9845
The pre-leukemic phase of Friend erythroleukemia results from activation of the erythropoietin receptor ( EpoR ) by the spleen focus forming virus (SFFV) envelope glycoprotein , followed by the emergence of leukemic clones characterized by overexpression of Spi-1 and mutation of the p53 tumor suppressor gene .
 Spi-1, p53 tumor suppressor gene, EpoR, erythropoietin receptor, spleen focus forming virus (SFFV) envelope glycoprotein
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:
 Spi-1, p53 tumor suppressor gene, EpoR, erythropoietin receptor, spleen focus forming virus (SFFV) envelope glycoprotein