9145
For the 30 smoking subjects , matching buccal brushings were also analyzed , and HPB - releasing DNA adducts were detected in 24 out of 27 samples with quantifiable DNA yield , averaging 44 . 7 pmol HPB / mg DNA .
 HPB, HPB
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Chemical 
Text: {0} 
Answer:
 HPB, HPB