Fig. 1

Cluster analysis of gene expression in mouse liver after DEN treatment quantified by qPCR. The expression of 50 genes was clustered by hierarchical clustering after DEN treatment. Results of 4 h and 28 days after a single shot were analyzed separately. The color displays show the log2 (expression ratio) as (1) red when the treatment sample is up-regulated relative to the control sample, (2) blue when the treatment sample is down-regulated relative to the control sample, and (3) white when the log2 (expression ratio) is close to zero [40]. At 4 h, all 20 Grp 1 genes showed a dose-dependent increase of more than 3–64-fold. Twelve Grp 2 genes were suggested to have a gradual dose-dependent increase of less than that for the expression in Grp1. Two Grp 4 genes exhibited a dose-dependent decrease of less than 0.3-fold. Fifteen Grp 3 genes showed few changes in gene expression. At 28 days, three Grp 1 genes showed a dose-dependent increase of more than four-fold. Seventeen Grp 2 genes were suggested to have a gradual dose-dependent increase, though less than that for the expression in Grp 1. Ungrouped Igfbp1 showed a dose-dependent decrease of less than 0.3-fold. 22 Grp 3 genes showed fewer changes in gene expression