Those studies involved the drug tamoxifen, which is used as a supplement in treating breast cancer, the document said.
The anticancer drug tamoxifen is also prescribed in unusual cases.
Some people use it to prevent cancer and to help breast cancer patients respond faster to treatment with the drug tamoxifen.
Some patients also take the drug tamoxifen as an adjunct to treatment.
Women with breast cancer or at high risk of developing it consider the drug tamoxifen to be a lifesaver.
The drug tamoxifen may be used to help prevent breast cancer in women at high risk of breast cancer.
They may also be advised to take the drug tamoxifen, which can reduce the breast cancer risk.
Women taking the drug tamoxifen to treat or prevent breast cancer are at very slightly increased risk.
Another option is to take the drug tamoxifen, but it reduces risk by only 45 percent, and can be taken for only 5 years.
The second gene could be activated at will by dosing the mice with the drug tamoxifen.