19785
The further studies by Comet assay at single cell level indicated that DNA damage in MG - 63 cells was triggered by 2b , following with the up - regulation of phosphorylated p53 and histone .
 None
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
 Entities:  
Answer:
 None