11690
Structurally , they contain a pyrazine - 2 - ( 1H ) - one core and were screened for antiproliferative activity on several cancer cell lines .
 pyrazine - 2 - ( 1H ) - one
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Chemical 
Text: {0} 
Answer:
 pyrazine - 2 - ( 1H ) - one