18988
The prostaglandin E synthase ( PGES ) responsible for acid - induced PGE2 production in BE , however , is not known .
 prostaglandin E, PGE2
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Chemical 
Text: {0} 
Answer:
 prostaglandin E, PGE2