5069
Moreover , we found that cyclin E , in contrast to cyclin D1 , was required for the G1 / S transition even in cells lacking retinoblastoma protein function .
 cyclin E, cyclin D1, retinoblastoma protein
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: GENE 
Text: {0} 
Answer:
 cyclin E, cyclin D1, retinoblastoma protein