Objective: To assess the possible relation between the MspI polymorphism of Cytochrome P4501A1(CYP1A1) gene and the susceptibility to laryngeal cancer.
Methods: The genotypes of CYP1A1 MspI site were detected using the methods of polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) in 62 cases of laryngeal squamous carcinoma and 56 healthy controls. Genetic risk of CYP1A1 genotypes was analyzed by smoking index (SI, cigarettes smoked per day x years of smoking).
Results: Three genotypes of CYP1A1 MspI were classified into the predominant homozygotes (A), heterozygotes (B) and the rare homozygotes (C). The frequency of heterozygote B (58.1%) and genotype C (14.5%) in the patients with laryngeal cancer were higher than that of the controls (39.3%, 7.1%, P < 0.05), while their odds ratios were 2.89 (95% confidence interval, CI: 1.31-6.37) and 3.97 (95% CI: 1.10-14.28), respectively. The odds ratios of genotype C was 9 (95% CI: 1.60-50.74) in the high dose cigarette smoking group, but was 4.5 (95% CI: 0.64-31.61) in the low dose cigarette smoking group.
Conclusions: With the carcinogenesis and development of laryngeal cancer, the polymorphism of CYP1A1 gene and smoking exposure together may play an important role. The individuals with genotype C are at especially high risk of laryngeal cancer, which grows with increasing cigarette consumption.