Figure 7: Semi-quantitative analysis of hepatic hypoxia inducible factor (HIF)-1a expression during DENA-initiated hepatocarcinogenesis in female Sprague-Dawley rats. One thousand cells were counted per animal and the results were based on 4 animals per group. Each bar represents the mean standard error (n = 4 livers). aP<0.001 as compared to normal group; bP<0.001 as compared to DENA control.