CYP2C19 and cancer: CYP2C19, one human cytochrome P450 enzyme, is not only a clinically important metabolic enzyme responsible for the metabolism of a number of therapeutic drugs but also the key enzyme of EETs synthesis and abundantly expressed in endothelial and smooth muscle cells [12], [13] Recently, there were several studies concerning the CYP2C19 polymorphism and cancer susceptibility [14]–[17].