Ring chromosomes have been found with some regularity as solid tumors have come increasingly under cytogenetic study. The full genetic content and significance of these rings remain unclear, Dermatofibrosarcoma protuberans, a tumor of the deep dermis, consistently has supernumerary ring chromosomes, sometimes as the sole detectable cytogenetic change. Using a modified method for comparative genomic hybridization and fluorescent in situ hybridization with a panel of various probes, we found that these ring chromosomes consistently contain the chromosome 22 centromere along with interstitial sequences from chromosomes 17 and 22, specifically from regions 17q23-24 and 22q11-12, The ring chromosomes in dermatofibrosarcoma protuberans are vehicles for a particular pattern of relatively low-level genomic amplification of selected sequences.

Mystery surrounds the mechanisms by which the uncommon cutaneous tumor dermatofibrosarcoma protuberans (DP) arises and progresses. A clue may be at hand in the form of extra abnormal chromosomes (one to three ring chromosomes per case with or without other chromosome abnormalities) seen in some 10 cases, including five cases in our experience. The specificity of the rings to DP would be enhanced if the rings were found to contain a contribution from a constant chromosome. We here report fluorescence in situ hybridization (FISH) results bearing on the chromosomal content of DP rings, together with clinical, pathologic, and cytogenetic documentation of our first two cases, which were briefly reported earlier, and three new DP cases. To dissect a translocation (in our 2nd case), we probed by FISH and discovered chromosome 17 sequences in the rings in all five DP cases. Nonfluorescent bands were seen on some rings painted with a whole chromosome 17 probe, indicating the presence in these rings of foreign chromosome sequences. The complexity of the rings was underscored by the detection in only one case of chromosome 17 centromeric sequences. The situation in DP seems to have parallels to that in well-differentiated liposarcoma, another tumor of intermediate malignancy with extra abnormal marker chromosome containing contributions from a constant chromosome and variable donors. In DP the supernumerary rings are clearly specific and significant.

Clinical GeneticsVolume 41, Issue 3 p. 167-168 Nonrandom chromosome breakpoints in 6q deletions Frederick Hecht, Frederick Hecht Molecular Medicine and Genetics The Children's Mercy Hospital 2401 Gillham Road Kansas City, Missouri 64108, USASearch for more papers by this authorBarbara K. Hecht, Barbara K. Hecht Molecular Medicine and Genetics The Children's Mercy Hospital 2401 Gillham Road Kansas City, Missouri 64108, USASearch for more papers by this author Frederick Hecht, Frederick Hecht Molecular Medicine and Genetics The Children's Mercy Hospital 2401 Gillham Road Kansas City, Missouri 64108, USASearch for more papers by this authorBarbara K. Hecht, Barbara K. Hecht Molecular Medicine and Genetics The Children's Mercy Hospital 2401 Gillham Road Kansas City, Missouri 64108, USASearch for more papers by this author First published: March 1992 https://doi.org/10.1111/j.1399-0004.1992.tb03656.xCitations: 5AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article.Citing Literature Volume41, Issue3March 1992Pages 167-168 RelatedInformation