22027
Gene expression analysis indicates that the enhancement of the effect of 5 - FU by SFRE might be explained by the downregulation of TYMS and TK1 , enzymes related to 5 - FU resistance .
 Chemical: 5 - FU; Chemical: 5 - FU
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: 5 - FU; Chemical: 5 - FU