194
Our findings suggest that significant progression of marrow reticulin fibrosis during imatinib therapy can be an indicator for a return or progression of CML and, in some patients with CML, imatinib may promote cytogenetic clonal evolution, resulting in a poor response to treatment.
 adverse event: during 
Please tell me event type and its trigger word from given type options. Output format is "type: trigger".  Option: adverse event, potential therapeutic event 
Text: {0} 
Answer:
 adverse event: during 