Figure 1B depicts the percentage of COX-2-positive cells in tumor sections from all experimental animal groups. Our quantitative analysis shows immunopositivity for more than 20% of mammary tumor cells in DMBA control animals. TPE at 50 mg/kg slightly increased the percentage of COX-2-positive cells; however the result did not reach the level of statistical significance. Interestingly, there was a significant (p < 0.01 or 0.001) inhibition of the percentage of COX-2-positive tumor cells in rats fed with 100 or 200 mg/kg TPE compared to the DMBA control group, respectively. This evidence concerns the gene PTGS2 and neoplasm.