CD34 and esophageal cancer: Two studies 41, 43 were excluded from the meta-analysis of CD34 and the sub-analysis showed a significant association between high CD34 expression in tumoral tissue and a poorer prognosis in patients affected by esophageal cancer (HR 2.02; 95%CI 1.22-3.33; I2 65%; p=0.006) (Figure 3A).