7687
Most erythroleukemic cell lines established in vitro coexpress erythrocytic and megakaryocytic markers that often are associated with expression of Spi-1 and/or Fli-1 transcription factors known as transactivators of megakaryocyte-specific promoters .
 Fli-1, transactivators of megakaryocyte-specific promoters, Spi-1, Fli-1 transcription factors, megakaryocyte-specific promoters, erythroleukemic cell lines
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:
 Fli-1, transactivators of megakaryocyte-specific promoters, Spi-1, Fli-1 transcription factors, megakaryocyte-specific promoters, erythroleukemic cell lines