24541
Promising results were also observed in estrogen receptor ( ER ) - positive , HER2 - negative breast cancer using a mammalian target of rapamycin inhibitor with tamoxifen or an aromatase inhibitor ( AI ) in the preoperative setting and for patients with metastatic breast cancer that had previously progressed on endocrine therapy alone .
 Chemical: estrogen; Chemical: rapamycin; Chemical: tamoxifen
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
 Chemical: estrogen; Chemical: rapamycin; Chemical: tamoxifen