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The increase in SCL protein levels in early erythroid precursors stimulated with Steel factor suggests one mechanism through which Steel factor may enhance normal erythroid proliferation .
 protein: SCL; protein: Steel factor; protein: Steel factor; cell type: erythroid precursors
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: cell line, protein, RNA, DNA, cell type 
Text: {0} 
 Entities: SCL, Steel factor, Steel factor, erythroid precursors 
Answer:
 protein: SCL; protein: Steel factor; protein: Steel factor; cell type: erythroid precursors