5622
Using this reporter gene system , we previously showed that EPO - induced activation of the c - fos promoter can be detected rapidly and sensitively as an elevation of cellular luciferase activity .
 EPO, c - fos promoter, cellular luciferase
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: GENE 
Text: {0} 
Answer:
 EPO, c - fos promoter, cellular luciferase