MINIMAL SIZES OF DELETIONS DETECTED BY COMPARATIVE GENOMIC HYBRIDIZATION

Comparative genomic hybridization (CGH) has been used widely for the m olecular cytogenetic analysis of tumors. Until now, the spatial resolu tion of this technique for diagnosing deletions of chromosomal sequenc es has not been assessed in detail. In the present study, we performed CGH analyses on five DNA samples derived from B-cell leukemias with 1 1q deletions, the sizes of which ranged from 3 Mbp to 14-18 Mbp. CGH e xperiments were evaluated by two established commercial analysis syste ms. Deletions down to a size of 10-12 Mbp were diagnosed based on a di agnostic threshold value of 0.8, if the vast majority of cells carried the deletion. For cases with smaller deletions, the ratio profiles we re shifted toward underrepresentation at the respective chromosomal ba nds; however, the diagnostic threshold value was not reached. In all f ive cases, there was complete agreement between the two image analysis systems. (C) 1998 Wiley-Liss, Inc.