Definition of chromosome aberrations in testicular germ cell tumor cell lines by 24-color karyotyping and complementary molecular cytogenetic analyses

Many of the reported karyotypes for adult testicular germ cell tumors (GCTs ) are complex and incomplete. although the presence of an isochromosome 12p . i(12p). and gain of 12p material have consistently been found. Here. an a ccurate definition of the chromosome aberrations associated with four cell lines derived from GCTs (GCT27. H12.1, Tera1. and Tera2) has been produced using 23-color karyotyping by mulifluor in situ hybridization, comparative genomic hybridization analysis, and further fluorescence in situ hybridizat ion analysis to confirm some chromosomal assignments and refine involvement of specific regions of 12p. There was karyotypic heterogeneity. Isochromos omes in addition to i(12p) were found, as were other rearrangements with br eakpoints at or near centromeric regions. The most frequent non-centromeric breakpoints were at 1p31 similar to p32 1p21 similar to p22, 11q13, and Xq 22, although consistent partner chromosomes were not involved One cell line (Teral) showed a subtle dosage increase in the copy number of a 12p probe known to be within the smallest overlapping region of amplification that ha s been defined in a number of testicular GCTs with amplicons at 12p11 simil ar to p12. The chromosome rearrangements and associated imbalances may he s ignificant in GCT progression and the characterized cell lines can be used to investigate these further. (C) 2001 Elsevier Science Inc. All rights res erved.