4104
These biochemical findings correlate perfectly with the selective ability of c-ErbB to cause sustained self renewal in erythroid progenitors .
 erythroid progenitors, c-ErbB
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, c-ErbB