1566
No genomic changes were found, and a CAT reporter gene with the CD18 promoter was inactive in the 3 of them, again suggesting lack of (a) transcriptional factor (s) necessary for CD18 expression .
 transcriptional factor, CD18 promoter, CAT reporter gene, CD18
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: cell line, protein, RNA, DNA, cell type 
Text: {0} 
Answer:
 transcriptional factor, CD18 promoter, CAT reporter gene, CD18