Aberrations of chromosome 8 in 16 breast cancer cell lines by comparative genomic hybridization, fluorescence in situ hybridization, and spectral karyotyping

Comparative genomic hybridization (CGH) studies have shown that chromosome 8 is a frequent target for chromosomal aberrations in breast cancer. We characterized these aberrations of chromosome 8 in 16 breast cancer cell lines (BT-474, BT-549, CAMA-1, DU-4475, MCF-7, MDA-MB-134, MDA-MB-157, MDA-MB-361, MDA-MB-415, MDA-MB-436, MPE600, SK-BR-3, T-47D, UACC-812, UACC-893 and ZR-75-1) by CGH, fluorescence in situ hybridization (FISH) with arm- and locus-specific probes, and spectral karyotyping (SKY). Chromosome 8 was structurally abnormal in 13 of 16 cell lines. Loss of 8p was detected in nine cell lines, gain of entire 8q in six cell lines, 8q21–qter in three, 8q23–qter in two, and 8q12–qter and 8p21–q21 in one cell line. Extra copies of the C-MYC oncogene were found in 11 cell lines, but high-level amplification only in SK-BR-3. Derivative chromosomes including material from chromosomes 8 were complex, and the breakpoints were strikingly dissimilar. Chromosome 11 was the most frequent translocation partner with chromosome 8 (in 7 cell lines). Isochromosomes and/or isoderivative 8q were found in four cell lines. The high frequency and complexity of alterations at 8q indicate a significant pathogenetic role in breast cancer. The high-level amplification of c-myc is less common than previously thought.