Associations between H19 gene polymorphisms and Wilms tumor susceptibility
The detailed characteristics of all the subjects were shown in Supplementary Table 1. A total of 355 patients and 1068 healthy controls were successfully genotyped. The genotype frequencies of the three selected H19 gene polymorphisms and their associations with Wilms tumor susceptibility were presented in Table 1. We observed the genotype frequency distributions of the selected H19 gene polymorphisms were no significant deviation with the Hardy-Weinberg equilibrium (P=0.245 for rs2839698 G>A, P=0.138 for rs3024270 C>G, P=0.992 for rs217727 G>A polymorphism) in controls. In single-locus analysis, we observed that all three polymorphisms were significantly associated with Wilms tumor risk individually. Specifically, the risk estimates for the these SNPs were as follows: the rs2839698 G>A polymorphism (AG vs. GG: adjusted OR=0.74, 95% CI=0.57-0.96, P=0.024; AA vs. GG: adjusted OR=1.52, 95% CI=1.05-2.22, P=0.027; AA vs. GG/AG: adjusted OR=1.75, 95% CI=1.23-2.50, P=0.002), the rs3024270 C>G polymorphism (CG vs. CC: adjusted OR=0.61, 95% CI=0.46-0.81, P=0.0007; CG/GG vs. CC: adjusted OR=0.73, 95% CI=0.57-0.95, P=0.018; GG vs. CC/CG: adjusted OR=1.38, 95% CI=1.05-1.82, P=0.023), and the rs217727 polymorphism (AG vs. GG: adjusted OR=0.76, 95% CI=0.58-0.99, P=0.035).
While analyzing the combined effect of risk genotypes, we found that subjects carrying 1 or 2 risk genotypes had a significantly increased Wilms tumor risk when compared with those without risk genotypes (adjusted OR=1.36, 95% CI=1.02-1.80, P=0.041; and adjusted OR=1.84, 95% CI=1.27-2.67, P=0.001). Moreover, we found that subjects with 1-2 risk genotypes were significantly more likely to develop Wilms tumor than subjects carrying no risk genotypes (adjusted OR=1.50, 95% CI=1.17-1.92, P=0.002).
We then performed a stratified analysis to explore how age, gender, and clinical stage influence the association between selected polymorphisms and Wilms tumor susceptibility (Table 2). Compared to the rs2839698 GG/AG genotype, the risk effects of AA genotypes were more predominant in children above 18 months of age (adjusted OR=1.73; 95% CI=1.09-2.74, P=0.020), female (adjusted OR=1.94, 95% CI=1.11-3.39, P=0.021), male (adjusted OR=1.63, 95% CI=1.02-2.58, P=0.040), and those with clinical stage I+II disease (adjusted OR=1.83, 95% CI=1.20-2.79, P=0.005). Consistently, with the rs217727 GG/AG genotype as references, AA genotype carriers was associated with an increased risk of Wilms tumor for children above 18 months of age (adjusted OR=1.65; 95% CI=1.06-2.58, P=0.027), male (adjusted OR=1.60, 95% CI=1.01-2.54, P=0.047), clinical stage I+II cases (adjusted OR=1.60, 95% CI=1.05-2.44, P=0.029). However, no association was observed between rs3024270 and Wilms tumor susceptibility in subgroups defined by age, sex, and clinical stages.
We also interrogated the cumulative effects of these SNPs on Wilms tumor risk in the stratified analysis. We found that the presence of 1-2 risk genotypes was significantly associated with the risk of Wilms tumor in children above 18 months of age (adjusted OR=1.66; 95% CI=1.21-2.27, P=0.002), male (adjusted OR=1.59, 95% CI=1.14-2.21, P=0.006), and clinical stage I+II patients (adjusted OR=1.64, 95% CI=1.21-2.22, P=0.002) when compared with those of 0 risk genotype.