4098
Activation of Stat 5b in erythroid progenitors correlates with the ability of ErbB to induce sustained cell proliferation .
 erythroid progenitors, ErbB, Stat 5b
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:
 erythroid progenitors, ErbB, Stat 5b