8996
To explore the pathogenesis of chronic lymphocytic leukemia ( CLL ), we examined whether phosphorylation of one or more signal transducer and activator of transcription (STAT) factors was abnormal in cells from CLL patients .
 ( protein: signal transducer and activator of transcription (STAT) factors, 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: signal transducer and activator of transcription (STAT) factors, None) 