TGFB1 and hepatocellular carcinoma: With a random-effect model, there was no difference on OS between high and low TGF-β1 expression in plasmas of HCC patients from both COX univariate analysis of three studies (pooling HR = 1.73, 95 % CI = 0.73–4.07, p = 0.21; Table 4 and Supplementary Figure 4) and COX multivariate analysis of two studies (pooling HR = 2.22, 95 % CI = 0.63–7.80, p = 0.21; Table 4 and Supplementary Figure 6).