3757
As exogenously expressed PKR can form heterodimers with endogenous PKR , the results obtained on the functional characterization of mutant forms of PKR have been taken with caution .
 GENE: PKR; GENE: endogenous PKR; GENE: PKR
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: GENE 
Text: {0} 
Answer:
 GENE: PKR; GENE: endogenous PKR; GENE: PKR