Increased Sphingosine Kinase 1 Expression Is Associated with Poor Prognosis in Human Solid Tumors: A Meta-Analysis

Figure 5

Begg’s funnel plots for assessment of potential publication bias in studies of SPHK1 in patients with solid tumor. Each study is represented by one circle. The horizontal line represented the pooled effect estimate. (a) Funnel plot of publication bias for studies reporting overall survival. (b) Funnel plot adjusted with trim and fill methods for studies reporting overall survival. (c) Funnel plot of publication bias for studies reporting disease-free survival.

(a)

(b)

(c)