8695
We recently demonstrated that venom extracted from Walterinnesia aegyptia ( WEV ) either alone or in combination with silica nanoparticles ( WEV + NP ) mediated the growth arrest and apoptosis of breast cancer cells .
 silica
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Chemical 
Text: {0} 
Answer:
 silica