20734
Recently , it has been shown that differential promoter usage in tissues results in expression of five OATP2B1 transcriptional start site variants which utilize distinct first exons but share common subsequent exons .
 None
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
 None