1705
RT - PCR indicated that p21 mRNA was induced 1 . 4 - , 2 . 0 - , and 3 . 1 - fold in the 2 - day neonatal , 7 - day neonatal , and adult stages , respectively , compared to the 17 - day fetal stage .
 GENE: p21 mRNA
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: p21 mRNA