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5fC / 5caC can be excised and repaired to regenerate unmodified cytosines by thymine - DNA glycosylase ( TDG ) and base excision repair ( BER ) pathway , but it is unclear to what extent and at which part of the genome this active demethylation process takes place .
 Chemical: 5fC; Chemical: 5caC; Chemical: cytosines; Chemical: thymine
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: 5fC; Chemical: 5caC; Chemical: cytosines; Chemical: thymine