Melanocytic nevi in very young children: The role of phenotype, sun exposure, and sun protection
ABSTRACT Melanocytic nevi are strongly associated with cutaneous melanoma, yet little is known about factors influencing nevus development in the first years of life.
We sought to identify phenotypic and environmental factors associated with nevus counts in very young children.
In a cluster prevalence survey, full body nevus counts and phenotypic assessments were conducted on 193 children aged 1 to 3 years. Information on each child's sun exposure and sun protection practices was obtained through parental questionnaire.
High total nevus counts were associated with heavy facial freckling, time spent outdoors on weekends in summer, and Caucasian ethnicity. Low nevus counts were associated with dark skin color, ability to tan, and frequent application of sunscreen. Frequent wearing of hats was specifically associated with low nevus counts on the face, but not at other sites.
Nevi are common at a very young age among children in Queensland, Australia, and are associated with sun exposure and freckling. Diligent sun protection practices appear to reduce nevus burden, even after accounting for the effects of phenotype and sun exposure factors. Primary prevention strategies aimed at reducing sun exposure in very early life may be effective in reducing nevus prevalence and melanoma risk.
- SourceAvailable from: William J Pavan
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- "Given the strong epidemiological associations of nevi with cutaneous melanoma and the inference that at least a proportion of melanomas appear to arise directly from nevi, substantial efforts were made to identify those factors that drive the development of nevi in humans. Epidemiological studies quickly established that high levels of sun exposure predicted higher numbers of nevi in early childhood (English and Armstrong, 1994; Fritschi et al., 1994; Harrison et al., 2000; Kelly et al., 1994; Whiteman et al., 2005). Subsequent studies have since provided convincing evidence that the number of nevi on the skin is under strong genetic control by comparing nevus counts among twins. "
ABSTRACT: Converging lines of evidence from varied scientific disciplines suggest that cutaneous melanomas comprise biologically distinct subtypes that arise through multiple causal pathways. Understanding the respective relationships of each subtype with etiologic factors such as UV radiation and constitutional factors is the first necessary step toward developing refined prevention strategies for the specific forms of melanoma. Furthermore, classifying this disease precisely into biologically distinct subtypes is the key to developing mechanism-based treatments, as highlighted by recent discoveries. In this review, we outline the historical developments that underpin our understanding of melanoma heterogeneity, and we do this from the perspectives of clinical presentation, histopathology, epidemiology, molecular genetics, and developmental biology. We integrate the evidence from these separate trajectories to catalog the emerging major categories of melanomas and conclude with important unanswered questions relating to the development of melanoma and its cells of origin.Pigment Cell & Melanoma Research 06/2011; 24(5):879-97. DOI:10.1111/j.1755-148X.2011.00880.x · 5.64 Impact Factor
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ABSTRACT: Les naevus, anciennement appelés nævus mélanocytaires, sont des hyperplasies mélanocytaires bénignes focalisées dans la peau. On suppose que les nævus banaux, présents chez tous les individus, sont des néoplasies acquises. On les oppose ainsi du point de vue pathogénique aux nævus congénitaux qui sont considérés comme des hamartomes et qui restent rares (1).
Article: Epidemiology of malignant melanoma[Show abstract] [Hide abstract]
ABSTRACT: Trends in melanoma incidence have shown an increase in thinner, less lethal tumors in recent years. The overall increases in melanoma incidence have begun to slow in Western Europe and North America. Environmental risk factors are important in the development of melanomas in individuals with high-risk phenotypes, and these people should modify their recreational and overall UV exposure. Primary prevention of melanoma and early detection are essential to reduce melanoma mortality in future years. The complex relationships between genetic factors and patterns of sun exposure, especially in childhood, are the focus of continued research.Surgical Clinics of North America 03/2003; 83(1):1-29. DOI:10.1016/S0190-9622(87)80341-9 · 1.93 Impact Factor