AFP and hepatocellular carcinoma: To improve the sensitivity and specificity for predicting the recurrence and metastasis of HCC, detection of AFP mRNA in circulating tumor cells (CTCs) and traveling cells in physiological fluids released from a primary or metastatic tumor can be an alternative method for the imaging and detection of serum AFP levels in that the imaging is too expensive and has size limitations for the metastasis tumor and serum AFP monitoring has delayed effect [109].