Association of GST genotypes with age of onset and lymph node metastasis in oral squamous cell carcinoma

Glutathione S-transferase theta 1 (GSTT1) deletion polymorphism and susceptibility to head and neck carcinoma: a systematic review with five analyses

Glutathione S-transferase theta 1 (GSTT1) enzyme plays a key role in the neutralization of electrophilic compounds such as carcinogens. Herein, we aimed to evaluate GSTT1 deletion polymorphism and susceptibility to head and neck carcinoma (HNC) according to 107 articles in a systematic review with five analyses. The databases of PubMed/Medline, Web of Science, Scopus, and Cochrane Library from the beginning of each database until June 21, 2023, with no restrictions to identify pertinent articles. The RevMan 5.3 software was used to calculate the effect sizes, which were displayed as the odds ratio (OR) along with a 95% confidence interval (CI). Both the publication bias and sensitivity analyses were performed using the CMA 3.0 software. A trial sequential analysis (TSA) was conducted. Of the 1966 records retrieved from four databases, 107 articles were included in the analysis. The combined analysis revealed that the pooled OR was 1.28 (95% CI: 1.14 to 1.44; p-value < 0.0001). The pooled OR was highest in mixed ethnicity. Nasopharyngeal cancer had the highest OR (1.84), followed by oral cancer (OR = 1.20), and laryngeal cancer (OR = 1.17). Studies with less than 200 samples had a higher OR compared to those with 200 or more samples. The studies with a quality score of 7 or more had a higher OR compared to those with a score of less than 7. When both age and sex are considered, while the OR of 1.42 is significant, the high heterogeneity suggests caution in interpreting these results. There is no evidence of publication bias. TSA reported that the study does not have sufficient statistical power. This comprehensive meta-analysis revealed a significant association between the GSTT1 null genotype and an increased risk of HNC, with variations based on factors such as ethnicity, cancer type, sample size, control source, and quality score.

Age-specific oncogenic pathways in head and neck squamous cell carcinoma - are elderly a different subcategory?

BACKGROUND

In recent clinical practice, an increasing number of elderly patients suffering from head and neck squamous cell carcinoma (HNSCC) of unknown pathophysiology is observed. The majority of HNSCC patients can roughly be divided into three subcategories. First, a small group of young patients who present with variants of genomic aberrations and inheritable diseases like Fanconi anaemia. Second, an increasing population of HPV-related HNSCCs that are regarded as genomic stable tumours with a more favourable prognosis. Though HPV-related tumours used to be more common among younger males, a notable rise in the elderly population is observed. The third subcategory, that of HPV-negative tumours, has been shown to be more heterogeneous with involvement of a variety of oncogenic pathways related to lifestyle factors like smoking and alcohol consumption, often seen in middle-aged males. Some of these pathways could be related to age, such as TP53 alterations, EGFR activation, apoptotic pathway alterations and field cancerization.

CONCLUSIONS

In this narrative review, we provide an overview of established and newly discovered age-specific pathophysiological mechanisms underlying HNSCC. We propose a fourth subcategory of patients with a suspected different pathophysiology: elderly (HPV-negative) HNSCC patients without a history of tobacco and alcohol consumption. In this subcategory, carcinogenesis seems to be a multi-step process based on genomic instability, immunosenescence, cell cycle disruption and telomere shortening. To conclude, we discuss suggestions for future research to fill the knowledge gap about age-dependent HNSCC carcinogenesis.

GSTM1 and GSTT1 copy number variants and the risk to Thai females of hepatocellular carcinoma

Background

Hepatocellular carcinoma (HCC) is a common malignancy found throughout the world that most often occurs in males. The cancer is associated with many risk factors such as viral infection, cirrhosis, alcohol, smoking, and fungal toxins. GSTM1 and GSTT1 are detoxification enzymes activated by the cleansing of carcinogenic compounds. Low DNA copy numbers of Glutathione S-transferases M1 and T1 result in a loss of enzyme activity, which causes carcinogenesis factors. DNA copy number variants (CNVs) were determined to compare the differences between the frequencies of GSTM1 and GSTT1 in a control group and patients. Then, the association of these genes with the pathological/survival status of HCC patients was investigated.

Methods

Forty-nine Thai HCC patients' DNA and the genomic DNA of 66 healthy controls were investigated for GSTM1 and GSTT1 CNVs by real-time polymerase chain reaction (PCR). Then, the correlations between GSTM1 and GSTT1 patients' CNVs, the control group, and clinico-pathological parameters were determined.

Results

The results show that were no differences between the CNVs of GSTM1 and GSTT1 in the controls and patients (P≥0.05). Only GSTT1 genotypes 0/0 correlated to an increase in the risk of hepatocellular carcinogenesis (OR value was 1.88). GSTM1 CNVs were associated with the gender of patients (P=0.002). However, no correlations were found between GSTT1 CNVs and any of the clinico-pathological parameters.

Conclusions

The results suggest that only GSTT1 CNVs are associated with increased risk factors of HCC in Thais. GSTM1 copy numbers had a dominant correlation with female HCC patients.

Association of CYP1A1 and GSTM1 Polymorphisms With Oral Cancer Susceptibility: A Meta-Analysis

Our meta-analysis was aimed to evaluate the association of CYP1A1 and glutathione-S-transferase M1 (GSTM1) polymorphisms with oral cancer susceptibility.The related articles were searched in PubMed, Embase, and CNKI databases. Fifty eligible studies were included in our meta-analysis. Odds ratios (ORs) with 95% confidence intervals (CIs) were used to evaluate the relationship of CYP1A1 (rs4646903 and rs1048943) and GSTM1 polymorphisms with oral cancer risk. A random-effects model or fixed-effects model was employed depending on the heterogeneity.In overall analysis, CYP1A1 rs4646903 polymorphism was associated with the risk of oral cancer (CC vs TT: OR 1.65, 95% CI 1.33-2.05; CC vs TC+TT: OR 1.77, 95% CI 1.48-2.11; C vs T: OR 1.17, 95% CI 1.07-1.28), whereas rs1048943 showed no obvious association with oral cancer susceptibility. Moreover, subgroup analysis by ethnicity demonstrated that rs4646903 and rs1048943 both related with increased risk of oral cancer in Asians. Moreover, the analysis based on source of control suggested that rs4646903 could increase the risk for oral cancer in both population- and hospital-based populations, whereas no remarkable relationship of rs1048943 with oral cancer susceptibility was observed. For GSTM1 gene, null genotype appeared to be a risk factor for oral cancer (null vs present: OR 1.23, 95% CI 1.12-1.34), which was also proved in the subgroup analysis.The results demonstrated that CYP1A1 rs4646903 and null genotype of GSTM1 polymorphisms might serve as risk factors for oral cancer.

Non-monotonic relationships between arsenic and selenium excretion and its implication on arsenic methylation pattern in a Bangladeshi population

The toxicity of arsenic differs markedly between individuals and populations, which might be related to the metabolism (methylation) of inorganic arsenic (As), as well as the selenium (Se) nutritional status. Urinary excretion of As (u-As) and Se (u-Se) was examined in an adult population (n=128) living in an As-contaminated area in Bangladesh. Although there was a significant negative correlation between u-Se and u-As (median 137; range 49-927 μg/g creatinine), closer examination revealed a non-monotonous relationship between them. A quadratic curve with an axis of As at 155 μg/g Cre gave a better fit, and u-As and u-Se were positively or negatively correlated depending on whether the As concentration was lower or higher than 155 μg As/g Cre, respectively. Likewise, the relationships between the As methylation pattern and glutathione-S-transferase (GST) polymorphism, body mass index (BMI), and u-Se differed depending on the u-As range; i.e., higher or lower than 155 μg/g Cre. Although we did not determine the causal mechanism for these observations, the non-monotonic relationship between As exposure and the variables examined suggested the existence of a threshold at which the handling of As by human body is qualitatively changed. The possible importance of Se nutrition for As toxicity is also discussed.

GSTM1 null polymorphisms and oral cancer risk: a meta-analysis

Many studies have examined the association between the GSTM1 null gene polymorphism and oral cancer risk in various populations, but their results have been inconsistent. To assess this relationship more precisely, a meta-analysis was performed. The PubMed and Embase databases were searched for case-control studies published up to May 2013. Data were extracted and pooled odds ratio (OR) with 95% confidence intervals (CI) were calculated. Ultimately, 39 studies, comprising of 4,704 oral cancer cases and 7,090 controls, were included. Overall, for null versus present, the pooled OR was 1.29 (95% CI = 1.20-1.40), and the heterogeneity was found in all studies. In the stratified analysis by ethnicity, significant risks were found among Asians (OR = 1.39, 95% CI = 1.27-1.53; P = 0.000 for heterogeneity), but not in Caucasians (OR = 0.99, 95% CI = 0.83-1.18; P = 0.677 for heterogeneity). In conclusion, this meta-analysis demonstrates that the GSTM1 null gene polymorphism may be an increased risk of oral cancer in Asians but not in Caucasians.

Glutathione S-transferase T1 null genotype is associated with oral cancer susceptibility in Asian populations

Though there are many studies assessing the association between glutathione S-transferase T1 (GSTT1) null genotype and oral cancer risk, the association between GSTT1 null genotype and oral cancer in Asian populations is still inconclusive. We performed a meta-analysis of 19 studies including 2,845 cases and 4,295 controls to derive a more precise estimation of the relationship. The pooled odds ratio (OR) with its corresponding 95 % confidence interval (95 % CI) was used to assess the relationship. Meta-analysis of those 19 studies suggested that there was an association between GSTT1 null genotype and elevated risk of oral cancer risk (OR = 1.25, 95 % CI = 1.00-1.56, P = 0.047). Sensitivity analysis by omitting one study at a time showed that the significance of the corresponding pooled ORs was materially altered frequently, indicating that the pooled ORs were not statistically stable. In addition, there was no obvious risk of publication bias in the meta-analysis. Therefore, the present meta-analysis suggests that the GSTT1 null genotype is a risk allele for oral cancer development in Asian populations, but more studies with large sample and well-matched controls are needed to further confirm the finding from the meta-analysis.

Polymorphisms of the CYP1A1 and CYP2E1 genes in head and neck squamous cell carcinoma risk

Polymorphisms in genes that encode P450 cytochrome enzymes may increase carcinogen activation or decrease their inactivation and consequently, promote the development of cancer. The aims of this study were to identify the MspI-CYP1A1, PstI-CYP2E1 and DraI-CYP2E1 polymorphisms in patients with head and neck cancer and to compare with individuals without cancer; to evaluate the association of these polymorphisms with risk factors and clinical histopathological parameters. In the study group, 313 patients were evaluated for CYP1A1, 217 for CYP2E1 (PstI) and 211 for CYP2E1 (DraI) and in the control group 417, 334 and 374 individuals, respectively. Molecular analysis was performed by PCR-RFLP technique, and chi-square and multiple logistic regression tests were used for statistical analysis. The result of analysis regarding individuals evaluated for CYP1A1 (MspI) showed that age (OR: 8.15; 95% CI 5.57-11.92) and smoking (OR: 5.37; 95% CI 3.52-8.21) were predictors for the disease; for the CYP2E1 (PstI and DraI), there were associations with age (PstI-OR: 9.10; 95% CI 5.86-14.14/DraI-OR: 8.07; 95% CI 5.12-12.72), smoking (PstI-OR: 4.10; 95% CI 2.44-6.89/DraI-OR: 5.73; 95% CI 3.34-9.82), alcohol (PstI-OR: 1.93; 95% CI 1.18-3.16/DraI-OR: 1.69; 95% CI 1.02-2.81), respectively, with disease development. CYP2E1 (PstI) was less frequent in patient group (OR: 0.48; 95% CI 0.23-0.98). Regarding clinical histopathological parameters, CYP1A1 polymorphism was less frequent in the larynx primary anatomic site (OR = 0.45; 95% CI = 0.28-0.73; P = 0.014). In conclusion, we confirm that age, smoking and alcohol consumption are risk factors for this disease and the polymorphisms investigated have no association with the development of head and neck cancer.

Glutathione S-transferase M1 (GSTM1) and glutathione S-transferase T1 (GSTT1) null polymorphisms, smoking, and their interaction in oral cancer: a HuGE review and meta-analysis

The association between glutathione S-transferase M1 (GSTM1) and glutathione S-transferase T1 (GSTT1) null polymorphisms and oral cancer is not consistent across studies, and data on their interaction with smoking in oral cancer are lacking. The authors systematically searched PubMed and SciVerse Scopus for case-control studies examining the association between null genotypes of the GSTM1 and GSTT1 genes and oral cancer. Twenty-eight case-control studies published in English were identified. Summary odds ratios were derived via random-effects models. The summary odds ratio for the GSTM1 null genotype was 1.43 in Asians (95% confidence interval (CI): 1.14, 1.78; P < 0.01, I (2) = 73%) and 0.98 in Caucasians (95% CI: 0.76, 1.28; P = 0.91, I (2) = 0%). Case-only analysis of 6 studies (552 cases) showed an inverse multiplicative interaction between GSTM1 null polymorphisms and smoking (ever/high levels of smoking vs. never/low levels) (odds ratio (OR) = 0.51, 95% CI: 0.32, 0.82; P = 0.01, I (2) = 34%). The GSTT1 null genotype was not significantly associated with oral cancer in Asians (OR = 1.07, 95% CI: 0.82, 1.38; P = 0.63, I (2) = 65%) or Caucasians (OR = 1.04, 95% CI: 0.41, 2.65; P = 0.93, I (2) = 55%). In conclusion, the GSTM1 null genotype may be associated with a higher risk of oral cancer in Asians but not in Caucasians, and this effect may be modified by smoking status. The GSTT1 null genotype may not be associated with oral cancer.

Detection and screening of oral cancer and pre-cancerous lesions

Oral cancer is a fatal disease, accounting for the fourth highest incidence of malignancy in males and the seventh in females in Taiwan. The relatively high prevalence of oral cancer in Taiwan is mainly because there is a high-risk group of 2.5 million people with the habit of smoking and betel nut chewing. Unfortunately, 50% of new cases in our medical center who present with TNM stage III or IV lesions have a shorter than 5-year survival after treatment. This highlights the need for: (1) early treatment of fresh oral cancer cases; (2) screening of the high-risk population to detect new lesions; (3) careful follow-up of cases after treatment; and (4) detection of occult early neck nodal adenopathy in surgical cases. It is generally accepted that prevention and screening of oral cancer are equally important to treatment due to its location. In this review article, we describe the nature of oral cancer and highlight the various conventional and novel methods of screening for this disease and ongoing important related research. Related literature is reviewed and future work that needs to be done is detailed.

CYP1A1 and GSTM1 polymorphisms and oral cancer risk: association studies via evidence-based meta-analyses

Previous studies have implicated CYP1A1 and GSTM1 polymorphisms as risk factors for various cancers. A number of studies have been devoted to the association of CYP1A1 or GSTM1 polymorphism with susceptibility to oral carcinoma and have yielded conflicting results. The aim of the present study was to assess the possible associations of oral cancer risk with CYP1A1 genetic variation and GSTM1 null genotype respectively via systematic meta-analyses. The data suggest that variant genotypes of CYP1A1 might not be risk factors for oral cancer, whereas GSTM1 null genotype significantly increases susceptibility to oral cancer in Asians but not Caucasians.

GSTT1 and GSTM1 polymorphism in cigarette smokers with head and neck squamous cell carcinoma

Gene variability related to carcinogen activation and detoxification may interfere with susceptibility to head and neck cancer.

Aim

To investigate the relation between GSTT1 and GSTM1 null polymorphisms and the risk of head and neck squamous cell carcinoma in cigarette smokers.

Material and Method

A case-control study conducted at the Sao Jose do Rio Preto Medical School, Brazil. GSTM1 and GSTT1 null genotype frequencies were evaluated by multiplex PCR in ⁴⁵ cigarette smokers with head and neck squamous cell carcinomas and ⁴⁵ cigarette smokers without this disease.

Results

The oral cavity was the most prevalent tumor site for squamous cell carcinoma. The GSTT1 null genotype was found in 33.3% of the Experimental Group and 23.3% of the Control Group (p= 0.311). Experimental and Control Groups had GSTM1 null genotype frequencies of 35% and 48.3% (p=0.582). No association between alcohol consumption and GSTT1 and GSTMI null genotypes was found in these groups (p-values>0.05). There were more men, and alcohol consumption was prevalent in both groups.

Conclusion

In this study we were unable to show a correlation between GSTM1 and GSTT1 genotypes and the development of head and neck squamous cell carcinomas in cigarette smokers.

The role of genetic factor in etiopathogenesis of squamous cell carcinoma of the head and neck in young adults

Patients with squamous cell carcinoma of the head and neck (HNSCC) aged less than 45 years are categorized as young adults (YA) and in opinion of many authors in comparison to older (typical) patients (OP) are characterized with more serious form of the disease and often lack the classical risk factors associated with the illness. Hence, there is a need of an exact clinical analysis and a search for additional causative factors. The purpose of this study was to estimate the role of genetic factors in the etiology of HNSCC in YA. Studies carried out on 60 patients of the study group (YA) and 72 older control patients were directed to: (1) a degree of spontaneous and induced chromosome breaks estimated by bleomycin test, (2) a degree of spontaneous and induced DNA damage and a potential of DNA repair determined by comet assay and (3) polymorphism of genes of glutathione transferases M1 and T1, responsible for detoxification of metabolites of carcinogens of tobacco smoke, studied by PCR-based genotyping. The level of chromosome breaks (spontaneous and induced), the level of DNA damage (spontaneous and induced), DNA repair potential and the distribution of polymorphic variants of GSTT1 gene are not significantly different in YA and in OP, which suggests that these factors do not appear the causative factors for HNSCC in young age. The significant risk factor of HNSCC in YA may be GSTM1 null genotype, which may cause the defective detoxification of metabolites of polycyclic aromatic hydrocarbons of tobacco smoke.

Glutathione S-transferase polymorphisms and oral cancer: a case-control study in Rio de Janeiro, Brazil

This study evaluates the influence of genetic polymorphisms at GSTM1, GSTT1 and GSTP1 gene loci on oral cancer susceptibility among Brazilians from Rio de Janeiro. DNA extracted from white blood cells of 231 oral cancer patients and 212 hospital controls was analyzed by polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) methods. GSTM1 polymorphism distribution was different between cases and controls (P=0.006), with an overrepresentation of GSTM1 A/B genotype in controls. GSTM1 A/B individuals were at decreased oral cancer risk (OR=0.08; 95% CI=0.05-0.62). No statistically significant association was observed for GSTT1 and GSTP1 polymorphisms. Differences in the GSTM1 and GSTT1 null genotype frequencies were observed between individuals of European origin and African origin, but these genotypes do not seem to influence the risk of oral cancer. Therefore, these results do not support the hypothesis of increased risk of GSTP1 G/G, GSTM1 or GSTT1 null genotypes for developing cancer in oral cavity, but the GSTM1 A/B genotype emerged as a protective factor.