['The aim of this study was to determine if variable number of tandem repeats (VNTR) in the second intron (STin2) of the serotonin transporter (SLC6A4) gene was associated with tobacco use disorder, successful smoking cessation, or smoking characteristics. In this case-control study, patients with current tobacco use disorder, diagnosed according to DSM IV criteria (n\u2009=\u2009185), and never-smokers, diagnosed according to CDC criteria (n\u2009=\u2009175), were recruited and received 52 weeks of combined pharmacotherapy and cognitive therapy. Successful smoking cessation was defined as exhaled carbon monoxide\u2009<\u20096 ppm. SLC6A4 gene STin2 VNTR polymorphism was assessed using a Multiplex-PCR-based method. At baseline, participants were evaluated using the Fagerström Test for Nicotine Dependence (FTND) and the ASSIST scale.', 'The STin2.12 allele (OR\u2009=\u20092.45; 95% CI\u2009=\u20091.44-4.15, p\u2009<\u20090.001) was associated with an increased risk for tobacco use disorder, while the STin2.10/10 genotype (OR\u2009=\u20090.42; 95% CI 0.25-0.71, p\u2009<\u20090.001) decreased risk. There were no significant associations between tobacco use disorder and the STin2.10 or STin2.9 alleles or the other genotypes (STin2.12/12, 12/10, 12/9, 10/9 or 9/9). There were no significant associations between the STin2 genotypes and alleles and successful smoking cessation, smoking characteristics and increased alcohol or sedative use risk.'] Is sLC6A4 STin2 VNTR genetic polymorphism associated with tobacco use disorder , but not with successful smoking cessation or smoking characteristics : a case control study?