Tamoxifen laboratory models

As previously mentioned, despite the benefits of tamoxifen in the treatment of breast cancer, it is known to increase the risk of endometrial cancer and the formation of blood clots in women. Raloxifen, Chart 3, is a benzothiophene selective oestrogen receptor modulator, which, like tamoxifen, acts as an oestrogen antagonist in the breast. Formally known as LY 156,758 or keoxifen, it was first developed in the early 1980s as a candidate for the treatment of breast cancer [76], However, it performed poorly against tamoxifen in laboratory models, and no further development followed until its ability to maintain bone density in postmenopausal women was recognised. It was approved under the new name of raloxifen for the treatment and prevention of osteoporosis (Evista ) [77, 78],... 

In addition to tamoxifen [125,134], clomiphene (originally chloramiphene or MRL-41 Figure 5.14) [260] resulted from a search for contraceptives in laboratory models, but in clinical trials unexpectedly induced ovulation in subfertile women [261], As a... 

Idoxifene inhibits the growth of carcinogen-induced rat mammary tumors [293] and MCF-7 tumors grown in athymic mice [294, 295]. When compared to tamoxifen, idoxifene appears to have more antagonistic and less agonistic effects on ER in laboratory studies. Also, idoxifene has been reported to develop acquired antiestrogen resistance more slowly than tamoxifen [294]. However, there appears to be crossresistance in laboratory models of tamoxifen-stimulated growth [281]. 

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