|
Effect of synthetic estrogens and progestins on mammary carcinogenesis |
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| Treatment |
Duration |
Mammary cancer incidence |
Rats with mammary cancer (%) |
Average number of cancers per rat |
|
|
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| Control |
3 weeks |
9/12 |
75 |
1.5 ± 0.3 |
| 100 μg eE + 30 mg megesterol |
3 weeks |
3/13* |
23 |
0.3 ± 0.2* |
| 30 mg tamoxifen + 30 mg progesterone |
3 weeks |
7/12 |
58 |
0.9 ± 0.3 |
| 100 μg eE + 30 mg megesterol |
1 week |
5/13 |
38 |
0.4 ± 0.1* |
| 100 μg eE + 30 mg norethindrone |
1 week |
3/12* |
25 |
0.2 ± 0.1* |
|
Rats were treated with N-methyl-N-nitrosourea at 7 weeks of age. At 9 weeks of age, the rats were treated with hormones for 1 or 3 weeks. Control rats received empty silastic capsules. eE, 17α-ethynyl estradiol. *P < 0.05 compared with controls. | ||||
Rajkumar et al. Breast Cancer Res 2004 6:R31 doi:10.1186/bcr734 |
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