20541
In addition to the classic nuclear estrogen receptors ( i . e . , ER alpha and ER beta ) , over the past decade a novel G - protein - coupled estrogen receptor ( GPER ) has been discovered in cancer and other cell types .
 Chemical: estrogen; Chemical: estrogen
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: estrogen