Hormone-Induced Protection of Mammary Tumorigenesisin Genetically Engineered Mouse Models - Genetic Engineering: Recent Developments in Applications - page 273

mice, only 2/66 (3%) produced tumors (p < 0.05). This experiment demonstrates
conclusively that a short-term hormone treatment can delay tumor development
in a non-carcinogen model of mammary cancer.
Figure 1. Effect of short-term hormone treatment on tumorigenesis in p53-null mammary epithelial transplants.
The data are the sum of two identical experiments (experiments 1 and 1A). Mice treated with estradiol and
progesterone had a significant decrease in tumor incidence (p < 0.05). Filled circles, untreated; open circles,
hormone-treated. The flow diagram illustrates the experimental treatment plan. C, clear mammary gland; T,
transplant; E, estrogen; P, progesterone.
Table 1. Tumorigenesis in short-term hormone-treated mice
Whole-mount analysis of the glands in experiments 1 and 1A at 4 weeks and
at 8 to 12 weeks after transplantation did not indicate a significant difference in