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To identify ets-related transcriptional regulators expressed in pre-B lymphocytes that may interact with either the pi or the microB site , we have used a PCR approach with degenerate oligonucleotides encoding conserved sequences in all members of the ets family .
 pre-B lymphocytes, ets-related transcriptional regulators, microB site, ets family, microB, pi
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:
 pre-B lymphocytes, ets-related transcriptional regulators, microB site, ets family, microB, pi