5987
Prior studies have shown MCP-1 expression is modulated by a variety of ligands that act through extracellular receptors .
 extracellular receptors, MCP-1
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:
 extracellular receptors, MCP-1