Association between CYP2E1 polymorphisms and susceptibility to prostate cancer

Identification of a Steroid Hormone-Associated Gene Signature Predicting the Prognosis of Prostate Cancer through an Integrative Bioinformatics Analysis

Simple Summary

Prostate cancer (PC) is the second most common cancer worldwide and steroid hormone plays an important role in prostate carcinogenesis. Most patients with PC are initially sensitive to androgen deprivation therapy (ADT) but eventually become hormone refractory and reflect disease progression. The aim of the study was to investigate the genes which regulate the steroid hormone functional pathways and associate with the disease progression of PC. We identified a panel of eight-gene signatures that modulated steroid-hormone pathways and predicted the prognosis of PC using integrative bioinformatics analysis of multiple datasets validated from external cohorts. This panel could be used for predicting the prognosis of PC patients and might be associated with the drug response of hormonal therapies. Moreover, these genes in the signature could be potential targets to develop a novel treatment for castration-resistant PC therapy.

Abstract

The importance of anti-androgen therapy for prostate cancer (PC) has been well recognized. However, the mechanisms underlying prostate cancer resistance to anti-androgens are not completely understood. Therefore, identifying pharmacological targets in driving the development of castration-resistant PC is necessary. In the present study, we sought to identify core genes in regulating steroid hormone pathways and associating them with the disease progression of PC. The selection of steroid hormone-associated genes was identified from functional databases, including gene ontology, KEGG, and Reactome. The gene expression profiles and relevant clinical information of patients with PC were obtained from TCGA and used to examine the genes associated with steroid hormone. The machine-learning algorithm was performed for key feature selection and signature construction. With the integrative bioinformatics analysis, an eight-gene signature, including CA2, CYP2E1, HSD17B, SSTR3, SULT1E1, TUBB3, UCN, and UGT2B7 was established. Patients with higher expression of this gene signature had worse progression-free interval in both univariate and multivariate cox models adjusted for clinical variables. The expression of the gene signatures also showed the aggressiveness consistently in two external cohorts, PCS and PAM50. Our findings demonstrated a validated eight-gene signature could successfully predict PC prognosis and regulate the steroid hormone pathway.

Interaction between dietary acrylamide intake and genetic variants for estrogen receptor-positive breast cancer risk

Purpose

The association between dietary acrylamide intake and estrogen receptor-positive (ER+) breast cancer risk in epidemiological studies is inconsistent. By analyzing gene-acrylamide interactions for ER+ breast cancer risk, we aimed to clarify the role of acrylamide intake in ER+ breast cancer etiology.

Methods

The prospective Netherlands Cohort Study on diet and cancer includes 62,573 women, aged 55–69 years. At baseline, a random subcohort of 2589 women was sampled from the total cohort for a case–cohort analysis approach. Dietary acrylamide intake of subcohort members (n = 1449) and ER+ breast cancer cases (n = 844) was assessed with a food frequency questionnaire. We genotyped single nucleotide polymorphisms (SNPs) in genes in acrylamide metabolism, sex steroid systems, oxidative stress and DNA repair. Multiplicative interaction between acrylamide intake and SNPs was assessed with Cox proportional hazards analysis, based on 20.3 years of follow-up.

Results

Unexpectedly, there was a statistically non-significant inverse association between acrylamide and ER+ breast cancer risk among all women but with no clear dose–response relationship, and no association among never smokers. Among the results for 57 SNPs and 2 gene deletions, rs1056827 in CYP1B1, rs2959008 and rs7173655 in CYP11A1, the GSTT1 gene deletion, and rs1052133 in hOGG1 showed a statistically significant interaction with acrylamide intake for ER+ breast cancer risk.

Conclusions

This study did not provide evidence for a positive association between acrylamide intake and ER+ breast cancer risk. If anything, acrylamide was associated with a decreased ER+ breast cancer risk. The interaction with SNPs in CYP1B1 and CYP11A1 suggests that acrylamide may influence ER+ breast cancer risk through sex hormone pathways.

Electronic supplementary material

The online version of this article (10.1007/s00394-018-1619-z) contains supplementary material, which is available to authorized users.

Association between CYP2E1 genetic polymorphisms and urinary cancer risk: a meta-analysis

Objective

Studies investigating the contribution of Cytochrome P4502E1 (CYP2E1) polymorphisms to the etiology of urinary cancer draw inconsistent conclusions. Thus, we performed a meta-analysis to evaluate the association between CYP2E1 Rsa I/Pst I and Dra I polymorphisms and urinary cancer susceptibility.

Materials and Methods

Meta-analysis based on the eligible case-control studies that assess the association of CYP2E1 Rsa I/Pst I and Dra I polymorphisms with urinary cancer was conducted. Subgroup analyses based on ethnicity and cancer type were also carried out. Odds ratios (OR) and 95% confidence intervals (95% CI) were calculated to evaluate the strength of the associations between the two polymorphisms. Funnel plot and Begg’s test were used for publication bias diagnosis.

Results

We found decreased urinary cancer risk among subjects carrying CYP2E1 RsaI/PstI c1c2 + c2c2 genotype and c2 allele (OR = 0.73, 95% CI = 0.68–0.79 and OR = 0.79, 95% CI = 0.74–0.85, respectively), with 3,301 cases and 3,786 controls from 14 studies. We also observed a significant difference in c1c2 + c2c2 vs. c1c1 and c2 vs. c1 among Asians (OR = 0.68, 95% CI = 0.60–0.78 and OR = 0.75, 95% CI = 0.66–0.85, respectively). However, the meta-analysis based on 5 eligible studies showed no significant association between CYP2E1 Dra I polymorphism and urinary cancer susceptibility in either dominant model or the allele model.

Conclusions

Our meta-analysis concluded that CYP2E1 Rsa I/Pst I polymorphism correlates with urinary cancers risk in Asian population; while CYP2E1 Dra I polymorphism might be not significantly associated with the urinary cancer risks. Large and well-designed studies are needed to confirm these results.

Toxicogenetic profile and cancer risk in Lebanese

An increasing number of genetic polymorphisms in drug-metabolizing enzymes (DME) were identified among different ethnic groups. Some of these polymorphisms are associated with an increased cancer risk, while others remain equivocal. However, there is sufficient evidence that these associations become significant in populations overexposed to environmental carcinogens. Hence, genetic differences in expression activity of both Phase I and Phase II enzymes may affect cancer risk in exposed populations. In Lebanon, there has been a marked rise in reported cancer incidence since the 1990s. There are also indicators of exposure to unusually high levels of environmental pollutants and carcinogens in the country. This review considers this high cancer incidence by exploring a potential gene-environment model based on available DME polymorphism prevalence, and their impact on bladder, colorectal, prostate, breast, and lung cancer in the Lebanese population. The examined DME include glutathione S-transferases (GST), N-acetyltransferases (NAT), and cytochromes P-450 (CYP). Data suggest that these DME influence bladder cancer risk in the Lebanese population. Evidence indicates that identification of a gene-environment interaction model may help in defining future research priorities and preventive cancer control strategies in this country, particularly for breast and lung cancer.

CYP2E1, GSTM1 and GSTT1 genetic polymorphisms and susceptibility to antituberculosis drug-induced hepatotoxicity: a nested case-control study

WHAT IS KNOWN AND OBJECTIVE

The pathogenic mechanism of antituberculosis drug-induced hepatotoxicity (ATDH) is thought to involve drug-metabolizing enzymes including N-acetyl transferase2 (NAT2), cytochrome P4502E1 (CYP2E1) and glutathione S-transferase (GST) M1, T1. The associations between genetic polymorphisms of those genes and ATDH have been reported but with inconsistent results. Moreover, most studies were hospital-based retrospective studies and not prospective. We aimed to investigate possible associations of CYP2E1, GSTM1 and GSTT1 genetic polymorphisms with ATDH using a more robust case-control study nested in a population-based prospective antituberculosis treatment cohort.

METHODS

A total of 4304 patients with smear-positive tuberculosis (TB) who received standard short-course chemotherapy were monitored for 6-9 months. Incidence density sampling method was adopted to select controls and 4 : 1 matched with each ATDH cases by age (± 5 years), sex, treatment history, disease severity and drug dosage. The CYP2E1, GSTM1 and GSTT1 polymorphisms were genotyped using PCR-RFLP and multiplex PCR methods. Conditional logistic regression model was used to calculate odds ratio (OR) and 95% confidence interval (CI), as well as corresponding P-values.

RESULTS AND DISCUSSION

A total of 89 ATDH cases and 356 controls were included in this study. There was no statistically significant association between CYP2E1 RsaI c1/c1 genotype or DraI C/C genotype and ATDH (OR = 0·99, 95% CI:0·62-1·59; OR = 1·13, 95% CI: 0·40-3·20, respectively) compared with CYP2E1 RsaI c1/c2 or c2/c2 genotypes or DraI D/D genotype, or between GSTM1/GSTT1 null genotypes and ATDH (OR = 1·22, 95% CI: 0·76-1·96; OR = 0·96, 95% CI: 0·60-1·52, respectively) compared with non-null genotypes.

WHAT IS NEW AND CONCLUSION

This is the first study of the involvement of CYP2E1, GSTM1 and GSTT1 genetic polymorphisms in ATDH using a nested case-control population-based prospective cohort design. We could not confirm positive associations of genetic polymorphisms of CYP2E1 RsaI, CYP2E1 DraI, GSTM1 null and GSTT1 null with ATDH reported by various groups, in our Chinese TB population.

Analysis of 4 single-nucleotide polymorphisms in relation to cervical dysplasia and cancer development using a high-throughput ligation-detection reaction procedure

BACKGROUND

Host genetic characteristics and environmental factors may correlate with risk for cervical cancer development. Here we describe a retrospective screening study for single nucleotide polymorphisms (SNPs) in genetic markers TP53, MTHFR, CYP1A1, and CYP2E1 in 749 patients.

METHODS

A multiplex ligation-dependent polymerase chain reaction approach was applied. We used archived material from human papillomavirus tests and correlated SNP genotypes to the corresponding clinical data. Semantic integration was used to identify and evaluate the clinical status from electronic health records.

RESULTS

An association with cervical cancer and high-grade dysplasia was found for the rare homozygous CC genotype (rs4646903) in CYP1A1 (odds ratio [OR], 8.862). Odds ratios were also significantly elevated for heterozygous MTHFR CT genotype (rs1801133; OR, 1.457). No significant association was found in TP53 (rs1042522) and CYP2E1 (rs3813867). In addition, we found smokers at higher risk (OR, 2.688) and identified pregnancies as a significant risk factor (OR, 1.54).

CONCLUSIONS

Our protocol enables a feasible way for further retrospective large sample size evaluation of potential genetic markers. This study revealed genetic associations of a rare SNP genotype with cervical dysplasia in one of the largest patient sample to date that warrants further investigation.

Polymorphisms in estrogen related genes may modify the protective effect of isoflavones against prostate cancer risk in Japanese men

Soy isoflavones and estrogen related genes may play a major role in the etiology of prostate cancer. This study examined whether the genetic polymorphisms of estrogen receptors (ESR-alpha and ESR-beta) and cytochrome P450 19A1 (CYP19A1) modified the protective effect of isoflavones against prostate cancer. One hundred and eighty cases and 177 controls were selected from three geographic areas of Japan. The odds ratio for more than or equal to 60 versus less than 60 mg/day of the intake of isoflavones was 0.63 (95% confidence interval=0.41-0.96). The TTTA long repeat was significantly associated with an increased risk (odds ratio=1.76, 95% confidence interval=1.15-5.70). The interaction between the polymorphisms and the intake of isoflavones on prostate cancer risk was analyzed by the multifactor dimensionality reduction method. The combination of the TTTA long repeats and the minor alleles of rs10046 in CYP19A1 and rs2077647 in ESR-alpha was a high risk for prostate cancer despite greater than or equal to 60 mg isoflavones/day. The combination of the TTTA short repeat and those homozygous for the major allele of rs10046 in CYP19A1 was low risk despite less than 60 mg isoflavones/day. In conclusion, the findings of this case-control study suggest that the protective effect of isoflavones may differ between the genotypes of estrogen related genes.

Implication of Xenobiotic Metabolizing Enzyme gene (CYP2E1, CYP2C19, CYP2D6, mEH and NAT2) polymorphisms in breast carcinoma

Background

Xenobiotic Metabolizing Enzymes (XMEs) contribute to the detoxification of numerous cancer therapy-induced products. This study investigated the susceptibility and prognostic implications of the CYP2E1, CYP2C19, CYP2D6, mEH and NAT2 gene polymorphisms in breast carcinoma patients.

Methods

The authors used polymerase chain reaction and restriction enzyme digestion to characterize the variation of the CYP2E1, CYP2C19, CYP2D6, mEH and NAT2 gene in a total of 560 unrelated subjects (246 controls and 314 patients).

Results

The mEH (C/C) mutant and the NAT2 slow acetylator genotypes were significantly associated with breast carcinoma risk (p = 0.02; p = 0.01, respectively). For NAT2 the association was more pronounced among postmenopausal patients (p = 0.006). A significant association was found between CYP2D6 (G/G) wild type and breast carcinoma risk only in postmenopausal patients (p = 0.04). Association studies of genetic markers with the rates of breast carcinoma specific overall survival (OVS) and the disease-free survival (DFS) revealed among all breast carcinoma patients no association to DFS but significant differences in OVS only with the mEH gene polymorphisms (p = 0.02). In addition, the mEH wild genotype showed a significant association with decreased OVS in patients with axillary lymph node-negative patients (p = 0.03) and with decreasesd DFS in patients with axillary lymph node-positive patients (p = 0.001). However, the NAT2 intermediate acetylator genotype was associated with decreased DFS in axillary lymph node-negative patients.

Conclusion

The present study may prove that polymorphisms of some XME genes may predict the onset of breast carcinoma as well as survival after treatment.

The CYP3A4∗1B polymorphism and prostate cancer susceptibility in a Portuguese population

Testosterone exposure has been implicated in prostate carcinogenesis, and genes that alter its metabolism, such as CYP3A4, have been associated with prostate cancer susceptibility. The aim of our study was to assess the relationship between the CYP3A4 *1B polymorphism and its possible role in the development of prostate cancer. DNA samples obtained from the peripheral blood cells of 414 individuals diagnosed with prostate cancer and 337 healthy male donors were used in this case-control study. The CYP3A4*1B polymorphism was analyzed by polymerase chain reaction-restriction fragment length polymorphism methodology. We found no statistically significant differences in the distribution of the CYP3A4*1B genotypes between cases and controls (P = 0.470; odds ratio = 1.191; 95% confidence interval=0.740-1.918), as well as after the stratification of our analysis, according to important clinicopathologic parameters of prostate cancer. Our results suggest that the CYP3A4*1B polymorphism is not associated with prostate cancer risk within the Portuguese population.

Association between FAS polymorphism and prostate cancer development

The role of FAS polymorphisms in prostate cancer has not been studied. Using the PCR-based restriction fragment-length polymorphism methodology, we evaluated FAS gene locus -670 genotypes in DNA from 904 men: 657 prostate cancer patients and 247 healthy controls. We found that carriers of AG or GG genotypes have a statistically significant protection (odds ratio (OR)=0.30; confidence interval (CI): 0.20-0.44 and OR=0.22; CI: 0.12-0.74, respectively) for disease with extra-capsular invasion. Taken together, a 72% protection was found for G allele carriers (OR=0.28; CI: 0.19-0.41). Fas exist as membrane-bound and soluble forms and with opposite roles. They derive from the same gene by alternative splicing. Membrane Fas receptors trigger apoptosis whereas, on the other hand, soluble Fas (sFas) bind to Fas ligand antagonizing Fas-Fas ligand apoptotic pathway. Our results suggest that G allele may reduce sFas levels preventing the apoptotic inhibition caused by the soluble form.

Association of the A870G cyclin D1 gene polymorphism with genetic susceptibility to nasopharyngeal carcinoma

BACKGROUND

Nasopharyngeal cancer (NPC) is multifactorial, and the genetic background may be a crucial etiologic factor. Cyclin D1 (CCND1) is a key regulator of the cell cycle, and its altered activity is associated with the development of cancer.

METHODS

We analyzed the A870G CCND1 polymorphism by polymerase chain reaction/restriction fragment length polymorphism (PCR-RFLP) in 281 individuals, including 94 patients with NPC and 187 healthy individuals.

RESULTS

Our results indicate that individuals carrying two G alleles have a 2.17-fold increase in the risk for the development of NPC (odds ratio [OR], 2.17; 95% confidence interval [CI], 1.19-3.98; p = .016). Age-adjusted logistic regression analysis confirmed this association (adjusted odds ratio [aOR], 2.14; 95% CI, 1.14-4.04; p = .018). Multivariate analysis demonstrates an independent association between GG CCND1 genotype (aOR, 2.06), male sex (aOR, 2.66), and age at diagnosis (aOR, 2.02) regarding the development of undifferentiated NPC. The proportion of NPC cases attributable to the GG CCND1 genotype was 14.76%.

CONCLUSIONS

Our results may be important in the definition of a biologic predictive profile for the development of NPC within our population.

Systematic replication study of reported genetic associations in prostate cancer: Strong support for genetic variation in the androgen pathway

BACKGROUND

Association studies have become a common and popular method to identify genetic variants predisposing to complex diseases. Despite considerable efforts and initial promising findings, the field of prostate cancer genetics is characterized by inconclusive reports and no prostate cancer gene has yet been established.

METHODS

We performed a literature review and identified 79 different polymorphisms reported to influence prostate cancer risk. Of these, 46 were selected and tested for association in a large Swedish population-based case-control prostate cancer population.

RESULTS

We observed significant (P < 0.05) confirmation for six polymorphisms located in five different genes. Three of them coded for key enzymes in the androgen biosynthesis and response pathway; the CAG repeat in the androgen receptor (AR) gene (P = 0.03), one SNP in the CYP17 gene (P = 0.04), two SNPs in the SRD5A2 gene (P = 0.02 and 0.02, respectively), a deletion of the GSTT1 gene (P = 0.006), and one SNP in the MSR1 gene, IVS5-59C > A, (P = 0.009).

CONCLUSIONS

Notwithstanding the difficulties to replicate findings in genetic association studies, our results strongly support the importance of androgen pathway genes in prostate cancer etiology.

-765G > C COX-2 polymorphism may be a susceptibility marker for gastric adenocarcinoma in patients with atrophy or intestinal metaplasia

AIM: To investigate the relationship between the -765G > C COX-2 polymorphism and the development of different gastric lesions: atrophy or intestinal metaplasia and gastric adenocarcinoma.

METHODS: A cross-sectional study was performed involving 320 Portuguese individuals (210 without evidence of neoplastic disease, 73 patients with gastric adenocarcinomas and 37 with atrophy or intestinal metaplasia) using a PCR-RFLP method.

RESULTS: -765C allele was overrepresented in the patients with gastric adenocarcinoma (51%) when compared either with the control group (38%) or patients with atrophy or intestinal metaplasia (27%). Callele was found to be very common in our population (0.22), and a multivariate logistic regression analysis revealed nearly 3-fold increased risk for the progression to gastric adenocarcinoma in patients with atrophy or intestinal metaplasia carrying the -765C allele (OR = 2.67, 95% CI = 1.03-6.93; P = 0.04).

CONCLUSION: -765C carrier status should be considered as another susceptibility marker for gastric adenocarcinoma development in patients with atrophy or intestinal metaplasia.

Global pharmacogenetics: giving the genome to the masses

With pharmacogenetics comes the promise of individualized therapy selection for many common diseases where multiple treatment options are available. Recent advances including the Human Genome Project, the International HapMap project, advances in throughput and reduction in cost of genetic testing, and the inclusion of genotype-related dosing recommendations into package inserts all point to the integration of pharmacogenetics into clinical practice. However, many countries will not have access to pharmacogenetics resources in the near future. Generation of global genotype profiles will provide a useful, but not perfect resource for incorporating pharmacogenetics into national drug formularies in the form of prioritization or surveillance where individual genotype data would not be attainable. The PharmacoGenetics for Every Nation Initiative is a first step to making pharmacogenetics applicable on a global level.

Joint effect among p53, CYP1A1, GSTM1 polymorphism combinations and smoking on prostate cancer risk: an exploratory genotype-environment interaction study

AIM

To assess the role of several genetic factors in combination with an environmental factor as modulators of prostate cancer risk. We focus on allele variants of low-penetrance genes associated with cell control, the detoxification processes and smoking.

METHODS

In a case-control study we compared people carrying p53cd72 Pro allele, CYP1A1 M1 allele and GSTM1 null genotypes with their prostate cancer risk.

RESULTS

The joint risk for smokers carrying Pro* and M1*, Pro* and GSTM1null or GSTM1 null and CYP1A1 M1* variants was significantly higher (odds ratio [OR]: 13.13, 95% confidence interval [CI]: 2.41-71.36; OR: 3.97, 95% CI: 1.13-13.95 and OR: 6.87, 95% CI: 1.68-27.97, respectively) compared with that for the reference group, and for non-smokers was not significant. OR for combinations among p53cd72, GSTM1 and CYP1A1 M1 in smokers were positively and significantly associated with prostate cancer risk compared with non-smokers and compared with the putative lowest risk group (OR: 8.87, 95% CI: 1.25-62.71).

CONCLUSION

Our results suggest that a combination of p53cd72, CYP1A1, GSTM1 alleles and smoking plays a significant role in modified prostate cancer risk on the study population, which means that smokers carrying susceptible genotypes might have a significantly higher risk than those carrying non-susceptible genotypes.

Genetic polymorphisms in the cytochrome P450 1A1 and 2E1 genes, smoking, drinking and prostate cancer susceptibility: A case-control study in a Han nationality population in Southern China

AIM

To investigate the association among the polymorphisms of the cytochrome P450 1A1 and 2E1 genes, smoking, drinking and the risk of prostate cancer (PCa) in a Han nationality population in Southern China.

METHODS

A case-control study including 225 PCa patients and 250 age-matched controls was conducted. The six polymorphic sites of the CYP 1A1 and CYP2E1 genes were analysed by polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) or allele-specific PCR technique using genomic DNA isolated from peripheral blood lymphocytes.

RESULTS

We found that the CYP1A1 Val/Val genotype significantly increased the risk for PCa (OR, 2.26; 95% CI, 1.09-4.68). In contrast, the CYP2E1 C1/C2 (OR, 0.67; 95% CI, 0.46-0.99) or C2/C2 genotype (OR, 0.31; 95% CI, 0.10-1.00) significantly decreased the risk. Furthermore, the individuals carrying the CYP1A1 Val allele and the CYP2E1 C1/C1 genotype showed the highest risk (OR, 2.50; 95% CI, 1.45-4.29). Though there was no significant difference with smoking history (P = 0.237) or drinking habit (P = 0.499) between cases and controls, a deep smoking habit (OR, 2.02; 95% CI, 1.28-3.17) and heavy smoking history (OR, 1.61; 95% CI, 1.04-2.50) significantly increased the susceptibility of PCa after stratification by smoking method and accumulative smoking amount. Moreover, both the CYP1A1 Val allele (OR, 2.82; 95% CI, 1.49-5.35) and CYP2E1 C1/C1 genotype (OR, 2.57; 95% CI, 1.31-5.02) had obvious interaction with heavy smoking history that significantly raised the risk. We also discovered a significant interaction between the CYP2E1 C1/C1 genotype and drinking (OR, 1.85; 95% CI, 1.04-3.28).

CONCLUSIONS

Individuals carrying the CYP1A1 Val allele or the CYP2E1 C1/C1 genotype with a smoking or drinking habit were at increased risk of PCa, which also showed a positive correlation with exposure dose of tobacco.

Cervical cancer and CYP2E1 polymorphisms: implications for molecular epidemiology

INTRODUCTION

Besides human papillomavirus (HPV) infection, several cofactors are considered important for the development of cervical cancer (CC). Among these, tobacco smoke, other sexually transmitted diseases, inflammation and nutritional factors have been intensively described. CYP2E1 polymorphisms have been associated with the metabolization of several carcinogens, some of them considered risk factors for CC development, such as tobacco smoke. The aim of this study was to evaluate the role of CYP2E1 polymorphisms in the susceptibility to cervical cancer in a Portuguese population.

PATIENTS AND METHODS

The genotypic analysis was performed with the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) methodology, using peripheral blood samples of 454 individuals: 122 presented invasive squamous cell carcinoma (ICC), 59 presented squamous intraepithelial lesions (SIL), and the control population was composed of 274 healthy individuals.

RESULTS

Concerning the DraI polymorphism, we observed a decreased risk for the development of squamous cervical lesions in the presence of the C allele [odds ratio (OR)=0.600; 0.378<OR<0.952; p=0.029]. In the stratification of the analysis according to the mean age, we observed an increased risk for the development of SIL, for women older than 39 years of age, in the presence of the D allele (OR=0.087; 0.012<OR<0.651; p=0.003). Regarding the RsaI polymorphism, we did not find any significant differences.

CONCLUSION

The decreased risk observed for the development of SIL and not ICC in the presence of the D allele may indicate that CYP2E1 interferes with the initial steps of the carcinogenic process, probably due to its involvement in the action of immunological mediators, expressed during cervical inflammation. These aspects may help to define new therapeutic strategies for chemoprevention.

TP53 and P21 polymorphisms: response to cisplatinum/paclitaxel-based chemotherapy in ovarian cancer

Ovarian cancer (OC) is the most lethal gynaecologic cancer and its standard treatment consists of platinum-based chemotherapy after cytoreductive surgery. The p53 protein plays a critical role on different cellular processes in response to DNA damage and it is responsible for transcriptional induction of the P21 gene. We have analysed 114 blood samples in order to investigate the effect of the TP53 codon 72 and the P21 3'UTR polymorphisms in response to cisplatinum/paclitaxel chemotherapy for OC treatment. The genotypes of the TP53 codon 72 and P21 3'UTR polymorphism were identified using AS-PCR and PCR-RFLP, respectively. Our results indicate that the TP53 P allele is associated with a worse prognosis (P=0.011) while P21 polymorphism genotypes did not reveal any statistically significant result (P>0.05). Furthermore, simultaneous carriers of the TP53 AA genotype and the P21 CC genotype demonstrate a longer progression-free interval (P=0.020). This study suggests that the characterisation of a genetic profile can contribute to the definition of a better chemotherapy treatment.

Characterization of HPV genotype profile in squamous cervical lesions in Portugal, a southern European population at high risk of cervical cancer

A different prevalence of human papillomavirus (HPV) types has been reported in distinct populations. Although Portugal has a relatively high incidence of cervical cancer within the European Union, no studies have been reported in the Portuguese population. Recently, a clinical trial using a vaccine targeted against HPV-16 demonstrated a high efficacy in preventing HPV-16 cervical lesions. The aim of the present study was the characterization of HPV genotype profile in squamous intraepithelial lesions (SIL) and invasive cervical cancer (ICC) from 608 patients using polymerase chain reaction (PCR) methodology. We frequently detected HPV-6/11 and HPV-16 in low-grade SIL (HPV-6/11, 18.9%; HPV-16, 44.2%). In high-grade SIL, HPV-16 was demonstrated in 74.2% of those lesions and in 80.0% of the cases with ICC. HPV-18 was found in 3.1%, 0.8% and in 15.0% of low, high SIL and ICC, respectively. The overall prevalence of multiple infections with high-risk HPV was 7.2%. Other types of HPV were detected in 7.0% of all cases. Our results demonstrate a high prevalence of HPV-16 in SIL and ICC in Portuguese women. Therefore, a prophylactic HPV-16/18 vaccine may be effective in the prevention of cervical cancer in a significant number of women from this southern European population.

The influence of smoking and other cofactors on the time to onset to cervical cancer in a southern European population

Cervical cancer is a complex and multifactorial disease. Although there are substantial data supporting the causative role of persistent human papillomavirus (HPV) infection in the development of cervical cancer, the complete course of the disease has never been completely understood. Several risk cofactors have been suggested with controversial results. Portugal has the highest incidence of squamous cell carcinoma (SCC) within western Europe and there are no known studies regarding the role of cofactors in SCC. The aim of our study was to evaluate the role of smoking, sexual behaviour, reproductive and contraceptive history, in the time-to-onset (TTO) of severe cervical lesions (HGSIL/SCC) in the Portuguese population. We verified that age of first sexual intercourse under 18 years (odds ratio (OR) 2.8), pregnancy (OR 2.9), first pregnancy under 21 years (2.6), number of pregnancies (OR 2.3-5.4) and parity (OR 1.9-5.7) are risk factors in the development of cervical neoplasia. Smoke exposure index (SEI) was significantly different (P=0.002) between cases and controls. Our results regarding time-to-onset demonstrate that smoking (P<0.001, log rank test), number of sexual partners (P<0.001, log rank test) and use of oral contraceptives (P<0.001, log rank test) are important determinants in the earlier onset of severe cervical lesions. Using this approach, our findings may help to clarify the role of smoking and other cofactors in the persistence and progression of cervical lesions.

Acetylation genotype and the genetic susceptibility to prostate cancer in a southern European population

BACKGROUND

Epidemiologic studies have suggested that environmental factors and diet are important risk factors in the pathogenesis of prostate cancer. The N-acetyltransferases (NAT) are important enzymes in activation and inactivation of various carcinogens, including those found in well-cooked meat and cigarette smoke.

METHODS

We analyzed DNA samples from 146 prostate cancer patients and 174 healthy men. We used PCR-RFLP method to analyze NAT 1 and NAT 2 polymorphisms.

RESULTS

We did not find statistically significant differences in NAT 1 genotypes frequencies between prostate cancer patients and control group. We observed an association of the slow acetylator genotype, NAT 2*6/NAT2*6 with prostate cancer protection (P=0.017; OR=0.31, 95% CI 0.11--0.84). Multivariate logistic regression analysis confirmed this association (0.030; OR=0.32, 95% CI 0.12--0.89).

CONCLUSIONS

Our results indicate a role of NAT2 polymorphisms in the carcinogenic pathway of prostate cancer, specifically in a population of Southern Europe.

TP53 codon 72 polymorphism and risk for cervical cancer in Portugal

High-risk human papillomavirus are essential for the development of cervical cancer; however, TP53 is the most frequently altered tumor suppressor gene among tumors and is described as a cofactor for cervical carcinogenesis. TP53 has two common polymorphic forms encoding either proline or arginine, at position 72, and the presence of homozygous arginine has been reported as a risk factor for cervical cancer in many populations. We evaluated the effect of this TP53 polymorphism in a northern Portuguese population. We analyzed blood samples of 385 women; 20 with low-grade squamous intraepithelial lesion (SIL), 56 with high-grade SIL, 164 with invasive cervical cancer, and 145 healthy controls, using allele specific-polymerase chain reaction methodology. We observed an increased frequency of the Arg/Arg genotype in the cancer group, but no statistical significance was found between cases and controls (P>0.05). Our results indicate that there is no association between the presence of the Arg allele in codon 72 of TP53 polymorphism and risk of cervical cancer in our population.

Increased risk of cervical cancer associated with cyclin D1 gene A870G polymorphism

Human papillomavirus (HPV) plays a major role in the etiology of cervical cancer. However, a complex correlation between viral and cellular genes is necessary for cell cycle control deregulation in the progression to invasive cervical cancer (ICC). Cyclin D1 (CCND1) is an important positive regulator of the G1/S phase of the cell cycle. The CCND1 gene is located at 11q13 and is often altered in human cancers. We analyzed the A870G CCND1 polymorphism by polymerase chain reaction/restriction fragment length polymorphism analysis in 246 women including 50 cases with high-grade squamous intraepithelial lesions of the cervix (HSIL), 93 with ICC, and 103 healthy women. The GG genotype was associated with a 4.32-fold higher risk for the development of HSIL [adjusted odds ratio (aOR)=4.32, 95% confidence interval (CI) 1.50-12.46, P=0.0067), and a 3.26-fold increased risk for the development of ICC (aOR=3.26, 95% CI 1.42-7.53, P=0.006). The proportion of cervical cancer cases attributable to the GG CCND1 genotype was 17.26%. This study indicates that the A870G CCND1 polymorphism could act as a cofactor of HPV in the initiation of cervical carcinogenesis, particularly in the transformation zone of HPV-infected women, supporting evidence for a genetic factor in ICC risk.

Leptin and prostate: implications for cancer prevention--overview of genetics and molecular interactions

Leptin's relation with obesity has been clearly demonstrated while its role in oncobiology is still largely unknown. Epidemiological studies on serum leptin provide valuable though controversial data, while in vitro studies consistently show leptin's angiogenic and proliferative potential in cancer. Leptin's activity is mediated by tissue-specific receptors, differentially expressed in organs such as the prostate. The molecular cascades triggered by leptin result in prostatic cell proliferation and angiogenic activity, thus linking the hormone mainly to prostate cancer prognosis. This review also addresses leptin's metabolic interactions with cytokines, growth factors or hormones, establishing perceptive pathways leading to carcinogenesis or prostate cancer progression and metastasis. Better understanding of these mechanisms may help in the development of new and more effective treatments for prostate cancer. The consolidation of leptin molecular genetics profile in prostate cancer patients may help to create susceptibility groups in normal individuals, facilitating a preventive dietary intervention or strategies for chemoprevention. We hypothesize that the balance between androgen and leptin levels may facilitate the increase in the ratio of androgen-independent prostate cancer cells to androgen-dependent cells in the tumour.

Angiotensin I–converting enzyme gene insertion/deletion polymorphism and endometrial human cancer in normotensive and hypertensive women

Endometrial carcinoma is one of the most common gynecological malignancies. Most cases are diagnosed in older patients with diabetes, hypertension, or obesity. The renin-angiotensin system (RAS) has a central role controlling blood pressure and sodium homeostasis. RAS polymorphisms have been reported as genetic determinants of essential hypertension. The objective of this study was to analyze angiotensin I-converting enzyme gene insertion/deletion polymorphism and endometrial human cancer in normotensive and hypertensive women. The presence of an angiotensin converting enzyme (ACE) polymorphism was analyzed by polymerase chain reaction in DNA isolated from peripheral blood samples of 171 women: 70 cases with endometrial cancer (age, 63.6 +/- 9.5 years) and 101 normal control women (age, 61.3 +/- 6.4 years). We detected DD genotype in 47.5%, ID genotype in 44.3%, and II genotype in 8.2% of cases. The allele frequency was 0.69 for D allele and 0.30 for I allele. In normotensives, we found that the presence of I allele (genotypes ID and II) is significantly associated to an earlier age (56.0 +/- 10.1 versus 65.8 +/- 9.9) of onset of endometrial carcinoma (P=0.029). We observed that normotensive women carriers of an allele I have a higher risk of development of endometrial cancer under the age of 63 years (odds ratio=3.60, 95% confidence interval=1.03-12.56; P=0.037). Our findings suggest that ACE polymorphism may be associated with the development of endometrial carcinoma and with the onset of this tumor in younger women. The definition of a pharmacogenomic profile of human neoplasia may help to identify targets for the development of therapeutic or chemoprevention strategies.

HER2 polymorphism and breast cancer risk in Portugal

Breast cancer is a major public health problem around the world, and its carcinogenesis is not yet well understood. The human epidermal growth factor Receptor 2 (HER2) seems to play an important role in the development of this neoplasia, and genetic alterations in this gene, such as point mutations and polymorphisms have been detected in breast cancer patients. We analysed the frequency of a single nucleotide polymorphism in the HER2 gene in blood samples from 152 breast cancer patients and 146 healthy controls using the polymerase chain reaction methodology, followed by restriction fragment length polymorphism (PCR-RFLP). We found a twofold increase in risk of breast cancer in women who are carriers of a Val allele genotype-Ile/Val and Val/Val genotypes [odds ratio (OR)=2.00; 95% confidence interval (CI) 1.23-3.25; P=0.005]. Our results indicate an association between the presence of the Val allele in the HER2 polymorphism and the risk of breast cancer. Further studies are needed to evaluate the role of this polymorphism in the behaviour of breast cancer.