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4 - ( Methylnitrosamino ) - 1 - ( 3 - pyridyl ) - 1 - butanone ( NNK ) metabolism - related enzymes gene polymorphisms , NNK metabolites levels and urothelial carcinoma .
 Chemical: 4 - ( Methylnitrosamino ) - 1 - ( 3 - pyridyl ) - 1 - butanone; Chemical: NNK; Chemical: NNK
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: 4 - ( Methylnitrosamino ) - 1 - ( 3 - pyridyl ) - 1 - butanone; Chemical: NNK; Chemical: NNK