10417
Transient , high - level Ras - expression induces transcriptional activation of p21 mediated by a GC - rich region in p21 promoter - 83 - 54 bp relative to the transcription initiation site containing binding sites for Sp1 - family transcription factors .
 Ras, p21, p21 promoter, Sp1 - family transcription factors
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: GENE 
Text: {0} 
Answer:
 Ras, p21, p21 promoter, Sp1 - family transcription factors