10554
Constitutive expression of E2a- Pbx1 did not induce apoptosis or continued cycling of Rat-1 fibroblasts in low serum conditions .
 protein: Pbx1; protein: E2a- Pbx1; cell line: Rat-1 fibroblasts
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: Pbx1, E2a- Pbx1, Rat-1 fibroblasts 
Answer:
 protein: Pbx1; protein: E2a- Pbx1; cell line: Rat-1 fibroblasts