15785
Hepatocarcinogens that induced cell proliferation after 28 - day treatment also caused an increase in p53 ( + ) cells in parallel with increased apoptotic cells , as well as increased population of cells expressing M phase - related proteins nuclear Cdc2 , phospho - Histone H3 , and HP1 alpha .
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Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
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