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Together these results suggest that the BAT box binding proteins are important in the B cell specific expression of CD20 and perhaps CD21 .
 CD20, BAT box binding proteins, CD21
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: cell line, protein, RNA, DNA, cell type 
Text: {0} 
Answer:
 CD20, BAT box binding proteins, CD21