6847
Through systematic DNA footprinting of the TNF (encoding tumour necrosis factor, TNF) promoter region, we have identified a single nucleotide polymorphism (SNP) that causes the helix-turn-helix transcription factor OCT-1 to bind to a novel region of complex protein-DNA interactions and alters gene expression in human monocytes .
 human monocytes, transcription factor
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:
 human monocytes, transcription factor