A case-only study of interactions between metabolic enzyme polymorphisms and industrial pollution in childhood acute leukemia.

Cancer risk is modulated by gene-environment interactions between toxic exposure and genetic variation in carcinogen metabolism. Our objective was to assess interactions between exposure to industrial pollutants and polymorphisms affecting cytochrome P450s (CYP1A1 and CYP2E1) and glutathione S-transferases (GSTP1 and GSTT) in childhood acute leukemia (AL). A case-only design was conducted in 123 Chinese children with sporadic AL. Industrial plants in the vicinity were recorded and, if present, their size and proximity to the usual place of residence of AL children was evaluated. Unconditional logistic regression analysis was performed across the AL study group adjusting for age, gender, parental education, occupation and smoking, indoor and outdoor pesticide use, presence of television sets, refrigerators, microwave ovens and furniture material in children's rooms, and electric transformers, power lines, and telecommunication transmitters within 500 m. This analysis revealed an interaction between the GSTT null allele and industrial plants within 500 m of the residences of childhood AL patients (interaction odds ratio, COR=2.96, 95% CI: 1.09-8.01). Furthermore, the COR for the interaction between GSTT null and industrial plants within 50 m was 5.99 (95% CI: 1.41-25.45). Our results suggest an association between proximity to industrial plants and the GSTT null allele in patients with childhood AL.