3915
The polycomb gene Bmi - 1 is required for the self - renewal of stem cells from diverse tissues , including the central nervous system ( CNS ) .
 stem cells, tissues, central nervous system, CNS
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Anatomy 
Text: {0} 
Answer:
 stem cells, tissues, central nervous system, CNS