In PCA with in vivo and RAID data, as well as the pathway analysis of PC-related genes (Figures 2, 3), the genes related to peroxisome proliferative activity and xenobiotic metabolism activity possibly leading to liver cancer, which were respectively characterized by Cyp1a induction via AHR and Cyp4 induction via PPARa, were identified as key features. Here, PPARA is linked to liver cancer.