6701
Novel therapeutic targets as different as epidermal stem cells , cellular senescence , epigenetic enzymes involved in carcinogenesis , epidermal growth factor and aryl hydrocarbon receptors , and metabolic CYP1 subfamily enzymes are highlighted .
 Chemical: aryl hydrocarbon
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: aryl hydrocarbon