10919
Histamine modulates the expression of c-fos through cyclic AMP production via the H2 receptor in the human promonocytic cell line U937 .
 H2 receptor, human promonocytic cell line U937, c-fos
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:
 H2 receptor, human promonocytic cell line U937, c-fos