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Whereas c-Fos /c-Jun heterodimers do not exist in B cells , they form and bind to the X2-box in class II nonexpressing cells .
 protein: c-Fos /c-Jun heterodimers; DNA: X2-box; cell line: class II nonexpressing cells; protein: c-Fos; protein: /c-Jun; cell line: B cells
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: cell line, protein, RNA, DNA, cell type 
Text: {0} 
Answer:
 protein: c-Fos /c-Jun heterodimers; DNA: X2-box; cell line: class II nonexpressing cells; protein: c-Fos; protein: /c-Jun; cell line: B cells