Glutathione S-transferase polymorphisms and risk of differentiated thyroid carcinomas: a case-control analysis.
OBJECTIVE
To determine the association between glutathione S-transferase (GST) polymorphisms and the risk of differentiated thyroid carcinoma (DTC) and benign thyroid tumors.


METHODS
Case-control study.


METHODS
Tertiary care cancer center.


METHODS
Two hundred one patients with DTC, 103 patients with benign thyroid tumors, and 680 cancer-free control subjects.


METHODS
Results of a polymerase chain reaction-based assay for genotyping. A multivariate logistic regression analysis was performed with adjustment for age, sex, ethnicity, tobacco use, and alcohol use.


RESULTS
The patients with DTC were younger, more likely to be female and nonwhite, and less likely to smoke or consume alcohol than the controls. Overall, 55.2% of the DTC cases and 52.6% of the controls were null for the gene for GST-mu1 (GSTM1) (P = .52), and 25.4% of the DTC subjects and 20.6% of the controls were null for the GST-theta1 gene (GSTT1) (P = .15). However, 15.9% of the DTC cases but only 9.4% of the controls were null for both genes (P = .009). In addition, the results of the adjusted multivariate regression analysis suggested that having both null genotypes was associated with an increased risk for DTC (odds ratio [OR], 2.1 [95% confidence interval, 1.3-3.5; P = .003]). This was particularly true for women (OR, 2.5), current smokers (OR, 3.6), and nonwhites (OR, 5.6). A similar analysis demonstrated a nonsignificant association between these genotypes and benign thyroid tumors (OR, 1.5 [95% confidence interval, 0.7-3.0; P=.30).


CONCLUSIONS
Our results suggest that the simultaneous presence of the GSTM1- and GSTT1-null genotypes is a susceptibility factor for DTC. Such knowledge may ultimately help refine cancer prevention efforts; however, larger studies are needed to verify these findings.
Ho
Tang
T
Department of Head and Neck Surgery, The University of Texas M. D. Anderson Cancer Center, Houston, Tex 77030-4009, USA.
Zhao
Chong
C
Zheng
Rong
R
Liu
Zhensheng
Z
Wei
Qingyi
Q
Sturgis
Erich M
EM
D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D016022:Case-Control Studies; D016009:Chi-Square Distribution; D003430:Cross-Sectional Studies; D005260:Female; D005838:Genotype; D005982:Glutathione Transferase / Q000235:genetics*; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D016133:Polymerase Chain Reaction; D011110:Polymorphism, Genetic; D012307:Risk Factors; D013964:Thyroid Neoplasms / Q000235:genetics*
D005982:Glutathione Transferase