Fine mapping of genetic susceptibility loci for melanoma reveals a mixture of single variant and multiple variant regions.

At least 17 genomic regions are established as harboring melanoma susceptibility variants, in most instances with genome-wide levels of significance and replication in independent samples. Based on genome-wide single nucleotide polymorphism (SNP) data augmented by imputation to the 1,000 Genomes reference panel, we have fine mapped these regions in over 5,000 individuals with melanoma (mainly from the GenoMEL consortium) and over 7,000 ethnically matched controls. A penalized regression approach was used to discover those SNP markers that most parsimoniously explain the observed association in each genomic region. For the majority of the regions, the signal is best explained by a single SNP, which sometimes, as in the tyrosinase region, is a known functional variant. However in five regions the explanation is more complex. At the CDKN2A locus, for example, there is strong evidence that not only multiple SNPs but also multiple genes are involved. Our results illustrate the variability in the biology underlying genome-wide susceptibility loci and make steps toward accounting for some of the "missing heritability."

Biologic markers of sun exposure and melanoma risk in women: pooled case-control analysis.

A model has been proposed whereby melanomas arise through two distinct pathways dependent on the relative influence of host susceptibility and sun exposure. Such pathways may explain site-specific patterns of melanoma occurrence. To explore this model, we investigated the relationship between melanoma risk and general markers of acute (recalled sunburns) and chronic (prevalent solar keratoses) sun exposure, stratified by anatomic site and host phenotype. Our working hypothesis was that head and neck melanomas have stronger associations with solar keratoses and weaker associations with sunburn than trunk melanomas. We conducted a collaborative analysis using original data from women subjects of 11 case-control studies of melanoma (2,575 cases, 3,241 controls). We adjusted for potential confounding effects of sunlamp use and sunbathing. The magnitude of sunburn associations did not differ significantly by melanoma site, nevus count or histologic subtype of melanoma. Across all sites, relative risk of melanoma increased with an increasing number of reported lifetime "painful" sunburns, lifetime "severe" sunburns and "severe" sunburns in youth (p(trend) < 0.001), with pooled odds ratios (pORs) for the highest category of sunburns versus no sunburns of 3.22 [95% confidence interval (CI) 2.04-5.09] for lifetime "painful" sunburns, 2.10 (95%CI 1.30-3.38) for lifetime "severe" sunburns and 2.43 (95%CI 1.61-3.65) for "severe" sunburns in youth. Solar keratoses strongly increased the risk of head and neck melanoma (pOR 4.91, 95%CI 2.10-11.46), but data were insufficient to assess risk for other sites. Reported sunburn is strongly associated with melanoma on all major body sites.

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.

Adjuvant therapy with pegylated interferon alfa-2b versus observation alone in resected stage III melanoma: final results of EORTC 18991, a randomised phase III trial.

BACKGROUND: Any benefit of adjuvant interferon alfa-2b for melanoma could depend on dose and duration of treatment. Our aim was to determine whether pegylated interferon alfa-2b can facilitate prolonged exposure while maintaining tolerability. METHODS: 1256 patients with resected stage III melanoma were randomly assigned to observation (n=629) or pegylated interferon alfa-2b (n=627) 6 mug/kg per week for 8 weeks (induction) then 3 mug/kg per week (maintenance) for an intended duration of 5 years. Randomisation was stratified for microscopic (N1) versus macroscopic (N2) nodal involvement, number of positive nodes, ulceration and tumour thickness, sex, and centre. Randomisation was done with a minimisation technique. The primary endpoint was recurrence-free survival. Analyses were done by intention to treat. This study is registered with ClinicalTrials.gov, number NCT00006249. FINDINGS: All randomised patients were included in the primary efficacy analysis. 608 patients in the interferon group and 613 patients in the observation group were included in safety analyses. The median length of treatment with pegylated interferon alfa-2b was 12 (IQR 3.8-33.4) months. At 3.8 (3.2-4.2) years median follow-up, 328 recurrence events had occurred in the interferon group compared with 368 in the observation group (hazard ratio 0.82, 95% CI 0.71-0.96; p=0.01); the 4-year rate of recurrence-free survival was 45.6% (SE 2.2) in the interferon group and 38.9% (2.2) in the observation group. There was no difference in overall survival between the groups. Grade 3 adverse events occurred in 246 (40%) patients in the interferon group and 60 (10%) in the observation group; grade 4 adverse events occurred in 32 (5%) patients in the interferon group and 14 (2%) in the observation group. In the interferon group, the most common grade 3 or 4 adverse events were fatigue (97 patients, 16%), hepatotoxicity (66, 11%), and depression (39, 6%). Treatment with pegylated interferon alfa-2b was discontinued because of toxicity in 191 (31%) patients. INTERPRETATION: Adjuvant pegylated interferon alfa-2b for stage III melanoma has a significant, sustained effect on recurrence-free survival.

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.

Long-term protective effect of mature DC-LAMP+ dendritic cell accumulation in sentinel lymph nodes containing micrometastatic melanoma.

PURPOSE: In a previous immunohistochemical study of dendritic cells (DC) in sentinel lymph nodes (SLN) draining regressing melanomas, we found that the accumulation of mature DC-LAMP(+) DCs in SLNs was associated with local expansion of antigen-specific memory effector CTLs and the absence of metastasis in downstream lymph nodes. The aim of this study was to investigate the prognostic importance of the maximal density of mature DCs in SLNs. EXPERIMENTAL DESIGN: A total of 458 consecutive patients with micrometastatic melanoma within SLNs were eligible for analysis. The maximal density of mature DC-LAMP(+) DCs was evaluated by three independent observers and categorized into three classes (<100, 100 to <200, and >or=200/mm(2)). RESULTS: There was excellent interobserver reproducibility for maximum density of mature DC-LAMP(+) DC scores (kappa score = 0.82). There were differences in the maximal density scores and staining intensity according to the treating melanoma center (P < 0.001). The higher the mature DC density in the SLN is, the longer is the duration of survival [P = 0.047; hazard ratio, 0.70; 95% confidence interval, 0.50-1.00]. Adjusted by thickness and ulceration, the prognostic importance of DC density was lower (P = 0.36). CONCLUSION: This study is the first to report the prognostic value of DC-LAMP(+) DC counts in SLNs containing metastatic melanoma. Patients with a high density of mature DCs (>or=200/mm(2)) have the lowest risk of death. It also provides evidence that a lack of maturation in the SLNs is important in biological facilitation of melanoma progression.

Features associated with germline CDKN2A mutations: a GenoMEL study of melanoma-prone families from three continents.

BACKGROUND: The major factors individually reported to be associated with an increased frequency of CDKN2A mutations are increased number of patients with melanoma in a family, early age at melanoma diagnosis, and family members with multiple primary melanomas (MPM) or pancreatic cancer. METHODS: These four features were examined in 385 families with > or =3 patients with melanoma pooled by 17 GenoMEL groups, and these attributes were compared across continents. RESULTS: Overall, 39% of families had CDKN2A mutations ranging from 20% (32/162) in Australia to 45% (29/65) in North America to 57% (89/157) in Europe. All four features in each group, except pancreatic cancer in Australia (p = 0.38), individually showed significant associations with CDKN2A mutations, but the effects varied widely across continents. Multivariate examination also showed different predictors of mutation risk across continents. In Australian families, > or =2 patients with MPM, median age at melanoma diagnosis < or =40 years and > or =6 patients with melanoma in a family jointly predicted the mutation risk. In European families, all four factors concurrently predicted the risk, but with less stringent criteria than in Australia. In North American families, only > or =1 patient with MPM and age at diagnosis < or =40 years simultaneously predicted the mutation risk. CONCLUSIONS: The variation in CDKN2A mutations for the four features across continents is consistent with the lower melanoma incidence rates in Europe and higher rates of sporadic melanoma in Australia. The lack of a pancreatic cancer-CDKN2A mutation relationship in Australia probably reflects the divergent spectrum of mutations in families from Australia versus those from North America and Europe. GenoMEL is exploring candidate host, genetic and/or environmental risk factors to better understand the variation observed.

High-risk melanoma susceptibility genes and pancreatic cancer, neural system tumors, and uveal melanoma across GenoMEL.

GenoMEL, comprising major familial melanoma research groups from North America, Europe, Asia, and Australia has created the largest familial melanoma sample yet available to characterize mutations in the high-risk melanoma susceptibility genes CDKN2A/alternate reading frames (ARF), which encodes p16 and p14ARF, and CDK4 and to evaluate their relationship with pancreatic cancer (PC), neural system tumors (NST), and uveal melanoma (UM). This study included 466 families (2,137 patients) with at least three melanoma patients from 17 GenoMEL centers. Overall, 41% (n = 190) of families had mutations; most involved p16 (n = 178). Mutations in CDK4 (n = 5) and ARF (n = 7) occurred at similar frequencies (2-3%). There were striking differences in mutations across geographic locales. The proportion of families with the most frequent founder mutation(s) of each locale differed significantly across the seven regions (P = 0.0009). Single founder CDKN2A mutations were predominant in Sweden (p.R112_L113insR, 92% of family's mutations) and the Netherlands (c.225_243del19, 90% of family's mutations). France, Spain, and Italy had the same most frequent mutation (p.G101W). Similarly, Australia and United Kingdom had the same most common mutations (p.M53I, c.IVS2-105A>G, p.R24P, and p.L32P). As reported previously, there was a strong association between PC and CDKN2A mutations (P < 0.0001). This relationship differed by mutation. In contrast, there was little evidence for an association between CDKN2A mutations and NST (P = 0.52) or UM (P = 0.25). There was a marginally significant association between NST and ARF (P = 0.05). However, this particular evaluation had low power and requires confirmation. This GenoMEL study provides the most extensive characterization of mutations in high-risk melanoma susceptibility genes in families with three or more melanoma patients yet available.

Long-term health risk to the skin of ultraviolet radiation.

The major well-proven long-term health risks of excessive exposure to ultraviolet (UV) radiation relate to the skin. Premalignant skin lesions are seen very much earlier in white skinned populations exposed to excessive sunlight, and over time these same individuals develop larger numbers of all of the three major skin cancers than individuals who do not experience excessive UV exposure. These three skin cancers are squamous cell carcinoma (SCC), basal cell carcinoma (BCC), and malignant melanoma. In the case of SCC the major aetiological pattern is chronic long-term exposure, but for BCCs the pattern appears to be slightly different with short-term burning episodes being more important. In the case of melanomas, there is evidence that for the 4 main types of melanomas, the pattern of excess UV exposure which is most injurious varies.

Post-surgery adjuvant therapy with intermediate doses of interferon alfa 2b versus observation in patients with stage IIb/III melanoma (EORTC 18952): randomised controlled trial.

BACKGROUND: Individuals affected by melanoma with thick primary tumours or regional node involvement have a poor outlook, with only 30-50% alive at 5 years. High-dose and low-dose interferon alfa have been assessed for the treatment of these patients, with the former having considerable toxicity and a consistent effect on disease free survival, but not on overall survival, and the latter no consistent effect on either. Our aim was, therefore, to assess the effect of two regimens of interferon of intermediate dose versus observation alone on distant metastasis-free interval (DMFI) and overall survival in such patients. METHODS: We did a randomised controlled trial in 1388 patients who had had a thick primary tumour (thickness > or = 4 mm) resected (stage IIb) or regional lymph node metastases dissected (stage III) and had been assigned to 13-months (n=553) or 25 months (n=556) of treatment with subcutaneous interferon alfa 2b, or observation (n=279). Treatment comprised 4 weeks of 10 million units (MU) of interferon alfa (5 days per week) followed by either 10 MU three times a week for 1 year or 5 MU three times a week for 2 years, to a total dose of 1760 MU. Our primary endpoint was DMFI. Analyses were by intent to treat. FINDINGS: After a median follow-up of 4.65 years, we had recorded 760 distant metastases and 681 deaths. At 4.5 years, the 25-month interferon group showed a 7.2% increase in rate of DMFI (hazard ratio 0.83, 97.5% CI 0.66-1.03) and a 5.4% improvement in overall survival. The 13-month interferon group showed a 3.2% increase in rate of DMFI at 4.5 years (0.93, 0.75-1.16) and no extension of overall survival. Toxicity was acceptable, with 18% (195 of 1076) of patients going off study because of toxicity or as a result of refusal of treatment because of side-effects. INTERPRETATION: Interferon alfa as used in the regimens studied does not improve outcome for patients with stage IIb/III melanomas, and cannot be recommended. With respect to efficacy of the drug, duration of treatment seemed more important than dose, and should be assessed in future trials.

Prevalence of exon 15 BRAF mutations in primary melanoma of the superficial spreading, nodular, acral, and lentigo maligna subtypes.

DNA was extracted from 52 thick primary melanomas and mutations sought in exon 15 of the BRAF (v-raf murine sarcoma viral oncogene homolog B1) gene using denaturing high performance liquid chromatograph (dHPLC) fragment analysis, sequencing, and allele-specific PCR. Exon 15 BRAF mutations were found in 13 of 52 (25%) primary melanomas. These comprised five of 17 (29%) superficial spreading melanomas, three of 11 (27%) nodular melanomas, two of 13 (15%) acral lentiginous melanomas, one of one (100%) mucosal melanoma and two of 10 (20%) lentigo maligna melanomas. In common with other groups, our findings show a relative concentration of the exon 15 BRAF mutation in superficial spreading and nodular melanomas, but add further evidence that this mutation not necessary for malignant transformation of the melanocyte.

Development and validation of a melanoma risk score based on pooled data from 16 case-control studies.

BACKGROUND: We report the development of a cutaneous melanoma risk algorithm based upon seven factors; hair color, skin type, family history, freckling, nevus count, number of large nevi, and history of sunburn, intended to form the basis of a self-assessment Web tool for the general public. METHODS: Predicted odds of melanoma were estimated by analyzing a pooled dataset from 16 case-control studies using logistic random coefficients models. Risk categories were defined based on the distribution of the predicted odds in the controls from these studies. Imputation was used to estimate missing data in the pooled datasets. The 30th, 60th, and 90th centiles were used to distribute individuals into four risk groups for their age, sex, and geographic location. Cross-validation was used to test the robustness of the thresholds for each group by leaving out each study one by one. Performance of the model was assessed in an independent UK case-control study dataset. RESULTS: Cross-validation confirmed the robustness of the threshold estimates. Cases and controls were well discriminated in the independent dataset [area under the curve, 0.75; 95% confidence interval (CI), 0.73-0.78]. Twenty-nine percent of cases were in the highest risk group compared with 7% of controls, and 43% of controls were in the lowest risk group compared with 13% of cases. CONCLUSION: We have identified a composite score representing an estimate of relative risk and successfully validated this score in an independent dataset. IMPACT: This score may be a useful tool to inform members of the public about their melanoma risk.

Genome-wide meta-analysis identifies five new susceptibility loci for cutaneous malignant melanoma.

Thirteen common susceptibility loci have been reproducibly associated with cutaneous malignant melanoma (CMM). We report the results of an international 2-stage meta-analysis of CMM genome-wide association studies (GWAS). This meta-analysis combines 11 GWAS (5 previously unpublished) and a further three stage 2 data sets, totaling 15,990 CMM cases and 26,409 controls. Five loci not previously associated with CMM risk reached genome-wide significance (P < 5 × 10(-8)), as did 2 previously reported but unreplicated loci and all 13 established loci. Newly associated SNPs fall within putative melanocyte regulatory elements, and bioinformatic and expression quantitative trait locus (eQTL) data highlight candidate genes in the associated regions, including one involved in telomere biology.

Absence of exon 15 BRAF germline mutations in familial melanoma.

We have analyzed DNA from peripheral blood of 42 cases of familial melanoma for germline mutations in exon 15 of the BRAF gene. No evidence of mutation was found. We have also analyzed DNA extracted from secondary melanoma from two members of these families. These results were also negative. In addition we have searched for exon 15 BRAF mutations in 24 samples of secondary melanoma from 22 cases of sporadic melanoma and detected the 1796T>A BRAF mutation which leads to a substitution of valine by glutamic acid at position 599 (V599E) in six samples. Peripheral blood DNA from two of these tumor-positive cases of sporadic melanoma were negative for the V599E BRAF mutation. This mutation therefore appears to be a somatic mutation associated with melanoma development and/or progression in a proportion of affected individuals.

Risk factors for the development of primary cutaneous malignant melanoma.

It is now possible to identify a small number of genes in which identifiable abnormalities are associated with an increased risk of melanoma, and a large number of phenotypic factors, which are associated with a lesser risk affecting a very much larger proportion of the melanoma population. As with colon cancer, it seems likely that there is a stepwise development of invasive malignant melanoma, and that interaction between genotype and environmental stimuli may be very different at each successive stage of melanoma progression. Unraveling these steps is the current challenge.

'This isn't what mine looked like': a qualitative study of symptom appraisal and help seeking in people recently diagnosed with melanoma.

OBJECTIVE: To explore symptom appraisal and help-seeking decisions among patients recently diagnosed with melanomas, and to compare experiences of people with 'thinner' (<1 mm) and 'thicker' (>2 mm) melanomas, as thickness at diagnosis is an important prognostic feature. METHODS: In-depth interviews with patients within 10 weeks of melanoma diagnosis explored the factors impacting on their pathways to diagnosis. Framework analysis, underpinned by the Model of Pathways to Treatment, was used to explore the data with particular focus on patients' beliefs and experiences, disease factors, and healthcare professional (HCP) influences. RESULTS: 63 patients were interviewed (29-93 years, 31 women, 30 thicker melanomas). All described their skin changes using rich lay vocabulary. Many included unassuming features such as 'just a little spot' as well as common features of changes in size, colour and shape. There appeared to be subtly different patterns of symptoms: descriptions of vertical growth, bleeding, oozing and itch were features of thicker melanomas irrespective of pathological type. Appraisal was influenced by explanations such as normal life changes, prior beliefs and whether skin changes matched known melanoma descriptions. Most decisions to seek help were triggered by common factors such as advice from family and friends. 11 patients reported previous reassurance about their skin changes by a HCP, with little guidance on monitoring change or when it would be appropriate to re-consult. CONCLUSIONS: Patients diagnosed with both thinner and thicker melanomas often did not initially recognise or interpret their skin changes as warning signs or prompts to seek timely medical attention. The findings provide guidance for melanoma awareness campaigns on more appropriate images, helpful descriptive language and the need to stress the often apparently innocuous nature of potentially serious skin changes. The importance of appropriate advice, monitoring and safety-netting procedures by HCPs for people presenting with skin changes is also highlighted.

The effect on melanoma risk of genes previously associated with telomere length.

Telomere length has been associated with risk of many cancers, but results are inconsistent. Seven single nucleotide polymorphisms (SNPs) previously associated with mean leukocyte telomere length were either genotyped or well-imputed in 11108 case patients and 13933 control patients from Europe, Israel, the United States and Australia, four of the seven SNPs reached a P value under .05 (two-sided). A genetic score that predicts telomere length, derived from these seven SNPs, is strongly associated (P = 8.92x10(-9), two-sided) with melanoma risk. This demonstrates that the previously observed association between longer telomere length and increased melanoma risk is not attributable to confounding via shared environmental effects (such as ultraviolet exposure) or reverse causality. We provide the first proof that multiple germline genetic determinants of telomere length influence cancer risk.

A variant in FTO shows association with melanoma risk not due to BMI.

We report the results of an association study of melanoma that is based on the genome-wide imputation of the genotypes of 1,353 cases and 3,566 controls of European origin conducted by the GenoMEL consortium. This revealed an association between several SNPs in intron 8 of the FTO gene, including rs16953002, which replicated using 12,313 cases and 55,667 controls of European ancestry from Europe, the USA and Australia (combined P = 3.6 × 10(-12), per-allele odds ratio for allele A = 1.16). In addition to identifying a new melanoma-susceptibility locus, this is to our knowledge the first study to identify and replicate an association with SNPs in FTO not related to body mass index (BMI). These SNPs are not in intron 1 (the BMI-related region) and exhibit no association with BMI. This suggests FTO's function may be broader than the existing paradigm that FTO variants influence multiple traits only through their associations with BMI and obesity.

Genome-wide association study identifies a new melanoma susceptibility locus at 1q21.3.

We performed a genome-wide association study of melanoma in a discovery cohort of 2,168 Australian individuals with melanoma and 4,387 control individuals. In this discovery phase, we confirm several previously characterized melanoma-associated loci at MC1R, ASIP and MTAP-CDKN2A. We selected variants at nine loci for replication in three independent case-control studies (Europe: 2,804 subjects with melanoma, 7,618 control subjects; United States 1: 1,804 subjects with melanoma, 1,026 control subjects; United States 2: 585 subjects with melanoma, 6,500 control subjects). The combined meta-analysis of all case-control studies identified a new susceptibility locus at 1q21.3 (rs7412746, P = 9.0 × 10(-11), OR in combined replication cohorts of 0.89 (95% CI 0.85-0.95)). We also show evidence suggesting that melanoma associates with 1q42.12 (rs3219090, P = 9.3 × 10(-8)). The associated variants at the 1q21.3 locus span a region with ten genes, and plausible candidate genes for melanoma susceptibility include ARNT and SETDB1. Variants at the 1q21.3 locus do not seem to be associated with human pigmentation or measures of nevus density.