were diagnosed after the first year of follow-up and 140 were advanced cases) among 23,080 men with complete dietary data. We found no association between meat type or specific cooking method and prostate cancer risk. However, intake of well or very well done total meat was associated with a 1.26-fold increased risk of incident prostate cancer (95% CI, 1.02-1.54) and a 1.97-fold increased risk of advanced disease (95% CI, 1.26-3.08) when the highest tertile was compared with the lowest. Risks for the two heterocyclic amines 2-amino-3,4,8-trimethylimidazo-[4,5-f]quinoxaline and 2-amino-3,8-dimethylimidazo-[4,5-b]quinoxaline were of borderline significance for incident disease [1.24 (95% CI, 0.96-1.59) and 1.20 (95% CI, 0.93-1.55), respectively] when the highest quintile was compared with the lowest. In conclusion, well and very well done meat was associated with an increased risk for prostate cancer in this cohort.

Role of hormonal and other factors in human prostate cancer

American men have a lifetime risk of about 18% for prostate cancer diagnosis. Large international variations in prostate cancer risks and increased risks among migrants from low- to high-risk countries indicate important roles for environmental factors. Major known risk factors include age, family history, and country/ethnicity. Type 2 diabetes appears to reduce risk, while high birth weight and adult height are linked to increased risk of aggressive prostate cancer. Limited evidence supports an association with a history of sexually transmitted infections. A previous meta-analysis of eight cohort studies indicated no associations with plasma androgen, estrogen, or sex hormone binding globulin (SHBG) levels. However, there were dose-response relationships with baseline plasma testosterone levels in two studies that adjusted for other serum hormones and obesity. Finasteride (a drug that blocks testosterone activation) reduced prostate cancer risk by 25%. Low-frequency genes linked to familial prostate cancer only explain a small fraction of all cases. Sporadic cases were linked to relatively common polymorphisms of genes involved in (1) androgen synthesis, activation, inactivation and excretion, (2) hormone and vitamin D receptors, (3) carcinogen metabolism, and (4) DNA repair. Epidemiologic evidence supports protective roles for dietary selenium, vitamin E, pulses, tomatoes/lycopene, and soy foods, and high plasma 1,25-dihydroxyvitamin D levels. There is inadequate evidence that vegetables, fruit, carotenoids, and vitamins A and C reduce risk and that animal fat, alpha-linoleic acid, meat, coffee, and tea increase risk. Two major cohort studies found dose-response relationships with dietary calcium intake. Total dietary energy intake may enhance risk. Limited evidence supports a protective role for physical activity and elevated risk for farmers and other men with occupational pesticide exposure, particularly to organochlorine compounds and phenoxy herbicides. There is inadequate evidence for a relationship with alcohol or smoking. Most known or suspected external risk factors may act through hormonal mechanisms, but our review found little supporting evidence, and substantial further research is needed.

Estrogens and Antiestrogens as Etiological Factors and Therapeutics for Prostate Cancer

Mounting evidence supports a key role played by estrogen or estrogen in synergy with an androgen, in the pathogenesis of prostate cancer (PCa). New experimental data suggest that this process could begin as early as prenatal life. During adulthood, estrogen carcinogenicity is believed to be mediated by the combined effects of hormone-induced, unscheduled cell proliferation and bioactivation of estrogens to genotoxic carcinogens. Increased bioavailability of estrogen through age-dependent increases in conversion from androgen could also be a contributing factor. Individual variations and race-/ethnic-based differences in circulating or locally formed estrogens or in tissue estrogen responsiveness may explain differential PCa risk among individuals or different populations. Estrogen receptor (ER)-alpha and ER-beta are the main mediators of estrogen action in the prostate. However, ER-beta is the first ER subtype expressed in the fetal prostate. During cancer development, ER-beta expression is first lost as tumors progress into high grade in the primary site. Yet, its reexpression occurs in all metastatic cases of PCa. A change in cytosine methylation in a regulatory CpG island located in the proximal promoter of ER-beta may constitute an "on/off" switch for reversible regulation of ER-beta expression. A variety of estrogenic/antiestrogenic/selective estrogen receptor modulator (SERM)-like compounds have been shown to use non-ERE pathways, such as tethering of ER-beta to NF-kappaB binding proteins, Sp2, or Ap1 for gene transactivation. These findings open new avenues for drug design that now focuses on developing a new generation of estrogen-based PCa therapies with maximal proapoptotic action but few or no side effects.