RESUMO
Lung cancer is a complex polygenic disease and many genetic factors are involved in the development of the disease. As one of the most important and widely studied families of microRNA, let-7 appears to play an important role in initiation and progression of lung cancer. Any small changes in miRNA level or its target point can cause significant changes in gene function. In this study, we examined whether a single-nucleotide polymorphism in the promoter region of the let-7 family (rs10877887) is associated with the susceptibility to and prognosis of lung adenocarcinoma cancer. A hospital-based case-control research model was used in our study. The single-nucleotide polymorphism was genotyped in 69 lung cancer patients and 75 healthy controls by direct sequencing. The correlation between rs10877887 genotypes and the susceptibility to lung cancer was evaluated using an unconditional logistic regression model. Populations with the CT+CC genotype had a significantly increased AC risk compared to those with the TT genotype (CT+CC vs TT: P = 0.043, OR = 2.032, 95%CI = 1.018-4.054). Furthermore, the risk effect was greater in subgroups of females over 60 years old (CT+CC vs TT: OR = 6.857, 95%CI = 1.425-33.008, P = 0.012), and the C allele were confirmed to be a risk factor related to lung cancer in these females (P = 0.012). The single-nucleotide polymorphism rs10877887 in the promoter region of the let-7 family was found to be responsible for the susceptibility to lung adenocarcinoma cancer in Chinese individuals. This association was significantly stronger in females who were more than 60 years old.