Putative association of the single nucleotide polymorphisms in RASSF1A promoter with Korean lung cancer

Abstract

The RASSF1 gene, a putative tumor suppressor gene located on human chromosome 3p21, has attracted a great deal of attention because of frequent allelic loss and gene silencing via promoter hypermethylation in a variety of human malignancies. To evaluate the role of RASSF1A gene in lung cancer risk, genotypes of the RASSF1A promoter region (-710 C>T and -392T>C) were determined in 410 lung cancer patients and 410 normal subjects. Furthermore, to examine potential effects of the common haplotypes (C-C, T-T and C-T haplotypes) on RASSF1A transcription, luciferase reporter assays were performed in H2009 and H358 non-small cell lung cancer (NSCLC) cell lines. We found that ht2 C-T haplotype was associated with susceptibility to the risk of lung cancer in dominant (odds ratio (OR): 0.69; 95% CI: 0.46-0.99) model. In particular, we found that C-T haplotype showed a decreased risk of lung cancer in males (codominant OR: 0.59; 95% CI: 0.38-0.93 and dominant OR: 0.58; 95% CI: 0.35-0.96) and in smokers (codominant OR: 0.58; 95% CI: 0.36-0.93 and dominant OR: 0.56; 95% CI: 0.33-0.96). Interestingly, C-T haplotype induced transcriptional activity by 50-60% compared with other haplotypes in NSCLC cell lines. These results suggest that RASSF1A promoter polymorphisms affect RASSF1A expression, further contributing to the genetic susceptibility to lung cancer.