14358
Numerous studies have shown that, upon HIV1 infection , human promonocytic U937 cells were induced to differentiate, as indicated, for example, by increased expression of adhesion molecules .
 U937 cells, adhesion molecules, human promonocytic U937 cells
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:
 U937 cells, adhesion molecules, human promonocytic U937 cells