Susceptibility to endometrial cancer: influence of allelism at p53, glutathione S-transferase (GSTM1 and GSTT1) and cytochrome P-450 (CYP1A1) loci

Genic-intergenic polymorphisms of CYP1A genes and their clinical impact

The humancytochrome P450 1A (CYP1A) subfamily genes, CYP1A1 and CYP1A2, encoding monooxygenases are critically involved in biotransformation of key endogenous substrates (estradiol, arachidonic acid, cholesterol) and exogenous compounds (smoke constituents, carcinogens, caffeine, therapeutic drugs). This suggests their significant involvement in multiple biological pathways with a primary role of maintaining endogenous homeostasis and xenobiotic detoxification. Large interindividual variability exist in CYP1A gene expression and/or catalytic activity of the enzyme, which is primarily due to the existence of polymorphic alleles which encode them. These polymorphisms (mainly single nucleotide polymorphisms, SNPs) have been extensively studied as susceptibility factors in a spectrum of clinical phenotypes. An in-depth understanding of the effects of polymorphic CYP1A genes on the differential metabolic activity and the resulting biological pathways is needed to explain the clinical implications of CYP1A polymorphisms. The present review is intended to provide an integrated understanding of CYP1A metabolic activity with unique substrate specificity and their involvement in physiological and pathophysiological roles. The article further emphasizes on the impact of widely studied CYP1A1 and CYP1A2 SNPs and their complex interaction with non-genetic factors like smoking and caffeine intake on multiple clinical phenotypes. Finally, we attempted to discuss the alterations in metabolism/physiology concerning the polymorphic CYP1A genes, which may underlie the reported clinical associations. This knowledge may provide insights into the disease pathogenesis, risk stratification, response to therapy and potential drug targets for individuals with certain CYP1A genotypes.

Individual effects of GSTM1 and GSTT1 polymorphisms on cervical or ovarian cancer risk: An updated meta-analysis

Background: Studies have shown that glutathione S-transferase M1 (GSTM1) and. glutathione S-transferase T1 (GSTT1) null genotype may increase the risk of cervical cancer (CC) or ovarian cancer (OC), however, the results of published original studies and meta-analyses are inconsistent. Objectives: To investigate the association between GSTM1 present/null and GSTT1 present/null polymorphisms, with the risk of cervical cancer or ovarian cancer. Methods: The odds ratios (ORs) and 95% confidence intervals (CIs) were used to assess the association between GSTM1 present/null and GSTT1 present/null polymorphisms and the risk of cervical cancer or ovarian cancer. To assess the confidence of statistically significant associations, we applied false positive reporting probability (FPRP) and bayesian false discovery probability (BFDP) tests. Results: Overall analysis showed that GSTM1 null was associated with an increased risk of cervical cancer, and subgroup analysis showed a significant increase in cervical cancer risk in Indian and Chinese populations; GSTT1 was not found null genotype are significantly associated with cervical cancer. Overall analysis showed that GSTM1 and GSTT1 null were not associated with the risk of ovarian cancer, subgroup analysis showed that GSTM1 null was associated with an increased risk of OC in East Asia, and GSTT1 null was associated with an increased risk of OC in South America. However, when we used false positive reporting probability and bayesian false discovery probability to verify the confidence of a significant association, all positive results showed "low confidence" (FPRP > .2, BFDP > .8). Conclusion: Overall, this study strongly suggests that all positive results should be interpreted with caution and are likely a result of missing plausibility rather than a true association.

Is There Any Association between Glutathione S-transferases M1 and Glutathione S-transferases T1 Gene Polymorphisms and Endometrial Cancer Risk? A Meta-analysis

Epidemiological evidence on the association between genetic polymorphisms in glutathione S-transferases M1 (GSTM1) and T1 (GSTT1) genes and risk of endometrial cancer (EC) has been inconsistent. In this meta-analysis, we seek to investigate the relationship between GSTM1 and GSTT1 polymorphisms and the risk of EC. We searched Medline, PubMed, Web of Science, Embase, Chinese National Knowledge Infrastructure database, and Chinese Biomedical Literature database to identify eligible studies. The pooled odds ratios (ORs) with 95% confidence intervals (CIs) for the association were determined using a fixed- or random-effect model. Tests for heterogeneity of the results and sensitivity analyses were performed. A total of six case-control studies were included in the final meta-analysis of GSTM1 (1293 cases and 2211 controls) and GSTT1 (1286 cases and 2200 controls) genotypes. Overall, GSTM1 null genotype was not significantly associated with an increased risk of EC (OR = 1.00, 95% CI = 0.76-1.30, P = 0.982). Similarly, for GSTT1 deletion genotype, we observed no association under the investigated model in the overall analysis (OR = 0.91, 95% CI = 0.64-1.30, P = 0.619). Subgroup analysis also showed no significant association between the GSTM1 null genotype and EC risk in hospital-based design (OR = 1.26, 95% CI = 0.93-1.71, P = 0.131) and no relationship between GSTT1 null genotype with EC risk in population-based design (OR = 1.18, 95% CI = 0.79-1.76, P = 0.407). However, GSTM1 null genotype contributed to an increased EC risk in population-based design (OR = 0.76, 95% CI = 0.60-0.97, P = 0.027), while null GSTT1 in hospital-based studies (OR = 0.70, 95% CI = 0.52-0.93, P = 0.015). The present meta-analysis suggested that GSTs genetic polymorphisms may not be involved in the etiology of EC. Large epidemiological studies with the combination of GSTM1 null, GSTT1 null, and design-specific with the development of EC are needed to prove our findings.

The Association Between p53 Codon 72 Polymorphism and Endometrial Cancer Risk: A System Review and Meta-analysis

Abstract

Polymorphism of p53 codon 72 plays an important role in pathogenesis and development of cancer. Published data on the association between the p53 codon 72 polymorphism and endometrial cancer risk are controversial. A meta-analysis was performed to assess whether the polymorphism of p53 codon 72 is associated with endometrial cancer risk. Medline, Embase, China National Knowledge Infrastructure, and Chinese Biomedicine Databases were searched to identify eligible studies. Pooled odds ratios (ORs) and 95% confidence intervals (CIs) for p53 codon 72 polymorphism and endometrial cancer were appropriately derived from fixed-effects or random effects models. A total of 12 studies were enrolled in this meta-analysis. The pooled analyses revealed that p53 codon 72 polymorphism was not associated with endometrial cancer risk. Stratified analysis by Hardy-Weinberg equilibrium exhibited a significantly increased risk of endometrial cancer among studies deviated from Hardy-Weinberg equilibrium in heterozygote comparison (Pro/Arg vs Arg/Arg; OR, 0.61; 95% CI, 0.42–0.87) and dominant model (Pro/Pro + Pro/Arg vs Arg/Arg; OR, 0.66; 95% CI, 0.47–0.92). This study indicated that the p53 codon 72 polymorphism may not be associated with endometrial cancer risk.

Comparative study and meta-analysis of meta-analysis studies for the correlation of genomic markers with early cancer detection

A large number of common disorders, including cancer, have complex genetic traits, with multiple genetic and environmental components contributing to susceptibility. A literature search revealed that even among several meta-analyses, there were ambiguous results and conclusions. In the current study, we conducted a thorough meta-analysis gathering the published meta-analysis studies previously reported to correlate any random effect or predictive value of genome variations in certain genes for various types of cancer. The overall analysis was initially aimed to result in associations (1) among genes which when mutated lead to different types of cancer (e.g. common metabolic pathways) and (2) between groups of genes and types of cancer. We have meta-analysed 150 meta-analysis articles which included 4,474 studies, 2,452,510 cases and 3,091,626 controls (5,544,136 individuals in total) including various racial groups and other population groups (native Americans, Latinos, Aborigines, etc.). Our results were not only consistent with previously published literature but also depicted novel correlations of genes with new cancer types. Our analysis revealed a total of 17 gene-disease pairs that are affected and generated gene/disease clusters, many of which proved to be independent of the criteria used, which suggests that these clusters are biologically meaningful.

GSTM1 and GSTT1 copy number variation in population-based studies of endometrial cancer risk

BACKGROUND

Glutathione S-transferases (GST) detoxify a broad range of carcinogenic metabolites and lack of GSTM1 and GSTT1 activity due to gene deletions are prevalent. The associations of GSTM1 and GSTT1 polymorphisms with endometrial cancer risk have been inconsistent.

METHODS

We investigated gene dosage effects of GSTM1 and GSTT1 copy number in 441 endometrial cancer cases and 1,237 matched controls selected from the Nurses' Health Study and Women's Health Study, as well as gene-environment interactions.

RESULTS

Carriers of at least 2 GSTT1 genes had an increased risk of endometrial cancer (OR = 1.51, 95% CI = 1.04-2.19; P(trend) = 0.04) compared with women who were GSTT1 null. GSTM1 was not associated with endometrial cancer risk (OR(2/3 vs. 0 copies) = 0.82, 95% CI = 0.52-1.27; P(trend) = 0.41). We did not observe effect modification of either the GSTM1 or GSTT1 association with cancer risk by smoking status, postmenopausal hormone use, or body mass index.

CONCLUSIONS

Our results suggested GSTM1 copy number does not influence endometrial cancer risk, whereas higher GSTT1 copy number may be associated with increased risk. Our findings supported that GSTT1 differs in its substrate specificity from GSTM1 and may generate intermediates more genotoxic to endometrial cells than the parent chemical. Future studies are needed to clarify this relationship.

IMPACT

We hypothesized risk associated with GST enzymes may differ depending on environmental and/or occupational exposures. Our assessment of gene-environment interactions suggested GSTM1 and GSTT1 are not involved in the in vivo human metabolism of estrogen and its metabolites.

Cytochrome P450 1A1 Gene Polymorphisms and Endometrial Cancer Risk: A Meta-Analysis

Introduction:

This meta-analysis aims to examine whether the genotype status of Msp1, Ile462Val, and Thr461Asn polymorphisms in cytochrome P450 1A1 (CYP1A1) is associated with endometrial cancer risk.

Methods:

Eligible case-control studies were identified through search in MEDLINE (end of search: August 2010). Pooled odds ratios (ORs) were appropriately derived from fixed-effects or random-effects models.

Results:

ConcerningMspI polymorphism, 8 studies were eligible (1456 cases and 2371 controls); 9 studies were eligible (1889 cases and 3662 controls) for Ile462Val and 6 studies were eligible (1272 cases and 2122 controls) for Thr461Asn.MspI polymorphism was not associated with endometrial cancer risk (for heterozygous TC vs TT carriers: OR = 0.83, 95% confidence interval [CI], 0.59-1.15, random effects; for homozygous CC vs TT carriers: OR = 1.00, 95% CI, 0.55-1.82, fixed effects). Similarly, Ile462Val polymorphism was not associated with endometrial cancer risk (for heterozygous Ile/Val vs Ile/Ile carriers: OR = 1.27, 95% CI, 0.78-2.06, random effects; for homozygous Val/Val vs Ile/Ile carriers: OR = 1.16, 95% CI, 0.48-2.81, fixed effects). Accordingly, Thr461Asn status was not significantly associated with endometrial cancer risk. The same results were reproduced in Caucasians.

Conclusions:

The 3 examined CYP1A1 genotype polymorphisms do not seem to confer any additional risk for endometrial cancer in Caucasians. Accumulation of further data seems mandatory for future race-specific analyses.

Study of specific genetic and epigenetic variables in multiple myeloma

Few studies have examined the association between methylenetetrahydrofolate reductase (MTHFR) SNPs, epigenetic changes, and multiple myeloma (MM). We wished to determine genotype distributions for MTHFR 1298AC SNP in cases of MM and healthy controls and to examine whether there is any correlation between the methylation status of the CpG island of CDKN2A and Snk/Plk2 and MTHFR genotypes and with overall survival (OS) and other relevant clinical parameters. Bone marrow and peripheral blood were obtained from 45 patients with MM and 77 controls, respectively. The frequencies of the MTHFR 1298AA, 1298AC, and 1298CC genotypes were 53.3%, 40%, and 6.7% for the patient population and 50.6%, 41.6%, and 7.8% for the controls. No statistically significant difference was found in genotype distribution between cases and controls. No correlation was noted between MTHFR genotypes and OS, disease stage, bone disease, anemia, and extramedullary disease. Regarding CDKN2A and Snk/Plk2 CpG island methylation analysis, we found 12 of 45 patients and 27 of 45, respectively, to be methylated. CDKN2A and Snk/Plk2 methylation did not correlate with MTHFR genotypes. Herein, we report the identification of Snk/Plk2 as a novel methylated gene in MM and show that methylation is not influenced in this CpG island or in that of a previously described methylated gene, CDKN2A, in MM. Further evaluation in a larger sample of patients is needed in order to better define the prognostic and clinical value, if any, of MTHFR 1298 polymorphisms and CDKN2A and Snk/Plk2 methylation in the pathogenesis of MM.

Polymorphisms in genes of the steroid hormone biosynthesis and metabolism pathways and endometrial cancer risk

OBJECTIVES

The incidence of endometrial cancer has recently increased substantially and studies have shown that altered levels of exogenous and endogenous hormones are associated with individual variation in endometrial cancer risk. The environmental and reproductive risk factors that influence these hormones are well known, however, genetic variants involved in hormone biosynthesis and estrogen metabolism have not been well established in endometrial cancer.

METHODS

To determine whether polymorphisms in genes of the steroid hormone biosynthesis and metabolism pathways are associated with endometrial cancer risk, 28 polymorphisms in 18 genes were genotyped in 191 endometrial cancer cases and 291 healthy controls.

RESULTS

The GSTM1 deletion and the variant (GG) genotype of the CYP1B1 rs1800440 polymorphism were associated with a decreased risk of developing endometrial cancer. Furthermore, combinations of haplotypes in CYP1A1, CYP1B1 and GSTs were associated with a decreased risk. The analysis of the repeat polymorphisms revealed that women with the long repeat allele length of the ESR1 (GT)n repeat polymorphism were at an increased risk of developing endometrial cancer. Conversely, women with two long repeat length alleles of the (CAG)n repeat polymorphism in the AR correlated with a decrease in endometrial cancer risk compared to women with one or two alleles with the short repeat length.

CONCLUSIONS

The findings are consistent with our hypothesis that variability in genes involved in steroidogenesis and estrogen metabolism may alter the risk of developing endometrial cancer, suggesting that they may be useful as biomarkers for genetic susceptibility to endometrial cancer.

Evaluation of the frequency of TP53 gene codon 72 polymorphisms in Iranian patients with endometrial cancer

Polymorphisms of the TP53 gene codon 72 exhibit less effective function in tumor suppression and usually are associated with human cancer. To investigate the frequency of proline and arginine alleles of TP53 codon 72, the present study analyzed the DNA from blood samples of 30 Iranian women with endometrial cancer, in comparison with 32 healthy women. A Pro/Pro genotype was associated with increased endometrial cancer risk (odds ratio OR = 3.7, 95% confidence interval CI = 0.539-25.59). In patients, Pro allele frequency (68%) was higher than Arg frequency (32%), and higher also than Pro frequency in healthy control subjects (55%) (OR = 1.9, 95% CI = 0.903-3.893). It could be that the Pro allele is less apoptotic than the Arg allele, and that the Arg allele most probably activates transcription factors more efficiently than the Pro variant. These novel findings on the frequency of TP53 gene codon 72 polymorphism in endometrial cancer in Iranian women indicate that in this population the Pro allele might be associated with increased risk of endometrial cancer.

Intron 3 16 bp duplication polymorphism of TP53 contributes to cancer susceptibility: a meta-analysis

A few genetic polymorphisms of TP53 are known to have a significant effect on cancer susceptibility. Intron 3 16 bp duplication polymorphism of TP53 has been reported to be associated with breast cancer, colorectal cancer, lung cancer and other cancers, but the reported results remain inconclusive. The present study, a meta-analysis including a total of 9801 cases and 10,391 controls from 26 studies, revealed that the 16 bp insertion (Ins) allele is significantly associated with an increased cancer risk in overall analysis [Ins/Ins + deletion (Del)/Ins versus Del/Del: odds ratio (OR) = 1.14, 95% confidence interval (CI) = 1.02-1.27, P = 0.02; Ins/Ins versus Del/Del: OR = 1.35, 95% CI = 1.11-1.63, P = 0.002; Del/Ins versus Del/Del: OR = 1.10, 95% CI = 0.98-1.23, P = 0.11.), particularly in breast cancer subgroup (Ins/Ins + Del/Ins versus Del/Del: OR = 1.16, 95% CI = 1.03-1.31, P = 0.02; Ins/Ins versus Del/Del: OR = 1.81, 95% CI = 1.30-2.52, P < 0.001; Del/Ins versus Del/Del: OR = 1.10, 95% CI = 0.97-1.25, P = 0.13). The relative risks to the colorectal and lung cancers increased but their association power was relatively weak, which may result from a limited number of studies of these two cancer types. These results suggest that intron 3 16 bp duplication polymorphism of TP53 is potentially an important and clinically relevant genetic marker contributing to cancer susceptibility.

Common genetic variation in the sex hormone metabolic pathway and endometrial cancer risk: pathway-based evaluation of candidate genes

BACKGROUND

Estrogen plays a major role in endometrial carcinogenesis, suggesting that common variants of genes in the sex hormone metabolic pathway may be related to endometrial cancer risk. In support of this view, variants in CYP19A1 [cytochrome P450 (CYP), family 19, subfamily A, polypeptide 1] have been associated with both circulating estrogen levels and endometrial cancer risk. Associations with variants in other genes have been suggested, but findings have been inconsistent.

METHODS

We examined 36 sex hormone-related genes using a tagging approach in a population-based case-control study of 417 endometrial cancer cases and 407 controls conducted in Poland. We evaluated common variation in these genes in relation to endometrial cancer risk using sequential haplotype scan, variable-sized sliding window and adaptive rank-truncated product (ARTP) methods.

RESULTS

In our case-control study, the strongest association with endometrial cancer risk was for AR (androgen receptor; ARTP P = 0.006). Multilocus analyses also identified boundaries for a region of interest in AR and in CYP19A1 around a previously identified susceptibility loci. We did not find evidence for consistent associations between previously reported candidate single-nucleotide polymorphisms in this pathway and endometrial cancer risk.

DISCUSSION

In summary, we identified regions in AR and CYP19A1 that are of interest for further evaluation in relation to endometrial cancer risk in future haplotype and subsequent fine mapping studies in larger study populations.

Germline polymorphism of cancer susceptibility genes in gynecologic cancer

The multifactorial process of carcinogenesis involves mutations in oncogenes, or tumor suppressor genes, as well as the influence of environmental etiological factors. Common DNA polymorphisms in low penetrance genes have emerged as genetic factors that seem to modulate an individual's susceptibility to malignancy. Genetic studies, which lead to a true association, are expected to increase understanding of the pathogenesis of each malignancy and to be a powerful tool for prevention and prognosis in the future. Here, we review the findings of genetic association studies of gene polymorphisms in gynecologic cancer with special reference to glutathione-S-transferase, FAS/CD95 and p53 genes including our recent research results.

Polymorphisms in TP53 and MDM2 combined are associated with high grade endometrial cancer

OBJECTIVES

Determinants of endometrial cancer grade have not been precisely defined, however, cell cycle control is considered to be integrally involved in endometrial cancer development. TP53 and MDM2 are essential components for cell cycle arrest and apoptosis. Polymorphisms in these genes cause TP53 inactivation and MDM2 over-expression, leading to accumulation of genetic errors.

METHODS

One polymorphism in MDM2, rs2279744 (SNP309) and three polymorphisms in TP53 rs1042522 (R72P), rs17878362 and rs1625895 were genotyped in 191 endometrial cancer cases and 291 controls using PCR-based fragment analysis, RFLP analysis and real-time PCR.

RESULTS

The results showed no associations of the three TP53 polymorphisms and MDM2 SNP309 alone or in combination with endometrial cancer risk. However, the combination of MDM2 SNP309 and the three TP53 polymorphisms was significantly associated with a higher grade of endometrial cancer (wild-type genotypes versus variant genotypes: OR 4.15, 95% CI 1.82-9.46, p=0.0003). Analysis of family history of breast cancer revealed that the variant genotypes of the three TP53 polymorphisms were significantly related to a higher frequency of family members with breast cancer in comparison to endometrial cancer cases without a family history of breast cancer (wild-type genotypes versus variant genotypes: OR 2.78, 95% CI 1.36-5.67, p=0.004).

CONCLUSIONS

The combination of the MDM2 SNP309 and the three TP53 polymorphisms appear to be related to a higher grade of endometrial cancer. The association of the endometrial cancer cases with family history of breast cancer and the three TP53 polymorphisms suggests that this constellation of malignancies may represent a low-risk familial cancer grouping.

Genetic polymorphisms and endometrial cancer risk

For most sporadic cancers, genetic susceptibility results from the additive effect of multiple genetic variants, each of which contributes a modest risk individually. The study of genetic single nucleotide polymorphisms (SNPs) may help explain the differences in individual cancer susceptibility and may assist in identifying novel markers of risk that can be utilized to create more effective and tailored cancer prevention strategies. Genetic polymorphisms in functionally critical genes have been suggested as risk factors for the development of a variety of cancers, including endometrial cancer. Candidate SNPs may be involved in DNA damage repair, steroid metabolism, carcinogen metabolism, cell-cycle control, apoptosis and steroid receptor activation pathways. In this review, recent findings of genetic association studies exploring genetic polymorphisms and their association with endometrial cancer are reported. In addition, the challenges of genetic association studies, such as power and bias, and the need for validation of promising findings are explored.

Novel molecular profiles of endometrial cancer-new light through old windows

Endometrial carcinoma (EC) is the most common gynecological malignancy in the western world. A widely accepted dualistic model, which has been established on a morphological basis, differentiates EC into two broad categories: Type I oestrogen-dependent adenocarcinoma with an endometrioid morphology and Type II non-oestrogen-dependent EC with a serous papillary or clear cell morphology. Molecular genetic evidence indicates that endometrial carcinoma, as described in other malignancies, likely develops as the result of a stepwise accumulation of alterations in cellular regulatory pathways, such as oncogene activation and tumor suppressor gene inactivation, which lead to dysfunctional cell growth. These molecular alterations appear to be specific in Type I and Type II cancers. In type I endometrioid endometrial cancer, PTEN gene silencing in conjunction with defects in DNA mismatch repair genes, as evidenced by the microsatellite instability phenotype, or mutations in the K-ras and/or beta-catenin genes, are recognized major alterations, which define the progression of the normal endometrium to hyperplasia, to endometrial intraepithelial neoplasia, and then on to carcinoma. In contrast, Type II cancers show mutations of TP53 and Her-2/neu and seem to arise from a background of atrophic endometrium. Nevertheless, despite the great effort made to establish a molecularly-based histological classification, the following issues must still be clarified: what triggers the tumor cells to invade the myometrium and what causes vascular or lymphatic dissemination, finally culminating in metastasis? RUNX1, a transcription factor, was recently identified as one of the most highly over-expressed genes in a microarray study of invasive endometrial carcinoma. Another candidate gene, which may be associated with an initial switch to myometrial infiltration, is the transcription factor ETV5/ERM. These studies, as well as those conducted for other genes possibly involved in the mitotic checkpoint as a major mechanism of carcinogenesis in non-endometrioid endometrial cancer, could help in understanding the differences in the biology and the clinical outcome among histological types.

Cytochrome P450 1A1, cigarette smoking, and risk of endometrial cancer (United States)

Cytochrome P450 1A1 (CYP1A1) is involved in the metabolism of estradiol and the activation of polycyclic aromatic hydrocarbons found in tobacco products. Polymorphic variation in CYP1A1 activity may modify susceptibility to endometrial cancer through the oxidative metabolism of estradiol and the activation of tobacco-smoke constituents. We prospectively evaluated the associations between three common CYP1A1 polymorphisms and endometrial cancer risk, as well as the potential modification of these associations by cigarette smoking, in a case-control study nested within the Nurses' Health Study. We investigated the MspI restriction-site polymorphism, a C --> A transversion at nucleotide 4887 (Thr461Asn) and a A --> G transition at nucleotide 4889 (Ile462Val) among 456 women with endometrial cancer and 1,134 matched controls. We used conditional logistic regression to calculate the adjusted odds ratios (OR) and 95% confidence intervals (CI) to quantify the risk of endometrial cancer among subjects who had at least one variant allele compared with that of subjects homozygous for the wild-type allele. We did not observe any statistically significant associations between the MspI, Thr461Asn or Ile462Val polymorphisms and endometrial cancer risk or any significant effect modification by cigarette-smoking status. These data suggest that these three polymorphisms are not important in determining genetic susceptibility to endometrial cancer, although larger sample sizes are needed to confirm these findings.

Single nucleotide polymorphism: a new risk factor for endometrial cancer?

Continuous identification of common polymorphisms in various genes helps us to understand the possible association between endometrial cancer risk and the germline polymorphism. Estrogen receptor genes and the group of genes associated with the metabolism of estrogen have been investigated well. Second, the polymorphism in the p53 gene and the genes involved in its downstream pathway were correlated to a risk of developing endometrial cancer. Finally, the polymorphism in the genes involved in cellular proliferation and differentiation, regulating cell cycles, and DNA-damage repair were studied. In this way, recent research has begun to identify common genetic polymorphisms that augment the effects of risk-factor exposure, such as genes that affect the metabolism of hormones or are involved in cellular anti-tumor activities. The accumulation of data through these approaches would make genetic testing for the risk of development of endometrial cancer possible in the near future.

CYP1A1 gene polymorphism and risk of endometrial hyperplasia and endometrial carcinoma

The cytochrome P4501A1 (CYP1A1) is involved in the metabolism of environmental carcinogens and estrogen. We hypothesized that CYP1A1 genetic polymorphism may be a susceptibility factor for endometrial hyperplasia (EH) and endometrial carcinoma (ECa). We therefore evaluated this hypothesis in patients with EH and ECa and control subjects using allele-specific polymerase chain reaction-based method in a Turkish population. The patients with CYP1A1 Ile/Val genotype had a fivefold higher risk of having EH than those with Ile/Ile. In contrast, a higher frequency of any Val genotype (Ile/Val and Val/Val) was found in patients with EH, indicating that persons carrying any Val allele are at increased risk for developing EH. In the ECa group, patients were also more likely to have CYP1A1 Ile/Val allele, with an adjusted odds ratio of 3.0. Moreover, there was a statistically significant increase in relative risk association with any Val genotype between patients and controls, suggesting that individuals carrying any Val genotype are at increased risk for developing ECa. We concluded that variant alleles of the CYP1A1 gene might be associated with EH and ECa susceptibility. Further studies with a large sample size should be considered to address issues of interactions between CYP1A1 and other risk factors.

Interactive effects between CYP1A1 genotypes and environmental polychlorinated dibenzo-p-dioxins and dibenzofurans exposures on liver function profile

Previous studies reported that polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) induced hepatic cytochrome P-4501A1 (CYP1A1). The aim of this study was to examine the interactive influence of CYP1A1 genotypes and PCDD/Fs exposure on liver function profile. PCDD/Fs levels and liver function parameters were determined in serum and correlated with genetic polymorphism of CYP1A1/Msp 1 in 225 human volunteers who had no or minimal occupational exposure to PCDD/F. The results showed that the highest glutamate pyruvate transaminase (GPT) activity levels were found in subjects with homozygous variant CYP1A1/Msp 1, followed by heterozygous variant, and finally homozygous wild type for those individuals whose serum PCDD/Fs levels were higher than 17.4 pg WHO-TEQ/g lipid. Data suggest that GPT activity levels may be modified by interaction of CYP1A1/Msp 1 genotype with dioxin after adjustment for age, alcohol consumption, and history of liver illness. Further studies are needed to characterize the variation in other related genes to verify whether a correlation exists between serum PCDD/Fs levels and adverse health effects.

CYP1A1 gene polymorphism as a risk factor for cervical intraepithelial neoplasia and invasive cervical cancer

OBJECTIVE

The purpose of this study was to evaluate the role of CYP1A1*3 gene polymorphism in the development of cervical cancer by comparing patients having cervical intraepithelial neoplasia (CIN) or invasive cervical cancer with control subjects.

METHODS

CYP1A1*3 polymorphism was analyzed using an allele-specific PCR-based method.

RESULTS

In the group of patients with CIN, the frequency of the Ile/Val and of any Val alleles was significantly higher than in the healthy control subjects (OR: 4.51; 95%CI = 2.42-8.43, and OR: 3.71; 95%CI = 2.03-6.78). In the CIN1 group, patients with Ile/Val and any Val genotypes were found to be significantly higher (OR: 10.53; 95%CI = 3.78-29.33 and OR: 8.38; 95%CI = 3.04-23.08). In the CIN2 group, patients with Ile/Val and any Val revealed a 4.06- and 3.23-fold higher risk than those with Ile/Ile (95%CI = 1.54-10.74 and 1.24-8.45). However, the variance in the group of patients with CIN3 did not reach statistical significance. Patients with cervical cancer were analyzed with respect to the histological diagnoses. In the adenocancer group, the estimated ORs with respect to the control subjects were 11.29 for Ile/Val (95%CI = 3.35-38.07) and 8.98 for any Val groups (95%CI = 2.69-30.01), with a statistical significance. Among the squamous cell cancer patients, Ile/Val and any Val were significantly higher than in controls (OR: 5.76; 95%CI = 3.13-10.59 and OR: 5.20; 95%CI = 2.91-9.28). Although Val/Val genotype did not reach a significant value, it was near significance with an OR of 3.03 (95%CI = 0.95-9.68).

CONCLUSION

These results suggest that CYP1A1*3 gene polymorphism is linked to a propensity for cervical carcinogenesis and further series are needed to detect the exact role of this unique variation.

Germline polymorphism of p53 codon 72 in gynecological cancer

OBJECTIVE

To investigate the biological significance of single nucleotide polymorphism at codon 72 of the p53 gene in the development of gynecological cancer.

METHODS

p53 codon 72 polymorphism was examined in a total of 354 blood samples from 95 normal, 83 cervical, 108 endometrial and 68 ovarian cancer cases using polymerase chain reaction and restriction fragment length polymorphism techniques.

RESULTS

When p53 codon 72 genotype was classified into two subgroups of Arg/Arg and Arg/Pro + Pro/Pro, the Arg/Arg genotype was associated with an increased risk for the development of endometrial cancer (OR = 1.86, 95% CI = 1.06 to 3.26) compared with the Arg/Pro + Pro/Pro genotype (P = 0.0301). The Arg allele also increased the risk of endometrial cancer (OR = 1.42, 95% CI = 0.93 to 1.52) compared with the Pro allele, but no statistical difference was found (P = 0.1031). There was no significant difference in the genotype or allele prevalence between control subjects and cervical or ovarian cancer patients.

CONCLUSION

Homozygous Arg at codon 72 of the p53 gene may be a risk factor for developing endometrial cancer in a Japanese population.

Estrogen-metabolizing gene polymorphisms and lipid levels in women with different hormonal status

Endogenous and exogenous sex steroid hormones have multiple effects on lipid and lipoprotein metabolism. It is also known that estrogen has antiatherogenic actions, therefore we considered examining whether there was any association between polymorphisms in estrogen-metabolizing genes and lipid levels in women. We investigated the association between variants in genes related to estrogen biosynthesis (CYP19-TTTA(n)) and estrogen catabolism (CYP1A1*2A, CYP1A1*2C, CYP1A2-Asn516Asn, CYP3A4*1B, and COMT-Val158Met) with serum lipid levels in a cross-sectional study with 472 Brazilian women of European descent. They were divided into three subgroups according to their hormonal status: premenopausal women (n=187), postmenopausal women exposed to hormonal replacement therapy (HRT) (n=118), and postmenopausal women unexposed to HRT (n=167). The postmenopausal women receiving HRT who were carriers of the CYP3A4*1B variant showed lower low-density lipoprotein cholesterol levels than wild-type homozygotes. Premenopausal women homozygous for the CYP1A1*2C allele had higher high-density lipoprotein cholesterol levels than heterozygotes. While the CYP1A1*2C variant probably has a higher catalytic activity, the functional implications of the CYP3A4 polymorphism are still uncertain. These data are the first attempt to associate estrogen metabolism genes to lipid levels in women.

Cytochrome P-450 1A1 gene polymorphisms and risk of breast cancer: a HuGE review

Cytochrome P-450 (CYP) 1A1 plays a key role in phase I metabolism of polycyclic aromatic hydrocarbons and in estrogen metabolism. It is expressed predominantly in extrahepatic tissues, including the breast. Four CYP1A1 gene polymorphisms (3801T --> C, Ile462Val, 3205T --> C, and Thr461Asp) have been studied in relation to breast cancer. The 3801C variant is more common than the Val variant. Both variants occur more frequently in Asians than in White populations. The 3205T --> C polymorphism has been observed in African Americans only. Little data are available on the geographic/ethnic distribution of the Thr461Asp polymorphism. The functional significance of the polymorphisms is unclear. In 17 studies, no consistent association between breast cancer and CYP1A1 genotype was found. Meta-analysis found no significant risk for the genotypes 1) 3801C/C (relative risk (RR) = 0.97, 95% confidence interval (CI): 0.52, 1.80) or 3801T/C (RR = 0.91, 95% CI: 0.70, 1.19) versus 3801T/T, 2) Val/Val (RR = 1.04, 95% CI: 0.63, 1.74) or Ile/Val (RR = 0.92, 95% CI: 0.76, 1.10) versus Ile/Ile, or 3) Asp/Asp (RR = 0.95, 95% CI: 0.20, 4.49) or Thr/Asp (RR = 1.12, 95% CI: 0.87, 1.43) versus Thr/Thr. Future studies should explore possible interactions between CYP1A1 and sources of polycyclic aromatic hydrocarbons, markers of estrogen exposure, other lifestyle factors influencing hormonal levels, and other genes involved in polycyclic aromatic hydrocarbon metabolism or hormonal biosynthesis.

Association of p73 G4C14-to-A4T14 polymorphism at exon 2 and p53 Arg72Pro polymorphism with the risk of endometrial cancer in Japanese subjects

To test the association of endometrial cancer with the p73 G4C14-to-A4T14 polymorphism in exon 2 and the p53 Arg72Pro polymorphism, an incident case-control study was performed in Japanese subjects. The cases comprised 114 endometrial cancer patients, and the controls were 320 healthy females and 122 noncancer female outpatients. An unconditional logistic regression model demonstrated a significant association between the p73 AA genotype and an increased risk of endometrial cancer (OR=2.82, 95% CI=1.36-5.82), especially of type-I tumors (OR=3.24, 95% CI=1.53-6.87). In contrast, there was no significant difference in the p53 Arg72Pro genotype frequency between the controls and cases.

Genetic Factors in Catechol Estrogen Metabolism in Relation to the Risk of Endometrial Cancer

2-Hydroxylated metabolites of estrogen have been shown to have antiangiogenic effects and inhibit tumor cell proliferation, whereas 4-hydroxylated metabolites have been implicated in carcinogenesis. We examined whether polymorphisms in certain genes involved in estrogen metabolism are associated with endometrial cancer risk in a population-based case-control study with 371 cases and 420 controls. Based on previously published genotype-phenotype correlation studies, we defined variant alleles thought to increase estrogen 2-hydroxylation as presumptively low-risk (CYP1A1 m1 T6235C and m2 Ile(462)Val) and those thought to increase estrogen 4-hydroxylation as high-risk (CYP1A1 m4 Thr(461)Asn, CYP1A2 A734C, and CYP1B1 Leu(432)Val). Odds ratios (OR) and 95% confidence intervals (95% CI) were calculated using unconditional logistic regression. Carrying at least one CYP1A1 m1 or m2 variant allele was associated with a decreased risk of endometrial cancer [ORs (95% CIs), 0.64 (0.44-0.93) and 0.54 (0.30-0.99), respectively]. No strong alteration in risk was observed among women with any of the putative high-risk alleles. When CYP1A1, CYP1A2, and CYP1B1 genotypes were combined and ranked by the number of putative low-risk genotypes carried, women with four or five low-risk genotypes had a reduced risk of endometrial cancer (OR, 0.29; 95% CI, 0.15-0.56) compared with women with one or none. No appreciable alteration in risk was observed among women carrying two or three low-risk genotypes. Some of our findings are consistent with the hypothesis that increased estrogen 2-hydroxylation is associated with decreased endometrial cancer risk, but replication of these results is required before any firm conclusions can be reached.

P53 codon 72 polymorphism and correlation with ovarian and endometrial cancer in Greek women

The polymorphism of codon 72 in the p53 tumour suppressor gene has been associated in the last decade with the risk of developing various neoplasias. An influence of this polymorphism on ovarian and endometrial cancer has also been suggested. We examined the genotype frequency of this polymorphism in archival samples from 56 patients with endometrial neoplasias and 51 patients with ovarian neoplasias. Cervical smears from 30 healthy, human papillomavirus (HPV)-negative women with normal cytology and colposcopy, served as control sample. Women with ovarian neoplasias, especially adenocarcinomas, had Arg/Arg more often than healthy controls [odds ratio (OR) 4.16 at P = 0.0058]. No statistically significant difference was found between women with endometrial cancer and controls. Differentiation of ovarian tumours did not appear to be associated in a statistically significant manner with the genotype, whereas a positive linear trend of Arg/Arg towards poor differentiation was noted in endometrial malignancies (mainly endometrioid adenocarcinomas). Our results suggest that homozygous arginine at codon 72 of p53 may represent a risk factor for developing ovarian malignancies and may affect the differentiation of endometrial cancer. Further studies need to be carried out in order to establish the clinical use of this polymorphism for risk assessment and possibly outcome prediction of ovarian and endometrial neoplasias.

CYP1A1 polymorphism and risk of gynecological malignancy in Japan

The incidence of endometrial cancer and ovarian cancer in Japan has been increasing in recent years. Results of epidemiologic studies suggest that the onset and multiplication of these cancers are associated with estrogen. Estrogens are metabolized by cytochrome P450 1A1 (CYP1A1) and converted into catecholestrogens, which are carcinogens. CYP1A1 has several polymorphisms, the major one being T6235C transition in the non-coding 3'-flanking region (MspI polymorphism), and another being A4889G transition in exon 7 (Ile/Val polymorphism). These polymorphisms can affect the metabolites of estrogens and contribute to the susceptibility to gynecological malignancy. In this study, to determine whether CYP1A1 polymorphism plays a role in the development of gynecological malignancy in the Japanese population, we assessed the association of CYP1A1 polymorphism in Japanese patients with gynecological malignancy in comparison to that in controls. The odds ratios (ORs) of Ile/Val polymorphism were 1.16 in ovarian cancer patients and 1.70 in endometrial cancer patients. The ORs of MspI polymorphism were 1.33 in ovarian cancer patients and 0.88 in endometrial cancer patients. No significant association was found between these CYP1A1 polymorphisms and gynecological malignancy. Although the frequency of CYP1A1 polymorphism in the Japanese population is higher than that in the Caucasian population, CYP1A1 polymorphism is not related to gynecological malignancies in Japanese population.

Metabolic enzyme polymorphisms and susceptibility to acute leukemia in adults

Genetic approaches to understanding the etiology of the acute leukemias are beginning to deliver meaningful insights. Polymorphic variants in xenobiotic metabolizer loci were a natural starting point to study the relevance of these changes. The finding that glutathione S-transferase (GST) T1 null variants increase leukemia risk has implicated oxidative stress in hematopoietic stem cells as an important etiological factor in acute myeloid leukemia (AML). The importance of these enzyme systems in handling specific substrates has also been confirmed by the finding of an increased risk of therapy-related leukemia in individuals with underactive variants of GSTP1 who have been exposed to a chemotherapeutic agent metabolized by this enzyme. Benzene is a well-recognized leukemogen, and genetic variants in its metabolic pathway can modulate the risk of leukemia following exposure. In particular, underactive variants of the NAD(P)H:quinone oxidoreductase 1 gene (NQO1) seem to increase the risk of AML. Other enzymes within the pathway are proving more difficult to study because of the absence of variants that significantly affect the biological activity of the enzyme under study. No effect of the myeloperoxidase (MPO) gene variants in altering the risk of AML has been seen in our studies. Another pathway recently shown to be important in determining leukemia risk is folic acid metabolism, particularly important in predisposition to acute lymphocytic leukemia (ALL). Polymorphic variants of the methylenetetrahydrofolate reductase gene (MTHFR) which impair its activity have been shown to be associated with a protective effect. This is thought to be due to an increased availability of nucleotide precursors for incorporation into DNA. This finding implicates misincorporation of uracil into DNA as an important mechanism of leukemic change in lymphoid precursors. Future studies will extend these observations but will require biological material collected from large well-controlled epidemiological studies. The technological challenges imposed by the high throughput of samples required by these studies are currently being addressed.

Mammalian class theta GST and differential susceptibility to carcinogens: a review

Glutathione S-transferases (GSTs) are an important part of the cellular detoxification system and, perhaps, evolved to protect cells against reactive oxygen metabolites. Theta is considered the most ancient among the GSTs and theta-like GSTs are found in mammals, fish, insects, plants, unicellular algae, and bacteria. It is thought that an ancestral theta-gene underwent an early duplication before the divergence of fungi and animals and further duplications generated the variety of the other classes of GSTs (alpha, mu, phi, etc.). The comparison of the aminoacidic homologies among mammals suggests that a duplication of an ancient GST theta occurred before the speciation of mammals and resulted in the subunits GSTT1 and GSTT2. The ancestral GST theta has a dehalogenase activity towards several halogenated compounds, such as the dichloromethane. In fact, some aerobic and anaerobic methylotrophic bacteria can use these molecules as the sole carbon and energy source. The mammalian GST theta cannot sustain the growth of bacteria but still retains the dehalogenating activity. Therefore, although mammalian GST theta behaves as a scavenger towards electrophiles, such as epoxides, it acts also as metabolic activator for halogenated compounds, producing a variety of intermediates potentially dangerous for DNA and cells. For example, mice exposed to dichloromethane show a dose-dependent incidence of cancer via the GSTT1-1 pathway. Because GSTT1-1 is polymorphic in humans, with about 20% of Caucasians and 80% of Asians lacking the enzyme, the relationship between the phenotype and the incidence of cancer has been investigated extensively in order to detect GSTT1-1-associated differential susceptibility towards endogenous or exogenous carcinogens. The lack of the enzyme is related to a slightly increased risk of cancer of the bladder, gastro-intestinal tract, and for tobacco-related tumors (lung or oral cavity). More pronounced risks were found in males with the GSTT1-null genotype for brain diseases and skin basal cell carcinomas not related to sunlight exposures. Moreover, there was an increased risk of kidney and liver tumors in humans with the GSTT1-1 positive genotype following exposures to halogenated solvents. Interestingly, the liver and kidney are two organs that express the highest level of GST theta in the human body. Thus, the GSTT1-1 genotype is suspected to confer decreased or increased risk of cancer in relation to the source of exposure; in vitro studies, mostly conducted on metabolites of butadiene, confirm the protective action of GSTT1-1, whereas, thus far, experimental studies prove that the increasing risk is limited.

Poor metabolizers at the cytochrome P450 2D6 and 2C19 loci are at increased risk of developing adult acute leukaemia

We have genotyped over 550 cases of acute leukaemia and 950 matched controls from a population-based case-control study, to investigate the impact cytochrome P450s 2D6, 2C19 and 1A1 have on susceptibility to adult acute leukaemia. Analysis included potential associations between polymorphic status and acute myeloid leukaemia (AML), acute lymphoblastic leukaemia (ALL), plus the FAB and cytogenetic subtypes therein. A significant increased risk was found for CYP2D6 poor metabolizer phenotype and acute leukaemia [odds ratio (OR) = 1.69, 95% confidence interval (CI) 1.17-2.43], a risk also found in AML and ALL. No interaction was found with smoking. However, a significant age-related association between CYP2D6 polymorphism and acute myeloid leukaemia implied that the excess risk was confined to persons aged 40 years and over (OR 2.38, 95% CI 1.53-3.71). Amongst AML cases, increased odds ratios were observed in both de-novo (OR 1.54, 95% CI 1.02-2.32) and secondary leukaemia (OR 2.83, 95% CI 0.91-8.77), and among patients with a chromosomal abnormality (OR 2.00, 95% CI 1.11-3.61). An increased risk was found for the CYP2C19 poor metabolizer phenotype (OR 1.68, 95% CI 0.97-2.92) which was also present in AML and ALL. For this CYP450 locus, an increased risk was suggested in secondary leukaemia (OR 2.67, 95% CI 0.44-16.3) and amongst AML cases with a chromosomal abnormality (OR 6.72, 95% CI 2.22-20.4). No difference in CYP1A1 genotype distribution was found for acute leukaemia, AML, ALL or any other diagnostic classification group used. No significant interactions between CYP2D6, CYP2C19 or CYP1A1 were found.

Association of p53 genomic instability with the glutathione S-transferase null genotype in gastric cancer in the Portuguese population

AIMS

p53 gene mutations are the most common genetic changes known to occur in human cancer. In previous studies, the presence of alterations to the p53 gene has been linked to the null phenotype of the glutathione S-transferase mu gene (GSTM1). GSTM1 appears to be part of a protective mechanism against the development of cancers in which environmental chemical carcinogens are involved. To screen for such an association in stomach cancer, p53 allelic loss and genomic instability and GSTM1 genotypes were investigated in gastric tumour DNA samples from 113 patients.

METHODS

The polymerase chain (PCR) reaction was used to amplify a (CA) repeat array in the p53 locus; electrophoresis, genotyping, and allele quantification were performed using an automated DNA sequencer and Genescan software. The presence of the GSTM1 gene was determined by means of a differential PCR in which multiple genes were co-amplified in the same reaction tube.

RESULTS

Loss of heterozygosity (LOH) of the p53 gene was found in 36 of 87 informative cases and genomic instability was present in eight of 113 cases. Further analysis into histological subtypes and sites of tumours did not show any positive association with p53 loss. An association between the presence of LOH and the GSTM1 null genotype was not seen; however, all the samples with genomic instability of the p53 gene (eight of 113) also showed a GSTM1 null genotype.

CONCLUSION

This study does not support the hypothesis of an association between LOH in the p53 gene and the GSTM1 null genotype, but suggests that the GSTM1 null genotype might influence p53 genomic instability.

Polymorphisms of N-acetyltransferases, glutathione S-transferases, microsomal epoxide hydrolase and sulfotransferases: influence on cancer susceptibility

It has become clear that several polymorphisms of human drug-metabolizing enzymes influence an individual's susceptibility for chemical carcinogenesis. This review gives an overview on relevant polymorphisms of four families of drug-metabolizing enzymes. Rapid acetylators (with respect to N-acetyltransferase NAT2) were shown to have an increased risk of colon cancer, but a decreased risk of bladder cancer. In addition an association between a NAT1 variant allele (NAT*10, due to mutations in the polyadenylation site causing approximately two fold higher activity) and colorectal cancer among NAT2 rapid acetylators was observed, suggesting a possible interaction between NAT1 and NAT2. Glutathione S-transferases M1 and T1 (GSTM1 and GSTT1) are polymorphic due to large deletions in the structural gene. Meta-analysis of 12 case-control studies demonstrated a significant association between the homozygous deletion of GSTM1 (GSTM1-0) and lung cancer (odds ratio: 1.41; 95% CI: 1.23-1.61). Combination of GSTM1-0 with two allelic variants of cytochrome P4501A1 (CYP1A1), CYP1A1 m2/m2 and CYP1A1 Val/Val further increases the risk for lung cancer. Indirect mechanisms by which deletion of GSTM1 increases risk for lung cancer may include GSTM1-0 associated decreased expression of GST M3 and increased activity of CYP1A1 and 1A2. Combination of GST M1-0 and NAT2 slow acetylation was associated with markedly increased risk for lung cancer (odds ratio: 7.8; 95% CI: 1.4-78.7). In addition GSTM1-0 is clearly associated with bladder cancer and possibly also with colorectal, hepatocellular, gastric, esophageal (interaction with CYP1A1), head and neck as well as cutaneous cancer. In individuals with the GSTT1-0 genotype more chromosomal aberrations and sister chromatid exchanges (SCEs) were observed after exposure to 1,3-butadiene or various haloalkanes or haloalkenes. Evidence for an association between GSTT1-0 and myelodysplastic syndrome and acute lymphoblastic leukemia has been presented. A polymorphic site of GSTP1 (valine to isoleucine at codon 104) decreases activity to several carcinogenic diol epoxides and was associated with testicular, bladder and lung cancer. Microsomal expoxide hydrolase (mEH) is polymorphic due to amino acid variation at residues 113 and 139. Polymorphic variants of mEH were associated with hepatocellular cancer (His-113 allele), ovarian cancer (Tyr-113 allele) and chronic obstructive pulmonary disease (His-113 allele). Three human sulfotransferases (STs) are regulated by genetic polymorphisms (hDHEAST, hM-PST, TS PST). Since a large number of environmental mutagens are activated by STs an association with human cancer risk might be expected.

Recent advances in the histopathology and molecular pathology of carcinoma of the endometrium

Endometrial carcinoma is the commonest malignancy of the female genital tract. The pathogenesis is complex and at least three pathogenetic subtypes exist with different prognostic implications. The molecular events involved remain poorly defined but several genes are involved and mutations of tp53, WAF1/CIP1, PTEN, bcl-2 and c-erbB-2 have been implicated. Although care is needed in interpreting the results, the majority of these mutations can be detected immunohistochemically and therefore have the potential to aid the pathologist and surgeon in assessing the prognosis of a tumour. However, for the time being, no molecular marker is as valuable in determining prognosis as conventional parameters such as tumour type, grade and vascular space involvement.