CYTOGENETIC ANALYSIS OF 3 BREAST-CARCINOMA CELL-LINES USING REVERSE CHROMOSOME PAINTING

Chromosome painting was used to determine the copy number-and identity of virtually all the chromosomes in three breast cancer cell lines, T -47D, MDA-MB-361, and ZR-75-1. The karyotypes of all three cell lines were very complex, and were consistent with the monosomic pattern of e volution suggested by Dutrillaux, in which nonreciprocal translocation s cause an initial reduction in chromosome number, followed by duplica tion of the entire genome and further chromosome loss. Twenty distinct abnormal chromosomes were identified in T-47D, seven of which were pr esent as two copies. MDA-MB-361 had 27 abnormal chromosomes, each as a single copy. Thirteen abnormal chromosomes in ZR-75-1 occur-red singl y, two were paired, and one was present as three copies. Most of the a bet-rant chromosomes were nonreciprocal translocations, although delet ions, duplications, isochromosomes, and amplifications (HSR of Iq) wer e also found. Chromosome arms present in abnormal chromosomes in all t hree lines were 1q, 6p, 7p, 8p, 8q, 10q, 11p, 11q, 12p, 13q, 14q, 15q, 16p, 16q, 17q, and 20q, The only chromosome arms present in four or m ore copies in all three lines were 8q and proximal 12p, while Ip, 17p, and bands 11q 12-13 were the only chromosome regions consistently red uced to two copies. The most striking feature common to all three line s was a translocation breakpoint on the shore arm of chromosome 8 at 8 p12. (C) 1997 Wiley-Liss, Inc.