3247
The induction of vascular endothelial growth factor ( VEGF ) and interleukin - 8 ( IL - 8 ) is an essential feature of tumor angiogenesis , and the hypoxia - inducible factor - 1 ( HIF - 1 ) transcription factor is known to be a key regulator of this process .
 tumor
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Anatomy 
Text: {0} 
Answer:
 tumor