2806
A model was developed in which these genes / pathways function as hypothetical enhancers or promoters of rat thyroid tumors , acting secondary to the key initiating event of thyroid hormone disruption .
 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