Detection of 6q deletions in breast carcinoma cell lines by fluorescence in situ hybridization

Dual-color fluorescence in situ hybridization was performed to detect the f requency and extent of 6q deletions in ten breast carcinoma cell lines. In five cell lines, the 6q deletions involved large regions extending from 6q1 2-q16 to 6q27, and in one the deletion extended from the region distal to Y AC 751G10 at 6q25.1 to 6q27. In two cell lines, 6q deletions occurred only in cells with polysomy 6, indicating that such deletions might be secondary chromosomal aberrations and reflect late genetic changes in breast carcino mas. In addition, an overrepresentation of 6q21-q22.2 was detected in one c ell line.