MOLECULAR DELINEATION OF 13Q DELETION BOUNDARIES IN 20 PATIENTS WITH MYELOID MALIGNANCIES

Fluorescent in situ hybridization (FISH) analysis with a panel of DNA probes for 13q13.1-q14.3 was performed on 20 cases of myeloid malignan cies, of which 17 showed a del(13)/(q) and three had translocations af fecting 13q. By chromosome morphology, deletions consistently involved bands q14 and q21. In addition to confirming the chromosome data, FIS H allowed us to delineate a commonly deleted region that was flanked b y YAC 833A2 and YAC 854D4. Three cases with 13q translocations unexpec tedly showed accompanying cryptic microdeletions of 13q, and in one ca se the commonly deleted region could be narrowed to a genomic segment, which includes YAC 937C7, RB1, and YAC 745E3. Homozygous deletions we re not detected. This region overlaps with the smallest deleted region of 13q14 in chronic lymphocytic leukemia. (C) 1998 by The American So ciety of Hematology.