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Here , the authors provide a review of the literature regarding the targeting of HIF , a key modulator of hypoxic - cell response under various disease conditions , by modulating histone or DNA using endogenous small RNAs or exogenous chemicals .
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Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
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