23888
We found that ATF2 expression levels at 2 , 4 , 8 and 10 mu M arsenic - treated cells were significantly higher than those of control cells , and the strongest expression occurred in 4 mu M NaAsO2 - treated cells .
 Chemical: arsenic; Chemical: NaAsO2
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
 Chemical: arsenic; Chemical: NaAsO2