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Consistent with these differences, we have previously demonstrated that the enhancer/promoter region of HIV-2 functions quite differently from that of HIV-1 .
 enhancer/promoter region
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:
 enhancer/promoter region