1839
B - cell lymphoma 2 ( Bcl - 2 ) family proteins are established regulators of cell survival , but their involvement in the normal function of primary cells has only recently begun to receive attention .
 None
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
 None