• Asian Pacific Journal of Cancer Prevention
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• v.15 no.5
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• pp.2319-2321
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• 2014

Our aim was to determine GSTT1 expression levels in left colon tumors and paired normal tissue in order to identify specific alterations in GSTT1 mRNA levels. Alterations in GSTT1 expression in twenty-four left-sided colon tumors and paired cancer free tissue were determined by qRT-PCR. Significant fold changes were determined with t-test. When compared with cancer free tissue, left colon cancers showed a significant decrease in GSTT1 expression. However, GSTT1 mRNA levels among different grades increased gradually in correlation with tumor grade. Our results suggest that downregulation of GSTT1 in left-sided colon cancers is an early event and is reversed with cancer progression, probably due to cellular defense mechanisms as a response to changes in the microenvironment.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.11
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• pp.6475-6479
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• 2013

Objectives: Glutathione S-transferase (GST) isoenzymes play important roles in resistance to cell apoptosis and carcinogenesis. We aimed to establish the relationship between GST expression and the prognosis of upper urinary tract urothelial carcinoma (UTT-UC) in Taiwan. Methods: This study retrospectively reviewed 46 patients with pathologically confirmed UUT-UC at Kaohsiung Medical University Hospital. In each patient, expression of GSTT1 and GSTP1 was compared between urothelial carcinoma and normal urothelial cells by Western blotting. Results: GSTP1 expression in the UUT-UC cells was significantly higher than that in normal urothelial cells (1.6 fold, p<0.001). Expression of GSTT1 was significantly associated with the invasiveness of the carcinoma (p=0.006). Conclusions: In UUT-UC, GSTP1 might be a potential tumor marker, whereas high GSTT1 expression could be used as an indicator of cancer progression. This study is the first to demonstrate potential applications of different GST isoenzymes for biomolecular analysis of UUT-UCs in Taiwan.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.4
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• pp.1515-1518
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• 2012

Aim: We conducted a prospective study in an Chinese population to detect the association between GSTM, GSTT and GSTP gene polymorphisms and survival of gastric cancer. Methods: A prospective follow-up study with 317 gastric cancer patients was conducted between January 2003 and January 2005. GSTM1, GSTT1 and GSTP1 genotyping was performed using ABI TaqMan Gene Expression assays. Results: Of 317 patients, 5 were lost to follow-up due to migration, while the remaining 302 patients completed the study. The median follow-up time was 34.2 months (range: 2 to 60 months), during which a total of 120 (39.1%) died of gastric cancer. The GSTT1-null genotype showed a significant increased risk of death from gastric cancer, with an HR (95% CI) of 1.59 (1.04-3.58). Moreover, we found individuals carrying null-GSTM1 and null-GSTT1 had a moderate higher risk of death from gastric cancer, with an HR of 1.92 (1.05-3.65). Conclusion: This study reported the carriage of null GSTT1 and null GSTM1 might be linked to the higher death risk from gastric cancer in Chinese population.

• Korean Journal of Head & Neck Oncology
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• v.19 no.2
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• pp.148-157
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• 2003

Background and Objectives: Individual genetic susceptibilities to chemical carcinogens have been recognized as a major important host factors in human cancers. The cytochrome P450 family (CYPs) and glutathione S-transferase(GST) have been reported to be associated with risks to the smoking-related human cancers. Inactivation of tumor suppressor genes like p53 playa key role in tumor progression. The purpose of this study is to demonstrate an association between p53 overexpression and the prevalence of the genetic polymorphisms of CYP1A1 and GSTs in Korean head and neck squamous cell carcinoma (HNSCC). Materials and Methods: The polymorphisms of CYPIA1 and GSTs were analyzed by PCR and PCR-RFLP in 98 Korean head and neck squamous cell carcinoma patients. The expression of p53 was analyzed by immunohistochemistry with anti-p53 Ab (DO7). Results: Overexpression of p53 detected in 45.9% of HNSCC. The odds ratio for p53 overexpression in GSTM1(-), GSTT1(-), GSTP1(val/val) and CYP1A1(val/val) were 1.53, 1.83, 1.17 and 1.47, respectively. Among the combined genotypes, the odds ratio of the CYP1A1 val/val, GSTM1 (-), CYP1A1 val/val, GSTT1(-), and CYP1A1 val/val, GSTT1(-) were 2.0, 2.34 and 4.68, respectively. Conclusion: Based on our results, it might be suggested that p53 overexpression is slightly increased in GSTM1(-), GSTT1(-), GSTP1 val/val, CYP1A1 val/val genotypes. The further study is needed to evaluate the relationship and mechanism between the p53 overexpression and the specific CYP1A1 and GSTs genotypes.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.12
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• pp.4803-4812
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• 2015

Chronic alcohol and tobacco abuse plays a crucial role in the development of different liver associated disorders. Intake promotes the generation of reactive oxygen species within hepatic cells exposing their DNA to continuous oxidative stress which finally leads to DNA damage. However in response to such damage an entangled protective repair machinery comprising different repair proteins like ATM, ATR, H2AX, MRN complex becomes activated. Under abnormal conditions the excessive reactive oxygen species generation results in genetic predisposition of various genes (as ADH, ALDH, CYP2E1, GSTT1, GSTP1 and GSTM1) involved in xenobiotic metabolic pathways, associated with susceptibility to different liver related diseases such as fibrosis, cirrhosis and hepatocellular carcinoma. There is increasing evidence that the inflammatory process is inherently associated with many different cancer types, including hepatocellular carcinomas. The generated reactive oxygen species can also activate or repress epigenetic elements such as chromatin remodeling, non-coding RNAs (micro-RNAs), DNA (de) methylation and histone modification that affect gene expression, hence leading to various disorders. The present review provides comprehensive knowledge of different molecular mechanisms involved in gene polymorphism and their possible association with alcohol and tobacco consumption. The article also showcases the necessity of identifying novel diagnostic biomarkers for early cancer risk assessment among alcohol and tobacco users.