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At early time - point PAH exposure , large - scale gene expression analysis resulted in characteristic molecular signatures for each PAH , and supervised analysis identified 1183 outlier genes as a distinct molecular signature discerning PAHs from the normal control group .
 Chemical: PAH; Chemical: PAH; Chemical: PAHs
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
 Chemical: PAH; Chemical: PAH; Chemical: PAHs