Figure 4.

The effect of hormone-induced systemic changes on tumorigenesis in p53-null mammary epithelial transplants. Mammary epithelial transplants in a host exposed to estradiol and progesterone before transplantation (open triangles and dot-dashed line) also had a significant decrease in tumor incidence (p < 0.05) compared with mice not exposed to the hormones (filled triangles and broken line). The flow diagrams illustrate the experimental treatment plans.