12210
However , during our work with a replication - deficient virus expressing the ASF / SF2 splicing factor from a progesterone antagonist - inducible gene cassette , we discovered that ASF / SF2 was expressed at a significant level in the 293 producer cell line , even in the absence of inducer .
 ASF, SF2, ASF, SF2
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: GENE 
Text: {0} 
Answer:
 ASF, SF2, ASF, SF2