Instability of chromosomes 1, 3, 16, and 17 in primary breast carcinomas inferred by fluorescence in situ hybridization.

Abnormalities of chromosomes 1, 3, 16, and 17 were examined in 203 metaphase cells from 12 cases of primary breast carcinoma using fluorescence in situ hybridization with chromosome painting probes. The most common structural abnormalities were chromosomal rearrangements, especially translocations, and chromosome 17 was most frequently involved in these types of changes. Chromosome 16 was preferentially involved in the losses and deletions, while chromosomes 1 and 17 were more involved in the gains, including amplifications, than other chromosomes. This approach has revealed a different profile of abnormalities from those normally shown by G-banding analysis. Some of these changes are likely to be novel and may be biologic or clinical importance in breast cancer.