Statistical analysis
The association between GAS5 polymorphisms and cancer risk was evaluated using odds ratio (OR) and 95% confidence intervals (95% CI). For each SNP, seven genetic models were adopted: allelic model (delvs. ins), recessive model (del/del vs. del/ins+ ins/ins), dominant model (del/del+ del/ins vs. ins/ins), over-dominant model (del/ins vs. del/del+ ins/ins), homozygote contrast model (del/del vs. ins/ins), additive model (del/del vs.ins/del) and heterozygote contrast model (del/ins vs. ins/ins). The Hardy-Weinberg Equilibrium (HWE) was calculated based on the control group’s genotype distribution through the X 2test, where a p-value of <0.05 was considered significant disequilibrium. Inter-study heterogeneity was calculated usingI2 statistics. The fixed-effect model was used when I2 was less than 50% (absence of heterogeneity); otherwise, the random-effect model was adopted. Sensitivity analysis was conducted stepwise, omitting one study at a time to determine the robustness of the pooled odds ratio and the stability of the results. Egger’s linear regression and Begg’s funnel plot were used to determine publication bias. All statistical analyses were performed using metagenyo online tool (Martorell-Marugan et al., 2017). A p-value of <0.05 was considered as the statistically significant threshold.