Figure 5. Funnel plot for publication bias in the studies investigating the association between -607C/A polymorphisms in IL-18 gene promoter and risk of cancer(heterozygous genetic model: CA vs. CC).

No publication bias was observed among studies using Begg’s P value (P = 0.167) and Egger’s (P = 0.387) test, which suggested there was no evidence of publication bias.