Polymorphisms of the glutathione S-transferase P1 gene and head and neck cancer susceptibility

Interaction of glutathione-s-transferase genotypes with environmental risk factors in determining susceptibility to head and neck cancer and treatment response and survival outcome

The present case-control study aimed to investigate the role of interaction of glutathione-s-transferase (GST) genotypes with environmental risk factors in determining susceptibility to head and neck squamous cell carcinoma (HNSCC) involving 1,250 cases and equal number of healthy controls. An increase in the risk of HNSCC and its subsites (larynx, pharynx, and oral cavity) was observed among the cases with null genotypes of GSTM1 (odds ratio [OR] = 1.87) or GSTT1 (OR = 1.39) while reduced risk (OR = 0.81) was observed the cases with variant genotype of GSTP1. Tobacco use in the form of smoking or chewing interacted multiplicatively with GSTM1 or GSTT1 to increase the risk several folds (3-10 folds) in HNSCC and its subsites. Alcohol use also increased the risk (2-3 folds) to HNSCC and its subsites in cases with null or variant genotypes of GSTs, though this risk was of lesser magnitude when compared to the tobacco users. A synergistic effect of both, tobacco smoking and alcohol drinking, led to several folds (25-folds) increased risk to HNSCC among the cases with null genotype of GSTM1 and GSTT1 when compared to nonsmokers and nondrinkers with wild genotype of GSTM1 and GSTT1 in controls. Furthermore, cases with variant genotypes of GSTP1 (Val/Val) showed superior treatment response with improved survival rate and lower risk of death when compared to the patients with wild type genotype (Ile/Ile). The data suggest that though polymorphism in GSTs may be a modest risk factor for determining HNSCC risk, gene-environment interactions significantly modify the susceptibility to HNSCC by several folds.

Multiple logistic regression analysis predicts cancer risk among tobacco usage with glutathione S-transferase p1 genotyping in patients with head and neck cancer

INTRODUCTION

Numerous studies have been investigated to understand the association between glutathione S-transferase P1 (GSTP1) polymorphism and risk of head and neck cancer (HNC) but yielded contradictory results, and no studies could confirm polymorphism in GSTP1 and that tobacco usage increases the risk of HNCs. Therefore, this study aimed to understand the association of GSTP1 Ile105Val polymorphism with or without tobacco usage in carcinogenesis and clinicopathological characteristics of patients with HNC.

MATERIALS AND METHODS

Binary logistic regression analysis was performed to predict HNC risk with tobacco use and GSTP1 genotyping. Five predictor variables such as gender, age, tobacco usage, familial, and GSTP1 genotypes were included in the model.

RESULTS

The results of the logistic regression analysis show that the full model which considered all the five independent variables together was statistically significant, log-likelihood = -111.820, and all slopes are zero: G = 74.297, degree of freedom (DF) = 5, P = 0.000. The strongest predictor in this model is tobacco usage (odds ratio = Z = -5.16, P = 0.000).

CONCLUSION

The study concludes that multiple logistic regression analysis model could predict the risk factors in case-control studies where control samples are compromised.

Glutathione S-transferase pi 1 variant and squamous cell carcinoma susceptibility: a meta-analysis of 52 case-control studies

Background

There are several meta-analyses on the genetic relationship between the rs1695 polymorphism within the GSTP1 (glutathione S-transferase pi 1) gene and the risk of different SCC (squamous cell carcinoma) diseases, such as ESCC (oesophageal SCC), HNSCC (head and neck SCC), LSCC (lung SCC), and SSCC (skin SCC). Nevertheless, no unified conclusions have been drawn.

Methods

Herein, an updated meta-analysis was performed to evaluate the probable impact of GSTP1 rs1695 on the susceptibility to different SCC diseases under six genetic models (allele, carrier, homozygote, heterozygote, dominant, and recessive). Three online databases, namely, PubMed, WOS (Web of Science), and Embase (Excerpta Medica Database), were searched.

Results

Initially, we obtained a total of 497 articles. Based on our selection criteria, we eventually included 52 case-control studies (9763 cases/15,028 controls) from 47 eligible articles. As shown in the pooling analysis, there was no difference in the risk of overall SCC disease between cases and controls [allele, P_a (P value of association test) = 0.601; carrier, P_a = 0.587; homozygote, P_a = 0.689; heterozygote, P_a = 0.167; dominant, P_a = 0.289; dominant, P_a = 0.548]. Similar results were obtained after stratification by race (Asian/Caucasian), genotyping, control source, and disease type (ESCC/HNSCC/LSCC/SSCC) (all P_a > 0.05).

Conclusion

The rs1695 polymorphism within the GSTP1 gene is not associated with the risk of overall SCC or a specific SCC type, including ESCC, HNSCC, LSCC, and SSCC.

Head and neck cancers: a clinico-pathological profile and management challenges in a resource-limited setting

BACKGROUND

Head and neck cancer (HNC) is one of the most common cancers worldwide and its incidence is reported to be increasing in resource-limited countries. There is a paucity of published data regarding head and neck cancers in Tanzania, and Bugando Medical Centre in particular. This study describes the clinicopathological profile of HNC in our local setting and highlights the challenges in the management of this disease.

METHODS

This was a retrospective study of histopathologically confirmed cases of head and neck cancers treated at Bugando Medical Center between January 2009 and December 2013.

RESULTS

A total of 346 patients (M:F = 2.1:1) were studied representing 9.5 % of all malignancies. The median age of patients was 42 years. Cigarette smoking (76.6 %) and heavy alcohol consumption (69.9 %) were the most frequently identified risk factors for head and neck cancer. The majority of patients (95.9 %) presented late with advanced stages. Twenty-five (7.2 %) patients were HIV positive with a median CD4+ count of 244 cells/μl. The oral cavity (37.3 %) was the most frequent anatomical site affected. The most common histopathological type was carcinomas (59.6 %) of which 75.7 % were squamous cell carcinoma. A total of 196 (56.6 %) patients underwent surgical procedures for HNC. Radiotherapy and chemotherapy was reported in 9.5 and 16.8 % of patients, respectively. Only 2 (0.6 %) patients received chemo-radiation therapy. The mortality rate was 24.4 %. The overall 5-year survival rate (5-YSR) was 20.6 %. The predictors of overall 5-YSR were age of patient at diagnosis, stage of disease, extent of lymph node involvement, HIV seropositivity and CD4+ count <200 cells/μl (P < 0.001). Local recurrence was reported in 22 (23.4 %) patients and this was significantly associated with positive resection margins, stage of the tumor and presence of metastasis at diagnosis and non-adherence to adjuvant therapy (P < 0.001).

CONCLUSION

Head and neck cancers are not uncommon at Bugando Medical Centre and show a trend towards a relative young age at diagnosis and the majority of patients present late with advanced stage cancer. Therefore, public enlightenment, early diagnosis, and effective cost-effective treatment and follow-up are urgently needed to improve outcomes of these patients in our environment.

Family history of cancer, personal history of medical conditions and risk of oral cavity cancer in France: the ICARE study

BACKGROUND

The aim of this study was to evaluate the role of family history of cancer and personal history of other medical conditions in the aetiology of the oral cavity cancer in France.

METHODS

We used data from 689 cases of oral cavity squamous cell carcinoma and 3481 controls included in a population-based case-control study, the ICARE study. Odds-ratios (ORs) associated with family history of cancer and personal medical conditions and their 95% confidence intervals (95% CI) were estimated by unconditional logistic regression and were adjusted for age, gender, area of residence, education, body mass index, tobacco smoking and alcohol drinking.

RESULTS

Personal history of oral candidiasis was related to a significantly increased risk of oral cavity cancer (OR 5.0, 95% CI 2.1-12.1). History of head and neck cancers among the first-degree relatives was associated with an OR of 1.9 (95% CI 1.2-2.8). The risk increased with the number of first-degree relatives with head and neck cancer.

CONCLUSION

A family history of head and neck cancer is a marker of an increased risk of oral cavity cancer and should be taken into account to target prevention efforts and screening. Further studies are needed to clarify the association between oral cavity cancer and personal history of candidiasis.

Association of GSTP1 Ile105Val polymorphism and risk of head and neck cancers: a meta-analysis of 28 case-control studies

BACKGROUND AND AIMS

The Glutathione S-transferase P1 (GSTP1) polymorphism have been considered a risk modifier for developing head and neck cancer (HNC) in many studies; however, the results of such studies are inconsistent. The aim of this study was to evaluate the possible association between the GSTP1 Ile105Val polymorphism and risk of HNC.

METHOD

We performed a search in the relevant electronic database and a meta-analysis based on 28 published case-control studies that included 6,404 cases and 6,523 controls. To take into account the possibility of heterogeneity across the studies, a Chi-square based I(2)-statistic test was performed. Crude pooled odds ratios (ORs) with 95% confidence intervals (CIs) were assessed using both fixed-effects and random-effects models.

RESULTS

The results of this meta-analysis showed that the GSTP1 Ile105Val polymorphism was not significantly associated with risk of HNC in the overall study population (pooled OR 1.00, 95% CI 0.92-1.09) or in subgroup analyses stratified by ethnicity, sample size, tumor site or publication year. Moreover, substantial evidence of heterogeneity among the studies was observed. Publication year was identified as the main cause of heterogeneity.

CONCLUSION

This meta-analysis does not support a significant association between the GSTP1 Ile105Val polymorphism and risk of HNC.

Association of genetic polymorphisms in glutathione S-transferases and susceptibility to head and neck cancer

Polymorphism in glutathione S-transferase (GST) genes (GSTM1, GSTT1 and GSTP1) and interaction with environmental factors such as tobacco (smoking or chewing) and alcohol on susceptibility to head and neck squamous cell carcinoma (HNSCC) was studied in a case-control study. The study group consisted of 175 patients suffering from HNSCC and 200 age matched healthy controls. Statistical analysis showed an increase in risk to HNSCC in the patients with null genotype of GSTM1 (OR: 2.02; 95% CI: 1.32-3.10; P=0.001) or GSTT1 (OR: 1.66; 95% CI: 1.02-2.69; P=0.04), though the risk was not found to be significant when adjusted for age, sex, smoking, tobacco chewing or alcohol use by multivariate logistic regression model. Our data further showed that combination of deletion genotypes of GST (GSTM1 and GSTT1) confer an even higher risk of HNSCC. Interestingly, GSTP1 wild type genotype in combination with GSTM1 null or GSTT1 null genotype increased susceptibility for HNSCC (OR: 2.49 and 2.75, respectively). Likewise a much greater risk for HNSCC was observed in the patients carrying a genotype combination of GSTM1 null, GSTT1 null and GSTP1 (Ile/Ile) (OR: 4.47; 95% CI: 1.62-12.31; P=0.002). Our data have further provided evidence that tobacco chewing and alcohol consumption are the important risk factors for HNSCC. The interaction between tobacco chewing and null genotype of GSTM1 or GSTT1 resulted in about 3.5- and 2.2-fold increase in the risk respectively in the patients when compared to those not chewing tobacco. Alcohol use resulted in more than 4-fold increase in the risk in the patients with null genotype of GSTM1 as compared to those who are non-drinkers. Alcohol consumption also increased the risk (approx. 3-fold) in the cases with null genotype of GSTT1, though the association was not found to be significant when compared to non-drinkers. Our data have provided evidence that GST polymorphism modifies the susceptibility to HNSCC and have further demonstrated importance of gene-environment interaction in modulating the risk to HNSCC.

Epidemiology of carcinogen metabolism genes and risk of squamous cell carcinoma of the head and neck

The risk association between tobacco and alcohol use with squamous cell carcinoma of the head and neck (SCCHN) is well recognized. However, clearly not all individuals who smoke or drink develop SCCHN. Individual genetic susceptibility differences in carcinogen-metabolizing enzyme function, mutagen sensitivity, apoptosis, and chromosomal aberrations either alone or in combination have been theorized to modify the risk of SCCHN. Nearly all carcinogens and procarcinogens require activation by metabolizing enzymes. Similarly, detoxifying enzymes exist and deactivate carcinogens as well as their intermediate by-products. Together these enzymes are termed xenobiotic-metabolizing enzymes; genetic polymorphisms of these enzymes can modify an individual's response to carcinogens and hence the carcinogenic potential of such exposures. In this review, we explore the available evidence in recent literature regarding the risk association between SCCHN and various xenobiotic-metabolizing enzymes, including cytochrome P450s, glutathione S-transferases, N-acetyltransferases, NAD(P)H:quinone oxidoreductase 1, alcohol dehydrogenase, and aldehyde dehydrogenase.

Association of the GSTP1 and NQO1 polymorphisms and head and neck squamous cell carcinoma risk

The GSTP1 and NQO1 have been reported to be associated with an increased risk for smoking related head and neck squamous cell carcinoma (HNSCC). The purpose of this study was to determine the effect of these metabolic gene polymorphisms on the risk of HNSCC. The study population included 294 histologically confirmed HNSCC cases and 333 controls without cancer. Genotyping analysis of the GSTP1 Ile105Val and NQO1 Trp139Arg genes was performed by polymerase chain reaction-based techniques on DNA prepared from peripheral blood. The Mantel-Haenszel chi2 test was used for statistical analysis. The allele frequencies of the GSTP1 and NQO1 polymorphisms were not statistically significant between cases and controls. In analyzing the association between smoking amounts and genetic polymorphisms, GSTP1 and NQO1 polymorphisms were associated with cigarette smoking amounts in cases. G allele containing genotypes in GSTP1 and T allele containing genotypes in NQO1 were associated with a tobacco dose-dependent increase in risk of HNSCC and these genotype distributions were statistically significant (p<0.05). We found that the GSTP1 105Val allele and NQO1 139Arg allele were associated with tobacco dose-dependent increase in risk of HNSCC. GSTP1 and NQO1 genotype polymorphisms may play an important role in the development of smoking related HNSCC.

Clinicopathological study of head and neck cancers in Ilorin, Nigeria

Eighty-nine cases of head and neck cancers were studied over a 5-year period (1997--2001) at the University of Ilorin Teaching Hospital, Nigeria. The most common cancer affecting the head and neck region was carcinoma which constituted 70.8% of all the cases studied. It was followed by the lymphomas and blastomas which accounted for 20.2% and 9%, respectively. The nose/paranasal sinuses were the most common site of primary cancer (18%) followed by thyroid (12.4%), nasopharynx (11.3%) and larynx (4.5%). Other sites include a hypopharynx (3.4%), eye (2.2%), palate (2.2%), tongue (2.2%), skin (1.1%), lip (1.1%), salivary gland (1.1%), oropharynx (1.1%). Cervical lymph node metastasis with unknown primary lesion was seen in 10.1%. The peak age incidence was in the fifth decade of life. The improvement in locoregional control of head and neck cancers over the last decades does not appear to modify the final survival of these patients. It is crucial to understand as accurately as possible the risk factors for these malignancies in order to improve primary prevention.

GST profiling may be useful in the screening for thyroid nodule malignancy

Screening tools are of utmost necessity in order to identify individuals at risk for thyroid nodule cancer. The polymorphic inheritance of human drug-metabolizing enzymes, such as those encoded by the Glutathione-S-Transferase (GST) system, plays an important role in the development of most human cancers. GSTP1 enzyme is the most important detoxification enzyme in human head and neck tissues. An aminoacid substitution (1105V) in the GSTP1 gene result in two genotypes, GSTP1AB and GSTP1BB. Those produce a variant enzyme with lower activity and less capability of effective detoxification of carcinogens than the wild type GSTP1AA. In order to look for the influence of GSTP1 enzymes inheritance pattern on thyroid cancer risk we used a PCR-SSCP-sequencing approach to compare the genotypes of 98 malignant nodules, including 77 papillary carcinomas (PC) and 21 follicular carcinomas (FC), to 44 benign nodules and to 157 healthy control individuals. Individuals with history of previous thyroid disease, exposure to radiation and antecedents of malignancy were excluded. Patients with PC and FC showed a significant over-representation of the variants of GSTP1 allele compared to the control population (p < 0.0001 The risk for thyroid cancer in individuals with the variant GSTP1 enzymes, after adjusting for gender, age, tobacco and drugs use, increased 7,092 (CI: 2,307-21,802) and 9,625 (CI: 2.484-37.291) times for PC and FC, respectively. We suggest that GST genotype may be associated with an increased susceptibility to thyroid cancer. GSTP1 profiling from peripheral blood may be a simple and useful tool in the screening for thyroid nodule malignancy. Glutathione-S-Transferase system; GSTP; Thyroid cancer; Screening.

Smoking and drinking can induce p15 methylation in the upper aerodigestive tract of healthy individuals and patients with head and neck squamous cell carcinoma

BACKGROUND

The consumption of tobacco and alcohol has been implicated in the development of head and neck squamous cell carcinoma (HNSCC). Promoter methylation of tumor suppressor genes is common in HNSCC. In this study, the authors evaluated the effects of tobacco and alcohol on p15 gene methylation of cells in cells from the mouth and throat of physically healthy individuals and patients with HNSCC.

METHODS

The study participants were divided into 3 groups, including a group of 37 healthy nonsmokers and nondrinkers, a group of 22 healthy smokers and/or drinkers and a group of 31 patients with HNSCC.

RESULTS

Methylation of p15 was detected in cells obtained from mouth and throat (M&T) rinsing fluid samples from 3 of 37 healthy individuals (8%) who did not drink or smoke, from 15 of 22 healthy smokers and/or drinkers (68%), and from 15 of 31 patients (48%) with HNSCC. Among 31 patients with HNSCC, 20 patients (65%) had methylated p15 gene in their tumor biopsies. With the use of beta-actin as a reference, the ratio of methylated p15 to beta-actin was calculated as an index of the percentage of cells with p15 methylation. The percentage of exfoliated cells from M&T rinsing fluid samples that had p15 methylation ranged from 0% to 11% for patients with HNSCC and from 0% to 21% for healthy smokers/drinkers, respectively. The methylation index of tumor cells with p15 methylation ranged from 0% to 65%.

CONCLUSIONS

The results suggest that p15 gene methylation can be induced by chronic smoking and drinking and may play a role in the very early stages of carcinogenesis in HNSCC.