Genetic polymorphism of cytochrome P4501A1 and susceptibility to oral squamous cell carcinoma and oral precancer lesions associated with smoking/betel use

Background: The importance of the CYP1A1 polymorphisms at exon 7 (lle/Val) and 3′-untranslated region (3′-UTR) has been controversial in oral squamous cell carcinoma (OSCC) or head and neck SCC (HNSCC) denoting the value of exploring the correlation between these polymorphisms and risk of betel/smoking associated OSCC. It is also important to evaluate the association between CYP1A1 polymorphisms and susceptibility of oral precancerous lesion (OPL) to confirm the findings in OSCC cases. Methods: We examined polymorphic prevalence of CYP1A1 at exon 7 (lle/Val) and 3′-UTR in 106 cases with OSCC, 60 cases with OPL, and 146 controls. DNA isolated from surgical specimens and whole blood was used for PCR-based genotyping. Results: The prevalence of the CYP1A1 A/G genotype (lle/Val) and G/G genotype (Val/Val) in exon 7 of cases with OSCC (79.2 and 7.6%) and OPL (68.3 and 10%) were significantly higher than in controls (53.4 and 1.4%) (P < 0.0001). The novelty of the present study is that we identified the onset age of OSCC in CYP1A1 A/G genotype to be significantly younger than that in A/A genotype (P < 0.01). No significant difference was seen between cases and controls regarding the polymorphisms at 3′-UTR. Conclusion: The findings indicate that the individuals with the CYP1A1 exon 7 containing G allele were at increased risk for OSCC and OPL.