1950
The tumors of A431 supplemented with F - 2 cells were profoundly vascularized throughout by the tubular structures formed by F - 2 cells , the lumen of which contained the host rat blood cells .
 tumors, A431, F - 2 cells, tubular structures, F - 2 cells, lumen, blood cells
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Anatomy 
Text: {0} 
Answer:
 tumors, A431, F - 2 cells, tubular structures, F - 2 cells, lumen, blood cells