The effect of sun exposure in determining nevus density in UK adolescent twins

Sun-Protective Clothing Worn Regularly during Early Childhood Reduces the Number of New Melanocytic Nevi: The North Queensland Sun-Safe Clothing Cluster Randomized Controlled Trial

Numerous pigmented moles are associated with sun exposure and melanomarisk. This cluster randomized controlled trial aimed to determine if sun-protective clothing could prevent a significant proportion of the moles developing in young children (ACTRN12617000621314; Australian New Zealand Clinical Trials Registry. Twenty-five childcare centers in Townsville (19.25° S), Australia, were matched on shade provision and socioeconomic status. One center from each pair was randomized to the intervention arm and the other to the control arm. Children at 13 intervention centers wore study garments and legionnaire hats at childcare and received sun-protective swimwear and hats for home use, while children at the 12 control centers did not. The 1–35-month-old children (334 intervention; 210 control) were examined for moles at baseline (1999–2002) and were re-examined annually for up to 4 years. Both groups were similar at baseline. Children at intervention centers acquired fewer new moles overall (median 12.5 versus 16, p = 0.02; 0.46 versus 0.68 moles/month, p = 0.001) and fewer new moles on clothing-protected skin (6 vs. 8; p = 0.021 adjusted for confounding and cluster sampling) than controls. Intervention children had 24.3% fewer new moles overall (26.5 versus 35) and 31.6% (13 versus 19) fewer moles on clothing-protected skin than controls after 3.5 years. Sunlight’s influence on nevogenesis is mitigated when children regularly wear UPF 30-50+ clothing covering half their body, implying that increased clothing cover reduces melanoma risk. Sun-protective clothing standards should mandate reporting of the percentage of garment coverage for childrenswear.

Melanocytic naevi, melanocytomas and emerging concepts

With the elucidation of the genetics of melanocytic tumours, new concepts have emerged. An important one is the identification of 'intermediate' melanocytic tumours, those with genetic progression events beyond those of melanocytic naevi but that are not fully malignant. Thus, melanocytic tumours exist on a genetic spectrum that likely corresponds to biological behaviour. There are multiple pathways to melanoma development with different initiating events and characteristic benign melanocytic neoplasms and the precise placement of tumours on these pathways remains to be established and the corresponding risks of progression quantified. In this review, I discuss the classification of melanocytic naevi based on clinical, histopathological and genetic features, as well as the concept of melanocytomas with discussion of specific recognisable subtypes.

The Interplay between Nevi and Melanoma Predisposition Unravels Nevi-Related and Nevi-Resistant Familial Melanoma

Genetic susceptibility to nevi may affect the risk of developing melanoma, since common and atypical nevi are the main host risk factors implicated in the development of cutaneous melanoma. Recent genome-wide studies defined a melanoma polygenic risk score based on variants in genes involved in different pathways, including nevogenesis. Moreover, a predisposition to nevi is a hereditary trait that may account for melanoma clustering in some families characterized by cases with a high nevi density. On the other hand, familial melanoma aggregation may be due to a Mendelian inheritance of high/moderate-penetrance pathogenic variants affecting melanoma risk, regardless of the nevus count. Based on current knowledge, this review analyzes the complex interplay between nevi and melanoma predisposition in a familial context. We review familial melanoma, starting from Whiteman's divergent pathway model to overall melanoma development, distinguishing between nevi-related (cases with a high nevus count and a high polygenic risk score) and nevi-resistant (high/moderate-penetrance variant-carrier cases) familial melanoma. This distinction could better direct future research on genetic factors useful to identify high-risk subjects.

Demographic, clinical and dermoscopic features of melanocytic nevi on the scalp

BACKGROUND

The scalp is a special anatomical area and dermoscopic findings of this region may significantly differ from other body parts.

OBJECTIVE

To investigate and compare the clinical and dermoscopic patterns of scalp melanocytic nevi in patients ≤15 years of age and above, and to analyse their relevance to demographic features, atypical mole syndrome (AMS) and total body nevus count (TBNC).

METHODS

In this retrospective cohort study, the clinical data and dermoscopic images of patients with scalp melanocytic nevi were retrieved, reviewed and analysed. Demographic, clinical and dermoscopic features were compared in patients ≤15 years of age and above.

RESULTS

A total of 196 scalp melanocytic nevi in 126 patients (female/male:64/62; ≤15/>15 years of age: 49/77) with a median age of 18.5 years (range 0-72) were evaluated. Statistically, the globular pattern was significantly higher in all age groups, and the papillomatous pattern was significantly lower in patients ≤15 years of age (P = 0.008 and P = 0.005, respectively). The eclipse pattern was significantly higher, and the homogenous pattern was significantly lower in patients ≤15 years of age with AMS (P = 0.003 and P = 0.014, respectively). Finally, patients ≤15 years of age with 50 to 100 TBNC had a higher eclipse pattern than those with 0 to 25 TBNC.

CONCLUSION

The findings of this retrospective study might implicate that children with eclipse pattern of scalp melanocytic nevi might be 'moley' in the future with an impending risk of AMS. This hypothesis requires confirmation in future prospective studies on a larger cohort of patients.

Photoprotective effect of the fucose-containing polysaccharide FucoPol

This study reports the performance of FucoPol, a fucose-containing bacterial polysaccharide, as a photostable agent with high absorption yield at concentrations as low as 0.02 % (w/v). FucoPol is non-cytotoxic, efficiently protects from UVA and UVB at concentrations of 0.02-2 % (w/v) and 0.2-2 % (w/v), respectively, has over 94 % overall photostability up to 1.5 h of irradiation time. The lowest concentration studied (0.02 %, w/v) shows a sun protection factor (SPF) of 2.61 ± 0.08. The SPF-to-concentration unit ratio showed that FucoPol is about 60-fold more photoprotective than combinations of common organic and inorganic UV filters. In vitro radiation exposure experiments of adhered Vero epithelial and PM1 keratinocytic cells in the presence of 0.25 % (w/v) FucoPol further showed that cell viability was preserved, and delayed radiation-induced cell death was prevented. Overall, FucoPol outperforms common cosmetic biopolymers like xanthan and fucogel. These results are very promising for the development of bio-based sunscreen formulations.

Clinical Characteristics in Early Childhood Associated with a Nevus-Prone Phenotype in Adults from Tropical Australia: Two Decades of Follow-Up of the Townsville Preschool Cohort Study

Having numerous melanocytic nevi increases melanoma risk. Few studies have enumerated nevi in children and re-examined them as adults. We aimed to determine if childhood nevus-counts predict nevus-prone adults, and further explore the relevance of host-factors and sun-exposure. Fifty-one Caucasian residents of Townsville (19.16° S, Queensland, Australia) had full-body nevus-counts aged 1–6 and 21–31 years-old. Sun-exposure was determined from questionnaires. Children in the upper-quartile of nevus-counts acquired nevi more rapidly than those in the bottom-quartile (13.3 versus 4.7 nevi/year; p < 0.0005). Children sunburnt before 7 years-old acquired more incident nevi by adulthood (238 versus 126, p = 0.003) particularly if sunburn was severe (321 versus 157.5, p = 0.003) or erythema occurred annually (380 versus 132, p = 0.008). Fair-skinned, freckled children with some nevi ≥ 3 mm, solar lentigines, or a family history of melanoma acquired more incident nevi than children without these attributes. Nevus-prone adults exhibit distinguishing features earlier in life (<7 years-old in Queensland) than has been shown previously. In addition to intervening with sun-protection counselling early enough to reduce risk, being able to reliably triage children into high- and low melanoma-risk groups may inform more efficacious and cost-effective targeted-screening in melanoma-prone populations. Further longitudinal research is needed to confirm that these attributes can reliably separate risk-groups.

Pigmentary traits, sun exposure, and risk of non-Hodgkin's lymphoma/chronic lymphocytic leukemia: A study within the French E3N prospective cohort

To investigate whether risk factors for keratinocyte carcinomas (KCs), namely pigmentary traits and sun exposure, are associated with risk of non‐Hodgkin's lymphomas (NHL) and chronic lymphocytic leukemia (CLL). E3N is a prospective cohort of French women aged 40–65 years at inclusion in 1990. Cancer data were collected at baseline and updated every 2–3 years. Hazard Ratios (HRs) and 95% confidence intervals (CIs) for associations between pigmentary traits and sun exposure, and risk of CLL/NHL were estimated using Cox models. With a median follow‐up of 24 years, 622 incident cases of CLL/NHL were ascertained among the 92,097 included women. The presence of nevi was associated with CLL/NHL risk: HR for “many or very many nevi” relative to “no nevi”: 1.56 [1.15; 2.11]. Such association with number of nevi appears to be mostly limited to risk of CLL: HR for “many or very many nevi”: 3.00 [1.38; 6.52]; versus 1.32 [0.94; 1.84] for NHL. Women whose skin was highly sensitive to sunburn also had a higher risk of CLL: HR = 1.96 [1.21; 3.18], while no increase in risk of NHL was observed. Skin or hair color, number of freckles, and average daily ultraviolet (UV) dose during spring and summer in location of residence at birth or at inclusion (kJ/m²) were not associated with CLL/NHL risk. Some pigmentary traits (presence of nevi and skin sensitivity), but not sun exposure, were associated with CLL/NHL. These observations suggest that CLL may share some constitutional risk factors with keratinocyte cancers.

Cutaneous nevi and internal cancer risk: Results from two large prospective cohorts of US women

Elevated cutaneous nevus number has been linked to longer telomeres. Recently, a large systematic Mendelian randomization study identified a significant positive association between telomere length and risk of cancer. Here, we hypothesized that higher nevus count, as a phenotypic marker of longer telomere, may be associated with increased risk of internal cancer, and prospectively examined the association between nevus count and total as well as site-specific cancer risk among participants in the Nurses' Health Study (NHS, 1986-2012) and the Nurses' Health Study 2 (NHS2, 1989-2013) using Cox proportional hazards models. During 3,900,264 person-years of follow-up, we documented a total of 23,004 internal cancer cases (15,484 in the NHS and 7,520 in the NHS2). Compared to participants who had no nevi, the multivariate hazard ratios of total cancer (excluding skin cancer) were 1.06 (95% confidence interval [CI], 1.03-1.09) for women with 1-5 nevi, 1.08 (95% CI, 1.03-1.15) for those who had 6-14 nevi and 1.19 (95% CI, 1.05-1.35) for those with 15 or more nevi (p trend <0.0001). Moreover, because nevus count has been associated with risk of breast cancer previously, we conducted a secondary analysis by excluding breast cancer from the outcomes of interest. The results were very similar to those of our primary analysis. For individual cancer, most of the associations with nevus count were positive but not statistically significant. In conclusion, we identified the number of cutaneous nevi as a phenotypic marker associated with internal cancer risk, which may be explained by telomere biology.

New and evolving concepts of melanocytic nevi and melanocytomas

In daily clinical practice melanocytic nevi are commonly encountered. Traditionally, both benign and malignant melanocytic tumors have been sub-classified by their histopathologic characteristics with differing criteria for malignancy applied to each group. Recently, many of the mutations that initiate nevus formation have been identified and specific sets of mutations are found in different subtypes of nevi. Whereas a single mutation appears sufficient to initiate a nevus, but is not enough to result in melanoma, specific combinations of mutations have been identified in some melanocytic tumors that are regarded to be of low biologic potential. The term "melanocytoma" has recently been proposed by the World Health Organization to describe those tumors that demonstrate genetic progression beyond the single mutations that are found in nevi but are not frankly malignant. Melanocytomas occupy intermediate genetic stages between nevus and melanoma and likely have an increased risk of malignant transformation as compared to nevi. This review provides an update on the broad spectrum of melanocytic nevi and melanocytomas and outlines their key histopathologic and genetic features.

Future reduction of cutaneous malignant melanoma due to improved sun protection habits and decreased common melanocytic nevi density among Swedish children?: A follow-up from 2002 to 2012

We have previously demonstrated significant improvements in sun protection regimens and significantly fewer common melanocytic nevi (CMN) among 7-year-old children in southern Sweden when comparing year 2007 with 2002. The aim of this study was to investigate whether the observed decreasing trend also can be observed at age 10 and, in addition, to compare the CMN density change between 7 and 10 years of age during two periods of time. Two open cohorts were used, cohort I with schoolchildren investigated in 2002 at age 7 and in 2005 at age 10 and cohort II with schoolchildren investigated in 2009 at age 7 and in 2012 at age 10. A significant decrease in CMN density (number/m² BSA) at age 10 from 2005 to 2012 was observed: 15.9 (14.7-17.2) and 11.4 (10.1-12.7), respectively. The density growth rate from 7 to 10 years was 2.8 (2.1-3.5) between 2002 and 2005 and decreased significantly to 0.9 (0.2-1.5) between 2009 and 2012. Significant increases were observed for 'often use of sunscreen', 'often staying in shade' and 'often staying indoors' from cohort I to cohort II: 65 vs 80%, 7.6 vs 13% and 7.3 vs 19%, respectively. The decrease in number of CMN among 10-year-old children confirms a current trend in Sweden. If this persists, a future reduction of cutaneous malignant melanoma incidence in Sweden might be anticipated. The results also indicate that CMN count could be used as an indicator of ultraviolet exposure.

Association of Phenotypic Characteristics and UV Radiation Exposure With Risk of Melanoma on Different Body Sites

Importance

Two pathways have been hypothesized for the development of cutaneous melanoma: one typically affects the head and neck, a site with chronic sun damage, and the other affects the trunk, which is less exposed to the sun. However, the possible cause of limb melanomas is less studied under this hypothesis.

Objective

To investigate the association between phenotypic characteristics, pattern of UV radiation exposure, and risk of melanoma on different body sites.

Design, Setting, and Participants

This study used data on 161 540 women with information on phenotypic characteristics and UV radiation exposure who were part of the Norwegian Women and Cancer study, a population-based prospective study established in 1991 with exposure information collected by questionnaires at baseline and every 4 to 6 years during follow-up through 2015. Data analysis was performed from October 2017 through May 2018.

Exposures

Participants reported hair color, eye color, untanned skin color, number of small symmetric and large asymmetric nevi, and freckling, as well as histories of sunburns, sunbathing vacations, and indoor tanning in childhood, adolescence, and adulthood.

Main Outcomes and Measures

The Norwegian Women and Cancer study was linked to the Cancer Registry of Norway for data on cancer diagnosis and date of death or emigration. Primary melanoma site was categorized as head and neck, trunk, upper limbs, and lower limbs.

Results

During follow-up of the 161 540 women in the study (mean age at study entry, 50 years [range, 34-70 years]; mean age at diagnosis, 60 years [range, 34-87 years]), 1374 incident cases of melanoma were diagnosed. Having large asymmetric nevi was a significant risk factor for all sites and was strongest for the lower limbs (relative risk [RR], 3.38; 95% CI, 2.62-4.38) and weakest for the upper limbs (RR, 1.96; 95% CI, 1.22-3.17; P = .02 for heterogeneity). Mean lifetime number of sunbathing vacations was significantly associated with risk of trunk melanomas (RR, 1.14; 95% CI, 1.07-1.22) and lower limb melanomas (RR, 1.12; 95% CI, 1.05-1.19) but not upper limb melanomas (RR, 0.98; 95% CI, 0.88-1.09) and head and neck melanomas (RR, 0.87; 95% CI, 0.73-1.04; P = .006 for heterogeneity). Indoor tanning was associated only with trunk melanomas (RR for the highest tertile, 1.49; 95% CI, 1.16-1.92) and lower limb melanomas (RR for the highest tertile, 1.33; 95% CI, 1.00-1.76; P = .002 for heterogeneity). Skin color, hair color, small symmetric nevi, and history of sunburns were associated with risk of melanoma on all sites.

Conclusions and Relevance

These results appear to support the hypothesis of divergent pathways to melanoma and that recreational sun exposure and indoor tanning are associated with melanoma on the lower limbs, the most common site of melanoma in women. These findings appear to have important preventive implications.

Formation of UV-induced DNA damage contributing to skin cancer development

UV-induced DNA damage plays a key role in the initiation phase of skin cancer. When left unrepaired or when damaged cells are not eliminated by apoptosis, DNA lesions express their mutagneic properties, leading to the activation of proto-oncogene or the inactivation of tumor suppression genes. The chemical nature and the amount of DNA damage strongly depend on the wavelength of the incident photons. The most energetic part of the solar spectrum at the Earth's surface (UVB, 280-320 nm) leads to the formation of cyclobutane pyrimidine dimers (CPDs) and pyrimidine (6-4) pyrimidone photoproducts (64PPs). Less energetic but 20-times more intense UVA (320-400 nm) also induces the formation of CPDs together with a wide variety of oxidatively generated lesions such as single strand breaks and oxidized bases. Among those, 8-oxo-7,8-dihydroguanine (8-oxoGua) is the most frequent since it can be produced by several mechanisms. Data available on the respective yield of DNA photoproducts in cells and skin show that exposure to sunlight mostly induces pyrimidine dimers, which explains the mutational signature found in skin tumors, with lower amounts of 8-oxoGua and strand breaks. The present review aims at describing the basic photochemistry of DNA and discussing the quantitative formation of the different UV-induced DNA lesions reported in the literature. Additional information on mutagenesis, repair and photoprotection is briefly provided.

Dermoscopic changes in melanocytic nevi covered with both opaque tape and sunscreen cream during narrowband ultraviolet B therapy

Background

Ultraviolet (UV) light may cause dermoscopic changes on melanocytic nevi (MN).

Objectives

To investigate the effects of sunscreen cream (SSc) application on dermoscopic changes in MN during narrowband UVB (NBUVB) therapy.

Methods

Half of the randomly selected MN in each patient were covered with opaque tape and SSc [SSc(+)], and the rest were covered with only opaque tape [SSc(−)] during NBUVB treatment sessions.

Results

More SSc(−) MN displayed dermoscopic changes at end of NBUVB therapy compared to the start of therapy (p=0.035). The number of the MN that decreased in size and showed loss of structure was significantly higher in SSc(−) MN (p=0.04 and p=0.026, respectively).

Conclusions

Sunscreen in combination with opaque tape may contribute to some dermoscopic changes in melanocytic nevi, including decrease in size and loss of structure.

Cutaneous melanoma primary site is linked to nevus density

There are at least two pathways driving cutaneous melanoma; one is linked to an inherent melanoma susceptibility to nevi development and the second to environmental cumulative ultraviolet light exposure. In this study, we examined the relation between nevus density, accrued sun damage and the site of primary melanoma excision. In a series of 888 consecutive cutaneous melanoma patients, melanomas appearing in skin areas with a high relative nevus density were most prominent in men, with an elevated nevus count, at sites without solar elastosis, but with an epidemiological history of previous sunburn. The present study associates melanoma development to sites with high nevus density. Our study supports more careful surveillance of body areas with increased nevus density in patients with high total body number of nevi, especially when they report a history of sunburns at these sites.

Pediatric Melanoma: A 35-year Population-based Review

Background:

Melanoma is a rare neoplasm in the pediatric population. Recent publications suggest a possible increase in incidence over the past few decades. The purpose of this study was to analyze trends in pediatric patients diagnosed with malignant melanoma in British Columbia (BC) in the past 35 years.

Methods:

A retrospective review was performed. All patients in BC diagnosed with melanoma before 18 years of age from 1979 to 2014 were included. Patient demographics, melanoma description, treatment details, and survival data were collected.

Results:

Seventy-eight subjects were identified for the study. Patients were equally distributed by sex. Sixty-one (78%) of the subjects were diagnosed in the postpubertal age (≥12 years old). The most common sites of occurrence were the extremities (n = 33) and the trunk (n = 27), with the location on the trunk showing the highest mortality rate (22%). All patients were surgically treated and some had additional chemotherapy (12) and/or radiotherapy (12). Fatal outcome was recorded in 12 of the 78 subjects, 10 of whom had postpubertal diagnosis. The average time from date of diagnosis to date of death was 9.3 years.

Conclusions:

The incidence of melanoma in the pediatric population remains exceedingly rare: less than 2.5 per million children younger than 18 years. The diagnosis is rarely made before puberty; the incidence is equal in males and females and has not changed over a 35-year time period in BC. Our study shows 85% survival with the majority of patients having had surgical excision only.

Risk Factors and Relationship of Cutaneous and Uveal Melanocytic Lesions in Monozygotic and Dizygotic Twin Pairs

BACKGROUND

The similar genetic background of a pair of twins, and the similar environmental impacts to which they are exposed allow an exact and objective investigation of various constitutional and environmental factors in naevus development. As far as we are aware, this is the first published survey that simultaneously examines cutaneous and ocular pigmented lesions in an appreciable sample of identical and non-identical twins.

METHODS

172 pairs of twins of Caucasian origin were included in this study. A whole-body skin examination and a detailed ophthalmological examination were performed to determine the density of melanocytic lesions. A standardized questionnaire was used to assess the data relating to constitutional, sun exposure and other variables.

RESULTS

A notably high proportion of the subjects (36.78%) manifested one or more clinically atypical melanocytic naevi (CAMNs), and approximately one-third (31.4%) of them at least one benign uveal pigmented lesion (BUPL). The incidence of iris freckles (IFs), iris naevi (INs) and choroidal naevi (CHNs) proved to be 25.35%, 5.98% and 3.52%, respectively. The interclass correlation coefficients for common melanocytic naevi (CMNs), CAMNs, and INs were 0.77, 0.76 and 0.86 in monozygotic twins, as compared with 0.5, 0.27 and 0.25 in dizygotic twin pairs, respectively. A statistically significant correlation was found between the prevalence of CAMNs and that of INs.

CONCLUSIONS

This significant correlation suggests the existence of a subgroup of Caucasian people with an increased susceptibility to both cutaneous and ocular naevus formation. There is accumulating evidence that, besides the presence of cutaneous atypical naevi, INs can serve as a marker of a predisposed phenotype at risk of uveal melanoma. The correlation between cutaneous and ocular pigmented lesions underlines the need for the adequate ophthalmological screening of subjects with CAMNs and INs.

Update on melanocytic nevi in children

A new or changing melanocytic nevus in a child or adolescent often leads to concern in parents and physicians. To avoid undue alarm and unnecessary procedures, dermatologists should be aware of the natural history and clinical spectrum of nevi in pediatric patients, as well as findings that are potentially worrisome in this age group. This review provides an update on melanocytic nevi in children, focusing on their dynamic evolution over time, molecular insights into nevogenesis, and phenotypic markers for increased risk of melanoma in adolescence and adulthood. Special considerations for Spitz nevi and nevi located in particular sites (eg, scalp, acral, genital) are highlighted. Current understanding of the risks associated with congenital melanocytic nevi of different sizes and strategies for the management of children with numerous acquired nevi, Spitz nevi, and congenital nevi are also discussed.

Association between melanocytic nevi and risk of breast diseases: The French E3N prospective cohort

BACKGROUND

While melanocytic nevi have been associated with genetic factors and childhood sun exposure, several observations also suggest a potential hormonal influence on nevi. To test the hypothesis that nevi are associated with breast tumor risk, we explored the relationships between number of nevi and benign and malignant breast disease risk.

METHODS AND FINDINGS

We prospectively analyzed data from E3N, a cohort of French women aged 40-65 y at inclusion in 1990. Number of nevi was collected at inclusion. Hazard ratios (HRs) for breast cancer and 95% confidence intervals (CIs) were calculated using Cox proportional hazards regression models. Associations of number of nevi with personal history of benign breast disease (BBD) and family history of breast cancer were estimated using logistic regression. Over the period 15 June 1990-15 June 2008, 5,956 incident breast cancer cases (including 5,245 invasive tumors) were ascertained among 89,902 women. In models adjusted for age, education, and known breast cancer risk factors, women with "very many" nevi had a significantly higher breast cancer risk (HR = 1.13, 95% CI = 1.01-1.27 versus "none"; ptrend = 0.04), although significance was lost after adjustment for personal history of BBD or family history of breast cancer. The 10-y absolute risk of invasive breast cancer increased from 3,749 per 100,000 women without nevi to 4,124 (95% CI = 3,674-4,649) per 100,000 women with "very many" nevi. The association was restricted to premenopausal women (HR = 1.40, ptrend = 0.01), even after full adjustment (HR = 1.34, ptrend = 0.03; phomogeneity = 0.04), but did not differ according to breast cancer type or hormone receptor status. In addition, we observed significantly positive dose-response relationships between number of nevi and history of biopsy-confirmed BBD (n = 5,169; ptrend<0.0001) and family history of breast cancer in first-degree relatives (n = 7,472; ptrend = 0.0003). The main limitations of our study include self-report of number of nevi using a qualitative scale, and self-reported history of biopsied BBD.

CONCLUSIONS

Our findings suggest associations between number of nevi and the risk of premenopausal breast cancer, BBD, and family history of breast cancer. More research is warranted to elucidate these relationships and to understand their underlying mechanisms.

Immunotherapy in the management of melanoma: current status

As the rate of melanoma continues to increase, so does the need for more effective and durable therapies. Despite considerable research, the management of advanced disease remains challenging. Numerous therapies are being investigated, many of which aim at upregulating the immune system’s innate ability to attack the tumor. Cytotoxic T lymphocyte antigen 4 antibodies are immune stimulants that act as negative regulators of the immune system by modifying an antitumor T-cell response. Ipilimumab, one such cytotoxic T lymphocyte antigen 4 antibody, and vemurafenib, a BRAF competitive inhibitor, were approved as first-line therapies in 2011 due to improved survival rates versus standard chemotherapy. Allovectin-7 is a lipid plasmid that encodes for major histone compatibility complex DNA sequences. It has led to increases in cytotoxic T-cell production, which subsequently attacks the tumor. OncoVEX, an oncolytic herpes virus, and PV-10, a chemoablative agent, have yielded promising results in metastatic lesions and have demonstrated a unique “bystander” phenomenon. In this paper we review the basics of melanoma from the pathophysiology, risk factors, signs, diagnostic approaches, and current status of immunologic management of melanoma.

Sunscreen use and melanocytic nevi in children: a systematic review

We conducted a systematic review of the association between melanocytic nevi (MN) in childhood and sunscreen use. A bibliographic search was conducted between November 2008 and January 2009 using the following key words on MEDLINE and EMBASE: child*, in combination with naevi, nevi, naevus, nevus and sunscreen, sun protection. We also used Medical Subject Headings [sunscreening agents], or [radiation protection] with [nevus, pigmented]. A first screening was done on title and abstract reading. Randomized trials and cohort and cross-sectional studies analyzing the relationship between the use of sunscreen and MN in children were selected. Three reviewers abstracted data from each article. The three sets of results were compared for concordance and rereviewed if necessary. Fifteen articles were included (20,743 children). The studies were not consistent in terms of the ages of the children, MN count methods, or sunscreen use assessment. Owing to this heterogeneity, we were unable to pool the studies and conduct a meta-analysis. Twelve studies did not report that the use of sunscreen had a protective effect against MN development. Three studies reported a lower MN count when sunscreen was applied. This systematic review underlines the methodologic differences between studies. Eight of 15 studies reported a positive association between sunscreen application and MN count. Differences in MN counts, overexposure to sun, and inadequate sunscreen application on fair-skinned children could explain the disparity in the results. There is still no evidence of a protective effect of sunscreen against MN development in children.

The melanomas: a synthesis of epidemiological, clinical, histopathological, genetic, and biological aspects, supporting distinct subtypes, causal pathways, and cells of origin

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.

Melanocytic nevi, nevus genes, and melanoma risk in a large case-control study in the United Kingdom

BACKGROUND

Increased number of melanocytic nevi is a potent melanoma risk factor. We have carried out a large population-based case-control study to explore the environmental and genetic determinants of nevi and the relationship with melanoma risk.

METHODS

We report nevus phenotype in relation to differing patterns of sun exposure, inherited variation at loci shown in recent genome-wide association studies to be nevus genes, and risk.

RESULTS

Increased numbers of nevi were associated with holiday sun exposure, particularly on intermittently sun-exposed body sites (test for P(trend) < 0.0001). Large nevi were also associated with holiday sun exposure (P = 0.002). Single nucleotide polymorphisms (SNP) on chromosomes 9 and 22 were associated with increased numbers of nevi (P = 0.04 and P = 0.002 respectively) and larger nevi (P = 0.03 and P = 0.002), whereas that on chromosome 6 was associated only with large nevi (P = 0.01). Melanoma risk was associated with increased nevus count, large nevi, and atypical nevi for tumors in all body sites (including rare sites) irrespective of age. The risk persisted when adjusted for inheritance of nevus SNPs.

CONCLUSIONS

The at-risk nevus phenotype is associated with behaviors known to increase melanoma risk (holiday sun exposure). Although SNPs on chromosomes 6, 9, and 22 were shown to be nevus genes, they explained only a small proportion of melanoma risk and nevus phenotype; therefore, several nevus genes likely remain to be identified.

IMPACT

This article confirms the importance of nevi in melanoma pathogenesis and increases understanding of their genetic determinants.

Effect of hair color and sun sensitivity on nevus counts in white children in Colorado

BACKGROUND

It has been widely reported that individuals with a light phenotype (ie, light hair color, light base skin color, and propensity to burn) have more nevi and are at greater risk for developing skin cancer. No studies have systematically investigated how phenotypic traits may interact in relation to nevus development.

OBJECTIVE

We sought to systematically examine whether any combinations of phenotype are associated with a greater or lesser risk for nevus development in white children.

METHODS

In the summer of 2007, 654 children were examined to determine full body nevus counts, skin color by colorimetry, and hair and eye color by comparison with charts. Interviews of parents were conducted to capture sun sensitivity, sun exposure, and sun protection practices.

RESULTS

Among 9-year-old children with sun sensitivity rating type II (painful burn/light tan), those with light hair had lower nevus counts than did those with dark hair (P value for interaction = .03). This relationship was independent of eye color, presence of freckling, sex, usual daily sun exposure, sunburn in 2004 to 2007, sun protection index, and waterside vacation sun exposure. The difference in nevus counts was further determined to be specific to small nevi (<2 mm) and nevi in intermittently exposed body sites.

LIMITATIONS

Geographic and genetic differences in other study populations may produce different results.

CONCLUSION

The standard acceptance that dark phenotype is a marker for low melanoma risk and light phenotype a marker for high risk may need to be reevaluated. In non-Hispanic white children, dark-haired individuals who burn readily and then tan slightly are more prone to nevus development, and may therefore be a previously underrecognized high-risk group for melanoma.

Tanning and increased nevus development in very-light-skinned children without red hair

OBJECTIVE

To examine the relationship between tanning and nevus development in very-light-skinned children.

DESIGN

Prospective cohort nested within a randomized controlled trial. Skin examinations in 3 consecutive years (2004, 2005, and 2006) included full-body counts of nevi, skin color and tanning measurement using colorimetry, and hair and eye color evaluation by comparison with charts. Telephone interviews of parents provided sun exposure, sun protection, and sunburn history.

SETTING

Large managed-care organization and private pediatric offices in the Denver, Colorado, metropolitan area.

PARTICIPANTS

A total of 131 very-light-skinned white children without red hair and 444 darker-skinned white children without red hair born in Colorado in 1998.

MAIN OUTCOME MEASURES

Full-body nevus counts at ages 6 to 8 years.

RESULTS

Among very-light-skinned white children, geometric mean numbers of nevi for minimally tanned children were 14.8 at age 6 years; 18.8 at age 7 years; and 22.3 at age 8 years. Mean numbers of nevi for tanned children were 21.2 at age 6 years; 27.9 at age 7 years; and 31.9 at age 8 years. Differences in nevus counts between untanned and tanned children were statistically significant at all ages (P < .05 for all comparisons). The relationship between tanning and number of nevi was independent of the child's hair and eye color, parent-reported sun exposure, and skin phototype. Among darker-skinned white children, there was no relationship between tanning and nevi.

CONCLUSIONS

Very-light-skinned children who tan (based on objective measurement) develop more nevi than children who do not tan. These results suggest that light-skinned children who develop tans may be increasing their risk for developing melanoma later in life.

Melanoma epidemiology

Melanoma is a complex, heterogeneous cancer that continues to increase in incidence. Multiple studies have consistently identified major host and environmental risk factors for melanoma. Nevi, particularly dysplastic nevi, confer much higher risks than most pigmentary characteristics. Ultraviolet radiation exposure is the predominant environmental risk factor for melanoma. Recently, both rare high risk susceptibility genes and common polymorphic genes contributing to melanoma risk have been identified.

Management of familial melanoma and nonmelanoma skin cancer syndromes

The clinical manifestations of hereditary skin cancer syndromes depend upon the interplay between environmental and genetic factors. Familial melanoma occurs in the setting of hereditary susceptibility, with a complex phenotype of early age of onset, multiple atypical moles, multiple primary melanomas, multiple melanomas in the family, and in some instances pancreatic cancer. Identification of individuals who may have a hereditary susceptibility for the development of melanoma is essential to provide an opportunity for primary prevention, and to target high-risk groups for early diagnosis and treatment. Consequently, the surgeon as one of the primary caregivers should be familiar with hereditary skin cancer syndromes and their pathogenesis, diagnosis, management, and surveillance recommendations. This article discusses a practical approach for some of the issues likely encountered by the surgeon in the management of familial melanoma and non-melanoma skin cancer.

Vacations to waterside locations result in nevus development in Colorado children

Nevi are a main risk factor for malignant melanoma, and most nevi develop in childhood. This study examined the relationship between vacations and nevi in 681 White children born in 1998 who were lifetime residents of Colorado. Vacation histories were assessed through telephone interviews of parents, whereas nevus and phenotypic characteristics were assessed through skin exams at age 7. Multiple linear and logistic regression were used to assess the influence of vacations on counts of nevi <2 mm in size and the presence of any nevi > or = 2 mm after controlling for other variables. Each waterside vacation > or = 1 year before the exam at age 7 was found to be associated with a 5% increase in nevi <2 mm. Waterside vacations <1 year before the skin exam were not related to nevus count (<2 mm); regardless of timeframe, waterside vacations were not related to the presence of nevi > or = 2 mm. UV dose received on waterside vacations, number of days spent on waterside vacations, and nonwaterside vacations were not significantly related to nevi <2 or > or = 2 mm. These results suggest that there is a lag of at least 1 year in the development of new nevi after vacation sun exposure. It appears that a threshold dose of UV exposure is received quickly on each waterside vacation. Parents of young children should exercise caution in selection of vacation locations to reduce melanoma risk.

A pooled analysis of melanocytic nevus phenotype and the risk of cutaneous melanoma at different latitudes

An abnormal nevus phenotype is associated with an increased risk of melanoma. We report a pooled analysis conducted using individual nevus data from 15 case-control studies (5,421 melanoma cases and 6,966 controls). The aims were to quantify the risk better and to determine whether relative risk is varied by latitude. Bayesian unconditional logistic random coefficients models were employed to study the risk associated with nevus characteristics. Participants with whole body nevus counts in the highest of 4 population-based categories had a greatly increased risk of melanoma compared with those in the lowest category (pooled odds ratio (pOR) 6.9 (95% confidence interval (CI): 4.4, 11.2) for those aged<50 years and pOR 5.1 (95% CI: 3.6, 7.5) for those aged>or=50). The pOR for presence compared with absence of any clinically atypical nevi was 4.0 (95% CI: 2.8, 5.8). The pORs for 1-2 and >or=3 large nevi on the body compared with none were 2.9 (95% CI: 1.9, 4.3) and 7.1 (95% CI: 4.7, 11.6), respectively. The relative heterogeneities among studies were small for most measures of nevus phenotype, except for the analysis of nevus counts on the arms, which may have been due to methodological differences among studies. The pooled analysis also suggested that an abnormal nevus phenotype is associated most with melanomas on intermittently sun-exposed sites. The presence of increased numbers of nevi, large nevi and clinically atypical nevi on the body are robust risk factors for melanoma showing little variation in relative risk among studies performed at different latitudes.

Appearance of melanocytic nevi on the backs of young Australian children: a 7-year longitudinal study

To determine the rate of appearance of nevi in a cohort of children between ages 6 and 12 years. The number of nevi has been established as the strongest known risk factor for melanoma, but whether the rate at which nevi appear during childhood varies by age is not well understood. The study involved analysis of nevus development over time in a cohort of 640 Western Australian school children who formed the control group in the Kidskin intervention trial. Children were assessed at ages 6, 10 and 12 years, with nevi on the back counted from photographs. The changes in both number and density of nevi between ages 6 and 12 years were linear with respect to age. The number and density of nevi increased at a greater rate for boys compared with girls; for children with blue, hazel and green eyes compared with those with brown eyes; for blonde versus dark haired children and for children with heavy freckling compared with those with no freckles. In conclusion, further research is needed to determine whether the linear increase in nevi continues into adolescence. If so, it suggests that skin cancer prevention campaigns should target older children and adolescents as well as younger children. Longitudinal studies have important advantages over cross-sectional studies in the description of nevus development with age, and should be the preferred study design.

Body-site distribution of common acquired melanocytic nevi associated with severe sunburns among children in Lithuania

BACKGROUND

The aim of this cross-sectional study is to provide information on subsite-specific densities of melanocytic nevi by age, sex, and in relation to the history of severe sunburns.

MATERIALS AND METHODS

This study was conducted in Kaunas, Lithuania, on a sample of 484 children aged 1-2 years, 4-5 years, 9-10 years, and 14-15 years. The questionnaire provided information about the history of severe sunburns since birth. Site-specific numbers and densities of melanocytic nevi of all sizes and nevi 2 mm or greater were studied. We used log-linear and Poisson regression models to estimate the effects of age, sex, and severe sunburns on the nevus density.

RESULTS

The predicted total body density of nevi shows a considerable increase up to the age of roughly 10 years. Thereafter, the density increase tapered off. Median densities of nevi were highest on the face. The median density of nevi on the upper arms is higher than on the forearms. Similarly, the median density of nevi on the thighs is higher than on the lower legs. Estimates of the relative nevus densities related to the history of severe sunburns tend to be small with the exception of the legs for nevi 2 mm or greater (relative nevus density = 2.09, 95% CI 1.49-2.93).

CONCLUSION

Nevus densities are highest on maximally or intermittently sun-exposed skin areas. With the exception of the legs among women, the subsite-specific ranking of nevus densities among adolescents follows a similar ranking as the skin melanoma incidence in Lithuania.

Measuring the effects of genes and environment on complex traits

Complex diseases and traits are influenced by a combination of genetic and environmental risk factors, some of which may be known, and many of which are unknown. It is possible to estimate the relative importance of the influence of genes and environment on a trait by studying correlations in the trait in related individuals. Known risk factors can be measured and included in the statistical models to understand disease etiology better. The joint effect of specific genes and environmental exposures can be estimated by measuring these in individuals, not necessarily related, with and without the disease of interest or with a range of trait values. These methods are illustrated by considering two example analyses in detail. The first is an analysis of a study of adolescent twins, quantifying the effect of genes and environment, including measured sun exposure, on the density of nevi. The second is an analysis of a case-control study, examining the joint effect of the GSTT1 gene and vegetable intake on risk of colorectal cancer.

Photoprotection

Sun exposure is the main cause of photocarcinogenesis, photoageing, and photosensitivity; thus, photoprotection is an important issue. In a skin cancer prevention strategy, behavioural measures--eg, wearing sun protective clothes and a hat and reducing sun exposure to a minimum--should be preferred to sunscreens. Often this solution is deemed to be unacceptable in our global, outdoor society, and sunscreens could become the predominant mode of sun protection for various societal reasons (eg, healthiness of a tan, relaxation in the sun). The application of a liberal quantity of sunscreen has been shown to be by far the most important factor for effectiveness of the sunscreen, followed by the uniformity of application and the specific absorption spectrum of the agent used. The sunscreen market--crowded by numerous products--shows various differences worldwide. Nevertheless, sunscreens should not be abused in an attempt to increase time in the sun to a maximum. Controversies about safety of sunscreens and clinical recommendations are discussed.

Pigmented lesions in children: when to worry

PURPOSE OF REVIEW

Although the incidence of melanoma in adolescents and adults has risen dramatically in the past few decades, childhood melanoma remains uncommon. It is therefore important for pediatricians to be aware of the natural history and clinical spectrum of melanocytic nevi in children as well as potentially worrisome features of pigmented lesions.

RECENT FINDINGS

Recent studies have provided insight into the development, evolution and molecular bases of acquired and congenital melanocytic nevi during childhood. This review summarizes the types of melanocytic nevi that are commonly observed in children, environmental (e.g. sun exposure) and genetic (e.g. the familial atypical mole and melanoma syndrome) factors that can contribute to the development of nevi and future risk of melanoma, and phenotypic markers (e.g. numerous acquired nevi or the 'red hair phenotype') that signal the need for periodic total-body cutaneous examinations. Current concepts of the risks associated with congenital melanocytic nevi of different sizes and strategies for the management of various types of nevi (including congenital, blue and Spitz nevi) are presented, and data on the clinical presentations and biologic behavior of prepubertal melanoma are discussed.

SUMMARY

Clinical and molecular investigations have helped to better understand the characteristics of melanocytic nevi and define pathways of melanocytic tumorigenesis.

Age distribution of biopsied junctional nevi

BACKGROUND

Junctional nevi are traditionally associated with children and younger patients. We noticed that these lesions are also often found in elderly patients.

OBJECTIVE

We sought to determine if junctional nevi are found in all age groups.

METHODS

All biopsy reports for junctional nevi for the year 2001 at the Penn State Milton S. Hershey Medical Center were reviewed. Age of patients and locations for these nevi were noted and the results analyzed.

RESULTS

The age distribution of junctional nevi shows that these lesions occur with similar frequency in the young and in the elderly. Lesions were more frequent in non-sun-exposed skin.

LIMITATIONS

The age distribution between biopsied nevi and nevi not biopsied may be different. Sampling error may also lead to mis-classification of nevi.

CONCLUSION

Junctional nevi are common in all age groups.

Sunscreen use and increased duration of intentional sun exposure: Still a burning issue

Sunscreen use is often proposed for sun protection because of their ability to block UV-induced sunburns (the sun protection factor--SPF). Among suntan seekers, however, risk of cutaneous melanoma may be increased because of extended sun exposure duration. We made a systematic review of the evidence linking sunscreen use to sun exposure duration. Five observational studies found that when sun exposure was associated with willingness to get a tan or to stay longer in the sun (i.e., intentional sun exposure), sunscreen use was associated with duration of sun exposure 13-39% longer. Paradoxically, sunburns tend to be more frequent among sunscreen users, probably because of greater natural sun sensitivity. When sun exposure was not intentional, sunscreen use did not increase time spent in the sun. Two European double-blind randomized trials conducted among young sun seekers found daily sun exposure duration, especially sunbathing, 19-25% longer with use of SPF 30 than with use of SPF 10 sunscreens. One randomized trial in a holiday resort in France found a 3-13% increase in sun exposure duration with use of SPF 12 versus SPF 40 sunscreen. But, the SPF 12 groups used 3.6-4.2 more sunscreen than the SPF 40 group, and thus the actual SPF in the SPF 12 group was higher than in the SPF 40 groups. In conclusion, sunscreen use leads to longer duration of sun exposure when sun exposure is intentional, but not when sun exposure is non intentional.

Management of familial melanoma

Relatives of patients with melanoma are at increased risk of melanoma. We review the evidence that this risk may be attributed both to shared susceptibility genes (both high-penetrance and lower-penetrance genes) and shared environment. The most frequent high-penetrance susceptibility gene is CDKN2A, and environmental effects on the risk to gene carriers are evident in that CDKN2A penetrance is higher in CDKN2A-mutation-positive families living in Australia than those in Europe. We review the approaches to managing melanoma families, in which the likelihood of there being detectable CDKN2A mutations is positively correlated with the number of cases of melanoma in the family. Within families, risk that an individual carries a germline mutation can be estimated by pedigree analysis for autosomal dominant genes with incomplete penetrance. Prevention advice to families relates to moderation of sun exposure and self-examination of naevi, although there are few supportive data.

Sun protection and the development of melanocytic nevi in children

Childhood sun exposure causes nevi (and melanoma), but there is little evidence regarding the effectiveness of sun protection strategies on the number of nevi. We previously found that boys but not girls receiving a school-based sun protection program had fewer nevi on their backs than controls. Here, we investigated whether specific program components (encouraging children to stay indoors in the middle of the day during summer, to wear clothing while outdoors, and to use sunscreen) were associated with fewer nevi. An observational analysis was done on data from a sun protection trial in 1,623 children in Perth, Australia. The outcome was number of nevi on the back 6 years after baseline, when the children were 12 years old. Information on sun protection was obtained by questionnaires 4 and 6 years after baseline. The data were analyzed by mixed-effects linear regression. The time spent outdoors between 11 a.m. and 2 p.m. and the proportion of total time outdoors that was between these hours were positively associated with number of nevi. Ratios of mean counts for doubling the respective measures were 1.09 [95% confidence interval (95% CI), 1.05-1.12] and 1.10 (95% CI, 1.05-1.14). Children whose backs were covered <70% of the time while outdoors had 1.53 (95% CI, 1.34-1.75) times more nevi than children whose backs were always covered. Using sunscreen on the back when it was uncovered was not associated with number of nevi (P = 0.59). Children who stayed indoors in the middle of the day and wore clothing while outdoors had fewer nevi.

Cutaneous malignant melanoma: facts about sunbeds and sunscreen

The incidence of cutaneous malignant melanoma is still increasing in most light-skinned populations. Sunscreen use has been proposed for the primary prevention of melanoma. However, sunscreen use may increase time spent in the sun when users are willing to acquire a tan or to stay in the sun for a long time, which may increase melanoma risk. When sun exposure is not associated with the desire to acquire a tan or stay in the sun for a long time, sunscreen use may prevent squamous cell skin carcinoma. Sun protection should give priority to clothing and sun exposure reduction. Over the last 20 years, tan acquisition through exposure to artificial sources of ultraviolet radiation has become frequent among fair-skinned adolescents and young adults. There is accumulating evidence that sunbed use is associated with melanoma when started before approximately 30 years of age.

Cutaneous melanoma and intervention strategies to reduce tumor-related mortality: what we know, what we don't know, and what we think we know that isn't so

The care of patients who have cutaneous melanoma (CM) has undergone a dramatic change during the past five decades. In an increasing majority of cases, CM is being discovered in a premetastatic phase of tumor progression. Most patients are being treated in the ambulatory setting with a minimum of inconvenience and economic cost, and modest re-excision margins have largely replaced the mutilating surgical exonerations that were once standard only four decades ago. Histopathologic assessment of the primary tumor is the most widely used staging procedure to determine who is most likely to develop metastatic disease. For patients who develop distant metastases, there is no therapy currently available, based on large-scale randomized trials, that will prolong patient survival. Therefore, establishing an early diagnosis in a premetastatic phase of tumor development must be the overriding goal of any intervention strategy that seeks to reduce CM-related mortality. Unfortunately, as a result of public messages that emphasize the role of ultraviolet radiation (UVR) exposure in tumor development, most general physicians and lay people believe that most if not all cases of CM are the direct result of UVR exposure. In fact, we do not know the case fraction of CM directly attributable to UVR, and the unintended consequences of current messages directly linking UVR exposure and CM development may be thwarting the primary intervention goal of reducing tumor-related mortality. More likely to have an immediate positive impact on CM-related mortality are public messages that encourage skin awareness and self-examination by patients, total skin screening examinations by physicians during routine care, and periodic lifetime surveillance of patients determined to have a high CM risk based on identifiable historic and phenotypic traits.