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Helix-loop-helix ( HLH ) transcription factors are involved in cellular growth and differentiation .
 protein: HLH; protein: Helix-loop-helix ( HLH ) transcription factors; protein: Helix-loop-helix
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: cell line, protein, RNA, DNA, cell type 
Text: {0} 
Answer:
 protein: HLH; protein: Helix-loop-helix ( HLH ) transcription factors; protein: Helix-loop-helix