Reverse painting of microdissected chromosome 19 markers in ovarian carcinoma identifies a complex rearrangement map

Abstract

Alterations of chromosome bands 19p13 and 19q13 in the form of added extra material of unknown origin are among the most frequent cytogenetic changes in ovarian carcinomas. To investigate the chromosomal composition of the 19p+ and/or 19q+ markers, we selected for examination 26 ovarian carcinomas which by G-banding had one to four 19p+ and/or 19q+, in total 37 markers. These cases were then subjected to chromosomal microdissection with subsequent reverse painting, which gave informative results on 29 markers. The breakpoints on chromosome 19 were located in both the short (p; n = 15) and the long (q; n = 10) arms, as well as in the centromeric (n = 2) and pericentromeric (n = 6) region. The analysis showed that many chromosomes added material to chromosome 19, but the chromosome arms 11q, 21q, and 22q were particularly common donors. Homogeneously staining regions (hsr) were seen in only three markers, in all of them consisting of 19p material. Eighteen markers were derived from an unbalanced translocation involving chromosome 19. In five markers, chromosome 19 was rearranged with two chromosomes. The most complex marker showed chromosome 19 rearranged with three other chromosomes, i.e., X, 13, and 16. In five markers, all of the additional material stemmed from chromosome 19 itself. This is the first large chromosome microdissection/FISH study of chromosome 19 markers in ovarian carcinomas. A detailed map of the rearrangements should provide clues to the positions of oncogenes and potential fusion genes important in ovarian carcinogenesis.

Genomic profile of ovarian carcinomas

“…Much later, we subjected a group of ovarian carcinomas showing additional material of unknown origin sitting on 19p/q to examination by microdissection followed by reverse in situ hybridization and were able to identify the nature of the rearrangements in more detail [6]. We also performed arrayCGH to identify the genomic regions that were gained or amplified on the structurally rearranged 19p/19q [17].…”

“…After 6-7 days of culturing in a selective medium [6], colchicine was added and the cultures harvested according to Mandahl [7]. The chromosomes of the dividing cells were then G-banded and a karyotype established according to the recommendations of the ISCN [8].…”

Copy Number and Expression Alterations of miRNAs in the Ovarian Cancer Cell Line OVCAR-3: Impact on Kallikrein 6 Protein Expression

“…Moreover, cytogenetic studies support the observation that chromosome 19 is typically involved in both clonal and nonclonal numerical and structural aberrations (8,31 ), and that the vast majority of OCas are polyploid (8,10,11,32 ). Therefore, the averaging algorithms of aCGH used in studies resulting in the frequent loss of the locus (33,34 ) failed to take into account ploidy and copy number heterogeneity (12 ).…”

Chromosome‐specific segmentation revealed by structural analysis of individually isolated chromosomes

“…One possible solution is to apply these powerful analytical technologies to individual chromosomes. Microdissection (MD) and flow sorting of chromosomes have been used to separate individual chromosomes and applied to the analysis of structural rearrangements including amplifications, deletions, and translocations (Mahjoubi et al, 2006;Backx et al, 2007;Gribble et al, 2007;Chen et al, 2008;Micci et al, 2009), haplotype analysis (Ma et al, 2010) and regional sequencing (Chen et al, 2010;Weise et al, 2010). The flow sorting method is effective, but its use is restricted to such chromosomes as are different from others in size or DNA content.…”