2704
Electrophoretic mobility shift assays indicate that MS-2beta and MS-2gamma interact with nuclear factors that are induced during U937 differentiation .
 MS-2gamma, U937, MS-2beta, nuclear factors
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:
 MS-2gamma, U937, MS-2beta, nuclear factors