2723
Tumor sections were stained for : endothelial cells with CD31 and PAS or hypoxia inducible factor 1alpha ( HIF ) .
 Tumor sections, endothelial cells
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Anatomy 
Text: {0} 
Answer:
 Tumor sections, endothelial cells