GSTT1-null genotype is a protective factor against bladder cancer

Area of Science:

• Environmental Health
• Genetic Epidemiology
• Cancer Research

Background:

• Glutathione S-transferases (GSTs) are crucial for detoxifying environmental carcinogens.
• Polymorphisms in GST genes, such as GSTM1 and GSTT1, can influence cancer susceptibility.
• Smoking is a major risk factor for bladder cancer, involving numerous carcinogens.

Purpose of the Study:

• To examine the combined effects of GSTM1 and GSTT1 gene deletions and smoking on bladder cancer risk.
• To investigate the association between GST gene variants, smoking, and bladder cancer incidence in a Korean population and across different countries.

Main Methods:

• A case-control study involving 216 bladder cancer patients and 449 healthy controls from Korea.
• Genotyping for GSTM1 and GSTT1 null genotypes using multiplex polymerase chain reaction.
• An ecological study analyzing age-standardized bladder cancer incidence, gene frequencies, and smoking prevalence across various nationalities.

Main Results:

• In the Korean case-control study, smoking history and the GSTT1-null genotype were significantly associated with bladder cancer.
• The GSTM1-null genotype showed no significant association with bladder cancer in the Korean cohort.
• Ecological data indicated a positive correlation between cigarette smoking and bladder cancer incidence, and a negative correlation with the GSTT1-null genotype frequency.

Conclusions:

• The GSTT1-null genotype may act as a protective factor against bladder cancer, rather than a risk factor.
• Smoking remains a significant risk factor for bladder cancer, independent of GSTM1 and GSTT1 genotypes.