7443
In summary, our results provide compelling evidence that NF-kappaB protects against Fas -mediated death and is likely to be an important regulator of T cell homeostasis and tolerance .
 Fas, NF-kappaB
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:
 Fas, NF-kappaB