Association between a 15q25 gene variant, smoking quantity and tobacco-related cancers among 17 000 individuals

Background: Genetic variants in 15q25 have been identified as potential risk markers for lung cancer (LC), but controversy exists as to whether this is a direct association, or whether the 15q variant is simply a proxy for increased exposure to tobacco carcinogens. Methods: We performed a detailed analysis of one 15q single nucleotide polymorphism (SNP) (rs16969968) with smoking behaviour and cancer risk in a total of 17 300 subjects from five LC studies and four upper aerodigestive tract (UADT) cancer studies. Results: Subjects with one minor allele smoked on average 0.3 cigarettes per day (CPD) more, whereas subjects with the homozygous minor AA genotype smoked on average 1.2 CPD more than subjects with a GG genotype (P20 CPD) [odds ratio (OR)=1.13, 95% confidence interval (CI) 0.96-1.34, P=0.13 for heterozygotes and 1.81, 95% CI 1.39-2.35 for homozygotes, P