Null Genotype of GSTT1 Contributes to Esophageal Cancer Risk in Asian Populations: Evidence from a Meta-analysis

Abstract

Background/Aims: Glutathione S-transferase T1 (GSTT1), a phase-II enzyme, plays an important role in detoxification of carcinogen electrophiles. Many studies have investigated the association between GSTT1 polymorphism and esophageal cancer risk in Asian populations, but its actual impact is not clear owing to apparent inconsistencies among those studies. Thus, a meta-analysis was performed to explore the effect of GSTT1 polymorphism on the risk of developing esophageal cancer. Methods: A literature search of PubMed, Embase, and Wanfang databases up to August 2012 was conducted and 15 eligible papers were finally selected, involving a total of 1,626 esophageal cancer cases and 2,216 controls. We used the pooled odds ratio (OR) with its corresponding 95% confidence interval (95%CI) to estimate the association of GSTT1 polymorphism with esophageal cancer risk. Subgroup analyses and sensitivity analyses were performed to further identify the association. Results: Meta-analysis of total studies showed the null genotype of GSTT1 was significantly associated with an increased risk of esophageal cancer in Asians (OR=1.26, 95%CI=1.05-1.52, P OR =0.015, I 2 =42.7%). Subgroup analyses by sample size and countries also identified a significant association. Sensitivity analysis further demonstrated a relationship of GSTT1 polymorphism to esophageal cancer risk in Asians. Conclusions: The present meta-analysis of available data showed a significant association between the null genotype of GSTT1 and an increased risk of esophageal cancer in Asians, particularly in China.

Association between GSTM1 and GSTT1 polymorphisms and esophageal squamous cell carcinoma: results from a case-control study in Kashmir, India

“…With regard to polymorphisms in the GSTT1 gene, this study supports findings of several other studies from regions with high ESCC incidence, including other Indian regions [34,35]. A meta-analysis also reported a significant association between GSTT1 polymorphism and ESCC risk in Asian populations (OR = 1.26, 95 %CI = 1.05-1.52) [36]. However, this association has not been supported by studies from low-incidence areas, including Japan and Europe [37].…”

Genetic Susceptibility to Esophageal Cancer due to CYP1A1 Gene Variant rs4646903 in Tobacco Addicted Patients of Pashtun Ethnicity: a Case Control Study in Khyber Pakhtunkhwa Province of Pakistan

“…In Pakistan, regions adjacent to the cancer built extending from Quetta through Dera Ismail Khan into Khyber Pakhtunkhwa have high incidence rate as compared to other areas and some expert suggest it as the 'extension of the Asian cancer belt' (Figure 1) (Jamal, 2010). Many factors have been implicated in these areas in the etiology of the disease including environmental factors such as mineral contents of the soil; dietary factors such as diet low in fruits, vegetables and animal proteins; personal habits such as tobacco intake and alcoholism (Cortes and Villasenor, 1997;Sharma et al, 2011;Yi and Li 2012). Besides that, age, gender, poor socioeconomic status and genetic factors also contribute towards the disease (Mao et al, 2012;Amani et al, 2013).…”

Cumulative evidence for association between genetic polymorphisms and esophageal cancer susceptibility: A review with evidence from meta‐analysis and genome‐wide association studies

“…For 51 SNPs identified by meta‐analysis, 38 SNPs had statistically significant association with EC or ESCC susceptibility . Meta‐analysis results showed that there were 27 SNPs associated with increased EC or ESCC risk, whereas 11 SNPs decreased the risk of EC or ESCC risk.…”