Inherited variants in the MC1R gene and survival from cutaneous melanoma: a BioGenoMEL study

Melanoma-associated melanocortin 1 receptor variants confer redox signaling-dependent protection against oxidative DNA damage

Cutaneous melanoma, a lethal skin cancer, arises from malignant transformation of melanocytes. Solar ultraviolet radiation (UVR) is a major environmental risk factor for melanoma since its interaction with the skin generates DNA damage, either directly or indirectly via oxidative stress. Pheomelanin pigments exacerbate oxidative stress in melanocytes by UVR-dependent and independent mechanisms. Thus, oxidative stress is considered to contribute to melanomagenesis, particularly in people with pheomelanic pigmentation. The melanocortin 1 receptor gene (MC1R) is a major melanoma susceptibility gene. Frequent MC1R variants (varMC1R) associated with fair skin and red or yellow hair color display hypomorphic signaling to the cAMP pathway and are associated with higher melanoma risk. This association is thought to be due to production of photosensitizing pheomelanins as well as deficient induction of DNA damage repair downstream of varMC1R. However, the data on modulation of oxidative DNA damage repair by MC1R remain scarce. We recently demonstrated that varMC1R accelerates clearance of reactive oxygen species (ROS)-induced DNA strand breaks in an AKT-dependent manner. Here we show that varMC1R also protects against ROS-dependent formation of 8-oxodG, the most frequent oxidative DNA lesion. Since the base excision repair (BER) pathway mediates clearance of these DNA lesions, we analyzed induction of BER enzymes in human melanoma cells of varMC1R genotype. Agonist-mediated activation of both wildtype (wtMC1R) and varMC1R significantly induced OGG and APE-1/Ref1, the rate-limiting BER enzymes responsible for repair of 8-oxodG. Moreover, we found that NADPH oxidase (NOX)-dependent generation of ROS was responsible for AKT activation and oxidative DNA damage repair downstream of varMC1R. These observations provide a better understanding of the functional properties of melanoma-associated MC1R alleles and may be useful for the rational development of strategies to correct defective varMC1R responses for efficient photoprotection and melanoma prevention in fair-skinned individuals.

Melanocortin-1 Receptor Expression as a Marker of Progression in Melanoma

PURPOSE

Melanocortin-1 receptor (MC1R) plays a critical role in human pigmentation and DNA repair mechanisms. MC1R-targeting agents are being investigated in clinical trials in patients with melanoma, yet large studies investigating the rate and degree of MC1R expression in primary and metastatic human melanoma tissue are lacking.

METHODS

Using tissue microarrays containing three large cohorts of 225 cases of benign nevi, 189 with primary melanoma, and 271 with metastatic melanoma, we applied quantitative immunofluorescence and immunohistochemistry to comprehensively study MC1R protein expression.

RESULTS

We show a stepwise elevation of MC1R expression in different stages of melanoma progression (nevi, primary, metastasis). Higher MC1R expression was seen in deeper (>1 mm) primary lesions and ulcerated lesions and was associated with shorter survival in primary and metastatic tumors. On multivariable analysis, Breslow thickness, male sex, and chronic sun exposure were independent predictors of worse overall survival in the primary melanoma cohort.

CONCLUSION

Our data suggest that MC1R might be a valuable drug target in aggressive melanoma. Additional studies are warranted to determine its functional significance in melanoma progression and its utility as a predictive biomarker in patients receiving MC1R-directed therapies.

Prognosis of CDKN2A germline mutation in patients with familial melanoma: a systematic review and meta-analysis

Familial melanoma is defined as melanoma occurring in two or more first-degree relatives by the WHO. Germline mutations are isolated in a subset of them. It is well known that CDKN2A is the most frequently mutated high-risk gene in familial melanoma, however, the prognosis it confers to patients who carry its mutations is still controversial. This review aims to assess whether germline mutations imply a worse prognosis in patients with familial melanoma. A systematic review and meta-analysis were conducted by searching the electronic databases PubMed/MEDLINE, EMBASE, and Cochrane Library. Data from 3 independent populations were eventually included in the meta-analysis, involving 291 cases and 57 416 controls. The results of this systematic review and meta-analysis suggest that there is a tendency for patients with germline mutations in the CDKN2A gene to have a worse overall survival (HR = 1.30, 95% CI = 0.99-1.69, P  = 0.05) and melanoma-specific survival (HR = 1.5, 95% CI = 0.97-2.31, P  = 0.07). Carrier patients would not only have more incidence of melanoma and a higher risk of a second melanoma, but they also seem to have a worse prognosis. The inclusion of gene panel testing in clinical practice and the collaboration within consortia are needed to provide further evidence on the prognosis of these patients.

MC1R signaling through the cAMP-CREB/ATF-1 and ERK-NFκB pathways accelerates G1/S transition promoting breast cancer progression

MC1R, a G-protein coupled receptor, triggers ultraviolet light-induced melanin synthesis and DNA repair in melanocytes and is implicated in the pathogenesis of melanoma. Although widely expressed in different tissue types, its function in non-cutaneous tissue is relatively unknown. Herein, we demonstrate that disruptive MC1R variants associated with melanomagenesis are less frequently found in patients with several cancers. Further exploration revealed that breast cancer tissue shows a significantly higher MC1R expression than normal breast tissue, and knocking down MC1R significantly reduced cell proliferation in vitro and in vivo. Mechanistically, MC1R signaling through the MC1R-cAMP-CREB/ATF-1 and MC1R-ERK-NFκB axes accelerated the G1-S transition in breast cancer cells. Our results revealed a new association between MC1R and breast cancer, which could be potentially targeted therapeutically. Moreover, our results suggest that MC1R-enhancing/activating therapies should be used cautiously, as they might be pro-tumorigenic in certain contexts.

Nevus Count, Pigmentary Characteristics, and Melanoma-specific Mortality among Norwegian Women with Melanoma >1.0 mm Thick

Little is known about if and how nevi and pigmentation are associated with melanoma-specific mortality. However, increased melanoma awareness in people with lighter pigmentation and many nevi may result in earlier diagnosis of thinner less-lethal tumors. The aim of this study was to investigate associations between nevus count (asymmetrical > 5 mm and small symmetrical), pigmentary characteristics (hair colour, eye colour, skin colour, freckling, pigmentary score), and melanoma-specific mortality in subjects with melanomas > 1 mm. Data from the Norwegian Women and Cancer cohort, established in 1991, with complete follow-up of melanoma patients until 2018 through the Cancer Registry of Norway, were used to estimate hazard ratios with 95% confidence intervals for the associations between nevus count, pigmentary characteristics, and melanoma-specific mortality, stratified by tumor thickness using Cox regression. Estimated hazard ratios consistently indicated a higher risk of melanoma death for those with darker vs lighter pigmentary characteristics in patients with tumors > 1.0-2.0 mm and > 2.0 mm thick (e.g. pigmentary score hazard ratio 1.25, 95% confidence interval (0.74-2.13)). Among women with melanomas > 1.0 mm thick, lighter pigmentation and asymmetrical nevi may be associated with lower melanoma-specific mortality, suggesting that factors that increase the risk of melanoma may also be associated with decreased risk of death from melanoma.

Melanin and Neuromelanin: Linking Skin Pigmentation and Parkinson's Disease

Neuromelanin-containing dopaminergic neurons in the substantia nigra pars compacta (SNpc) are the most vulnerable neurons in Parkinson's disease (PD). Recent work suggests that the accumulation of oxidized dopamine and neuromelanin mediate the convergence of mitochondrial and lysosomal dysfunction in patient-derived neurons. In addition, the expression of human tyrosinase in mouse SNpc led to the formation of neuromelanin resulting in the degeneration of nigral dopaminergic neurons, further highlighting the importance of neuromelanin in PD. The potential role of neuromelanin in PD pathogenesis has been supported by epidemiological observations, whereby individuals with lighter pigmentation or cutaneous malignant melanoma exhibit higher incidence of PD. Because neuromelanin and melanin share many functional characteristics and overlapping biosynthetic pathways, it has been postulated that genes involved in skin pigmentation and melanin formation may play a role in the susceptibility of vulnerable midbrain dopaminergic neurons to neurodegeneration. Here, we highlight potential mechanisms that may explain the link between skin pigmentation and PD, focusing on the role of skin pigmentation genes in the pathogenesis of PD. We also discuss the importance of genetic ancestry in assessing the contribution of pigmentation-related genes to risk of PD. © 2022 International Parkinson and Movement Disorder Society.

A genome-wide association study of germline variation and melanoma prognosis

Background

The high mortality of cutaneous melanoma (CM) is partly due to unpredictable patterns of disease progression in patients with early-stage lesions. The reliable prediction of advanced disease risk from early-stage CM, is an urgent clinical need, especially given the recent expansion of immune checkpoint inhibitor therapy to the adjuvant setting. In our study, we comprehensively investigated the role of germline variants as CM prognostic markers.

Methods

We performed a genome-wide association analysis in two independent cohorts of N=551 (discovery), and N=550 (validation) early-stage immunotherapy-naïve melanoma patients. A multivariable Cox proportional hazard regression model was used to identify associations with overall survival in the discovery group, followed by a validation analysis. Transcriptomic profiling and survival analysis were used to elucidate the biological relevance of candidate genes associated with CM progression.

Results

We found two independent associations of germline variants with melanoma prognosis. The alternate alleles of these two SNPs were both associated with an increased risk of death [rs60970102 in MELK: HR=3.14 (2.05-4.81), p=1.48×10-7; and rs77480547 in SH3BP4: HR=3.02 (2.02-4.52), p=7.58×10-8, both in the pooled cohort]. The addition of the combined risk alleles (CRA) of the identified variants into the prognostic model improved the predictive power, as opposed to a model of clinical covariates alone.

Conclusions

Our study provides suggestive evidence of novel melanoma germline prognostic markers, implicating two candidate genes: an oncogene MELK and a tumor suppressor SH3BP4, both previously suggested to affect CM progression. Pending further validation, these findings suggest that the genetic factors may improve the prognostic stratification of high-risk early-stage CM patients, and propose putative biological insights for potential therapeutic investigation of these targets to prevent aggressive outcome from early-stage melanoma.

Novel loss-of-function variant in DENND5A impedes melanosomal cargo transport and predisposes to familial cutaneous melanoma

PURPOSE

More than half of the familial cutaneous melanomas have unknown genetic predisposition. This study aims at characterizing a novel melanoma susceptibility gene.

METHODS

We performed exome and targeted sequencing in melanoma-prone families without any known melanoma susceptibility genes. We analyzed the expression of candidate gene DENND5A in melanoma samples in relation to pigmentation and UV signature. Functional studies were carried out using microscopic approaches and zebrafish model.

RESULTS

We identified a novel DENND5A truncating variant that segregated with melanoma in a Swedish family and 2 additional rare DENND5A variants, 1 of which segregated with the disease in an American family. We found that DENND5A is significantly enriched in pigmented melanoma tissue. Our functional studies show that loss of DENND5A function leads to decrease in melanin content in vitro and pigmentation defects in vivo. Mechanistically, harboring the truncating variant or being suppressed leads to DENND5A losing its interaction with SNX1 and its ability to transport the SNX1-associated vesicles from melanosomes. Consequently, untethered SNX1-premelanosome protein and redundant tyrosinase are redirected to lysosomal degradation by default, causing decrease in melanin content.

CONCLUSION

Our findings provide evidence of a physiological role of DENND5A in the skin context and link its variants to melanoma susceptibility.

Canine coat pigmentation genetics: a review

Our understanding of canine coat colour genetics and the associated health implications is developing rapidly. To date, there are 15 genes with known roles in canine coat colour phenotypes. Many coat phenotypes result from complex and/or epistatic genetic interactions among variants within and between loci, some of which remain unidentified. Some genes involved in canine pigmentation have been linked to aural, visual and neurological impairments. Consequently, coat pigmentation in the domestic dog retains considerable ethical and economic interest. In this paper we discuss coat colour phenotypes in the domestic dog, the genes and variants responsible for these phenotypes and any proven coat colour-associated health effects.

Genetic markers for characterization and prediction of prognosis of melanoma subtypes: a 2021 update

In this article we examined the most important genetic markers involved in melanoma susceptibility, initiation and progression, and their impact on the prognosis of the disease. Current knowledge in melanoma genetics identifies distinct pathways to the development of different melanoma subtypes characterized by specific clinico-pathological features and partially known genetic markers, modulated by high, low or absence of cumulative sun damage. The most prevalent somatic mutations are related to the activation of the MAPK pathway, which are classified into four major subtypes: BRAF mutant, NRAS mutant, NF1 mutant and triple wild type. Moreover, germinal mutations are also involved in the characterization and predictions of prognosis in melanoma. Currently, CDKN2A is seen as the main high-risk gene involved in melanoma susceptibility being mutated in around 20% of melanoma-prone families. Other high-risk susceptibility genes described include CDK4, POT1, BAP1, TERT promoter, ACD, and TERF2IP. Melanoma is one of the most genetically predisposed among all cancers in humans, and ultraviolet light from the sun is the main environmental factor. This genetic predisposition is starting to be understood, impacting not only on the risk of developing melanoma but also on the risk of developing other types of cancer, as well as on the prognosis of the disease.

Phenotypic Characteristics and Melanoma Thickness in Women

Patients' phenotypic characteristics might be associated with melanoma aggressiveness, but the evidence is scarce. This study examined the associations be-tween pigmentary characteristics, naevi and melanoma thickness. Data from the Norwegian Women and Cancer (NOWAC) study were analysed. By 2014, 1,243 women were diagnosed with a primary melanoma, and 1,140 had information on thickness. Using ordinal logistic regression models, the probability of being diagnosed with a specific thickness category was calculated by pigmentary score and naevi. Fair pigmentary score was associated with thinner trunk melanomas (probabilities of being diagnosed with a tumour ≤1.0 mm thickness were 74%, 66%, and 51% for fair, medium and dark pigmentary scores, respectively), but not the other sites. High number of naevi was associated with thicker nodular melanoma (NM) but not with super-ficial spreading melanoma. These findings suggest the need for greater overall vigilance and skin checks among women with fair pigmentary score. The association between naevi and NM suggest possible biological mechanisms.

Influence of germline genetic variants on dermoscopic features of melanoma

Nevus count is highly determined by inherited variants and has been associated with the origin of melanoma. De novo melanomas (DNMMs) are more prevalent in patients with a low nevus count and have distinctive dermoscopic features than nevus-associated melanomas. We evaluated the impact of nine single nucleotide polymorphisms (SNPs) of MTAP (rs10811629, rs2218220, rs7023329 and rs751173), PLA2G6 (rs132985 and rs2284063), IRF4 (rs12203592), and PAX3 (rs10180903 and rs7600206) genes associated with nevus count and melanoma susceptibility, and the MC1R variants on dermoscopic features of 371 melanomas from 310 patients. All MTAP variants associated with a low nevus count were associated with regression structures (peppering and mixed regression), blue-whitish veil, shiny white structures, and pigment network. SNPs of PLA2G6 (rs132985), PAX3 (rs7600206), and IRF4 (rs12203592) genes were also associated with either shiny white structures or mixed regression (all corrected p-values ≤ .06). Melanomas from red hair color MC1R variants carriers showed lower total dermoscopy score (p-value = .015) and less blotches than melanomas from non-carriers (p-value = .048). Our results provide evidence that germline variants protective for melanoma risk and/or associated with a low nevus count are associated with certain dermoscopic features, more characteristic of de novo and worse prognosis melanomas.

Germline variants are associated with increased primary melanoma tumor thickness at diagnosis

Germline genetic variants have been identified, which predispose individuals and families to develop melanoma.

Tumor thickness is the strongest predictor of outcome for clinically localized primary melanoma patients. We sought to determine whether there is a heritable genetic contribution to variation in tumor thickness. If confirmed, this will justify the search for specific genetic variants influencing tumor thickness.

To address this, we estimated the proportion of variation in tumor thickness attributable to genome-wide genetic variation (variant-based heritability) using unrelated patients with measured primary cutaneous melanoma thickness. As a secondary analysis, we conducted a genome-wide association study (GWAS) of tumor thickness.

The analyses utilized 10 604 individuals with primary cutaneous melanoma drawn from nine GWAS datasets from eight cohorts recruited from the general population, primary care and melanoma treatment centers. Following quality control and filtering to unrelated individuals with study phenotypes, 8125 patients were used in the primary analysis to test whether tumor thickness is heritable. An expanded set of 8505 individuals (47.6% female) were analyzed for the secondary GWAS meta-analysis. Analyses were adjusted for participant age, sex, cohort and ancestry.

We found that 26.6% (SE 11.9%, P = 0.0128) of variation in tumor thickness is attributable to genome-wide genetic variation. While requiring replication, a chromosome 11 locus was associated (P < 5 × 10⁻⁸) with tumor thickness. Our work indicates that sufficiently large datasets will enable the discovery of genetic variants associated with greater tumor thickness, and this will lead to the identification of host biological processes influencing melanoma growth and invasion.

MC1R variants and cutaneous melanoma risk according to histological type, body site, and Breslow thickness: a pooled analysis from the M-SKIP project

Little is known on whether melanocortin 1 receptor (MC1R) associated cutaneous melanoma (CM) risk varies depending on histological subtype and body site, and whether tumour thickness at diagnosis (the most important prognostic factor for CM patients) differs between MC1R variant carriers and wild-type individuals. We studied the association between MC1R variants and CM risk by histological subtype, body site, and Breslow thickness, using the database of the M-SKIP project. We pooled individual data from 15 case-control studies conducted during 2005-2015 in Europe and the USA. Study-specific, multi-adjusted odds ratios were pooled into summary odds ratios (SOR) and 95% confidence intervals (CI) using random-effects models. Six thousand eight hundred ninety-one CM cases and 5555 controls were included. CM risk was increased among MC1R variant carriers vs. wild-type individuals. The increase in risk was comparable across histological subtypes (SOR for any variant vs. wild-type ranged between 1.57 and 1.70, always statistical significant) except acral lentiginous melanoma (ALM), for which no association emerged; and slightly greater on chronically (1.74, 95% CI 1.47-2.07) than intermittently (1.55, 95% CI 1.34-1.78) sun-exposed skin. CM risk was greater for those carrying 'R' vs. 'r' variants; correlated with the number of variants; and was more evident among individuals not showing the red hair colour phenotype. Breslow thickness was not associated with MC1R status. MC1R variants were associated with an increased risk of CM of any histological subtype (except ALM) and occurring on both chronically and intermittently sun-exposed skin.

Features associated with melanoma metastasis in Latvia

Cutaneous melanoma (CM) is the most aggressive form of skin cancer, exhibits an increasing incidence worldwide and has a high potential to develop metastasis. The current study aimed to identify a set of parameters that may aid in predicting the probability and timing of the onset of CM metastasis. A retrospective analysis was performed using the archive data of 2,026 patients with CM that were treated at the Riga East University Hospital Latvian Oncology Centre, which is the largest oncological hospital in the country, between 1998 and 2015. A case-control study design was employed, where patients with metastasis (n=278) were used as the cases and patients without metastasis were used as the controls. The present study examined the associations between metastasis and potential risk factors and constructed multivariate models of features that predicted metastasis using stepwise regression. Time until metastasis was analyzed using negative binomial regression models. The results of the present study indicated an increase in the number of melanomas that developed metastases during 1998–2015. Tumor Breslow thickness was demonstrated to be significantly larger in patients with metastasis compared with those without (P=0.012). The presence of ulceration significantly increased the risk of metastases [odds ratio (OR), 1.66; 95% CI, 1.07-2.59; P=0.033]. The absence of pigment in melanoma tissues was indicated to lead to a greater likelihood of metastasis (OR, 2.14; 95% CI, 1.10-4.19; P=0.035). Shorter times from diagnosis until the onset of metastases were observed in older patients (incident rate ratio (IRR), 6.85; 95% CI, 2.43-19.30; P=2.78×10⁻⁴), and a borderline significant association was observed in those with ulcerated tumors (IRR, 1.33; 95% CI, 0.98-1.80; P=0.064). Therefore, the main features associated with the development of melanoma metastasis in Latvia were indicated to be tumor ulceration, absence of pigment and Breslow thickness.

The complementary effect of rs1042522 in TP53 and rs1805007 in MC1R is associated with an elevated risk of cutaneous melanoma in Latvian population

Genetic factors serve important roles in melanoma susceptibility. Although much genetic variation has been associated with cutaneous melanoma (CM), little is known about the interactions between genetic variants. The current study investigated the joint effect of rs1042522 in the tumour protein 53 (TP53) gene, rs2279744 in the murine double minute-2 (MDM2) gene and several single nucleotide polymorphisms (SNPs) in the melanocortin 1 receptor (MC1R) gene. All of these genes are interconnected in a single signalling pathway that regulates pigmentation. The current study included 479 individuals, of which, 255 were patients with CM and 224 were controls from the Latvian population. Multifaceted analyses of potential interactions between SNPs were performed, whilst taking into account the pigmentation phenotypes of individuals and tumour characteristics (Breslow thickness and ulceration). Univariate analyses revealed a borderline significant association between rs1042522 in the TP53 gene and CM risk. The results also confirmed a known association with rs1805007 in the MC1R gene. The rs1042522 was also selected as a CM risk factor in multivariate models, suggesting an effect that is independent from and complementary to that of rs1805007. The results indicated that these SNPs need to be taken into account when determining melanoma risk. A strong association between CM and red hair was identified for rs1805007, and rs1805008 in the MC1R gene was mainly associated with red hair. An association was also determined between rs2279744 in the MDM2 gene and brown eye colour. No convincing associations were identified between the analysed SNPs and Breslow thickness of tumours or ulcerations.

Inherited MC1R variants in patients with melanoma are associated with better survival in women

Background

Women have a better melanoma prognosis, and fairer skin/hair colour. The presence of inherited MC1R variants has been associated with a better melanoma prognosis, but its interaction with sex is unknown.

Objectives

To evaluate the relationship between germline MC1R status and survival, and determine any association with sex.

Methods

This was a cohort study including 1341 patients with melanoma from the Melanoma Unit of the Hospital Clinic of Barcelona, between January 1996 and April 2018. We examined known sex‐related prognosis factors as they relate to features of melanoma and evaluated the sex‐specific role of MC1R in overall and melanoma‐specific survival. Hazard ratios (HRs) were calculated using univariate and multivariate Cox logistic regression.

Results

Men showed lower overall survival than women (P < 0·001) and the presence of inherited MC1R variants was not associated with better survival in our cohort. However, in women the presence of MC1R variants was associated with better overall survival in the multivariate analysis [HR 0·57, 95% confidence interval (CI) 0·38–0·85; P = 0·006] but not in men [HR 1·26, 95% CI 0·89–1·79; P = 0·185 (P‐value for interaction 0·004)]. Analysis performed for melanoma‐specific survival showed the same level of significance.

Conclusions

Inherited MC1R variants are associated with improved overall survival in women with melanoma but not in men. Intrinsic sex‐dependent features can modify the role of specific genes in melanoma prognosis. We believe that survival studies of patients with melanoma should include analysis by sex and MC1R genotype.

What's already known about this topic?

Inherited MC1R variants have been associated with a better melanoma prognosis, but their interaction with sex is unknown.

What does this study add?

MC1R variants are related to better overall survival and melanoma‐specific survival in women but not in men.

What is the translational message?

These differences between the sexes could imply future changes in melanoma follow‐up and treatment strategies.

This provides a basis for understanding the interaction between sex‐related genes and germline variants in cancer.

https://www.bjdonline.com/article/

Linked Editorial:https://doi.org/10.1111/bjd.18555

MC1R variants in childhood and adolescent melanoma: a retrospective pooled analysis of a multicentre cohort

BACKGROUND

Germline variants in the melanocortin 1 receptor gene (MC1R) might increase the risk of childhood and adolescent melanoma, but a clear conclusion is challenging because of the low number of studies and cases. We assessed the association of MC1R variants with childhood and adolescent melanoma in a large study comparing the prevalence of MC1R variants in child or adolescent patients with melanoma to that in adult patients with melanoma and in healthy adult controls.

METHODS

In this retrospective pooled analysis, we used the M-SKIP Project, the Italian Melanoma Intergroup, and other European groups (with participants from Australia, Canada, France, Greece, Italy, the Netherlands, Serbia, Spain, Sweden, Turkey, and the USA) to assemble an international multicentre cohort. We gathered phenotypic and genetic data from children or adolescents diagnosed with sporadic single-primary cutaneous melanoma at age 20 years or younger, adult patients with sporadic single-primary cutaneous melanoma diagnosed at age 35 years or older, and healthy adult individuals as controls. We calculated odds ratios (ORs) for childhood and adolescent melanoma associated with MC1R variants by multivariable logistic regression. Subgroup analysis was done for children aged 18 or younger and 14 years or younger.

FINDINGS

We analysed data from 233 young patients, 932 adult patients, and 932 healthy adult controls. Children and adolescents had higher odds of carrying MC1R r variants than did adult patients (OR 1·54, 95% CI 1·02-2·33), including when analysis was restricted to patients aged 18 years or younger (1·80, 1·06-3·07). All investigated variants, except Arg160Trp, tended, to varying degrees, to have higher frequencies in young patients than in adult patients, with significantly higher frequencies found for Val60Leu (OR 1·60, 95% CI 1·05-2·44; p=0·04) and Asp294His (2·15, 1·05-4·40; p=0·04). Compared with those of healthy controls, young patients with melanoma had significantly higher frequencies of any MC1R variants.

INTERPRETATION

Our pooled analysis of MC1R genetic data of young patients with melanoma showed that MC1R r variants were more prevalent in childhood and adolescent melanoma than in adult melanoma, especially in patients aged 18 years or younger. Our findings support the role of MC1R in childhood and adolescent melanoma susceptibility, with a potential clinical relevance for developing early melanoma detection and preventive strategies.

FUNDING

SPD-Pilot/Project-Award-2015; AIRC-MFAG-11831.

Melanoma susceptibility variant rs869330 in the MTAP gene is associated with melanoma outcome

The rising incidence of cutaneous melanoma (CM), an aggressive skin cancer, emphasizes the need for novel biomarkers to guide personalized care and better predict outcome. Genetic factors including germline risk variants are promising candidates for this aim. We explored the association between germline risk variants and melanoma outcome in a large genetically homogenous Belgian melanoma population, focusing on single nucleotide polymorphisms which generated the highest association with melanoma susceptibility. Between 2004 and 2014, blood samples of 1088 patients with histologically confirmed CM were collected and genotyped for nine variants. Cox proportional hazard models were used to assess the association between each single nucleotide polymorphism and relapse-free survival and overall survival, adjusted by age, sex, melanoma stage, site, and subtype. We identified significant associations for rs869330 (in the methylthioadenosine phosphorylase - MTAP gene) with overall survival (hazard ratio = 0.760, P = 0.048, 95% confidence interval: 0.580-0.998) and relapse-free survival (hazard ratio = 0.800, P = 0.020, 95% confidence interval: 0.650-0.970). This exploratory study is the first to show a significant association between the rs869330 variant (in the MTAP gene) and outcome in a large CM population.

CDKN2A germline mutations are not associated with poor survival in an Italian cohort of melanoma patients

BACKGROUND

Cyclin dependent kinase inhibitor 2A gene (CDKN2A) germline mutations have recently been associated with poor survival in patients with melanoma. Despite the high mutation rate in our cohort (up to 10% in patients with apparently sporadic melanoma), information on the impact of CDKN2A on survival in this cohort is lacking.

OBJECTIVE

To investigate whether poor survival associated with CDKN2A germline mutations was confirmed in a high mutation-prevalence cohort of Italian patients with melanoma undergoing a mutation-based follow-up.

METHODS

A total of 1239 patients with cutaneous melanoma were tested for CDKN2A mutational status and then assigned to a follow-up scheme according not only to family history but also to CDKN2A mutational status, as follow-up intervals were more frequent for CDKN2A germline mutation-positive (MUT⁺) patients. From this cohort, we selected 106 MUT⁺ patients (with familial melanoma or apparently sporadic melanoma) and 199 CDKN2A germline mutation-negative (MUT^-) patients with sporadic melanoma who were matched by age and sex and had a similar tumor stage distribution.

RESULTS

We found no difference in overall survival (hazard ratio, 0.85; 95% confidence interval, 0.48-1.52; P = .592,) or melanoma-specific survival (hazard ratio, 0.86; 95% confidence interval, 0.38-1.95; P = .718,) between MUT⁺ and MUT^- patients. MUT⁺ patients were more likely to develop multiple melanomas and to undergo surgical excision of dysplastic nevi than were MUT^- patients.

LIMITATIONS

Retrospective study.

CONCLUSION

CDKN2A mutations were not associated with survival in our cohort.

Sun Exposure and Melanoma, Certainties and Weaknesses of the Present Knowledge

Sun exposure is the main risk factor for cutaneous malignant melanoma (CMM). However, the UV-related pathogenetic mechanisms leading to CMM are far to be fully elucidated. In this paper we will focus on what we still don't fully know about the relationship between UVR and CMM. In particular, we will discuss: the action spectrum of human CMM, how different modalities of exposure (continuous/ intermittent; erythemal/ suberythemal) relate to different CMM variants, the preferential UVR induced DNA mutations observed in different CMM variants, the role of UV-related and UV-unrelated genetic damages in the same melanoma cells. Moreover, we will debate the importance of UVA induced oxidative and anaerobic damages to DNA and other cell structures and the role of melanins, of modulation of innate and acquired immunity, of vitamin D and of chronic exposure to phototoxic drugs and other xenobiotics. A better understanding of these issues will help developing more effective preventative strategies and new therapeutic approaches.

Functional interplay between secreted ligands and receptors in melanoma

Melanoma, the most aggressive form of skin cancer, results from the malignant transformation of melanocytes located in the basement membrane separating the epidermal and dermal skin compartments. Cutaneous melanoma is often initiated by solar ultraviolet radiation (UVR)-induced mutations. Melanocytes intimately interact with keratinocytes, which provide growth factors and melanocortin peptides acting as paracrine regulators of proliferation and differentiation. Keratinocyte-derived melanocortins activate melanocortin-1 receptor (MC1R) to protect melanocytes from the carcinogenic effect of UVR. Accordingly, MC1R is a major determinant of susceptibility to melanoma. Despite extensive phenotypic heterogeneity and high mutation loads, the molecular basis of melanomagenesis and the molecules mediating the crosstalk between melanoma and stromal cells are relatively well understood. Mutations of intracellular effectors of receptor tyrosine kinase (RTK) signalling, notably NRAS and BRAF, are major driver events more frequent than mutations in RTKs. Nevertheless, melanomas often display aberrant signalling from RTKs such as KIT, ERRB1-4, FGFR, MET and PDGFR, which contribute to disease progression and resistance to targeted therapies. Progress has also been made to unravel the role of the tumour secretome in preparing the metastatic niche. However, key aspects of the melanoma-stroma interplay, such as the molecular determinants of dormancy, remain poorly understood.

MC1R variants as melanoma risk factors independent of at-risk phenotypic characteristics: a pooled analysis from the M-SKIP project

PURPOSE

Melanoma represents an important public health problem, due to its high case-fatality rate. Identification of individuals at high risk would be of major interest to improve early diagnosis and ultimately survival. The aim of this study was to evaluate whether MC1R variants predicted melanoma risk independently of at-risk phenotypic characteristics.

MATERIALS AND METHODS

Data were collected within an international collaboration - the M-SKIP project. The present pooled analysis included data on 3,830 single, primary, sporadic, cutaneous melanoma cases and 2,619 controls from seven previously published case-control studies. All the studies had information on MC1R gene variants by sequencing analysis and on hair color, skin phototype, and freckles, ie, the phenotypic characteristics used to define the red hair phenotype.

RESULTS

The presence of any MC1R variant was associated with melanoma risk independently of phenotypic characteristics (OR 1.60; 95% CI 1.36-1.88). Inclusion of MC1R variants in a risk prediction model increased melanoma predictive accuracy (area under the receiver-operating characteristic curve) by 0.7% over a base clinical model (P=0.002), and 24% of participants were better assessed (net reclassification index 95% CI 20%-30%). Subgroup analysis suggested a possibly stronger role of MC1R in melanoma prediction for participants without the red hair phenotype (net reclassification index: 28%) compared to paler skinned participants (15%).

CONCLUSION

The authors suggest that measuring the MC1R genotype might result in a benefit for melanoma prediction. The results could be a valid starting point to guide the development of scientific protocols assessing melanoma risk prediction tools incorporating the MC1R genotype.

cAMP-independent non-pigmentary actions of variant melanocortin 1 receptor: AKT-mediated activation of protective responses to oxidative DNA damage

The melanocortin 1 receptor gene (MC1R), a well-established melanoma susceptibility gene, regulates the amount and type of melanin pigments formed within epidermal melanocytes. MC1R variants associated with increased melanoma risk promote the production of photosensitizing pheomelanins as opposed to photoprotective eumelanins. Wild-type (WT) MC1R activates DNA repair and antioxidant defenses in a cAMP-dependent fashion. Since melanoma-associated MC1R variants are hypomorphic in cAMP signaling, these non-pigmentary actions are thought to be defective in MC1R-variant human melanoma cells and epidermal melanocytes, consistent with a higher mutation load in MC1R-variant melanomas. We compared induction of antioxidant enzymes and DNA damage responses in melanocytic cells of defined MC1R genotype. Increased expression of catalase (CAT) and superoxide dismutase (SOD) genes following MC1R activation was cAMP-dependent and required a WT MC1R genotype. Conversely, pretreatment of melanocytic cells with an MC1R agonist before an oxidative challenge with Luperox decreased (i) accumulation of 8-oxo-7,8-dihydro-2'-deoxyguanine, a major product of oxidative DNA damage, (ii) phosphorylation of histone H2AX, a marker of DNA double-strand breaks, and (iii) formation of DNA breaks. These responses were comparable in cells WT for MC1R or harboring hypomorphic MC1R variants without detectable cAMP signaling. In MC1R-variant melanocytic cells, the DNA-protective responses were mediated by AKT. Conversely, in MC1R-WT melanocytic cells, high cAMP production downstream of MC1R blocked AKT activation and was responsible for inducing DNA repair. Accordingly, MC1R activation could promote repair of oxidative DNA damage by a cAMP-dependent pathway downstream of WT receptor, or via AKT in cells of variant MC1R genotype.

Combining molecular and immunohistochemical analyses of key drivers in primary melanomas: interplay between germline and somatic variations

Due to the high mutational somatic burden of Cutaneous Malignant Melanoma (CMM) a thorough profiling of the driver mutations and their interplay is necessary to explain the timing of tumorigenesis or for the identification of actionable genetic events. The aim of this study was to establish the mutation rate of some of the key drivers in melanoma tumorigenesis combining molecular analyses and/or immunohistochemistry in 93 primary CMMs from an Italian cohort also characterized for germline status, and to investigate an interplay between germline and somatic variants. BRAF mutations were present in 68% of cases, while CDKN2A germline mutations were found in 16 % and p16 loss in tissue was found in 63%. TERT promoter somatic mutations were detected in 38% of cases while the TERT -245T>C polymorphism was found in 51% of cases. NRAS mutations were found in 39% of BRAF negative or undetermined cases. NF1 was expressed in all cases analysed. MC1R variations were both considered as a dichotomous variable or scored. While a positive, although not significant association between CDKN2A germline mutations, but not MC1R variants, and BRAF somatic mutation was found, we did not observe other associations between germline and somatic events. A yet undescribed inverse correlation between TERT -245T>C polymorphism and the presence of BRAF mutation was found. It is possible to hypothesize that -245T>C polymorphism could be included in those genotypes which may influence the occurrence of BRAF mutations. Further studies are needed to investigate the role of -245T>C polymorphism as a germline predictor of BRAF somatic mutation status.

Detrimental effects of melanocortin-1 receptor (MC1R) variants on the clinical outcomes of BRAF V600 metastatic melanoma patients treated with BRAF inhibitors

Melanocortin-1 receptor (MC1R) plays a key role in skin pigmentation, and its variants are linked with a higher melanoma risk. The influence of MC1R variants on the outcomes of patients with metastatic melanoma (MM) treated with BRAF inhibitors (BRAFi) is unknown. We studied the MC1R status in a cohort of 53 consecutive BRAF-mutated patients with MM treated with BRAFi. We also evaluated the effect of vemurafenib in four ^V600 BRAF melanoma cell lines with/without MC1R variants. We found a significant correlation between the presence of MC1R variants and worse outcomes in terms of both overall response rate (ORR; 59% versus 95%, P = 0.011 univariate, P = 0.028 multivariate analysis) and progression-free survival (PFS) shorter than 6 months (72% versus 33%, P = 0.012 univariate, P = 0.027 multivariate analysis). No difference in overall survival (OS) was reported, probably due to subsequent treatments. Data in vitro showed a significant different phosphorylation of Erk1/2 and p38 MAPK during treatment, associated with a greater increase in vemurafenib IC50 in MC1R variant cell lines.

Melanocortin 1 receptor (MC1R) polymorphisms' influence on size and dermoscopic features of nevi

The melanocortin 1 receptor (MC1R) is a highly polymorphic gene. The loss-of-function MC1R variants ("R") have been strongly associated with red hair color phenotype and an increased melanoma risk. We sequenced the MC1R gene in 175 healthy individuals to assess the influence of MC1R on nevus phenotype. We identified that MC1R variant carriers had larger nevi both on the back [p-value = .016, adjusted for multiple parameters (adj. p-value)] and on the upper limbs (adj. p-value = .007). Specifically, we identified a positive association between the "R" MC1R variants and visible vessels in nevi [p-value = .033, corrected using the FDR method for multiple comparisons (corrected p-value)], dots and globules in nevi (corrected p-value = .033), nevi with eccentric hyperpigmentation (corrected p-value = .033), a high degree of freckling (adj. p-value = .019), and an associative trend with presence of blue nevi (corrected p-value = .120). In conclusion, the MC1R gene appears to influence the nevus phenotype.

MC1R signaling. Intracellular partners and pathophysiological implications

The melanocortin-1 receptor (MC1R) preferentially expressed in melanocytes is best known as a key regulator of the synthesis of epidermal melanin pigments. Its paracrine stimulation by keratinocyte-derived melanocortins also activates DNA repair pathways and antioxidant defenses to build a complex, multifaceted photoprotective response. Many MC1R actions rely on cAMP-dependent activation of two transcription factors, MITF and PGC1α, but pleiotropic MC1R signaling also involves activation of mitogen-activated kinases and AKT. MC1R partners such as β-arrestins, PTEN and the E3 ubiquitin ligase MGRN1 differentially regulate these pathways. The MC1R gene is complex and polymorphic, with frequent variants associated with skin phenotypes and increased cancer risk. We review current knowledge of signaling from canonical MC1R, its splice isoforms and natural polymorphic variants. Recently discovered intracellular targets and partners are also discussed, to highlight the diversity of mechanisms that may contribute to normal and pathological variation of pigmentation and sensitivity to solar radiation-induced damage. This article is part of a Special Issue entitled: Melanocortin Receptors - edited by Ya-Xiong Tao.

IRF4 rs12203592 functional variant and melanoma survival

Inherited genetic factors may modulate clinical outcome in melanoma. Some low-to-medium risk genes in melanoma susceptibility play a role in melanoma outcome. Our aim was to assess the role of the functional IRF4 SNP rs12203592 in melanoma prognosis in two independent sets (Barcelona, N = 493 and Essen, N = 438). Genotype association analyses showed that the IRF4 rs12203592 T allele increased the risk of dying from melanoma in both sets (Barcelona: odds ratio [OR] = 6.53, 95% CI 1.38-30.87, Adj p = 0.032; Essen: OR = 1.68, 95% CI 1.04-2.72, Adj p = 0.035). Survival analyses only showed significance for the Barcelona set (hazard ratio = 4.58, 95% CI 1.11-18.92, Adj p = 0.036). This SNP was also associated with tumour localization, increasing the risk of developing melanoma in head or neck (OR = 1.79, 95% CI 1.07-2.98, Adj p = 0.032) and protecting from developing melanoma in the trunk (OR = 0.59, 95% CI 0.41-0.85, Adj p = 0.004). These findings suggest for the first time that IRF4 rs12203592 plays a role in the modulation of melanoma outcome and confirms its contribution to the localization of the primary tumour.

A comprehensive genome-wide analysis of melanoma Breslow thickness identifies interaction between CDC42 and SCIN genetic variants

Breslow thickness (BT) is a major prognostic factor of cutaneous melanoma (CM), the most fatal skin cancer. The genetic component of BT has only been explored by candidate gene studies with inconsistent results. Our objective was to uncover the genetic factors underlying BT using an hypothesis-free genome-wide approach. Our analysis strategy integrated a genome-wide association study (GWAS) of single nucleotide polymorphisms (SNPs) for BT followed by pathway analysis of GWAS outcomes using the gene-set enrichment analysis (GSEA) method and epistasis analysis within BT-associated pathways. This strategy was applied to two large CM datasets with Hapmap3-imputed SNP data: the French MELARISK study for discovery (966 cases) and the MD Anderson Cancer Center study (1,546 cases) for replication. While no marginal effect of individual SNPs was revealed through GWAS, three pathways, defined by gene ontology (GO) categories were significantly enriched in genes associated with BT (false discovery rate ≤5% in both studies): hormone activity, cytokine activity and myeloid cell differentiation. Epistasis analysis, within each significant GO, identified a statistically significant interaction between CDC42 and SCIN SNPs (pmeta-int =2.2 × 10(-6) , which met the overall multiple-testing corrected threshold of 2.5 × 10(-6) ). These two SNPs (and proxies) are strongly associated with CDC42 and SCIN gene expression levels and map to regulatory elements in skin cells. This interaction has important biological relevance since CDC42 and SCIN proteins have opposite effects in actin cytoskeleton organization and dynamics, a key mechanism underlying melanoma cell migration and invasion.

Germline MC1R status influences somatic mutation burden in melanoma

The major genetic determinants of cutaneous melanoma risk in the general population are disruptive variants (R alleles) in the melanocortin 1 receptor (MC1R) gene. These alleles are also linked to red hair, freckling, and sun sensitivity, all of which are known melanoma phenotypic risk factors. Here we report that in melanomas and for somatic C>T mutations, a signature linked to sun exposure, the expected single-nucleotide variant count associated with the presence of an R allele is estimated to be 42% (95% CI, 15-76%) higher than that among persons without an R allele. This figure is comparable to the expected mutational burden associated with an additional 21 years of age. We also find significant and similar enrichment of non-C>T mutation classes supporting a role for additional mutagenic processes in melanoma development in individuals carrying R alleles.

Inherited functional variants of the lymphocyte receptor CD5 influence melanoma survival

Despite the recent progress in treatment options, malignant melanoma remains a deadly disease. Besides therapy, inherited factors might modulate clinical outcome, explaining in part widely varying survival rates. T-cell effector function regulators on antitumor immune responses could also influence survival. CD5, a T-cell receptor inhibitory molecule, contributes to the modulation of antimelanoma immune responses as deduced from genetically modified mouse models. The CD5 SNPs rs2241002 (NM_014207.3:c.671C > T, p.Pro224Leu) and rs2229177 (NM_014207.3:c.1412C > T, p.Ala471Val) constitute an ancestral haplotype (Pro224-Ala471) that confers T-cell hyper-responsiveness and worsens clinical autoimmune outcome. The assessment of these SNPs on survival impact from two melanoma patient cohorts (Barcelona, N = 493 and Essen, N = 215) reveals that p.Ala471 correlates with a better outcome (OR= 0.57, 95% CI = 0.33-0.99, Adj. p = 0.043, in Barcelona OR = 0.63, 95% CI = 0.40-1.01, Adj. p = 0.051, in Essen). While, p.Leu224 was associated with increased melanoma-associated mortality in both cohorts (OR = 1.87, 95% CI = 1.07-3.24, Adj. p = 0.030 in Barcelona and OR = 1.84, 95% CI = 1.04-3.26, Adj. p = 0.037, in Essen). Furthermore survival analyses showed that the Pro224-Ala471 haplotype in homozygosis improved melanoma survival in the entire set of patients (HR = 0.27, 95% CI 0.11-0.67, Adj. p = 0.005). These findings highlight the relevance of genetic variability in immune-related genes for clinical outcome in melanoma.

Pigmentary Markers in Danes--Associations with Quantitative Skin Colour, Nevi Count, Familial Atypical Multiple-Mole, and Melanoma Syndrome

To investigate whether pigmentation genes involved in the melanogenic pathway (melanogenesis) contributed to melanoma predisposition, we compared pigmentary genetics with quantitative skin pigmentation measurements, the number of atypical nevi, the total nevus count, and the familial atypical multiple mole and melanoma (FAMMM) syndrome. We typed 32 pigmentary SNP markers and sequenced MC1R in 246 healthy individuals and 116 individuals attending periodic control for malignant melanoma development, 50 of which were diagnosed with FAMMM. It was observed that individuals with any two grouped MC1R variants (missense, NM_002386:c. 456C > A (p.TYR152*), or NM_002386:c.83_84insA (p.Asn29Glnfs*14) had significantly (p<0.001) lighter skin pigmentation of the upper-inner arm than those with none or one MC1R variant. We did not observe any significant association of the MC1R variants with constitutive pigmentation measured on the buttock area. We hypothesize that the effect of MC1R variants on arm pigmentation is primarily reflecting the inability to tan when subjected to UVR. A gender specific effect on skin pigmentation was also observed, and it was found that the skin pigmentation of females on average were darker than that of males (p<0.01). We conclude that MC1R variants are associated with quantitative skin colour in a lightly pigmented Danish population. We did not observe any association between any pigmentary marker and the FAMMM syndrome. We suggest that the genetics of FAMMM is not related to the genetics of the pigmentary pathway.

Germline determinants of clinical outcome of cutaneous melanoma

Cutaneous melanoma (CM) is the most lethal form of skin cancer. Despite the constant increase in melanoma incidence, which is in part due to incremental advances in early diagnostic modalities, mortality rates have not improved over the last decade and for advanced stages remain steadily high. While conventional prognostic biomarkers currently in use find significant utility for predicting overall general survival probabilities, they are not sensitive enough for a more personalized clinical assessment on an individual level. In recent years, the advent of genomic technologies has brought the promise of identification of germline DNA alterations that may associate with CM outcomes and hence represent novel biomarkers for clinical utilization. This review attempts to summarize the current state of knowledge of germline genetic factors studied for their impact on melanoma clinical outcomes. We also discuss ongoing problems and hurdles in validating such surrogates, and we also project future directions in discovery of more powerful germline genetic factors with clinical utility in melanoma prognostication.

MC1R gene variants and non-melanoma skin cancer: a pooled-analysis from the M-SKIP project

BACKGROUND

The melanocortin-1-receptor (MC1R) gene regulates human pigmentation and is highly polymorphic in populations of European origins. The aims of this study were to evaluate the association between MC1R variants and the risk of non-melanoma skin cancer (NMSC), and to investigate whether risk estimates differed by phenotypic characteristics.

METHODS

Data on 3527 NMSC cases and 9391 controls were gathered through the M-SKIP Project, an international pooled-analysis on MC1R, skin cancer and phenotypic characteristics. We calculated summary odds ratios (SOR) with random-effect models, and performed stratified analyses.

RESULTS

Subjects carrying at least one MC1R variant had an increased risk of NMSC overall, basal cell carcinoma (BCC) and squamous cell carcinoma (SCC): SOR (95%CI) were 1.48 (1.24-1.76), 1.39 (1.15-1.69) and 1.61 (1.35-1.91), respectively. All of the investigated variants showed positive associations with NMSC, with consistent significant results obtained for V60L, D84E, V92M, R151C, R160W, R163Q and D294H: SOR (95%CI) ranged from 1.42 (1.19-1.70) for V60L to 2.66 (1.06-6.65) for D84E variant. In stratified analysis, there was no consistent pattern of association between MC1R and NMSC by skin type, but we consistently observed higher SORs for subjects without red hair.

CONCLUSIONS

Our pooled-analysis highlighted a role of MC1R variants in NMSC development and suggested an effect modification by red hair colour phenotype.

Age-related characteristics of cutaneous melanoma in a Spanish Mediterranean population

BACKGROUND

Melanoma is considered a heterogeneous tumor with genetic and environmental factors involved in its pathogenesis. The impact of these factors varies depending on age.

OBJECTIVE

The aim of this study was to characterize the epidemiological, phenotypic, and histological features of patients with melanoma according to three age groups: ≤40, 41-65, and >65 years.

METHODS

A total of 1122 consecutive patients with invasive melanoma definitively treated in our institution since January 2000 were selected from our melanoma database. Epidemiological, phenotypic, and histological data were retrieved and analyzed as a function of age.

RESULTS

Female patients predominated in the younger age group. The location of cutaneous malignant melanoma differed with age. In the younger and middle age groups, tumors presented mainly on the trunk, while in the older group they were mainly found on the head/neck. Signs of actinic damage such as actinic keratoses, solar lentigines, or other skin tumors increased with age, while genetic factors such as family history of melanoma or a high number of common melanocytic nevi were more frequent in the younger group.

CONCLUSION

Our results suggest that melanoma development in younger patients is the result of genetic factors, particularly related to multiple nevi, whereas in older patients environmental factors such as severe chronic sun exposure play a major role.

MC1R variants increased the risk of sporadic cutaneous melanoma in darker-pigmented Caucasians: a pooled-analysis from the M-SKIP project

The MC1R gene is a key regulator of skin pigmentation. We aimed to evaluate the association between MC1R variants and the risk of sporadic cutaneous melanoma (CM) within the M-SKIP project, an international pooled-analysis on MC1R, skin cancer and phenotypic characteristics. Data included 5,160 cases and 12,119 controls from 17 studies. We calculated a summary odds ratio (SOR) for the association of each of the nine most studied MC1R variants and of variants combined with CM by using random-effects models. Stratified analysis by phenotypic characteristics were also performed. Melanoma risk increased with presence of any of the main MC1R variants: the SOR for each variant ranged from 1.47 (95%CI: 1.17-1.84) for V60L to 2.74 (1.53-4.89) for D84E. Carriers of any MC1R variant had a 66% higher risk of developing melanoma compared with wild-type subjects (SOR; 95%CI: 1.66; 1.41-1.96) and the risk attributable to MC1R variants was 28%. When taking into account phenotypic characteristics, we found that MC1R-associated melanoma risk increased only for darker-pigmented Caucasians: SOR (95%CI) was 3.14 (2.06-4.80) for subjects with no freckles, no red hair and skin Type III/IV. Our study documents the important role of all the main MC1R variants in sporadic CM and suggests that they have a direct effect on melanoma risk, independently on the phenotypic characteristics of carriers. This is of particular importance for assessing preventive strategies, which may be directed to darker-pigmented Caucasians with MC1R variants as well as to lightly pigmented, fair-skinned subjects.

Molecular pathology of cutaneous melanoma

Cutaneous melanoma is associated with strong prognostic phenotypic features, such as gender, Breslow's thickness and ulceration, although the biological significance of these variables is largely unknown. It is likely that these features are surrogates of important biological events rather than directly promoting cutaneous melanoma progression. In this article, we address the molecular mechanisms that drive these phenotypic changes. Furthermore, we present a comprehensive overview of recurrent genetic abnormalities, both germline and somatic, in relation to cutaneous melanoma subtypes, ultraviolet exposure and anatomical localization, as well as pre-existing and targeted therapy-induced mutations that may contribute to resistance. The increasing knowledge of critically important oncogenes and tumor-suppressor genes is promoting a transition in melanoma diagnosis, in which single-gene testing will be replaced by multiplex and multidimensional analyses that combine classical histopathological characteristics with the molecular profile for the prognostication and selection of melanoma therapy.

Inherited variation at MC1R and ASIP and association with melanoma-specific survival

Melanocortin-1 receptor (MC1R) is a marker of melanoma risk in populations of European ancestry. However, MC1R effects on survival are much less studied. We investigated associations between variation at MC1R and survival in an international, population-based series of single primary melanoma patients enrolled into the Genes, Environment, and Melanoma study. MC1R genotype data was available for 2,200 participants with a first incident primary melanoma diagnosis. We estimated the association of MC1R genotypes with melanoma-specific survival (i.e., death caused by melanoma) and overall survival using COX proportional hazards modeling, adjusting for established prognostic factors for melanoma. We also conducted stratified analyses by Breslow thickness, tumor site, phenotypic index, and age. In addition, we evaluated haplotypes involving polymorphisms near the Agouti signaling protein gene (ASIP) locus for their impacts on survival. Melanoma-specific survival was inversely associated with carriage of MC1R variants in the absence of consensus alleles compared to carriage of at least one consensus allele (hazard ratio (HR) = 0.60; 95% confidence interval (CI): 0.40, 0.90). MC1R results for overall survival were consistent with no association. We did not observe any statistical evidence of heterogeneity of effect estimates in stratified analyses. We observed increased hazard of melanoma-specific death among carriers of the risk haplotype TG near the ASIP locus (HR = 1.37; 95% CI: 0.91, 2.04) when compared to carriers of the most common GG haplotype. Similar results were noted for overall survival. Upon examining the ASIP TG/TG diplotype, we observed considerably increased hazard of melanoma-specific death (HR = 5.11; 95% CI: 1.88, 13.88) compared to carriers of the most common GG/GG diplotype. Our data suggest improved melanoma-specific survival among carriers of two inherited MC1R variants.

Red meat and fruit intake is prognostic among patients with localized cutaneous melanomas more than 1mm thick

BACKGROUND

As the 10-year mortality for localized cutaneous melanoma more than 1.00 mm thick approaches 40% following complete resection, non-therapeutic interventions that can supplement recommended active surveillance are needed. Although guidelines recommending nutrition, physical activity and tobacco cessation for cancer survivors have been published, data describing their associations with melanoma survivorship are lacking.

METHODS

Analysis of modifiable lifestyle behaviors collected on the 249 cases with melanomas more than 1.00 mm thick enrolled in the Connecticut Case-Control Study of Skin Self-Examination study was conducted. Independent associations with melanoma-specific survival were evaluated through Cox proportional hazards modeling adjusting for age, gender, Breslow thickness, ulceration and the presence of microsatellites. Independently significant variables were then combined into a single model and backwards elimination was employed until all remaining variables were significant at p<0.05.

RESULTS

Following adjustment for age, Breslow thickness and anatomic site of the index melanoma, daily fruit consumption was associated with improved melanoma-specific survival (HR=0.54; 95% CI: 0.34-0.86) whereas at least weekly red meat consumption was associated with worse outcomes (HR=1.84; 95% CI: 1.02-3.30). Natural red (HR=0.44; 95% CI: 0.22-0.88) or blond (HR=0.52; 95% CI: 0.29-0.94) hair were also favorably prognostic. Higher fish consumption was of borderline significance for improved survival only when considered independently (HR=0.65; 95% CI: 0.40-1.05); no association was seen following adjustment for red meat and fruit consumption (p>0.10).

CONCLUSIONS

Dietary choices at the time of diagnosis are associated with melanoma-specific survival in patients with melanomas more than 1.00 mm thick. Further validation of our findings in larger cohorts with repeated post-diagnostic measures is warranted to further evaluate whether dietary modification during the survivorship period can improve melanoma-specific survival.

MC1R, the cAMP pathway, and the response to solar UV: extending the horizon beyond pigmentation

The melanocortin 1 receptor (MC1R) is a G protein-coupled receptor crucial for the regulation of melanocyte proliferation and function. Upon binding melanocortins, MC1R activates several signaling cascades, notably the cAMP pathway leading to synthesis of photoprotective eumelanin. Polymorphisms in the MC1R gene are a major source of normal variation of human hair color and skin pigmentation, response to ultraviolet radiation (UVR), and skin cancer susceptibility. The identification of a surprisingly high number of MC1R natural variants strongly associated with pigmentary phenotypes and increased skin cancer risk has prompted research on the functional properties of the wild-type receptor and frequent mutant alleles. We summarize current knowledge on MC1R structural and functional properties, as well as on its intracellular trafficking and signaling. We also review the current knowledge about the function of MC1R as a skin cancer, particularly melanoma, susceptibility gene and how it modulates the response of melanocytes to UVR.

Inherited variation in the PARP1 gene and survival from melanoma

We report the association of an inherited variant located upstream of the poly(adenosine diphosphate-ribose) polymerase 1 (PARP1) gene (rs2249844), with survival in 11 BioGenoMEL melanoma cohorts. The gene encodes a protein involved in a number of cellular processes including single-strand DNA repair. Survival analysis was conducted for each cohort using proportional hazards regression adjusting for factors known to be associated with survival. Survival was measured as overall survival (OS) and, where available, melanoma-specific survival (MSS). Results were combined using random effects meta-analysis. Evidence for a role of the PARP1 protein in melanoma ulceration and survival was investigated by testing gene expression levels taken from formalin-fixed paraffin-embedded tumors. A significant association was seen for inheritance of the rarer variant of PARP1, rs2249844 with OS (hazard ratio (HR) = 1.16 per allele, 95% confidence interval (CI) 1.04–1.28, p = 0.005, eleven cohorts) and MSS (HR = 1.20 per allele, 95% CI 1.01–1.39, p = 0.03, eight cohorts). We report bioinformatic data supportive of a functional effect for rs2249844. Higher levels of PARP1 gene expression in tumors were shown to be associated with tumor ulceration and poorer OS.

An inherited variant in the gene coding for vitamin D-binding protein and survival from cutaneous melanoma: a BioGenoMEL study

An association between low serum vitamin D levels and poorer melanoma survival has been reported. We have studied inheritance of a polymorphism of the GC gene, rs2282679, coding for the vitamin D-binding protein, which is associated with lower serum levels of vitamin D, in a meta-analysis of 3137 melanoma patients. The aim was to investigate evidence for a causal relationship between vitamin D and outcome (Mendelian randomization). The variant was not associated with reduced overall survival (OS) in the UK cohort, per-allele hazard ratio (HR) for death 1.23 (95% confidence interval (CI) 0.93, 1.64). In the smaller cohorts, HR in OS analysis was 1.07 (95% CI 0.88, 1.3) and for all cohorts combined, HR for OS was 1.09 (95% CI 0.93, 1.29). There was evidence of increased melanoma-specific deaths in the seven cohorts for which these data were available. The lack of unequivocal findings despite the large sample size illustrates the difficulties of implementing Mendelian randomization.

Association between genetic polymorphisms in apoptosis-related genes and risk of cutaneous melanoma in women and men

BACKGROUND

The P53 Arg72Pro, MDM2 c.+309T>G, BAX c.-248G>A, and BCL2 c.-717C>A polymorphisms have variable roles in the apoptosis pathways.

OBJECTIVE

To clarify the roles of these polymorphisms in the risk for cutaneous melanoma (CM).

METHODS

Genomic DNA of 200 CM patients and 215 controls was analyzed by PCR-RFLP.

RESULTS

In women, the frequencies of BAX GG (83.0% vs. 71.0%, P=0.04), BCL2 AA (32.0% vs. 15.0%, P=0.003), P53 ArgArg plus BAX GG (84.9% vs. 63.2%, P=0.01), P53 ArgArg plus BCL2 AA (37.0% vs. 13.1%, P=0.003), BAX GG plus BCL2 AA (70.3% vs. 33.3%, P=0.001), MDM2 GG plus BAX GG plus BCL2 AA (27.3% vs. 3.7%, P=0.03), and P53 ArgArg plus MDM2 GG plus BAX GG plus BCL2 AA (33.3% vs. 5.6%, P=0.04) genotypes were higher in patients than in controls. Female carriers of the respective genotypes were under 1.98 (95% CI: 1.01-3.91), 2.87 (95% CI: 1.43-5.77), 3.48 (95% CI: 1.34-9.04), 4.23 (95% CI: 1.63-10.96), 6.04 (95% CI: 2.10-17.37), 25.61 (95% CI: 1.29-507.24), and 25.69 (95% CI: 1.11-593.59)-fold increased risks for CM than others, respectively. In men, the frequencies of BCL2 CA+AA (83.0% vs. 67.6%, P=0.01) and MDM2 TG+GG plus BCL2 CA+AA (94.2% vs. 68.3%, P=0.003) genotypes were higher in patients than in controls. Male carriers of the respective genotypes were under 2.43 (95% CI: 1.23-4.82) and 9.22 (95% CI: 2.16-39.31)-fold increased CM risks than others, respectively.

CONCLUSION

The data suggest for the first time that P53 Arg72Pro, MDM2 c.+309T>G, BAX c.-248G>A, and BCL2 c.-717C>A polymorphisms, enrolled in apoptosis pathways, constitute distinct determinants of CM in women and men.

Clinical characteristics of patients with cutaneous melanoma according to variants in the melanocortin 1 receptor gene

INTRODUCTION

Patients with cutaneous melanoma who are carriers of polymorphisms in the melanocortin 1 receptor gene (MC1R) have distinctive clinical characteristics. The objective of this study was to determine the clinical characteristics associated with differing degrees of functional impairment of the melanocortin 1 receptor, as determined by the number and type (R and r) of MC1R polymorphisms.

MATERIAL AND METHODS

In total, 1044 consecutive patients with melanoma diagnosed in our hospital after January 2000 were selected from the melanoma database. These patients were divided into 3 groups according to a score based on nonsynonymous MC1R polymorphisms. The frequencies of epidemiologic, phenotypic, and histologic variables and personal and family history of cancer were compared.

RESULTS

Patients with a score of 3 or more were more likely to develop melanoma before the age of 50 years (odds ratio [OR]=1.47), have a tumor on the head or neck (OR=3.04), have a history of basal cell carcinoma or cutaneous squamous cell carcinoma (OR=1.70), have atypical nevi (OR=1.74), and have nevi associated with the melanoma (OR=1.87).

CONCLUSIONS

The use of a scoring system for MC1R polymorphisms allowed us to identify associations between the degree of functional impairment of the melanogenesis pathway and the clinical characteristics of the patients and melanoma presentation.

Melanoma risk loci as determinants of melanoma recurrence and survival

Background

Steadily high melanoma mortality rates urge for the availability of novel biomarkers with a more personalized ability to predict melanoma clinical outcomes. Germline risk variants are promising candidates for this purpose; however, their prognostic potential in melanoma has never been systematically tested.

Methods

We examined the effect of 108 melanoma susceptibility single nucleotide polymorphisms (SNPs), associated in recent GWAS with melanoma and melanoma-related phenotypes, on recurrence-free survival (RFS) and overall survival (OS), in 891 prospectively accrued melanoma patients. Cox proportional hazards models (Cox PH) were used to test the associations between 108 melanoma risk SNPs and RFS and OS adjusted by age at diagnosis, gender, tumor stage, histological subtype and other primary tumor characteristics.

Results

We identified significant associations for rs7538876 (RCC2) with RFS (HR = 1.48, 95% CI = 1.20-1.83, p = 0.0005) and rs9960018 (DLGAP1) with both RFS and OS (HR = 1.43, 95% CI = 1.07-1.91, p = 0.01, HR = 1.52, 95% CI = 1.09-2.12, p = 0.01, respectively) using multivariable Cox PH models. In addition, we developed a logistic regression model that incorporates rs7538876, rs9960018, primary tumor histological type and stage at diagnosis that has an improved discriminatory ability to classify 3-year recurrence (AUC = 82%) compared to histological type and stage alone (AUC = 78%).

Conclusions

We identified associations between melanoma risk variants and melanoma outcomes. The significant associations observed for rs7538876 and rs9960018 suggest a biological implication of these loci in melanoma progression. The observed predictive patterns of associated variants with clinical end-points suggest for the first time the potential for utilization of genetic risk markers in melanoma prognostication.