Table 3

Effect of estrogen metabolites on mammary carcinogenesis
Treatment
 Duration
 Mammary cancer incidence
 Rats with mammary cancer (%)
 Average number of cancers per rat
Control
 3 weeks
 9/12
 75
 1.3 ± 0.5
2 mg 2-hydroxy estradiol
 3 weeks
 8/10
 80
 1.4 ± 0.3
2 mg 2-hydroxy estradiol + 30 mg progesterone
 3 weeks
 6/10
 60
 1.5 ± 0.5
2 mg 2-methoxy estradiol
 3 weeks
 6/10
 60
 0.7 ± 0.2
2 mg 2-methoxy estradiol + 30 mg progesterone
 3 weeks
 3/10*
 30
 0.4 ± 0.2

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 3 weeks. Control rats received empty silastic capsules. *P < 0.05 compared with controls.

Rajkumar et al. Breast Cancer Res 2004 6:R31   doi:10.1186/bcr734

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