3765
In lymphoid cell lines only, the E(gre) -binding protein complexes included ALF1 or HEB and E2A basic helix-loop-helix proteins .
 ALF1, lymphoid cell lines, basic helix-loop-helix proteins, E2A basic helix-loop-helix proteins, E(gre), E(gre) -binding protein complexes, HEB
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:
 ALF1, lymphoid cell lines, basic helix-loop-helix proteins, E2A basic helix-loop-helix proteins, E(gre), E(gre) -binding protein complexes, HEB