8900
In addition , we find that E2F - 1 can cause apoptosis in p53 - / - tumour cells and further p300 , which also functions as a co - activator for the E2F / DP heterodimer , enhances the apoptotic activity of E2F - 1 .
 E2F - 1, p53 - / -, p300, E2F, DP, E2F - 1
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: GENE 
Text: {0} 
Answer:
 E2F - 1, p53 - / -, p300, E2F, DP, E2F - 1