AFP and hepatocellular carcinoma: Guo et al. (2019) reported that T stage, N stage, brain metastasis, and intrahepatic metastasis were risk factors for bone metastasis from HCC. Chen et al. (2019) pointed out that bone metastasis was significantly associated with brain metastasis from HCC. Besides, positive AFP, bilobar HCC lesions, multiplicity of HCC lesions, and primary tumor size ≥5 cm at initial diagnosis were also the independent predictors for distant metastases of HCC (Lee et al., 2019; Elmoghazy et al., 2019; Carr & Guerra, 2016; Can et al., 2014).