5544
Although MMP - 1 and VEGFR2 co - exist in many normal and pathophysiological conditions , the effect of MMP - 1 on cellular VEGFR2 that can promote the above processes is unknown .
 None
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Chemical 
Text: {0} 
Answer:
 None