Fig. 3

PCA of the gene expression levels under treatment with 3 types of carcinogens in rat liver as quantified by qPCR. Genotoxic hepatocarcinogens (red-colored, DENL: DEN low dose, DEN-M: DEN middle dose, DEN-H: DEN high dose, DNT-L: DNT low dose, DNT-H: DNT high dose), a non-genotoxic carcinogen (brown-colored, DEHP-L: DEHP low dose, DEHP-H: DEHP high dose) and a non-genotoxic non-hepatocarcinogen (blue-colored, PNT-L: PNT low dose, PNT-H: PNT high dose). The mean values of triplicate qPCR assays for each sample were analyzed statistically using the PCA program in GeneSpringGX11.0.1. The results of the PCA are shown as the two-dimensional contribution scores for component numbers 1 and 2 (PC1 and PC2). The contribution scores were produced by conversion from each eigenvector value, at 4 h with 16 genes and at 48 h with 10 genes described in the text. PCA successfully differentiated the genotoxic hepatocarcinogen (red circle) from the non-genotoxic hepatocarcinogen (brown circle) and non-genotoxic and non-hepatocarcinogen (blue circle) with PC1 and PC2. Fig. 2 in [15]