CRLF2 and acute lymphoblastic leukemia: Among the 386 BCP-ALL patients, 12 (3.1%) showed dim or strong homogeneous expression of CRLF2 (nMFI-scores ranging from 2 to 10), whereas, 10 (2.6%) exhibited bimodal dim or strong CRLF2 expression, thereby suggesting the presence of CRLF2-positive subclones.