TTK and hepatocellular carcinoma: As shown in Table 1, high expression of TTK was significantly correlated with high level of serum AFP (P = 0.050), large tumor size (P = 0.006), advanced TNM-stage (P = 0.020), more presence of portal vein tumor thrombus (PVTT, P = 0.003) and distant metastasis (P = 0.004), which indicates the important role of TTK in HCC tumor growth and metastasis.