22940
Several members of the ABC family , including proteins from the ABCA , ABCB , ABCC and ABCG subfamilies , have been shown to be functional in the placenta with clinically significant roles in xenobiotic efflux .
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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:
 None