5675
PURPOSE : To evaluate the kinetics of erythropoietin ( EPO ) production and address the pathogenesis of anemia of prematurity , we measured EPO levels in infants during the first year of life .
 erythropoietin, EPO, EPO
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: GENE 
Text: {0} 
Answer:
 erythropoietin, EPO, EPO