Transforming growth factor-β1 (TGF-β1) functions as a suppressor of tumor initiation by inhibiting cellular proliferation or by promoting cellular differentiation or apoptosis in the early phase of cancer development. Variations in the DNA sequence in the TGF-β1 gene may lead to altered TGF-β1 production and/or activity, and so this can modulate an individual's susceptibility to lung cancer. To test this hypothesis, we investigated the association of the TGF-β1 −509C>T and 869T>C (L10P) polymorphisms and their haplotypes with the risk of lung cancer in a Korean population.

The TGF-β1 genotypes were determined in 432 lung cancer patients and in 432 healthy control subjects who were frequency-matched for age and gender. The TGF-β1 haplotypes were predicted using a Bayesian algorithm in the Phase program.

Individuals with at least one −509T allele were at a significantly decreased risk of adenocarcinoma (AC) and small cell carcinoma (SM), as compared with carriers with the −509CC genotype [adjusted odds ratio (OR), 0.63; 95% confidence interval (CI), 0.42–0.96; P=0.04; and adjusted OR, 0.45; 95% CI, 0.27–0.76; P=0.002; respectively]. For the 869T>C polymorphism, the combined TC+CC genotype was associated with a significantly decreased risk of SM compared with the TT genotype (adjusted OR, 0.52; 95% CI, 0.31–0.88; P=0.01). Consistent with the results of the genotyping analyses, the −509T/869C haplotype was associated with a significantly decreased risk of AC and SM as compared with the −509C/869T haplotype (adjusted OR, 0.75; 95% CI, 0.57–0.98; P=0.04; and adjusted OR, 0.67; 95% CI, 0.47–0.96; P=0.02; respectively).

The TGF-β1 −509C>T and 869T>C polymorphisms and their haplotypes may contribute to genetic susceptibility to AC and SM of the lung.