6000
Cytotoxic activity was evaluated for human laryngeal epidermoid carcinoma cell ( Hep - 2 ) , human cervical adenocarcinoma ( HeLa ) and human normal epithelial embryonic kidney ( Hek - 293 ) .
 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