Tobacco smoking, GSTP1 polymorphism, and bladder carcinoma.
BACKGROUND
Although cigarette smoking is considered a major risk factor for bladder carcinoma, little is known about the interaction between metabolic genes such as glutathione-S-transferase P1 and tobacco smoking in this process. GSTP1 may play a role in detoxification of tobacco-related carcinogens.


METHODS
In this case-control study of 145 cases with bladder carcinoma (male:female = 7.5:1) and 170 noncancer controls (male:female = 3.7:1), the relation between genetic polymorphisms of GSTP1 and susceptibility to bladder carcinoma was investigated and the gene-environment interaction between tobacco smoking and GSTP1 polymorphism was evaluated. Epidemiological data were collected for all cases and controls by a standard questionnaire. Polymorphisms of GSTP1 were measured by polymerase chain reaction-restriction fragment length polymorphism. The logistic regression model in SAS was used to estimate odds ratios (ORs) and 95% confidence intervals (95% CIs).


RESULTS
Cigarette smoking was confirmed as a risk factor of bladder carcinoma with an OR of 3.1 (95% CI: 1.7-5.9) after controlling for potential confounding factors. The OR for pack-years of smoking as a continuous variable was 2.4 (95% CI: 2.0-2.8). The ORs were 7.6 (95% CI: 1.18-49.51) for isoleucine/valine (Ile/Val) and 6.5 (95% CI: 1.01-41.56) for Ile/Ile when the homozygous Val/Val was considered as comparison group after adjusting for age, gender, race, and education. The adjusted OR for interaction between smoking and the GSTP1 (any Ile genotype) was 11.42 (95% CI: 0.53-248.15).


CONCLUSIONS
The results indicate that the Ile 105 allele is associated with an increased risk of bladder carcinoma and suggest that individuals who smoke and possess the Ile allele might be at increased risk for bladder carcinoma.
Cao
Wei
W
Department of Epidemiology, UCLA School of Public Health, and Jonsson Comprehensive Cancer Center, Los Angeles, California 90095-1772, USA.
Cai
Lin
L
Rao
Jian-Yu
JY
Pantuck
Allan
A
Lu
Ming-Lan
ML
Dalbagni
Guido
G
Reuter
Victor
V
Scher
Howard
H
Cordon-Cardo
Carlos
C
Figlin
Robert A
RA
Belldegrun
Arie
A
Zhang
Zuo-Feng
ZF
D000428:Alcohol Drinking / Q000235:genetics; D016022:Case-Control Studies; D004273:DNA, Neoplasm / Q000097:blood / Q000302:isolation & purification; D005260:Female; D051549:Glutathione S-Transferase pi / Q000235:genetics*; D006801:Humans; D007532:Isoleucine / Q000235:genetics; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D018579:Patient Selection; D011110:Polymorphism, Genetic; D012150:Polymorphism, Restriction Fragment Length; D012907:Smoking / Q000235:genetics*; D001749:Urinary Bladder Neoplasms / Q000235:genetics*
D004273:DNA, Neoplasm; D007532:Isoleucine; C496556:GSTP1 protein, human; D051549:Glutathione S-Transferase pi