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c - Ski , originally identified as a proto - oncogene product , is an important negative regulator of transforming growth factor ( TGF ) - beta family signaling through interaction with Smad2 , Smad3 , and Smad4 .
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Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Anatomy 
Text: {0} 
Answer:
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