2014
There were slightly increased proliferating cell nuclear antigen - positive cells in the ILK / liver - / - animals at day 2 as compared to WT after PB administration .
 Chemical: PB
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Disease, Chemical 
Text: {0} 
Answer:
 Chemical: PB