7077
The chemokine SDF - 1 ( CXCL12 ) selectively binds to CXCR4 , a member of the G protein - coupled receptor ( GPCR ) superfamily .
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Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
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