8994
The recent identification and characterization of several key transcription factors has helped to elucidate the molecular mechanisms of T helper cell cytokine gene expression .
 T helper cell cytokine gene, transcription factors
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:
 T helper cell cytokine gene, transcription factors