PKM and hepatocellular carcinoma: In the stratified analysis by tumor type, high levels of PKM2 were significantly correlated with a poorer OS for patients with breast cancer (pooled HR = 1.85, 95%CI = 1.44-2.38), esophageal squamous cell cancer (pooled HR = 1.72, 95%CI = 1.30-2.28), gallbladder cancer (pooled HR = 2.10, 95%CI = 1.45-3.05) and hepatocellular carcinoma (pooled HR = 1.60, 95%CI = 1.40-1.83).