Method of treating cancer using selective estrogen receptor modulators

1. A method of treating an estrogen receptor positive breast cancer in a subject, wherein the estrogen receptor positive breast cancer is resistant to an estrogen receptor modulator, the method comprising administering a composition comprising a compound of (R)-6-{2-{ethyl[4-(2-ethylaminoethyl)benzyl]amino}-4-methoxyphenyl}-5,6,7,8-tetrahydronaphthalen-2-ol.

2. The method of claim 1 , wherein the estrogen receptor positive breast cancer is de novo resistant to the estrogen receptor modulator.

3. The method of claim 1 , wherein the resistance to the estrogen receptor modulator is acquired.

4. The method of claim 1 , wherein the estrogen receptor modulator is a selective estrogen receptor modulator (SERM).

5. The method of claim 4 , wherein the SERM is tamoxifen, idoxifene, raloxifene or ICI 182,780.

6. The method of claim 1 , wherein an effective amount of the composition is administered.

7. The method of claim 1 , wherein the effective amount comprises a high dosage.

8. The method of claim 7 , wherein the high dosage is more than about 20 mg/kg.

9. The method of claim 1 , wherein the composition is administered by oral administration, intravenous administration, intradermal injection, intramuscular injection or subcutaneous injection.

10. The method of claim 1 , further comprising administering an effective amount of at least one compound selected from the group consisting of a cyclin-dependent kinase 4 and 6 inhibitor (CDK4/6 inhibitor), an antiestrogen, a ligand of retinoic acid or retinoxic X receptor, an antiprogestin, an antiandrogen, vitamin D or metabolite thereof, a farnesyl transferase inhibitor, a PPARα or gamma agonist and a MAP kinase inhibitor.