Fig. 2

Forest plots and funnel plots demonstrating the associations between programmed cell death protein 4 (PDCD4) expression and clinical stage of various types of cancer. a Forest plot shows that low PDCD4 expression is significantly associated with advanced stages of head and neck cancers. Two cancer types were reported by Ma et al.: Ma [26] (01) for gastric cancer and Ma [26] (02) for pancreatic cancer. OR odds ratio, CI confidence interval. b Funnel plot shows no evidence of publication bias among papers on the association between PDCD4 expression and clinical stage of various types of cancer