Genetic Analysis of Polymorphisms in Dopamine Receptor and Transporter Genes for Association with Smoking among Cancer Patients

Abstract

<b><i>Background:</i></b> Smoking among Russian cancer patients may be related to variations in the <i>DRD2/ANKK1</i> (Taq1), <i>DRD4</i> (exon III VNTR), and <i>SLC6A3</i> genes. <b><i>Methods:</i></b> Seven hundred fifty patients provided smoking history and DNA. <b><i>Results:</i></b> Current smokers were more likely to be <i>DRD2 </i>A2 allele carriers versus nonsmokers (former/never smokers; 69 vs. 56%; OR = 1.69; 95% CI 1.13–2.53, p = 0.01) and former smokers (69 vs. 59%; OR = 1.54; 95% CI 0.97–2.46, p = 0.07). Ever smokers (current/former smokers) were more likely to be <i>DRD2</i> A2 allele carriers versus never smokers (65 vs. 55%; OR = 1.50; 95% CI 1.00–2.27, p = 0.05). The risk of current smoking among <i>DRD2</i> A2 allele carriers was present if the <i>DRD4</i> short allele was also present (OR = 1.76; 95% CI 1.12–2.78, p = 0.02), and the risk of ever smoking among <i>DRD2</i> A2 allele carriers was present if the <i>DRD4</i> short allele was also present (OR = 1.62; 95% CI 1.02–2.55, p = 0.04). <i>DRD2</i> A2 allele carriers had a shorter period of previous abstinence versus <i>DRD2</i> A1 carriers (p = 0.02). Effects were not statistically significant when controlling for multiple comparisons. <b><i>Conclusions:</i></b> The <i>DRD2</i> A2 allele may increase the risk of smoking among cancer patients, convergent with studies using non-Western samples. However, additional replication is needed.