5307
2 , 3 , 7 , 8 - Tetrachlorodibenzo - p - dioxin - mediated production of reactive oxygen species is an essential step in the mechanism of action to accelerate human keratinocyte differentiation .
 Chemical: 2 , 3 , 7 , 8 - Tetrachlorodibenzo - p - dioxin; Chemical: oxygen
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: 2 , 3 , 7 , 8 - Tetrachlorodibenzo - p - dioxin; Chemical: oxygen