20205
Importantly , these 5 genes were also effective for classifying independent series of post - radiotherapy ( 5 PTC ) and post - Chernobyl ( 6 PTC ) tumors compared to independent series of sporadic tumors ( 8 PTC and 6 PTC , respectively ) ( testing tumors ) Moreover , part of each post - radiotherapy ( 32 genes ) and post - Chernobyl signature ( 16 genes ) cross - classified the respective series of thyroid tumors .
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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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