4682
In the future , large - scale studies will be required to verify the association between the single nucleotide polymorphisms of NNK metabolism - related enzymes and UC risk .
 Chemical: nucleotide; 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: nucleotide; Chemical: NNK