6884
By using interleukin - 3 - dependent cells that ectopically express the three ErbB proteins or their combinations , we found that ErbB - 3 is devoid of any biological activity but both ErbB - 1 and ErbB - 2 can reconstitute its extremely potent mitogenic activity .
 interleukin - 3, ErbB proteins, ErbB - 3, ErbB - 1, ErbB - 2
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: GENE 
Text: {0} 
Answer:
 interleukin - 3, ErbB proteins, ErbB - 3, ErbB - 1, ErbB - 2