Age does not appear to be a major indicator of CDKN2A or CDK4 mutations in melanoma patients in Spain

CDKN2A germline alterations in melanoma patients with personal or familial history of pancreatic cancer

CDKN2A germline mutations increase the risk of melanoma development and are present in 20 and 10% of familial and multiple melanoma cases, respectively. Pancreatic cancer has been associated with CDKN2A in some populations and, accordingly, its presence in first-degree or second-degree relatives of a melanoma patient is considered as a criterion for genetic testing. In this study, we show that in an area with low melanoma incidence, CDKN2A germline mutations in patients with melanoma and personal or family history of pancreatic cancer are mainly present in the setting of familial or multiple melanoma cases. In addition, a relatively young age (≤52 years) at pancreatic diagnosis is an additional single criterion that might also be considered.

Characterization of individuals at high risk of developing melanoma in Latin America: bases for genetic counseling in melanoma

Purpose:

CDKN2A is the main high-risk melanoma-susceptibility gene, but it has been poorly assessed in Latin America. We sought to analyze CDKN2A and MC1R in patients from Latin America with familial and sporadic multiple primary melanoma (SMP) and compare the data with those for patients from Spain to establish bases for melanoma genetic counseling in Latin America.

Genet Med18 7, 727–736.

Methods:

CDKN2A and MC1R were sequenced in 186 Latin American patients from Argentina, Brazil, Chile, Mexico, and Uruguay, and in 904 Spanish patients. Clinical and phenotypic data were obtained.

Genet Med18 7, 727–736.

Results:

Overall, 24 and 14% of melanoma-prone families in Latin America and Spain, respectively, had mutations in CDKN2A. Latin American families had CDKN2A mutations more frequently (P = 0.014) than Spanish ones. Of patients with SMP, 10% of those from Latin America and 8.5% of those from Spain had mutations in CDKN2A (P = 0.623). The most recurrent CDKN2A mutations were c.-34G>T and p.G101W. Latin American patients had fairer hair (P = 0.016) and skin (P < 0.001) and a higher prevalence of MC1R variants (P = 0.003) compared with Spanish patients.

Genet Med18 7, 727–736.

Conclusion:

The inclusion criteria for genetic counseling of melanoma in Latin America may be the same criteria used in Spain, as suggested in areas with low to medium incidence, SMP with at least two melanomas, or families with at least two cases among first- or second-degree relatives.

Genet Med18 7, 727–736.

High- and low-penetrance cutaneous melanoma susceptibility genes

The aim of this review is to report the current understanding of the molecular genetics of melanoma predisposition. To date, two high-penetrance melanoma susceptibility genes, cyclin-dependent kinas inhibitor (CDKN)2A on chromosome 9p21 and cyclin-dependent kinase (CDK4) on 12q13, have been identified. Germline inactivating mutations of the CDKN2A gene are the most common cause of inherited susceptibility to melanoma. Worldwide, a few families have been found to harbor CDK4 mutations. However, predisposing alterations to familial melanoma are still unknown in a large proportion of kindreds. Other melanoma susceptibility loci have been mapped through genome-wide linkage analysis, although the putative causal genes at these loci have yet to be identified. Much ongoing research is being focused on the identification of low-penetrance melanoma susceptibility genes that confer a lower melanoma risk with more frequent variations. Specific variants of the MC1R gene have been demonstrated to confer an increase in melanoma risk. In addition, conflicting data are available on other potential low-penetrance genes encoding proteins involved in pigmentation, cell growth and differentiation, DNA repair or detoxifying of metabolites.

Childhood exposure to ultraviolet radiation and harmful skin effects: epidemiological evidence

We review the general amount and patterns of exposure to solar ultraviolet (UV) radiation that children and teenagers experience and the spectrum of UV-related skin damage that can occur as a result. Data about the amount of solar UV received by children and teenagers are relatively few but suggest that around 40-50% of total UV to age 60 occurs before age 20. Among white children, those with the palest complexions suffer the most damage. Comparisons of prevalence and incidence of outcomes in children and teenagers sharing common ancestry, but living at different latitudes, show that prevalence rates of photoaging and melanocytic naevi are higher in Australian compared with British children, and similarly for melanoma. Genetic risk for the majority of the melanomas in teens is a function of genes controlling naevus propensity and pigmentation in the skin. High numbers of naevi and freckles, red hair, blue eyes, inability to tan, as well as a family history are the primary determinants of melanoma among adolescents. Beyond the signs of skin damage seen in children are the latent effects observed later in adulthood. Childhood is believed to be a susceptible window for long-term harmful effects of UV, as evidenced by clear differences in skin cancer risk between child and adult migrants from high to low latitudes. Effective UV radiation protection from childhood is necessary to control both immediate and long-term harmful effects on children's skin.

Selection criteria for genetic assessment of patients with familial melanoma

Approximately 5% to 10% of melanoma may be hereditary in nature, and about 2% of melanoma can be specifically attributed to pathogenic germline mutations in cyclin-dependent kinase inhibitor 2A (CDKN2A). To appropriately identify the small proportion of patients who benefit most from referral to a genetics specialist for consideration of genetic testing for CDKN2A, we have reviewed available published studies of CDKN2A mutation analysis in cohorts with invasive, cutaneous melanoma and found variability in the rate of CDKN2A mutations based on geography, ethnicity, and the type of study and eligibility criteria used. Except in regions of high melanoma incidence, such as Australia, we found higher rates of CDKN2A positivity in individuals with 3 or more primary invasive melanomas and/or families with at least one invasive melanoma and two or more other diagnoses of invasive melanoma and/or pancreatic cancer among first- or second-degree relatives on the same side of the family. The work summarized in this review should help identify individuals who are appropriate candidates for referral for genetic consultation and possible testing.