Confined trisomy 8 mosaicism of meiotic origin: A rare cause of aneuploidy in childhood cancer.
Author
Summary, in English
Whether chromosome abnormalities observed in tumor cells may in some cases reflect low-grade somatic mosaicism for anomalies present already at zygote formation, rather than acquired somatic mutations, has for long remained a speculation. We here report a patient with Wilms tumor, where constitutional somatic mosaicism of trisomy 8 was detected in a previously healthy 2 ½-year-old boy. Single Nucleotide Polymorphism (SNP) array analysis of tumor tissue revealed a complex distribution of allele frequencies for chromosome 8 that could not be explained solely by mitotic events. Combined analysis of allele frequencies, chromosome banding, and fluorescence in situ hybridization revealed that the majority of tumor cells contained four copies of chromosome 8, with three distinct haplotypes at a 2:1:1 ratio. Because the patient had not been subject to organ transplantation, these findings indicated that the tumor karyotype evolved from a cell with trisomy 8 of meiotic origin, with subsequent somatic gain of one additional chromosome copy. Haplotype analysis was consistent with trisomy 8 through nondisjunction at meiosis I. Matched normal renal tissue or peripheral blood did not contain detectable amounts of cells with trisomy 8, consistent with the complete lack of mosaic trisomy 8 syndrome features in the patient. This case provides proof of principle for the hypothesis that tumor genotypes may in rare cases reflect meiotic rather than mitotic events, also in patients lacking syndromic features. © 2014 Wiley Periodicals, Inc.
Department/s
- Division of Clinical Genetics
- BioCARE: Biomarkers in Cancer Medicine improving Health Care, Education and Innovation
Publishing year
2014
Language
English
Pages
634-638
Publication/Series
Genes, Chromosomes and Cancer
Volume
53
Issue
7
Links
Document type
Journal article
Publisher
John Wiley & Sons Inc.
Topic
- Medical Genetics
Status
Published
ISBN/ISSN/Other
- ISSN: 1045-2257