Dataset Information

Excessive genomic DNA copy number variation in the Li-Fraumeni cancer predisposition syndrome.

ABSTRACT: DNA copy number variations (CNVs) are a significant and ubiquitous source of inherited human genetic variation. However, the importance of CNVs to cancer susceptibility and tumor progression has not yet been explored. Li-Fraumeni syndrome (LFS) is an autosomal dominantly inherited disorder characterized by a strikingly increased risk of early-onset breast cancer, sarcomas, brain tumors and other neoplasms in individuals harboring germline TP53 mutations. Known genetic determinants of LFS do not fully explain the variable clinical phenotype in affected family members. As part of a wider study of CNVs and cancer, we conducted a genome-wide profile of germline CNVs in LFS families. Here, by examining DNA from a large healthy population and an LFS cohort using high-density oligonucleotide arrays, we show that the number of CNVs per genome is well conserved in the healthy population, but strikingly enriched in these cancer-prone individuals. We found a highly significant increase in CNVs among carriers of germline TP53 mutations with a familial cancer history. Furthermore, we identified a remarkable number of genomic regions in which known cancer-related genes coincide with CNVs, in both LFS families and healthy individuals. Germline CNVs may provide a foundation that enables the more dramatic chromosomal changes characteristic of TP53-related tumors to be established. Our results suggest that screening families predisposed to cancer for CNVs may identify individuals with an abnormally high number of these events.

SUBMITTER: Shlien A

PROVIDER: S-EPMC2516272 | biostudies-literature | 2008 Aug

REPOSITORIES: biostudies-literature

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Excessive genomic DNA copy number variation in the Li-Fraumeni cancer predisposition syndrome.

Shlien Adam A Tabori Uri U Marshall Christian R CR Pienkowska Malgorzata M Feuk Lars L Novokmet Ana A Nanda Sonia S Druker Harriet H Scherer Stephen W SW Malkin David D

Proceedings of the National Academy of Sciences of the United States of America 20080806 32

DNA copy number variations (CNVs) are a significant and ubiquitous source of inherited human genetic variation. However, the importance of CNVs to cancer susceptibility and tumor progression has not yet been explored. Li-Fraumeni syndrome (LFS) is an autosomal dominantly inherited disorder characterized by a strikingly increased risk of early-onset breast cancer, sarcomas, brain tumors and other neoplasms in individuals harboring germline TP53 mutations. Known genetic determinants of LFS do not ...[more]

PMID: 18685109

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Project description:Background:Li-Fraumeni syndrome (LFS) is a cancer predisposition disorder characterized by germline mutations of the p53 tumor-suppressor gene. In response to DNA damage, p53 stimulates protective cellular processes including cell-cycle arrest and apoptosis to prevent aberrant cell proliferation. Current cancer therapies involve agents that damage DNA, which also affect non-cancerous hematopoietic stem/progenitor cells. Here, we report on a child with LFS who developed genomic instability during craniospinal irradiation for metastatic choroid plexus carcinoma (CPC). Case presentation:This previously healthy 4-year-old boy presented with parieto-temporal brain tumor, diagnosed as CPC grade-3. Screening for cancer-predisposing syndrome revealed heterozygous p53 germline mutation, leading to LFS diagnosis. After tumour resection and systemic chemotherapy, entire craniospinal axis was irradiated due to leptomeningeal seeding, resulting in disease stabilization for nearly 12?months. Blood lymphocytes of LFS patient (p53-deficient) and age-matched tumor-children (p53-proficient) were collected before, during and after craniospinal irradiation and compared with asymptomatic carriers for identical p53 mutation, not exposed to DNA-damaging treatment. In p53-deficient lymphocytes of LFS patient radiation-induced DNA damage failed to induce cell-cycle arrest or apoptosis. Although DNA repair capacity was not impaired, p53-deficient blood lymphocytes of LFS patient showed significant accumulation of 53BP1-foci during and even several months after irradiation, reflecting persistent DNA damage. Electron microscopy revealed DNA abnormalities ranging from simple unrepaired lesions to chromosomal abnormalities. Metaphase spreads of p53-deficient lymphocytes explored by mFISH revealed high amounts of complex chromosomal aberrations after craniospinal irradiation. Conclusions:Tumor suppressor p53 plays a central role in maintaining genomic stability by promoting cell-cycle checkpoints and apoptosis. Here, we demonstrate that a patient with LFS receiving craniospinal irradiation including large volumes of bone marrow developed progressive genomic instability of the hematopoietic system. During DNA-damaging radiotherapy, genome-stabilizing mechanisms in proliferating stem/progenitor cells are perturbed by p53 deficiency, increasing the risk of cancer initiation and progression.

Dataset Information

Excessive genomic DNA copy number variation in the Li-Fraumeni cancer predisposition syndrome.

Publications

Excessive genomic DNA copy number variation in the Li-Fraumeni cancer predisposition syndrome.

Similar Datasets

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