A118G Polymorphism in μ-Opioid Receptor Gene and Interactions with Smoking and Drinking on Risk of Oesophageal Squamous Cell Carcinoma

Aim: To investigate the single nucleotide polymorphism (SNP) of A118G and its interaction with smoking and drinking on oesophageal squamous cell carcinoma (ESCC) risk.

Methods: A total of 960 subjects (545 males and 415 females) with a mean age of 58.1 ± 13.4 years were selected, including 490 ESCC patients and 470 normal control subjects. A logistic regression model was used to examine the association between A118G and ESCC and its interaction with A118G and current smoking and drinking. The odds ratio (OR) and 95% confident interval (95%CI) were calculated.

Results: The frequency for the A allele of A118G was significantly higher in ESCC cases, OR (95%CI) = 1.22 (1.08-1.59). Logistic regression analysis showed a significant association between the A allele in A118G and increased ESCC risk. The ESCC risk was significantly higher in carriers of the A allele of the A118G polymorphism than those with GG (AG + AA vs. GG, adjusted OR (95%CI) = 1.20 (1.05-1.53)). We found that current smokers with AG or AA of the A118G genotype have the highest ESCC risk compared with never smokers with a GG genotype; the OR (95%CI) was 2.57 (1.66-3.33). Current drinkers with AG or AA of the A118G genotype have the highest ESCC risk compared with not currently drinking subjects with the GG genotype, OR (95%CI) = 2.36 (1.47-3.25), after adjusting for covariates.

Conclusion: The A allele of A118G and ESCC and additional interaction between the A allele of A118G and smoking or drinking were associated with increased ESCC risk.