Several papers have reported that tumor differentiation [20], tumor size [21], microscopic portal invasion [22], microscopic venous invasion [22] and tumor stage [23] are associated with a poor prognosis, and these findings might be related to the poor RFS of patients with down-regulation of the CYP2C19 gene compared to those without such down-regulation. This evidence concerns the gene CYP2C19 and neoplasm.