2606
These results show that there is no evidence of specific expression of the progesterone receptor in pregnancy and exclude any prognostic character in spontaneous abortion .
 ( protein: progesterone receptor, None) 
Locate the role in the text that participated in the event based on the event type and return it in the event list. 
 Option: Event type: RNA,cell type,protein,cell line,DNA, Arguments type: . 
Text: {0} 
Answer:
 ( protein: progesterone receptor, None) 