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TNF-alpha RNA was undetectable in U937 cells , whereas a low constitutive level was detected in U9-IIIB cells .
 cell line: U9-IIIB cells; RNA: TNF-alpha RNA; protein: TNF-alpha; cell line: U937 cells
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:
 cell line: U9-IIIB cells; RNA: TNF-alpha RNA; protein: TNF-alpha; cell line: U937 cells