Contribution of Endothelial Dysfunction to Cancer Susceptibility and Progression: A Comprehensive Narrative Review on the Genetic Risk Component

Venous thromboembolism (VTE) is a challenging clinical obstacle in oncological settings, marked by elevated incidence rates and resulting morbidity and mortality. In the context of cancer-associated thrombosis (CAT), endothelial dysfunction (ED) plays a crucial role in promoting a pro-thrombotic environment as endothelial cells lose their ability to regulate blood flow and coagulation. Moreover, emerging research suggests that this disorder may not only contribute to CAT but also impact tumorigenesis itself. Indeed, a dysfunctional endothelium may promote resistance to therapy and favour tumour progression and dissemination. While extensive research has elucidated the multifaceted mechanisms of ED pathogenesis, the genetic component remains a focal point of investigation. This comprehensive narrative review thus delves into the genetic landscape of ED and its potential ramifications on cancer progression. A thorough examination of genetic variants, specifically polymorphisms, within key genes involved in ED pathogenesis, namely eNOS, EDN1, ACE, AGT, F2, SELP, SELE, VWF, ICAM1, and VCAM1, was conducted. Overall, these polymorphisms seem to play a context-dependent role, exerting both oncogenic and tumour suppressor effects depending on the tumour and other environmental factors. In-depth studies are needed to uncover the mechanisms connecting these DNA variations to the pathogenesis of malignant diseases.

Genetic variants in the renin-angiotensin-aldosterone system: Impact on cancer risk, prognosis, and therapeutic directions

Although renin-angiotensin-aldosterone system (RAAS) is known to maintain blood pressure and electrolyte balance, it has recently been linked to a number of biological processes such as angiogenesis, tumorigenesis, metastasis, and cellular proliferation, increasing the risk of cancer development and progression. Multiple genetic variants have been found to affect the genes encoding RAAS components, altering gene transcription and protein expression. This review provides an up-to-date insight into the role of RAAS in carcinogenesis, as well as the impact of RAAS genetic variants on the risk of cancer development, progression, and patient survival and outcomes, as well as response to treatment. This paves the way for the application of precision medicine in cancer risk assessment and management by implementing preventative programs in individuals at risk and guiding the therapeutic direction in cancer patients.

Contact Dermatitis to Diabetes Medical Devices

Skin adverse reactions to diabetes medical devices have been reported frequently over recent years. Adhesives attaching glucose sensors and continuous insulin infusion sets to the skin are proven to cause both allergic contact dermatitis and irritant contact dermatitis in patients with diabetes mellitus. Several allergens contained in adhesives and/or parts of medical devices are documented to cause allergic contact dermatitis, with acrylate chemicals being the most common culprit-especially isobornyl acrylate (IBOA), but also 2,2'-methylenebis(6-tert-butyl-4-methylphenol) monoacrylate or cyanoacrylates. Epoxy resin, colophonium and nickel were also identified as causative allergens. However, repetitive occlusion, maceration of the skin and resulting disruption of the skin barrier seem to have an impact on the development of skin lesions as well. The purpose of this study is to highlight the burden of contact dermatitis triggered by diabetes medical devices and to show possible mechanisms responsible for the development of contact dermatitis in a group of diabetic patients.

Angiotensin-converting Enzyme Insertion/Deletion Polymorphism (rs4646994) and Susceptibility to Acute Lymphoblastic Leukemia: A Case–control Study

BACKGROUND: Angiotensin-converting enzyme (ACE) stimulates the proliferation of bone marrow hematopoietic progenitors and thought to be involved in pathological neoplastic hematopoiesis and leukemogenesis. AIM: This study aimed to investigate the association between ACE gene I/D polymorphism and the risk of acute lymphoblastic leukemia (ALL). MATERIALS AND METHODS: A total of 96 subjects were recruited for the study, 48 patients with ALL, and 48 apparently healthy volunteers as a control group. Genomic DNA was extracted from peripheral leukocytes and ACE I/D polymorphism was analysed using allele-specific polymerase chain reaction. RESULTS: In both study groups, the ACE D/D polymorphic genotype was the most frequent (52.1% and 54.2%, respectively), followed by the ID genotype (47.9% and 45.8% respectively), while the II genotype was completely absent in both study groups. The distribution of the polymorphic genotypes among the study groups was not significantly different (p = 0. 0.398). The frequency of the D allele was 0.76 in the patients and 0.77 in the control group, while the frequency of I allele was 0.24 in the patients and 0.23 in the control group. No deviation from Hardy–Weinberg equilibrium was observed (χ2 = 4.24, df = 1, p = 0.12). CONCLUSION: ACE I/D polymorphism is not associated with susceptibility to ALL among the Sudanese population.

Lung cancer in the older population:Interactive effects of angiotensin converting enzyme gene polymorphism (rs 4340 ID) and tobacco addiction in risk assessment

BACKGROUND

rs4340ID polymorphism of angiotensin-converting enzyme (ACE) correlates with serum ACE levels in many known cancers. This study analyzed ACE rs4340 ID polymorphism in lung cancer (LC) in older patients of North India and correlated it with addiction status.

METHODS

The study enrolled all subjects aged 60 years and above with 154 LC and 205 healthy controls. Genotyping was done by polymerase chain reaction (PCR) and validated by sequencing of 10% of the sample. Statistical analysis was done by SPSS Statistics 21.

RESULTS

Genotype II was observed to have a significant 2.21-fold increased risk of LC as compared to the DD genotype and 3.43-folds enhanced risk with interaction of I allele with tobacco consumption habits as compared to D allele in LC was seen.

CONCLUSION

The risk of LC was higher with II genotype as compared to DD genotype. Interactive effect showed that I allele with tobacco habits may increase the risk of LC.

Associations between I/D polymorphism in the ACE gene and lung cancer: an updated systematic review and a meta-analysis

Background

We evaluated the association between the I/D polymorphism in the ACE gene and lung cancer risk by performing a meta-analysis.

Methods

The heterogeneity in the study was tested using the Cochran χ²-based Q statistic test and I² test, and then the random ratio or fixed effect was utilized to merge the odds ratios (ORs) and 95% confidence intervals (CIs) to estimate the strength of the association between ACE polymorphisms and susceptibility to lung cancer. Sensitivity analysis was also performed. Using funnel plot and Begg’s rank test, we investigated the publication bias. All statistical analyses were performed using Stata 12.0 and RevMan 5.3.

Results

A total of 4307 participants (2181 patients; 2126 controls) were included in the 12 case–control studies. No significant association was found between the ACE I/D polymorphism and lung cancer risk (II vs. ID + DD: OR = 1.22, 95% CI = 0.89–1.68; II + ID vs. DD: OR = 1.21, 95% CI = 0.90–1.63; I vs. D: OR = 1.15, 95% CI = 0.95–1.39). In the subgroup analysis by ethnicity, no significant association between the ACE I/D polymorphism and lung cancer risk was found among Asian and Caucasian populations for the comparisons of II vs. ID + DD, II + ID vs. DD, and I vs. D genetic models.

Conclusion

The ACE I/D polymorphism is not associated with the risk of lung cancer.

Association between the ACE-I/D polymorphism and nicotine dependence amongst patients with lung cancer

The biologically active peptide angiotensin II is cleaved from angiotensinogen by the renin and the angiotensin-converting enzyme (ACE), an enzymatic cascade known as the renin-angiotensin system (RAS). RAS may be important in the etiology of nicotine dependence by influencing dopaminergic signaling. In the present study, the association between an insertion/deletion (I/D) polymorphism of ACE and nicotine dependence amongst patients with lung cancer was assessed. To date, several studies have shown the relevance of this polymorphic variant in both nicotine dependence and lung cancer. However, the present study is the first to address the potential role of the ACE-I/D polymorphism in nicotine dependence among patients with lung cancer. Genotyping was performed in 305 patients with lung cancer (males/females, 214/91). Significantly more male smokers had the ACE-I allele compared with male non-smokers (44.9 vs. 20.0%; P<0.05). The risk of smoking was ~5-fold higher for males with the ACE-I allele (ACE-II homozygous and ACE-ID heterozygous) vs. ACE-DD homozygous (odds ratio, 5.47; 95% confidence interval, 1.4-21.9; P=0.016). The pack-year smoking history in a subgroup of females with squamous cell carcinoma carrying the ACE-I allele was significantly lower compared with ACE-DD (37.1±14.1 vs. 57.0±29.1; F=4.5; P=0.046). The ACE-I/D polymorphism accounted for 17.6% of the smoking severity in this patient group (β, -0.42; multiple R² change, 0.176; P=0.046). These results suggest that the ACE-I/D polymorphism contributes to the risk of nicotine dependence and smoking severity in lung cancer patients in a sex-specific manner.

Association between the ACE gene I/D polymorphism and osteoporosis in a Turkish population

PURPOSE

The purpose of this study was to assess the relationship between osteoporosis and the angiotensin-converting enzyme (ACE) gene insertion/deletion (I/D) polymorphism in a Turkish population.

METHODS

The study group consisted of 238 unrelated women with osteoporosis and 124 unrelated healthy female controls. All participants, patients and healthy controls, were of Turkish origin from the central region of Turkey. Genomic DNA was isolated from whole venous blood samples using a commercial DNA isolation kit. The ACE gene I/D polymorphism was analysed by polymerase chain reaction and gel electrophoresis.

RESULTS

Frequencies of the DD, ID and II genotypes in the patients were 44.5, 41.2 and 14.3 %, and in the controls they were 25.0, 51.6 and 23.4 %, respectively. A significant difference was observed between patients and controls according to genotype frequency (p=0.001). D and I allele frequencies of the I/D polymorphism were 65.1 and 34.9 % in the patient group and 50.8 and 49.2 % in the control group, respectively (p<0.001).

CONCLUSION

The ACE gene I/D polymorphism could be a genetic factor associated with osteoporosis.

Angiotensin-converting enzyme insertion/deletion gene polymorphism and lung cancer risk: A meta-analysis

OBJECTIVE

Angiotensin-converting enzyme (ACE) I/D polymorphism has been reported to be associated with lung cancer, but the results of previous studies are conflicting. The present study was designed to investigate the association between this polymorphism and the risk of lung cancer using a meta-analysis of the published studies.

METHODS

Two investigators independently searched the PubMed, Embase and CNKI databases. This meta-analysis covered six case-control studies, including 807 lung cancer patients and 816 healthy controls.

RESULTS

The results of this meta-analysis based on all the studies showed no significant association between ACE I/D gene polymorphism and lung cancer risk (DD vs II: OR = 1.18, 95% CI = 0.68-2.04; DI vs II: OR = 0.93, 95% CI = 0.56-1.53; DD+DI vs II: OR = 1.01, 95% CI = 0.68-1.50; DD vs II+DD: OR =1.11, 95% CI = 0.73-1.71). In the subgroup analysis by race and the larger studies (n > 200 participants), no significant associations between the ACE I/D polymorphism and risk of lung cancer were indicated. However, when the analyses were restricted to small studies (n ≤ 200 participants), a significantly higher risk was observed (DD vs II: OR = 2.57, 95% CI = 1.24-5.30).

CONCLUSIONS

This meta-analysis suggests that the ACE gene I/D polymorphism may not be associated with the risk of lung cancer, and the observed increase in the risk of lung cancer may be due to small-study bias.

Angiotensin-converting enzyme insertion/deletion gene polymorphisms is associated with risk of glioma in a Chinese population

INTRODUCTION

The insertion/deletion (I/D) polymorphism of the angiotensin-converting enzyme (ACE) gene has recently been linked to the pathogenesis and progression of human cancers. The aim of this study was to evaluate the potential association between ACE I/D polymorphism and glioma in a Chinese population.

MATERIALS AND METHODS

A case-control study involving patients with 800 glioma and 800 controls was conducted. Polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) assay was applied to assess the ACE I/D genotypes.

RESULTS

Glioma cases had a significantly higher frequency of DD genotype [odds ratio (OR) = 1.61, 95% confidence interval (CI) = 1.12, 2.32; p = 0.01] than controls. When stratified by the grade of glioma, cases with WHO IV glioma had a significantly higher frequency of DD genotype (OR = 1.51, 95% CI = 1.03, 2.21; p = 0.03). When stratified by the histology of glioma, there was no significant difference in the distribution of each genotype.

CONCLUSION

Our study suggested that the ACE DD genotype was associated with a higher glioma risk in this Chinese population. To the best of our knowledge, this is the first report describing the potential association between ACE I/D polymorphism and glioma. Additional studies are needed to confirm this finding.

Association of insertion/deletion polymorphism of angiotensin-converting enzyme gene among Malay male hypertensive subjects in response to ACE inhibitors

INTRODUCTION

Several studies show that the insertion/deletion (I/D) polymorphism of the angiotensin-converting enzyme (ACE) gene has been associated with hypertension in various populations. The present study sought to determine the association of the I/D gene polymorphism among Malay male essential hypertensive subjects in response to ACE inhibitors (enalapril and lisinopril).

MATERIALS AND METHODS

A total of 72 patients with newly diagnosed hypertension and 72 healthy subjects were recruited in this study. Blood pressure was recorded from 0 to 24 weeks of treatment with enalapril or lisinopril. Genotyping of the I/D polymorphism was carried out using a standard PCR method.

RESULTS

Statistically significant association of the D allele of the ACE gene was observed between the case and control subjects (p < 0.01). There was a decrease in blood pressure in the patients carrying the DD genotype (SBP=18.5±8.1 mmHg, DBP=15.29±7.1 mmHg) rather than the ID (SBP=4.1±3.3 mmHg, DBP=9.1±3.5 mmHg) and II genotypes (SBP= 3.0±0.2 mmHg, DBP 0.11±6.1 mmHg) of the ACE gene.

CONCLUSION

Patients carrying the DD genotype had higher blood pressure-lowering response when treated with ACE inhibitors enalapril or lisinopril than those carrying ID and II genotypes, suggesting that the D allele may be a possible genetic marker for essential hypertension among Malay male subjects.

An updated meta-analysis on association between angiotensin I-converting enzyme gene insertion/deletion polymorphism and cancer risk

The Alu repetitive sequence insertion/deletion (I/D, rs4646994) polymorphism in the angiotensin I-converting enzyme (ACE) gene may alter cancer susceptibility, but results of current studies are inconclusive. To derive a more precise estimation of the relationship between the ACE I/D polymorphism and cancer risk, we performed an updated meta-analysis of all eligible studies. All studies published up to July 2013 concerning the association between the ACE I/D polymorphism and cancer risk were identified by systematically searching PubMed, EMBASE, Wanfang, CNKI, and Cqvip databases. The odds ratios (ORs) with 95 % confidence intervals (CIs) were pooled using the fixed/random-effects model in Review Manager 5.1 and STATA 12.0. A total of 46 case-control studies including 7,025 cases and 34,911 controls were identified and evaluated. Overall, we did not observe a direct association between the ACE I/D polymorphism and general cancer risk (DD + DI vs. II OR = 0.95, 95 %CI = 0.84-1.07, P = 0.40). In the subgroup analysis by cancer type, a significant increased susceptibility of prostate cancer was found for variant homozygotes (DD vs. II + ID OR = 2.15, 95 %CI = 1.01-4.55, P = 0.05). Additionally, no significant association was observed in other subgroup analyses according to ethnicity, control source, sample size and quality control of genotyping. In summary, our results suggested that the ACE I/D polymorphism might not be a common risk factor for overall cancer susceptibility, but might contribute to the susceptibility of prostate cancer. More studies with larger sample sizes are required in the future.

The relationship between three well-characterized polymorphisms of the angiotensin converting enzyme gene and lung cancer risk: a case-control study and a meta-analysis

BACKGROUND AND OBJECTIVE

The gene encoding angiotensin converting enzyme (ACE) is a promising candidate for lung cancer. We aimed to assess three well-characterized polymorphisms of the ACE gene (A-240T, I/D, A2350G) and lung cancer in Chinese people, and complete a meta-analysis of the association of I/D polymorphism with lung cancer.

METHODS AND RESULTS

In our case-control study, a total of 684 patients with lung cancer and 602 age-matched controls were recruited. Genotyping was performed using polymerase chain reaction (PCR) and ligase detection reactions (LDR) techniques. Single-locus analysis indicated that carriers of the A-240T allele had a significantly increased risk for lung cancer under additive (odds ratio (OR)=1.2; 95% confidence interval (CI): 1.02-1.42; P=0.027) and recessive (OR=1.8; 95% CI: 1.24-2.63; P=0.002) models, and that DD genotype carriers were 1.97 times more likely to develop lung cancer (95% CI: 1.25-3.11; P=0.004) compared with those with the I allele under the recessive model. However, no significance was observed in further haplotype analysis (P>0.05). In a meta-analysis of ACE gene insertion-deletion (I/D) polymorphism from six studies with 1183 lung cancer patients and 1065 controls, we failed to detect any significant association (overall OR=1.09; 95% CI: 0.84-1.41). A low probability of publication bias was observed.

CONCLUSIONS

Our results suggest that ACE gene A-240T polymorphism might be a genetic marker for the development of lung cancer in Chinese people.

Angiotensin-converting enzyme insertion/deletion gene polymorphism in lung cancer patients

Lung cancer is a complex disease, and many factors, including environmental and occupational exposure, cigarette smoking, and genetics, contribute to its progression. Angiotensin-converting enzyme (ACE) is an important regulator of blood pressure and cardiovascular homeostasis. Plasma levels of ACE depend on an insertion/deletion (I/D) polymorphism in its gene. Current correlation data between lung cancer and the ACE I/D polymorphism are contradictory or insufficient. We investigated whether the ACE I/D polymorphism is associated with a risk for lung cancer development in the Croatian population, representing the first report in a population of Slavic origin. A total of 308 lung cancer patients and 353 control subjects were genotyped for the ACE I/D polymorphism by polymerase chain reaction. The observed distribution of genotypes and alleles showed no significant difference between total patients and controls (p>0.050). However, in a subgroup of nonsmall cell lung cancer patients with squamous cell carcinoma, a significantly higher frequency of the DD genotype (37.7% vs. 27.8%, p=0.030, OR=1.57, 95% CI=1.05-2.36) and D allele was observed compared with the control group (61.3% vs. 52.8%, p=0.015, OR=1.41, 95% CI=1.07-1.87). The DD genotype of ACE may contribute to a higher risk of developing squamous cell carcinoma in the Croatian population.

The insertion/deletion (I/D) polymorphism in the Angiotensin-converting enzyme gene and cancer risk: a meta-analysis

Background

The insertion/deletion (I/D) polymorphism in the Angiotensin-converting enzyme (ACE) gene has been implicated in susceptibility to cancer, but a large number of studies have reported inconclusive results. The aim of this study is to assess the association between the I/D polymorphism in the ACE gene and cancer risk by meta-analysis.

Methods

A search was performed in Pubmed database, Embase database, Chinese Biomedical (CBM) database, China National Knowledge Infrastructure (CNKI) database and Weipu database, covering all studies until August 31, 2010. Statistical analysis was performed by using Revman4.2 and STATA 10.0.

Results

A total of 25 case-control studies comprising 3914 cancer patients and 11391 controls were identified. No significant association was found between the I/D polymorphism and over all cancer risks (OR = 0.88, 95%CI = 0.73-1.06, P = 0.17 for DD+DI vs. II). In the subgroup analysis by ethnicity, no significant association was found among Asians and Europeans for the comparison of DD+DI vs. II. In the subgroup analysis by cancer types, no significant associations were found among lung cancer, breast cancer, prostate cancer, colorectal cancer, gastric cancer for the comparison of DD+DI vs. II. Results from other comparative genetic models also indicated the lack of associations between this polymorphism and cancer risks.

Conclusions

This meta-analysis suggested that the ACE D/I polymorphism might not contribute to the risk of cancer.

Allergic contact dermatitis: epidemiology, molecular mechanisms, in vitro methods and regulatory aspects. Current knowledge assembled at an international workshop at BfR, Germany

Contact allergies are complex diseases, and one of the important challenges for public health and immunology. The German ‘Federal Institute for Risk Assessment’ hosted an ‘International Workshop on Contact Dermatitis’. The scope of the workshop was to discuss new discoveries and developments in the field of contact dermatitis. This included the epidemiology and molecular biology of contact allergy, as well as the development of new in vitro methods. Furthermore, it considered regulatory aspects aiming to reduce exposure to contact sensitisers. An estimated 15–20% of the general population suffers from contact allergy. Workplace exposure, age, sex, use of consumer products and genetic predispositions were identified as the most important risk factors. Research highlights included: advances in understanding of immune responses to contact sensitisers, the importance of autoxidation or enzyme-mediated oxidation for the activation of chemicals, the mechanisms through which hapten-protein conjugates are formed and the development of novel in vitro strategies for the identification of skin-sensitising chemicals. Dendritic cell cultures and structure-activity relationships are being developed to identify potential contact allergens. However, the local lymph node assay (LLNA) presently remains the validated method of choice for hazard identification and characterisation. At the workshop the use of the LLNA for regulatory purposes and for quantitative risk assessment was also discussed.

[Genetics of contact allergy]

The genetics of contact allergy (CA) is still only partly understood, despite decades of research. This might be due to inadequately defined phenotypes used in the past. Therefore we suggested studying an extreme phenotype, namely, polysensitization (sensitization to 3 or more unrelated allergens). Another approach to unravel the genetics of CA has been the study of candidate genes. In this review, we summarize studies on the associations between genetic variation (e.g. SNPs) in certain candidate genes and CA. The following polymorphisms and mutations were studied: (1) filaggrin, (2) N-acetyltransferase (NAT1 and 2), (3) glutathione-S-transferase (GST M and T), (4) manganese superoxide dismutase, (5) angiotensin-converting enzyme (ACE), (6) tumor necrosis factor (TNF), and (7) interleukin-16 (IL16). The polymorphisms of NAT1/2, GST M/T, ACE, TNF, and IL16 were shown to be associated with an increased risk of CA. In one of our studies, the increased risk conferred by the TNF and IL16 polymorphisms was confined to polysensitized individuals. Other relevant candidate genes may be identified by studying diseases related to CA in terms of clinical symptoms, a more general pathology (inflammation) and possibly an overlapping genetic background, such as irritant contact dermatitis.

Association between polymorphisms of the renin-angiotensin system genes and breast cancer risk: a meta-analysis

The renin-angiotensin system (RAS) has been considered to be implicated in the development of breast cancer. However, the results are inconsistent. In this study, we conducted a meta-analysis to assess the association between four polymorphisms, including angiotensin I-converting enzyme (ACE) I/D and A240T, angiotensin II type 1 receptor (AGTR1) A1166C and angiotensinogen (AGT) M235T polymorphisms, and breast cancer risk. Published literature from PubMed, ISI web of science, and Embase databases were retrieved. All studies evaluating the association between ACE I/D, ACE A240T, AGTR1 A1166C, or AGT M235T polymorphism and breast cancer risk were included. Pooled odds ratio (OR) with 95% confidence interval (CI) was calculated using fixed- or random-effects model. Ten studies (1,650 cases and 9,283 controls) on ACE I/D polymorphism, six studies (1,316 cases and 2,632 controls) on ACE A240T polymorphism, three studies (235 cases and 601 controls) on AGTR1 A1166C polymorphism, and two studies (273 cases and 3,547 controls) on AGT M235T polymorphism were included. Overall, the meta-analysis showed no significant association between I/D or A240T polymorphism and breast cancer risk in either genetic model. Further subgroup analysis by ethnicity also revealed non-significant association in Caucasian or Asian populations except for Africans (the statistically significant association for ACE I/D or A240T polymorphism in Africans derived from only one study). A marginally significant association was observed for AGTR1 A1166C polymorphism in Caucasians (CC vs. AA: OR = 0.31, 95% CI 0.10-0.99). In addition, there was a significant association between AGT M235T polymorphism and breast cancer risk in Caucasians (OR = 1.45, 95% CI 1.12-1.88). The present meta-analysis suggested that ACE I/D and A240T polymorphisms might not be a good predictor of breast cancer risk, while AGTR1 A1166C and AGT M235T polymorphisms might be implicated in the pathogenesis of breast cancer. Given the limited sample size, the findings warrant further investigation.

Genetic factors in contact allergy--review and future goals

The genetics of contact allergy are still only partly understood, despite decades of research; this might be a consequence of inadequately defined phenotypes used in the past. A recommendation is to study an extreme phenotype, namely, polysensitization (sensitization to three or more unrelated allergens). Another approach to unravel the genetics of contact allergy is the study of candidate genes. In this review, we summarize studies on the associations between genetic variation (e.g. single-nucleotide polymorphisms) in certain candidate genes and contact allergy. Polymorphisms and mutations affecting the following proteins were studied: (i) filaggrin; (ii) N-acetyltransferase (NAT) 1 and 2; (iii) glutathione-S-transferase (GST) M and T; (iv) manganese superoxide dismutase; (v) angiotensin-converting enzyme (ACE); (vi) tumour necrosis factor (TNF); and (vii) interleukin-16 (IL-16). The polymorphisms of NAT1, NAT2, GSTM, GSTT, ACE, TNF and IL-16 were shown to be associated with an increased risk of contact allergy. In one of our studies, the increased risk conferred by the TNF and IL-16 polymorphisms was confined to polysensitized individuals. Other relevant candidate genes may be identified by studying diseases related to contact allergy in terms of clinical symptoms, a more general pathology (inflammation), and possibly an overlapping genetic background, such as irritant contact dermatitis.