RETENTION OF POLYSOMY AT 9P23-24 DURING KARYOTYPIC EVOLUTION IN HUMANBREAST-CANCER CELL-LINE COLO-824

Somatic genetic alterations of 9p have been seen in a wide range of hu man cancers, including breast cancer. Loss of heterozygosity analysis of primary breast cancer tumors has revealed a high frequency of delet ion of DNA from 9p21-22 encompassing the MTS1 (P16/CDKN2A) gene. We re port the approximately tenfold increase in copy number of DNA from 9p2 3-24, which is far distal to P16/CDKN2A in female breast cancer cell l ine COLO 824, as revealed by fluorescence in situ hybridization, compa rative genomic hybridization, and microsatellite analysis. Amplificati on of DNA has been reported previously to encompass multiple sites of the genome of the breast cancer cell, but increase in DNA copy number has not been seen in distal 9p. Genes Chromosomes Cancer 24:87-93, 199 9. (C) 1999 Wiley-Liss. Inc.