7965
Tissues from women undergoing elective termination of uterine pregnancy and from women with ectopic pregnancy were used to detect the presence of cells important for the maintenance of pregnancy, such as BCL-2+ , CD56+ , CD3+ , CD8+ and CD68+ cells , and the presence of oestrogen ( ER ) and progesterone receptors ( PR ) by immunohistochemistry .
 ( protein: oestrogen, None) , ( protein: oestrogen ( ER ) and progesterone receptors, None) , ( protein: progesterone receptors, None) , ( protein: PR, None) , ( protein: ER, 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: oestrogen, None) , ( protein: oestrogen ( ER ) and progesterone receptors, None) , ( protein: progesterone receptors, None) , ( protein: PR, None) , ( protein: ER, None) 