Stratification analysis of the combined genotypes of the PTEN, AKT1, MDM2 and p53 polymorphisms and risk of nasopharyngeal carcinoma.

Abbreviations: OR, odds ratio; CI, confidence interval.aORs and P values were calculated by multivariate logistic regression, adjusted for age, sex, smoking and drinking status, smoking level and nationality when appropriate within the strata.bFor differences in ORs within each stratum.cLow-risk group, individuals carrying 0–2 risk genotypes; high-risk group, individuals carrying 3–4 risk genotypes.