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The serum erythropoietin ( EPO ) concentrations of 15 male triathletes ( 26 . 3 U . ml - 1 ) were significantly lower than those of 45 male distance runners ( 31 . 6 U . ml - 1 ; P less than 0 . 05 ) .
 GENE: erythropoietin; GENE: EPO
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: erythropoietin; GENE: EPO