STAT3 rs3816769 polymorphism correlates with gene expression level and may predispose to nonsmall cell lung cancer: a preliminary study

INTRODUCTION The STAT3 gene functions as both the oncogene and the regulator of immunity. Despite its important role in cancer development and regulation of the immune cells, studies of single nucleotide polymorphisms (SNPs) of the STAT3 gene and the associated risk of lung cancer are sparse.
OBJECTIVES In the present study, we evaluated the association of SNPs (rs744 166 [AG] and rs3 816 769 [CT]) with predisposition to nonsmall cell lung cancer (NSCLC) development and their potential effect on STAT3 expression.
PATIENTS AND METHODS DNA and RNA, isolated from lung tissue samples, were obtained from patients with diagnosed NSCLC (n = 71) and those without NSCLC, included in a control group (n = 104). STAT3 SNP genotyping and relative expression were performed using TaqMan® probes. 
RESULTS STAT3 CC (rs3 816 769) and AA genotypes (rs744 166) were associated with lower lung cancer risk, whereas TT (rs3 816 769) and GG genotypes (rs744 166) were found to be associated with significantly elevated lung cancer risk. In the NSCLC group, odds ratio analysis showed that allele A was rare and might be linked with decreased while allele G with increased lung cancer risk. We demonstrated that overexpression of STAT3 positively correlated with TT genotype (rs3 816 769) in NSCLC patients (P = 0.0464). Moreover, the differences in STAT3 gene expression between squamous cell carcinoma and large cell carcinoma histopathological subtypes were observed.
CONCLUSIONS It has been shown that rs3816769 STAT3 gene polymorphisms are associated with NSCLC susceptibility and might be regarded as having a significant functional and diagnostic value.