Three-way and two-way rearrangements involving chromosomes 10, 2, 5 and 5, 2 in two marker chromosomes of a human melanoma cell line

Two marker chromosomes (mar1 and mar2), provided with two closely spaced heterochromatic bands, were observed in the 14932 cell line established from a human metastatic melanoma. Fluorescence in situ hybridization (FISH) with the alphoid sequence p82H common to all human centromeres showed strong signals over the double C-bands of mar1 and mar2. These were recognized by a chromosome 2-specific alphoid probe, although chromosome in situ suppression (CISS) hybridization with a chromosome 2 library failed to reveal any painting along mar1 and mar2. The centromere of mar1 was identified by a chromosome 10-specific alphoid sequence and the marker chromosome was decorated from pter to a region proximal to the interpolated C-band by a chromosome 10 library. The centromere of mar2 could not be recognized by any chromosome-specific alphoid probe, but the whole mar2 was decorated by a chromosome 5 library. This library also painted the distal q arm of mar1, which was not painted by the chromosome 10 library, as well as a small band proximal to the double C-band. Identification of the two marker chromosomes reveals their common origin and indicates a role for chromosomes 2, 5 and 10 in the genesis and/or progression of the 14932 melanoma. Alteration to the chromosome-specific alphoid sequence in the centromere of mar2 provides evidence for rearrangement of constitutive heterochromatin alphoid sequences in human tumours