3683
Recombinant virus was detected in the culture medium of the transfected psi 2 cells , which is capable of transmitting the human PAH gene into mouse NIH 3T3 cells by infection leading to stable incorporation of the recombinant provirus .
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Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Disease 
Text: {0} 
Answer:
 None