An Epidemiological Review of Diet and Cutaneous Malignant Melanoma

Quercetin Limits Tumor Immune Escape through PDK1/CD47 Axis in Melanoma

Quercetin (3,3[Formula: see text],4[Formula: see text],5,7-pentahydroxyflavone) is a bioactive plant-derived flavonoid, abundant in fruits and vegetables, that can effectively inhibit the growth of many types of tumors without toxicity. Nevertheless, the effect of quercetin on melanoma immunology has yet to be determined. This study aimed to investigate the role and mechanism of the antitumor immunity action of quercetin in melanoma through both in vivo and in vitro methods. Our research revealed that quercetin has the ability to boost antitumor immunity by modulating the tumor immune microenvironment through increasing the percentages of M1 macrophages, CD8[Formula: see text] T lymphocytes, and CD4[Formula: see text] T lymphocytes and promoting the secretion of IL-2 and IFN-[Formula: see text] from CD8[Formula: see text] T cells, consequently suppressing the growth of melanoma. Furthermore, we revealed that quercetin can inhibit cell proliferation and migration of B16 cells in a dose-dependent manner. In addition, down-regulating PDK1 can inhibit the mRNA and protein expression levels of CD47. In the rescue experiment, we overexpressed PDK1 and found that the protein and mRNA expression levels of CD47 increased correspondingly, while the addition of quercetin reversed this effect. Moreover, quercetin could stimulate the proliferation and enhance the function of CD8[Formula: see text] T cells. Therefore, our results identified a novel mechanism through which CD47 is regulated by quercetin to promote phagocytosis, and elucidated the regulation of quercetin on macrophages and CD8[Formula: see text] T cells in the tumor immune microenvironment. The use of quercetin as a therapeutic drug holds potential benefits for immunotherapy, enhancing the efficacy of existing treatments for melanoma.

Associations of Dietary Factors with Cutaneous Melanoma: A Case-Control Study in Greece with Literature Review

INTRODUCTION

It has been postulated that nutrition may influence the risk for cutaneous melanoma (CM); therefore, we aimed to assess the associations of food groups and individual nutrient intakes with CM in a Greek population.

METHODS

In this case-control study, 151 patients with histologically confirmed CM, newly diagnosed and treated in the Oncology Department of the "Laikon" University Hospital (Athens, Greece), and 151 age- and sex-matched healthy individuals residing in the Athens metropolitan area, recruited among participants for routine health examinations, were included. All participants completed a questionnaire comprising anthropometric measurements, sociodemographic, lifestyle, and health-related variables. A validated, semiquantitative food frequency questionnaire was used to assess average consumption of 136 food items during the 12 months preceding the onset of disease. Multivariate conditional regression models were used to derive odds ratios (ORs) with 95% confidence intervals (95% CI) regarding the association of nine food groups and seven macronutrients with CM.

RESULTS

Statistically significant positive associations with CM were found with higher energy intake (OR: 1.67, 95% CI: 1.22-2.30) and intake of saturated fatty acids (OR: 2.28, 95% CI: 1.00-5.28), after adjusting for sun sensitivity, major depression history, and alcohol intake. Inverse associations with higher intake of milk and dairy products (OR: 0.65, 95% CI: 0.48-0.88), fruits (OR: 0.68, 95% CI: 0.51-0.90), added lipids (OR: 0.65, 95% CI: 0.47-0.91), and sugars and syrups (OR: 0.70, 95% CI: 0.53-0.93) were also observed.

CONCLUSIONS

Beyond intrinsic risk factors, our results support associations of CM with multiple food groups and nutrients; if confirmed by prospective studies, these findings can add further knowledge about this fatal cancer.

Global Incidence, Mortality, Risk Factors and Trends of Melanoma: A Systematic Analysis of Registries

BACKGROUND

Melanoma of the skin is the most dangerous skin cancer in the world, though the numbers of reported new cases and melanoma-related deaths are low.

OBJECTIVE

This study evaluated the global incidence, mortality, risk factors and temporal trends by age, sex and locations of melanoma skin cancer.

PATIENTS AND METHODS

Cancer Incidence in Five Continents (CI5) volumes I-XI; the Nordic Cancer Registries (NORDCAN); the Surveillance, Epidemiology and End Results (SEER) Program; and the World Health Organization (WHO) International Agency for Research on Cancer (IARC) mortality database were accessed for worldwide incidence and mortality rates. Average Annual Percentage Change (AAPC) was calculated using a Joinpoint regression to examine trends.

RESULTS

Age-standardized rates of cancer incidence and mortality were 3.4 and 0.55 per 100,000 worldwide in 2020. Australia and New Zealand reported the highest incidence and mortality rates. Associated risk factors included higher prevalence of smoking, alcohol consumption, unhealthy diet, obesity and metabolic diseases. Increasing incidence trends were observed mostly in European countries, whilst mortality displayed an overall decreasing trend. For both sexes in the age group 50 years and above, a significant increase in incidence trend was observed.

CONCLUSIONS

Although mortality rates and trends were found to decrease, global incidence has increased, especially in older age groups and males. Whilst incidence increase may be attributed to improved healthcare infrastructure and cancer detection methods, the growing prevalence of lifestyle and metabolic risk factors in developed countries should not be discounted. Future research should explore underlying variables behind epidemiological trends.

Systemic Photoprotection in Melanoma and Non-Melanoma Skin Cancer

Non-melanoma skin cancers (NMSCs), which include basal cell carcinoma (BCC), squamous cell carcinoma (SCC), and actinic keratosis (AK), are the most common cancer diseases in the Caucasian race. If diagnosed late and improperly treated, BCC and SCC can become locally advanced and metastasize. Malignant melanoma (MM) is less frequent but more lethal than NMSC. Given the individual and social burdens of skin cancers, performing an adequate prevention is needed. Ultraviolet (UV) ray exposure is one of the main risk factors for skin cancer. Thus, the first-choice prevention strategy is represented by photoprotection that can be both topical and systemic. The latter consists of the oral administration of molecules which protect human skin against the damaging effects of UV rays, acting through antioxidant, anti-inflammatory, or immunomodulator mechanisms. Although several compounds are commonly used for photoprotection, only a few molecules have demonstrated their effectiveness in clinical trials and have been included in international guidelines for NMSC prevention (i.e., nicotinamide and retinoids). Moreover, none of them have been demonstrated as able to prevent MM. Clinical and preclinical data regarding the most common compounds used for systemic photoprotection are reported in this review, with a focus on the main mechanisms involved in their photoprotective properties.

Onset of p53/NF-κB signaling crosstalk in human melanoma cells in response to anti-cancer theabrownin

As a major tea component, theabrownin represents a promising anti-cancer candidate. However, its effect on the melanoma is unknown. To evaluate the in vitro and in vivo anti-melanoma efficacy of TB, we conducted cell viability, immunostaining, comet, and TUNEL assays on human A375 melanoma cells, and employed a zebrafish xenograft model of A375 cells. Real-time PCR (qPCR) and western blot were conducted to explore the molecular mechanisms of TB. In vitro, TB significantly inhibited the proliferation of A375 cells, and A375 cells showed the highest inhibitory rate among the other melanoma cell line (A875) and human dermal fibroblasts. TB triggered DNA damage and induced apoptosis of A375 cells and significantly inhibited the growth of A375 xenograft tumors in zebrafishes. Several key molecular events were activated by TB, including DNA damage-associated p53 and NF-κB pathways, through up-regulation of GADD45α, γ-H2A.X, phospho-ATM(p-ATM), phospho-ATR (p-ATR), phospho-p53 (p-p53), phospho-IKKα/β (p-IKKα/β), phospho-p65 (p-p65), etc. However, the TB-activated molecular events were counteracted by either knockdown of p53 or p65, and only dual knockdown of both p53 and p65 completed counteracted the anti-melanoma efficacy of TB. In conclusion, TB triggered DNA damage and thereby inhibited proliferation and induced cellular senescence and apoptosis of melanoma cells through mechanisms mediated by p53/NF-κB signaling crosstalk. This is the first report on the efficacy and mechanisms of TB on melanoma cells, making TB a promising candidate for anti-melanoma agent development.

Fish intake and risk of melanoma in the NIH-AARP diet and health study

PURPOSE

Prior epidemiological studies evaluating the association between fish intake and melanoma risk have been few and inconsistent. Few studies distinguished different types of fish intake with risk of melanoma.

METHODS

We examined the associations between intake of total fish and specific types of fish and risk of melanoma among 491,367 participants in the NIH-AARP Diet and Health Study. We used multivariable-adjusted Cox proportional hazards regression to estimate hazard ratios (HRs) and 95% confidence intervals (CIs).

RESULTS

During 6,611,941 person-years of follow-up with a median of 15.5 years, 5,034 cases of malignant melanoma and 3,284 cases of melanoma in situ were identified. There was a positive association between higher total fish intake and risk of malignant melanoma (HR = 1.22, 95% CI = 1.11-1.34 for top vs. bottom quintiles, ptrend = 0.001) and melanoma in situ (HR = 1.28, CI = 1.13-1.44 for top vs. bottom quintiles, ptrend = 0.002). The positive associations were consistent across several demographic and lifestyle factors. There were also positive associations between tuna intake and non-fried fish intake, and risk of malignant melanoma and melanoma in situ. However, fried fish intake was inversely associated with risk of malignant melanoma, but not melanoma in situ.

CONCLUSIONS

We found that higher total fish intake, tuna intake, and non-fried fish intake were positively associated with risk of both malignant melanoma and melanoma in situ. Future studies are needed to investigate the potential biological mechanisms underlying these associations.

Primary vitreoretinal involvement and immunopositivity for BRAFV600E help distinguish metastatic from primary intraocular melanoma: a detailed histopathologic study of metastatic cutaneous melanoma to the eye

OBJECTIVE

To evaluate the clinicopathologic characteristics of metastatic cutaneous melanoma to the eye and identify potential distinguishing characteristics from the more common primary uveal melanoma; particularly, tumour location within the eye, cytomorphology and immunohistochemical/specific molecular genetic features.

METHODS

A retrospective observational case series using surgical enucleation and diagnostic vitrectomy cytologic specimens from seven patients with suspected intraocular melanoma, eventually diagnosed as metastatic melanoma, was conducted. Haematoxylin and eosin-stained sections of tumour and immunohistochemical (IHC) stains for BRAFV600E and Ki-67 were critically reviewed; BAP1 IHC was also evaluated in cases where additional tissue was available. Clinical imaging studies and medical records were reviewed.

RESULTS

The majority of patients (86%) with metastatic melanoma have primary vitreoretinal (not uveal) involvement and epithelioid, highly malignant cytomorphology (100%); many (50%) harbour BRAFV600E mutations, a finding not seen in large cohorts of primary uveal melanoma.

CONCLUSIONS

Characteristics favouring or defining metastatic intraocular melanoma over primary uveal melanoma include high-grade epithelioid cytology, predominant involvement of the vitreous cavity and/or retina, and presence of positive immunostaining for BRAFV600E.

Clustering trends of melanoma incidence and mortality: A worldwide assessment from 1995 to 2019

BACKGROUND

Melanoma is a skin cancer that has higher mortality among cutaneous malignant tumours. Tumour incidence in most world regions is rising. Here, we intend to highlight these trends in the world.

METHODS

We used the global burden of disease dataset to assess the incidence and mortality of melanoma from 1995 to 2019 in 204 countries/territories. To identify country/territory groups with similar trends of melanoma incidence and mortality, a model-based clustering with a mixture of multivariate t-distributions was used.

RESULTS

Australia and New Zealand had the largest incidence and mortality rates. Men in Egypt and women in Sri Lanka and Guam had the lowest incidence and mortality rates. The clustering analysis revealed 4 classes of incidence in both gender and 3 and 2 classes of mortality in male and female, respectively. All groups had a growing incidence rate in both gender, similar to the worldwide trend. In 10% of the countries/territories, central and Western Europe, the incidence increase rate was greater than in the countries/territories with the greatest incidence. The total mortality rate for men was steadily growing, although it was decreasing in Asian and African countries/territories. Overall, the mortality rate for women remained relatively steady over time.

CONCLUSION

Due to the increasing trend of melanoma in the world, primary and secondary prevention of this disease, especially in areas with higher incidence and mortality, is essential. Raising awareness about the disease is helpful in prevention and early detection of melanoma.

The cure from within? a review of the microbiome and diet in melanoma

Therapy for cutaneous melanoma, the deadliest of the skin cancers, is inextricably linked to the immune system. Once thought impossible, cures for metastatic melanoma with immune checkpoint inhibitors have been developed within the last decade and now occur regularly in the clinic. Unfortunately, half of tumors do not respond to checkpoint inhibitors and efforts to further exploit the immune system are needed. Tantalizing associations with immune health and gut microbiome composition suggest we can improve the success rate of immunotherapy. The gut contains over half of the immune cells in our bodies and increasingly, evidence is linking the immune system within our gut to melanoma development and treatment. In this review, we discuss the importance the skin and gut microbiome may play in the development of melanoma. We examine the differences in the microbial populations which inhabit the gut of those who develop melanoma and subsequently respond to immunotherapeutics. We discuss the role of dietary intake on the development and treatment of melanoma. And finally, we review the landscape of published and registered clinical trials therapeutically targeting the microbiome in melanoma through dietary supplements, fecal microbiota transplant, and microbial supplementation.

Impact of Wide Local Excision on Melanoma Patient Survival: A Population-Based Study

Introduction

Promoting standardization and quality assurance (QA) in oncology on the strength of real-world data is essential to ensure better patient outcomes. Wide excision after primary tumor biopsy is a fundamental step in the therapeutic pathway for cutaneous malignant melanoma (CMM). The aim of this population-based cohort study is to assess adherence to wide local excision in a cohort of patients diagnosed with CMM and the impact of this recommended procedure on overall and disease-specific survival.

Materials and Methods

This retrospective cohort study concerns CMM patients diagnosed in the Veneto region (north-east Italy) in 2017, included in the high-resolution Veneto Cancer Registry, and followed up through linkage with the regional mortality registry up until February 29th, 2020. Using population-level real-world data, linking patient-level cancer registry data with administrative records of clinical procedures may shed light on the real-world treatment of CMM patients in accordance with current guidelines. After excluding TNM stage IV patients, a Cox regression analysis was performed to test whether the completion of a wide local excision was associated with a difference in melanoma-specific and overall survival, after adjusting for other covariates.

Results

No wide excision after the initial biopsy was performed in 9.7% of cases in our cohort of 1,305 patients. After adjusting for other clinical prognostic characteristics, Cox regression revealed that failure to perform a wide local excision raised the hazard ratio of death in terms of overall survival (HR = 4.80, 95% CI: 2.05-11.22, p < 0.001) and melanoma-specific survival (HR = 2.84, 95% CI: 1.04-7.76, p = 0.042).

Conclusion

By combining clinical and administrative data, this study on real-world clinical practice showed that almost one in ten CMM patients did not undergo wide local excision surgery. Monitoring how diagnostic-therapeutic protocols are actually implemented in the real world may contribute significantly to promoting quality improvements in the management of oncological patients.

Nutrition and melanoma prevention

There has been considerable research in recent years on dietary factors and/or nutritional elements that might impact melanoma risk. A wide variety of dietary compounds have been studied, but only a selected group will be discussed in this review. Many have promising in vitro evidence supporting their potential, and some have been associated with decreased melanoma risk in epidemiologic studies; however, data from randomized controlled trials in humans are lacking. Future studies may be able to clarify the potential role of dietary components in melanoma risk reduction.

Melanoma Risk Factors and Prevention

In the Western population, 1 out of every 50 individuals will develop melanoma. The incidence of melanoma is increasing faster than any other malignancy. The development of melanoma is multifactorial arising from an interaction between genetic susceptibility and environmental exposures. Sixty to seventy percent of melanomas are thought to be caused by ultraviolet radiation. Most cutaneous melanomas are of increased risk. Prevention strategies involve mitigating the environmental risk factors and identifying individuals with phenotypic risk factors for increased surveillance.

Research Interest and Public Interest in Melanoma: A Bibliometric and Google Trends Analysis

INTRODUCTION

Melanoma is a severe skin cancer that metastasizes quickly. Bibliometric analysis can quantify hotspots of research interest. Google Trends can provide information to address public concerns.

METHODS

The top 15 most frequently cited articles on melanoma each year from 2015 to 2019, according to annual citations, were retrieved from the Web of Science database. Original articles, reviews, and research letters were included in this research. For the Google Trends analysis, the topic "Melanoma" was selected as the keyword. Online search data from 2004 to 2019 were collected. Four countries (New Zealand, Australia, the United States and the United Kingdom) were selected for seasonal analysis. Annual trends in relative search volume and seasonal variation were analyzed, and the top related topics and rising related topics were also selected and analyzed.

RESULTS

The top 15 most frequently cited articles each year were all original articles that focused on immunotherapy (n=8), omics (n=5), and the microbiome (n=2). The average relative search volume remained relatively stable across the years. The seasonal variation analysis revealed that the peak appeared in summer, and the valley appeared in winter. The diseases associated with or manifestations of melanoma, treatment options, risk factors, diagnostic tools, and prognosis were the topics in which the public was most interested. Most of the topics revealed by bibliometric and Google Trends analyses were consistent, with the exception of issues related to the molecular biology of melanoma.

CONCLUSION

This study revealed the trends in research interest and public interest in melanoma, which may pave the way for further research.

Epidemiology and Survival Outcomes for Eyelid Primary Malignant Melanoma: An Analysis of 1397 Cases in the SEER Database

Purpose

There has not been a recent population-based study regarding the epidemiological trend and survival of eyelid primary malignant melanoma (PMM). Our study aims to evaluate the updated incidence trends and discuss the factors affecting the survival outcomes of eyelid PMM.

Methods

A total of 1397 eyelid PMM cases diagnosed between 1975 and 2016 were retrospectively identified from the Surveillance, Epidemiology, and End Results (SEER) database. Age-adjusted incidence rates and annual percent changes (APC) were calculated. Kaplan-Meier and Cox proportional hazards regression models were used to calculate survival outcomes and identify potential prognostic factors.

Results

The overall age-adjusted incidence of eyelid PMM rose from 0.039 (95% confidence interval [CI], 0.012–0.088) in 1975 to 0.103 (95% CI, 0.070–0.143) per 100 000 population in 2016, with significant APC of 1.313% (p < 0.001). Male subjects showed a higher average age-adjusted incidence rate than female subjects (p < 0.001). Survival analyses showed that 5-year accumulative overall survival (OS) and disease-specific survival (DSS) for patients with eyelid PMM were 70.5% and 90.6%. Additionally, 10-year OS and DSS were 51.8% and 86.1%, respectively. Analyses of Kaplan-Meier survival curves with the log-rank test revealed that older age, White race, nodular melanoma, higher American Joint Committee on Cancer (AJCC) stage (II to IV), advanced stage, distant metastasis, and no-surgery treatment were associated with lower OS and DSS rates. Age, histology, AJCC stage, and stage at diagnosis were found to be independent predictors of OS and DSS in multivariate models.

Conclusion

The incidence of eyelid PMM increased with significant APC and male predominance. Age, histology, AJCC stage, and stage at diagnosis might be independent predictors of prognosis, emphasizing the importance of improved diagnosis of eyelid PMM.

Ethanol consumption synergistically increases ultraviolet radiation induced skin damage and immune dysfunction

BACKGROUND

Excessive UV radiation disrupts skin homeostasis by multiple mechanisms that extend beyond the simple erythema associated with sunburns including reduction of antioxidants, increased DNA damage, and impairment of skin immune responses. Recreational UV exposure frequently occurs concurrently with excessive ethanol (EtOH). Epidemiological studies suggest a harmful, dose-dependent impact of EtOH in the setting of high UV exposure, leading to increased severity of sunburns relative to those generated in the absence of EtOH. Furthermore, EtOH consumption and UV radiation have multiple overlapping effects on the skin that could account for the epidemiological association.

OBJECTIVE

To elucidate the relationship between excessive EtOH ingestion and UV exposures on early skin damage and downstream immune dysfunction.

METHODS

We examined the impact of UVB on local skin damage, including inflammation, sunburned cells, apoptotic cells, melanin and antioxidant levels, DNA damage and immune dysfunction in the presence or absence of EtOH ingestion by combining standard mouse models of EtOH consumption and UVB exposure models. To confirm that the observed changes in mouse skin were relevant to human skin, we investigated the effects of EtOH on UV-induced skin damage with human skin explants.

RESULTS

We demonstrated that EtOH consumption and UV exposure act synergistically to increase the severity of local skin damage resulting in impaired melanin responses, reduced antioxidants, greater DNA damage, and immune dysfunction as measured by reduced contact hypersensitivity.

CONCLUSIONS

The results support incorporation of the risks of combined UV exposure and excessive alcohol consumption into public health campaigns.

Theaflavin Induces Apoptosis of A375 Human Melanoma Cells and Inhibits Tumor Growth in Xenograft Zebrafishes Through P53- and JNK-Related Mechanism

Theaflavin (TF) is a major active pigment and polyphenol of tea, possessing anti-cancer activities. However, little is known about its activity and mechanism on melanoma cells. To fill this gap, we conducted in vitro experiments (cell viability assay, morphology observation, DAPI staining, and flow cytometry) and in vivo experiment by using a xenograft model of larval zebrafishes. Real-time PCR (qPCR) and Western blot (WB) analyses were conducted to explore the mechanism of TF. The in vitro data showed that TF exerted significant anti-proliferative and pro-apoptotic effects on A375 cells in a concentration-dependent manner. In vivo, TF significantly inhibited A375 tumor growth in larval zebrafishes at 0.67 and 2.0 μg/ml (1.3 to 3.9 μM). qPCR and WB data showed that TF significantly activated the P53 pathway-related proteins (ATM, CHK1/2, P53, and CASP8/3) and the JNK pathway-related proteins (ASK1, JNK, and C-JUN) through phosphorylation and cleavage, followed by activation of pro-apoptotic molecules (PARP, BAX, BIM, PUMA, and P53). In sum, TF possessed cytotoxic pro-apoptotic and tumor-inhibitory effects on A375 cells through activations of P53 and JNK pathways. This is the first report on TF regarding its effects and mechanism on A375 cells, making it a promising candidate of natural products for clinical treatment of melanoma.

25-Hydroxyvitamin D status, vitamin D intake, and skin cancer risk: a systematic review and dose-response meta-analysis of prospective studies

Sun exposure is a major environmental risk factor for skin cancers and is also an important source of vitamin D. However, while experimental evidence suggests that vitamin D may have a protective effect on skin cancer risk, epidemiologic studies investigating the influence of 25-hydroxyvitamin D (25(OH)D) level and/or vitamin D intake on skin cancer risk are conflicting. A systematic review and dose–response meta-analyses of prospective studies was conducted to clarify these associations. Relevant studies were identified by searching the PubMed database up to 30th August 2019. Random effects dose–response meta-analyses were used to estimate summary relative risks (SRRs) and 95% confidence intervals (CIs). Overall, thirteen prospective studies were included. Circulating level of 25(OH)D was associated with higher risks of melanoma (SRR (95% CI) per 30 nmol = 1.42 (1.17–1.72)) and keratinocyte cancer (KC) (SRR (95% CI) per 30 nmol/L = 1.30 (1.13–1.49)). The SRR (95% CI) per 30 nmol/L increase in 25(OH) D level was 1.41 (1.19–1.67), and 1.57 (0.64–3.86), for basal cell carcinomas (BCCs) and squamous cell carcinomas (SCCs), respectively. However, while we found that vitamin D intake (from diet, supplemental and total) was not associated with risks of melanoma and SCC, vitamin D intake was associated with slightly increased BCC risk, albeit with no heterogeneity across skin cancer type. This meta-analysis suggests positive associations between circulating 25(OH)D level and risk of melanoma and KC, however, this finding is most likely confounded by sun exposure. We found no associations between vitamin D intake skin cancers, except positive associations with BCC risk.

MicroRNA-21-Enriched Exosomes as Epigenetic Regulators in Melanomagenesis and Melanoma Progression: The Impact of Western Lifestyle Factors

DNA mutation-induced activation of RAS-BRAF-MEK-ERK signaling associated with intermittent or chronic ultraviolet (UV) irradiation cannot exclusively explain the excessive increase of malignant melanoma (MM) incidence since the 1950s. Malignant conversion of a melanocyte to an MM cell and metastatic MM is associated with a steady increase in microRNA-21 (miR-21). At the epigenetic level, miR-21 inhibits key tumor suppressors of the RAS-BRAF signaling pathway enhancing proliferation and MM progression. Increased MM cell levels of miR-21 either result from endogenous upregulation of melanocytic miR-21 expression or by uptake of miR-21-enriched exogenous exosomes. Based on epidemiological data and translational evidence, this review provides deeper insights into environmentally and metabolically induced exosomal miR-21 trafficking beyond UV-irradiation in melanomagenesis and MM progression. Sources of miR-21-enriched exosomes include UV-irradiated keratinocytes, adipocyte-derived exosomes in obesity, airway epithelium-derived exosomes generated by smoking and pollution, diet-related exosomes and inflammation-induced exosomes, which may synergistically increase the exosomal miR-21 burden of the melanocyte, the transformed MM cell and its tumor environment. Several therapeutic agents that suppress MM cell growth and proliferation attenuate miR-21 expression. These include miR-21 antagonists, metformin, kinase inhibitors, beta-blockers, vitamin D, and plant-derived bioactive compounds, which may represent new options for the prevention and treatment of MM.

Patterns of Omega-3 and Omega-6 Fatty Acid Dietary Intake and Melanoma Thickness at Diagnosis

BACKGROUND

Experimental evidence suggests that dietary intakes of omega-3 and omega-6 polyunsaturated fatty acids have divergent effects on melanoma growth, but epidemiologic evidence on their combined effect is lacking.

METHODS

In 634 Australian patients with primary melanoma, we assessed prediagnosis consumption of 39 food groups by food frequency questionnaires completed within 2 months of diagnosis. We derived, by reduced rank regression, dietary patterns that explained variability in selected omega-3 and omega-6 fatty acid intakes. Prevalence ratios (PR) and 95% confidence intervals (CI) for the association between tertiles of dietary patterns and melanoma thickness >2 mm versus ≤2 mm were estimated using Poisson regression.

RESULTS

Overall omega-3 fatty acid intakes were low. Two major fatty acid dietary patterns were identified: "meat, fish, and fat," positively correlated with intakes of all fatty acids; and "fish, low-meat, and low-fat," positively correlated with long-chain omega-3 fatty acid intake, and inversely with medium-chain omega-3 and omega-6 fatty acid intakes. Prevalence of thick melanomas was significantly higher in those in the highest compared with lowest tertile of the "meat, fish, and fat" pattern (PR, 1.40; 95% CI, 1.01-1.94), especially those with serious comorbidity (PR, 1.83; 95% CI, 1.15-2.92) or a family history (PR, 2.32; 95% CI, 1.00-5.35). The "fish, low-meat, and low-fat" pattern was not associated with melanoma thickness.

CONCLUSIONS

People with high meat, fish, and fat intakes, who thus consumed relatively high levels of omega-3 and high omega-6 fatty acid intakes, are more likely to be diagnosed with thick than thin melanomas.

IMPACT

High omega-3 and omega-6 fatty acid intakes may contribute to patients' presentation with thick melanomas.

Trends in malignant melanoma mortality in 31 countries from 1985 to 2015

BACKGROUND

Malignant melanoma (MM) causes the highest absolute number of deaths among skin cancers. An up-to-date analysis of international MM mortality trends is required for assessing the burden of disease, and may support the assessment of the effectiveness of new diagnostic, therapeutic and preventative strategies.

OBJECTIVES

To report MM mortality trends between 1985 and 2015 using the World Health Organization (WHO) Mortality Database.

MATERIALS AND METHODS

We used country-level MM mortality data from the WHO Mortality Database for all countries with high usability death registration data. Mortality trends were described using Joinpoint regression modelling.

RESULTS

Thirty-one countries met the inclusion criteria. All countries, except the Czech Republic, demonstrated increased age-standardized death rates (ASDRs) in males over the observation period. More countries exhibited decreased or stable MM mortality in females. The median mortality rate for 2013-2015 was 2·57 deaths per 100 000 for males and 1·55 per 100 000 for females. Australia and Norway had the highest ASDRs for males (5·72 per 100 000 and 4·55 per 100 000, respectively). Norway and Slovenia had the highest ASDRs for females (3·02 per 100 000 and 2·58 per 100 000, respectively). MM mortality was greater for males than females in all countries, with sex disparity increasing across the period. Disparity in mortality between older and younger cohorts in several countries was also found.

CONCLUSIONS

An overall increase in MM mortality over the past 30 years was observed. However, there was notable variation in mortality trends between countries, as well as between males and females, and between different age groups.

Genetic variants in the folate metabolic pathway genes predict cutaneous melanoma-specific survival

BACKGROUND

Folate metabolism plays an important role in DNA methylation and nucleic acid synthesis and thus may function as a regulatory factor in cancer development. Genome-wide association studies (GWASs) have identified some single-nucleotide polymorphisms (SNPs) associated with cutaneous melanoma-specific survival (CMSS), but no SNPs were found in genes involved in the folate metabolic pathway.

OBJECTIVES

To examine associations between SNPs in folate metabolic pathway genes and CMSS.

METHODS

We comprehensively evaluated 2645 (422 genotyped and 2223 imputed) common SNPs in folate metabolic pathway genes from a published GWAS of 858 patients from The University of Texas MD Anderson Cancer Center and performed the validation in another GWAS of 409 patients from the Nurses' Health Study and Health Professionals Follow-up Study, in which 95/858 (11·1%) and 48/409 (11·7%) patients died of cutaneous melanoma, respectively.

RESULTS

We identified two independent SNPs (MTHFD1 rs1950902 G>A and ALPL rs10917006 C>T) to be associated with CMSS in both datasets, and their meta-analysis yielded an allelic hazards ratio of 1·75 (95% confidence interval 1·32-2·32, P = 9·96 × 10^-5 ) and 2·05 (1·39-3·01, P = 2·84 × 10^-4 ), respectively. The genotype-phenotype correlation analyses provided additional support for the biological plausibility of these two variants' roles in tumour progression, suggesting that variation in SNP-related mRNA expression levels is likely to be the mechanism underlying the observed associations with CMSS.

CONCLUSIONS

Two possibly functional genetic variants, MTHFD1 rs1950902 and ALPL rs10917006, were likely to be independently or jointly associated with CMSS, which may add to personalized treatment in the future, once further validated. What is already known about this topic? Existing data show that survival rates vary among patients with melanoma with similar clinical characteristics; therefore, it is necessary to identify additional complementary biomarkers for melanoma-specific prognosis. A hypothesis-driven approach, by pooling the effects of single-nucleotide polymorphisms (SNPs) in a specific biological pathway as genetic risk scores, may provide a prognostic utility, and genetic variants of genes in folate metabolism have been reported to be associated with cancer risk. What does this study add? Two genetic variants in the folate metabolic pathway genes, MTHFD1 rs1950902 and ALPL rs10917006, are significantly associated with cutaneous melanoma-specific survival (CMSS). What is the translational message? The identification of genetic variants will make a risk-prediction model possible for CMSS. The SNPs in the folate metabolic pathway genes, once validated in larger studies, may be useful in the personalized management and treatment of patients with cutaneous melanoma.

Mediterranean dietary pattern and skin cancer risk: A prospective cohort study in French women

BACKGROUND

The Mediterranean diet (MD) has been reported to be associated with lower cancer risk. However, while previous studies explored major single components of the MD, only 1 previous study has investigated adherence to the MD in relation to melanoma risk.

OBJECTIVE

The aim of this study was to explore the relations between adherence to the MD and the risk of skin cancer, including melanomas, basal cell carcinomas (BCCs), and squamous cell carcinomas (SCCs).

DESIGN

Etude Epidémiologique auprès de femmes de la Mutuelle Générale de l'Education Nationale (E3N) is a prospective cohort of 98,995 French women aged 40-65 y in 1990. Dietary data were collected via a validated food questionnaire in 1993. Adherence to the MD was assessed using a 9-unit dietary score that incorporates intakes of fruit, vegetables, legumes, cereal products, olive oil, fish, dairy products, meat products, and alcohol. We used Cox proportional hazards regression models to compute HRs and 95% CIs adjusted for age and main known skin cancer risk factors.

RESULTS

From 1993 to 2008, a total of 2003 skin cancer cases were ascertained among 67,332 women, including 404 melanomas, 1367 BCCs, and 232 SCCs. Score of adherence to the MD was associated with lower risk of skin cancer (HR: 0.83; 95% CI: 0.73, 0.93 for high compared with low score, Ptrend = 0.001). MD score was also inversely and linearly associated with risks of melanoma (HR: 0.72; 95% CI: 0.54, 0.96; Ptrend = 0.02) and BCC (HR: 0.77; 95% CI: 0.66, 0.90; Ptrend = 0.0006) but not SCC (HR: 1.08; 95% CI: 0.75, 1.55; Ptrend = 0.68), although with no heterogeneity across skin cancer types (Pheterogeneity = 0.23).

CONCLUSION

These findings suggest that adherence to the MD is associated with a lower skin cancer risk in women, particularly melanoma and BCC. If confirmed in future research, these findings may have important implications in skin cancer prevention.

Food and Beverage Consumption and Melanoma Risk: A Population-Based Case-Control Study in Northern Italy

It has been suggested that diet may influence the risk of melanoma, but few studies are available on this topic. We assessed the relation between food consumption and the risk of cutaneous melanoma in a Northern Italy population. We carried out a population-based case-control study involving 380 cases of melanoma and 719 age- and sex-matched controls. Dietary habits were established through a self-administered semi-quantitative food frequency questionnaire. We computed the odds ratios (ORs) of melanoma and the corresponding 95% confidence intervals (CIs) according to tertiles of daily intake of each food item, using multiple logistic regression models adjusted for major confounding factors. We observed an indication of a positive association between melanoma risk and consumption of cereals and cereal products (OR = 1.32; 95% CI 0.89-1.96, higher vs. lowest tertile), sweets (OR = 1.22; 95% CI 0.84-1.76), chocolate, candy bars. etc., (OR = 1.51; 95% CI 1.09-2.09) and cabbages (OR = 1.51; 95% CI 1.09-2.09). Conversely, an inverse association with disease risk was found for the intake of legumes (OR = 0.77; 95% CI 0.52-1.13), olive oil (OR = 0.77; 95% CI 0.51-1.16), eggs (OR = 0.58; 95% CI 0.41-0.82), and onion and garlic (OR = 0.80; 95% CI 0.52-1.14). No relationship was observed with beverage consumption. Our results suggest potentially adverse effects on melanoma risk of foods characterized by high contents of refined flours and sugars, while suggesting a protective role for eggs and two key components of the Mediterranean diet, legumes and olive oil. These associations warrant further investigation and, if confirmed, they might have important public health implications for the reduction of melanoma incidence through dietary modification.

Modifiable Host Factors in Melanoma: Emerging Evidence for Obesity, Diet, Exercise, and the Microbiome

PURPOSE OF REVIEW

We discuss how potentially modifiable factors including obesity, the microbiome, diet, and exercise may impact melanoma development, progression, and therapeutic response.

RECENT FINDINGS

Obesity is unexpectedly associated with improved outcomes with immune and targeted therapy in melanoma, with early mechanistic data suggesting leptin as one mediator. The gut microbiome is both a biomarker of response to immunotherapy and a potential target. As diet is a major determinant of the gut microbiome, ongoing studies are examining the interaction between diet, the gut microbiome, and immunity. Data are emerging for a potential role of exercise in reducing hypoxia and enhancing anti-tumor immunity, though this has not yet been well-studied in the context of contemporary therapies. Recent data suggests energy balance may play a role in the outcomes of metastatic melanoma. Further studies are needed to demonstrate mechanism and causality as well as the feasibility of targeting these factors.

Dietary compounds and cutaneous malignant melanoma: recent advances from a biological perspective

Cutaneous malignant melanoma is a heterogeneous disease, being the consequence of specific genetic alterations along several molecular pathways. Despite the increased knowledge about the biology and pathogenesis of melanoma, the incidence has grown markedly worldwide, making it extremely important to develop preventive measures. The beneficial role of correct nutrition and of some natural dietary compounds in preventing malignant melanoma has been widely demonstrated. This led to numerous studies investigating the role of several dietary attitudes, patterns, and supplements in the prevention of melanoma, and ongoing research investigates their impact in the clinical management and outcomes of patients diagnosed with the disease. This article is an overview of recent scientific advances regarding specific dietary compounds and their impact on melanoma development and treatment.