Deep molecular response in chronic myelogenous leukemia: ensuring accuracy and consistency

Abstract

We read with interest the recent laboratory recommendations by European Treatment Outcome Study (EUTOS)1 on monitoring deep molecular response in chronic myelogenous leukemia (CML). The European LeukemiaNet recently adopted the concept of deep molecular response2 to clarify and re-define the previous obscure concept of ‘complete molecular response’. The EUTOS recommendations1 provide important and practical guidance on how to measure and categorize such deep molecular response (MR) in a standardized way in CML. In this correspondence, we raise three issues closely related to the discussion in the EUTOS recommendations that laboratories performing real-time reverse transcriptase PCR (RQ-PCR) for CML monitoring may encounter.