20207
Conclusions Overall , our data suggest that thyroid tumors that developed following either external exposure or internal 131I contamination shared common molecular features , related to DNA repair , oxidative and endoplasmic reticulum stresses , allowing their classification as radiation - induced tumors in comparison with sporadic counterparts , independently of doses and dose rates , which suggests there may be a " general " radiation - induced signature of thyroid tumors .
 None
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
 None