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Oncogene. 2014 Jul 3;33(27):3506-18. doi: 10.1038/onc.2013.323. Epub 2013 Aug 19.

The telomere profile distinguishes two classes of genetically distinct cutaneous squamous cell carcinomas.

Author information

1
Division of Genetics of Skin Carcinogenesis, German Cancer Research Center, Heidelberg, Germany.
2
Institute of Human Genetics, University of Heidelberg, Heidelberg, Germany.
3
1] Division of Genetics of Skin Carcinogenesis, German Cancer Research Center, Heidelberg, Germany [2] Institute of Human Genetics, University of Heidelberg, Heidelberg, Germany.
4
Department of Dermatology, University of Würzburg, Würzburg, Germany.
5
Department of Dermatology, University of Köln, Würzburg, Germany.
6
Skin Cancer Unit, German Cancer Research Center Heidelberg and Department of Dermatology, Venereology and Allergology, University Medical Center Mannheim, Ruprecht-Karl University of Heidelberg, Mannheim, Germany.
7
Department of Dermatology, University of Heidelberg, Heidelberg, Germany.
8
UK Cancer Research UK Skin Tumour Laboratory, Blizard Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, UK.

Abstract

The incidence of skin cancer is increasing worldwide and cutaneous squamous cell carcinomas (SCCs) are associated with considerable morbidity and mortality, particularly in immunosuppressed individuals ('carcinomatous catastrophy'). Yet, molecular mechanisms are still insufficiently understood. Besides ultraviolet (UV)-indicative mutations, chromosomal aberrations are prominent. As telomeres are essential in preserving chromosome integrity, and telomere erosion as well as aberrant spatial telomere distribution contribute to genomic instability, we first established telomere length profiles across the whole tissue and identified normal skin (10/30) harboring discrete epidermal sites (stem cell territories) of evenly short telomeres. Precancerous actinic keratoses (AKs) (17) and SCCs (27) expressed two telomere phenotypes: (i) tissue-wide evenly short to intermediate and (ii) longer and tissue-wide heterogeneous telomere lengths, suggesting two modes of initiation, with one likely to originate in the epidermal stem cells. Although tumor histotype, location, patient gender or age failed to distinguish the two SCC telomere phenotypes, as did telomerase activity, we found a trend for a higher degree of aberrant p53 and cyclin D1 expression with long/heterogeneous telomeres. In addition, we established an association for the short/homogeneous telomeres with a simpler and the heterogeneous telomeres with a more complex karyotype correlating also with distinct chromosomal changes. SCCs (13) from renal transplant recipients displayed the same telomere dichotomy, suggesting that both telomere subtypes contribute to 'carcinomatous catastrophy' under immunosuppression by selecting for a common set (3, 9p and 17q) and subtype-specific aberrations (e.g., 6p gain, 13q loss). As a second mechanism of telomere-dependent genomic instability, we investigated changes in telomere distribution with its most severe form of telomeric aggregates (TAs). We identified a telomere length-independent but progression-dependent increase in cells with small telomere associations in AKs (17/17) and additional TAs in SCCs (24/32), basal cell carcinomas (30/31) and malignant melanomas (15/15), and provide evidence for a reactive oxygen species-dependent mechanism in this UV-induced telomere organization-dependent genomic instability.

PMID:
23955078
DOI:
10.1038/onc.2013.323
[Indexed for MEDLINE]

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