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To study the functional differences between cutaneous HPV5 and HPV8 E7s and genital HPV16 E7 , we cloned each of the E7 open reading frames and tested their immortalizing and transforming activities , the binding ability of their products with retinoblastoma protein ( RB ) and their complementation activity of a RB - nonbinding adenovirus E1A mutant .
 E7s, genital HPV16 E7, E7, retinoblastoma protein, RB, RB - nonbinding adenovirus E1A mutant
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: GENE 
Text: {0} 
Answer:
 E7s, genital HPV16 E7, E7, retinoblastoma protein, RB, RB - nonbinding adenovirus E1A mutant