17634
We examined the relationship between PAH - DNA adduct levels in the placental tissue , measured by a highly sensitive ( 32 ) P - postlabeling assay , and the risk of fetal neural tube defects ( NTDs ) .
 PAH, ( 32 ) P
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Chemical 
Text: {0} 
Answer:
 PAH, ( 32 ) P