Familial melanoma risk genes in Queensland

Read, Jazlyn (2016). Familial melanoma risk genes in Queensland MPhil Thesis, School of Medicine, The University of Queensland. doi:10.14264/uql.2016.393

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Author Read, Jazlyn
Thesis Title Familial melanoma risk genes in Queensland
School, Centre or Institute School of Medicine
Institution The University of Queensland
DOI 10.14264/uql.2016.393
Publication date 2016-07-01
Thesis type MPhil Thesis
Supervisor Nicholas K. Hayward
H. Peter Soyer
Total pages 137
Language eng
Subjects 1112 Oncology and Carcinogenesis
Formatted abstract
Melanoma 'risk' is multifaceted, with genetic, phenotypic, and environmental factors all contributing to melanoma predisposition. Although the majority of melanoma is attributable to random acquired mutations in melanocytes, a positive family history is associated with an increased risk of developing the disease, and the presence of heritable germline variants is an important component of melanoma susceptibility for some families. Mutation in one of the known high penetrance melanoma predisposition genes, comprising CDKN2A, CDK4, BAP1, POT1, ACD, TERF2IP, and TERT, underpins melanoma risk for approximately half of all high-density familial clustering of melanoma. However, the underlying genetic basis of disease remains unexplained for many families.

It is likely that a polygenic component to melanoma predisposition accounts for the remainder of families, where overall susceptibility is influenced by combinations of low to moderate risk polymorphisms, rare high penetrance germline mutations, and modulation of risk by environmental and genetic factors. Although no single presently known germline alteration guarantees disease development, the main impact of predisposition genes is the elevation of baseline melanoma risk. For an individual with existing genetic susceptibility, it is likely that fewer sporadic mutations are required to accumulate before a critical level for oncogenesis is reached. Beyond conferring risk of cutaneous melanoma, some ‘melanoma’ predisposition genes have been linked to diverse cancer phenotypes. Familial risk has been proposed as a shared feature of many cancers, and clustering of additional cancers in melanoma families has been observed at rates greater than expected by chance.

In a cohort of 178 'intermediate risk' melanoma families, cancer development was assessed over a 33 year period, and identified significantly more than expected bladder cancer, lymphoid leukaemia, and myeloma. Further to population level cancer risk, it is proposed that some cancer dense families carry known and possibly as-yet-unidentified melanoma predisposition genes.

Eight families with high melanoma case density and eleven individuals with three or more invasive cancer types including melanoma were selected for further follow up with whole exome or whole genome sequencing. Multiple damaging variants in cancer-associated genes were identified, supporting a polygenic basis for melanoma susceptibility. Given the diversity of genetic variants and other cancer types in the cohort, it is possible that some cancer-associated genes identified here also have pleiotropic effects in predisposing to melanoma.
Keyword Cancer
Familial
Genetic
Hereditary cancer
Melanoma
Melanoma genetics
Polygenic inheritance
Skin - Cancer
Risk allele

Document type: Thesis
Collections: UQ Theses (RHD) - Official
UQ Theses (RHD) - Open Access
 
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Created: Thu, 30 Jun 2016, 05:27:55 EST by Jazlyn Read on behalf of Learning and Research Services (UQ Library)