A microRNA cluster as a target of genomic amplification in malignant lymphoma

sion. An abnormal karyotype developed in eight of our patients, usually preceding, and in every case associated with, leukemic evolution as observed in seven of 19 patients developing AML and one patient developing RAEB with monosomy 7. In summary, screening of 33 cases of MDS with normal karyotype failed to detect a monoallelic deletion of PI-PLCb1 gene. All FAB classes and IPSS risk groups were represented. This seems to indicate that the cryptic deletion that appears to be associated with very short survival is a rare event in MDS and thus of limited utility as a prognostic marker. This letter is also a call to other groups to share their experience with the use of this marker.