Molecular Characterization of 12 p Abnormalities in Hematologic Malignancies : Deletion of K I P I , Rearrangement of TEL , and Amplification of CCND 2

Twenty patients with hematologic malignancies with 12p abnormalities were investigated by fluorescence in situ hybridization (FISH) using probes mapped to specific regions in 12p. The initial analysis using the YAC 964~10 (D12S736) revealed that all four cases with cytogenetically identified del(l2p) had lost one copy of this YAC and that submicroscopic deletions had occurred in 10 of the 16 neoplasms with other 12p abnormalities, ie, translocations, additions, and insertions. The deletions were partially mapped with cosmids localized to subregions of 12p. One copy of the gene for ~ 2 7 ' ' ~ ' (Klf71, involved in cell cycle entrance, was found to be lost in all cases in which deletions could be detected by other probes and in one case with a translocation as the only detectable change. This implicates KlP7 as a possible