5578
Thrombopoietin induces tyrosine phosphorylation of Stat3 and Stat5 in human blood platelets .
 Stat5, human blood platelets, Thrombopoietin, Stat3
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:
 Stat5, human blood platelets, Thrombopoietin, Stat3