Cytogenetic and molecular analysis of complex chromosome rearrangements in human cancer: Application of chromosome microdissection.

Abstract

Cytogenetic analysis was performed on 50 short-term culture of human ovarian carcinoma from 48 patients. All 50 cases evidenced clonal karyotypic abnormalities with 32/50 displaying numeric changes, and 49/50 displaying structural alterations. The most notable numeric abnormalities were loss of the X chromosome and gain of chromosome 7. Structural alterations appeared to be nonrandom. Chromosomes most frequently involved in structural alterations included chromo-somes 1>7>11>12>3>6. When the chromosomal breakpoints were analyzed they were shown to cluster to several chromosomal band regions including: 1p31-p36, 1p13-q1, 6q22-q25, 7p15-p22, 7q31-34, 11p15, and 12p11-pl13. In addition, a novel procedure for chromosome microdissection and in vitro amplification of dissected DNA was developed and applied to several areas. Microdissection and in vitro amplification of dissected chromosomal fragments were performed, followed by labeling for fluorescent in situ hybridization (FISH) to normal metaphase chromosomes (Micro-FISH). Micro-FISH probes have been used successfully to determine the derivation of chromosome segments unidentifiable by conventional cytogenetic analysis. Micro-FISH probes were also generated following microdissection of unidentifiable portions of nonreciprocal translocations, allowing determination of the derivation of these unknown chromosome segments. Another application of the microdissection procedure has been to generate whole chromosome "painting" probes by microdissection of an entire chromosome. Finally, a chromosome microdissection combining microcloning technique has been developed and used to generate chromosomal band-specific DNA libraries for physical mapping. A genomic library of >20,000 clones, which is highly enriched for sequences encompassing 6q21, was constructed. Clones from this library have been characterized and localized to the target region by hybridization to a chromosome-6 mapping panel.