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The serum response element ( SRE ) in the c-fos regulatory region participates in induction of transcription by various growth factors and by phorbol esters and subsequent squelching of transcription.
 SRE, c-fos regulatory region, growth factors, serum response element
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: cell line, protein, RNA, DNA, cell type 
Text: {0} 
Answer:
 SRE, c-fos regulatory region, growth factors, serum response element