9852
These results show that Spi-1/ PU.1 requires signals emanating from specific cytokine and growth factor receptors to affect the survival, proliferation and differentiation control of primary erythroblasts .
 PU.1, primary erythroblasts
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:
 PU.1, primary erythroblasts