Role of obesity on the thickness of primary cutaneous melanoma

The Effect of Body Mass Index on Melanoma Biology, Immunotherapy Efficacy, and Clinical Outcomes: A Narrative Review

Recent studies indicate that a higher body mass index (BMI) might correlate with improved responses to melanoma treatment, especially with immune checkpoint inhibitors (ICIs), despite the general association of obesity with an increased risk of cancer and higher mortality rates. This review examines the paradoxical relationship between BMI and clinical outcomes in melanoma patients by exploring molecular links, the efficacy of immunotherapy, and patient survival outcomes. Our comprehensive literature search across the PubMed and Embase databases revealed a consistent pattern: increased BMI is associated with a better prognosis in melanoma patients undergoing ICI treatment. This "obesity paradox" might be explained by the metabolic and immunological changes in obesity, which could enhance the effectiveness of immunotherapy in treating melanoma. The findings highlight the complexity of the interactions between obesity and melanoma, suggesting that adipose tissue may modulate the immune response and treatment sensitivity favorably. Our review highlights the need for personalized treatment strategies that consider the metabolic profiles of patients and calls for further research to validate BMI as a prognostic factor in clinical settings. This nuanced approach to the obesity paradox in melanoma could significantly impact treatment planning and patient management.

Thickness of melanocytes in giant congenital melanocytic nevus for complete surgical excision: clinicopathological evaluation of 117 lesions according to the area and size

BACKGROUND

Giant congenital melanocytic nevi (GCMN) are usually defined as nevi that exceed 20 cm in maximal diameter or 15% of the total body surface area. There have been reports of life-long malignant change risks arising from GCMN, leading to surgical excision of GCMN. This study aims to evaluate the thickness of melanocytes based on clinical factors in order to provide objective information for the complete resection of the lesion.

METHODS

Overall, 75 patients diagnosed with GCMN between 2000 and 2021 were included, and their clinical records were collected retrospectively. 117 pathologic slides obtained during excision were reviewed to measure nevus thickness. Clinical factors were assessed with a generalized estimated equation model for association with nevus thickness.

RESULTS

The thickness of nevus was significantly associated with the location and size. Nevus thickness was more superficial in the distal extremity than in the head and trunk (P = 0.003 [head]; P < 0.001 [trunk]; P = 0.091 [Proximal extremity]). Nevi sized 60 cm or more were significantly deeper than those measuring 20-29.9 cm (P = 0.035). An interaction between size and location existed (P < 0.001). Trunk and distal extremity lesions consistently exhibited uniform thickness regardless of lesion size, whereas head and proximal extremity lesions showed variations in thickness based on lesion size.

CONCLUSION

GCMNs have differences in thickness according to location and size. Therefore, it is necessary to devise an approach optimized for each patient to treat GCMN. In the study, it was emphasized that the thickness of GCMN is correlated with clinical factors, specifically the location and size of the nevus. Consequently, these findings underscore the need for individualized treatment plans for effective surgical intervention.

Identification of genomic-wide genetic links between cutaneous melanoma and obesity-related physical traits via cFDR

BACKGROUND

Both epidemiological and clinical studies have suggested the comorbidity between cutaneous melanoma (CM) and obesity-related physical traits. However, it remains unclear about their shared genetic architecture.

OBJECTIVE

To determine the shared genetic architecture between CM and obesity-related physical traits through conditional false discovery rate (cFDR) analysis.

METHOD

Quantile-quantile plots were firstly built to assess the pleiotropic enrichment of shared single nucleotide polymorphisms between CM and each trait. Then, cFDR and conjunctional cFDR (ccFDR) were used to identify the shared risk loci between CM and each trait. Moreover, the functional evaluation of shared risk genes was carried out through analyses of expression quantitative trait loci (eQTL), Kyoto Encyclopedia of Genes and Genomes and gene ontology, respectively. Finally, single-cell sequence analysis was performed to locate the expression of eQTL-mapped genes in tissues.

RESULTS

Successive pleiotropic enrichment was found between CM and 5 obesity-related traits or height. 24 shared risk loci were identified between CM and 13 traits except appendicular lean mass using ccFDR analysis, with 17 novel and 4 validated loci. The functions of ccFDR-identified and eQTL-mapped genes were revealed to be mainly involved in cellular senescence, proliferation, meiotic nuclear division, cell cycle, and the metabolism of lipid, cholesterol and glucose. Single-cell sequence analysis showed that keratinocytes contribute to the occurrence and aggressiveness of CM through secreting paracrine cytokines.

CONCLUSION

Our findings demonstrate the significant genetic correlation between CM and obesity-related physical traits, which may provide a novel genetical basis for the pathogenesis and treatment of CM.

The Influence of Obesity on Melanoma and Sentinel Lymph Node Diagnosis: A Retrospective Monocentric Study in 1001 Patients

(1) Background: While obesity is a known independent risk factor in the development of melanoma, there is no consensus on its influence on melanoma prognosis. (2) Methods: In a monocentric retrospective study, data was collected from patients who underwent sentinel lymph node (SLN) biopsy for stage IB-IIC melanoma between 2013 and 2018. Patients were divided into groups according to their body mass index (BMI). The association between BMI and melanoma features, as well as the risk factors for metastases in SLN were examined. (3) Results: Of the 1001 patients, 336 had normal weight (BMI < 25), 402 were overweight (BMI >= 25 and <30), 173 obese (BMI >= 30 and <35) and 90 extremely obese (BMI >= 35). Overweightness and obesity were associated with higher tumor thicknesses at time of diagnosis. Ulceration was not influenced by the patient’s weight. Metastases in sentinel lymph node was almost twice more likely in extremely obese patients than in normal weight patients. Independent risk factors for metastases in SLN in our study were tumor thickness, ulceration, and BMI > 35. (4) Conclusions: This is the first study to show higher metastases rates in high-BMI patients with melanoma, raising important questions regarding the screening and treatment of this specific patient population.

Obesity and immune-checkpoint inhibitors in advanced melanoma: A meta-analysis of survival outcomes from clinical studies

Obesity is a chronic inflammatory condition that has been associated with different types of cancer. However, its role in melanoma incidence, progression, and response to immune-checkpoint-inhibitors (ICI) is still controversial. On the one hand, increased levels of lipids and adipokines can promote tumor proliferation and several genes associated with fatty acid metabolism have been found to be upregulated in melanomas. On the other hand, immunotherapy seems to be more effective in obese animal models, presumably due to an increase in CD8 + and subsequent decrease in PD-1 + T-cells in the tumor microenvironment. In humans, several studies have investigated the role of BMI (body mass index) and other adiposity-related parameters as potential prognostic markers of survival in advanced melanoma patients treated with ICI. The aim of this research has been to systematically review the scientific literature on studies evaluating the relationship between overweight/obesity and survival outcomes in patients with advanced melanoma treated with ICI and to perform a meta-analysis on those sharing common characteristics. After screening 1070 records identified through a literature search, 18 articles assessing the role of BMI-related exposure in relation to survival outcomes in ICI-treated patients with advanced melanoma were included in our review. In the meta-analysis of the association between overweight (defined as BMI>25 or BMI 25-30), overall survival (OS), and progression free survival (PFS), 7 studies were included, yielding a summary HR of 0.87 (95% CI: 0.74-1.03) and 0.96 (95% CI: 0.86-1.08), respectively. Our results show that, despite few suggestive findings, the use of BMI as a valuable predictor of melanoma patients' survival in terms of PFS and OS should not be currently recommended, due to the limited evidence available.

Modeling the effects of genetic- and diet-induced obesity on melanoma progression in zebrafish

Obesity is a rising concern and associated with an increase in numerous cancers, often in a sex-specific manner. Preclinical models are needed to deconvolute the intersection between obesity, sex and melanoma. Here, we generated a zebrafish system that can be used as a platform for studying these factors. We studied how germline overexpression of Agrp along with a high-fat diet affects melanomas dependent on BRAFV600E and loss of p53. This revealed an increase in tumor incidence and area in male, but not female, obese fish, consistent with the clinical literature. We then determined whether this was further affected by additional somatic mutations in the clinically relevant genes rb1 or ptena/b. We found that the male obesogenic effect on melanoma was present with tumors generated with BRAF;p53;Rb1 but not BRAF;p53;Pten. These data indicate that both germline (Agrp) and somatic (BRAF, Rb1) mutations contribute to obesity-related effects in melanoma. Given the rapid genetic tools available in the zebrafish, this provides a high-throughput system to dissect the interactions of genetics, diet, sex and host factors in obesity-related cancers.

Frequency of skin cancer and evaluation of risk factors: A hospital-based study from Turkey

OBJECTIVES

Skin cancers are the most common type of cancer with a significantly increasing incidence. The purpose of the study was to uncover the one-year frequency of melanoma and non-melanoma skin cancers (NMSC) and to determine the risk factors in the development of skin cancer.

METHODS

The study included 7396 people from all age groups admitted to the dermatology clinic between October 2020 and 2021. The sociodemographic characteristics, sun protection habits, chronic diseases, and drug and vitamin use were evaluated. Lesions with clinical suspicion of skin cancer were excised.

RESULTS

The frequency of skin cancer was found to be 2.7%, basal cell cancer (BCC) 1.2%, squamous cell cancer (SCC) 1.1%, malignant melanoma (MM) was 0.4%. Daily black tea consumption was found to be a risk factor for three type of skin cancer, BCC (p = 0.021), SCC (p = 0.006), and MM (p = 0.002), respectively. Obesity was observed as a risk factor for BCC (p = 0.005) and MM (p = 0.008). We found that having a history of alcohol use were an independent risk factor for all skin cancer types and BMI <30 for SCC. Vitamin D and supplemental drugs intake were observed as protective factors for BCC (p = 0.035, p = 0.007, respectively). Daily coffee consumption was determined as a protective factor for SCC (p < 0.001) and MM (p = 0.049).

CONCLUSION

This study estimates the frequency of NMSC and melanoma. Also provides evidence to determine the risk factors and probably protective factors for the development of skin cancers.

Adipocyte extracellular vesicles decrease p16INK4A in melanoma: an additional link between obesity and cancer

Obesity is a recognized factor for increased risk and poor prognosis of many cancers, including melanoma. Here, using genetically engineered mouse models of melanoma (NRAS^Q61K transgenic expression, associated or not with Cdkn2A heterozygous deletion), we show that obesity increases melanoma initiation and progression by supporting tumor growth and metastasis thereby reducing survival. This effect is associated with a decrease in p16^INK4A expression in tumors. Mechanistically, adipocytes downregulate p16^INK4A in melanoma cells through β-catenin-dependent regulation, which increases cell motility. Furthermore, β-catenin is directly transferred from adipocytes to melanoma cells in extracellular vesicles, thus increasing its level and activity, which represses p16^INK4A transcription. Adipocytes from obese individuals have a stronger effect than those from lean individuals, mainly due to an increase in the number of vesicles secreted, thus increasing the amount of β-catenin delivered to melanoma cells, and, consequently, amplifying their effect. In conclusion, here, we reveal that adipocyte extracellular vesicles control p16^INK4A expression in melanoma, which promotes tumor progression. This work expands our understanding of the cooperation between adipocytes and tumors, particularly in obesity.

Body Mass Index and Melanoma Prognosis

Introduction

Obesity has been suggested as a risk factor in the progression of malignancies, including melanoma. Most studies defined obesity using body mass index (BMI), although the index is considered an imperfect measure of body composition.

Objective

The aim of this article is to examine whether BMI can impact on the prognosis of cutaneous melanoma, regardless of anti-tumor therapy. The relationship between BMI and specific prognostic factors in melanoma patients has been reviewed.

Methods

Literature search was conducted on PubMed using the terms "melanoma" and "body mass index" or "obesity". We selected articles, published up to 30 November 2020, examining the prognostic aspects of melanoma. Articles evaluating the risk and incidence of melanoma were excluded as well as studies regarding morbidity and complications following surgical procedures, or those performed in metastatic melanoma patients treated with anti-tumor therapies.

Results

Mixed results have emerged from studies assessing the clinical outcomes in melanoma patients in relation to BMI. More consistent data seem to support the relationship between BMI and Breslow thickness.

Conclusions

Studies that focus specifically on the link between obesity and melanoma prognosis are limited; further research is needed to deepen our knowledge on this link.

Body mass index (BMI) and outcome of metastatic melanoma patients receiving targeted therapy and immunotherapy: a multicenter international retrospective study

BACKGROUND

Obesity is a risk factor for malignancy; however, its prognostic role in patients with metastatic melanoma is controversial. We aim to investigate the prognostic role of body mass index (BMI) in patients with metastatic melanoma receiving mitogen-activated pathway kinase inhibitors (MAPKi), immune checkpoint inhibitors (ICIs) alone or their sequence.

METHODS

Data on patients with metastatic melanoma receiving ≥1 line of systemic treatment were retrieved from prospectively collected databases. Progression-free survival (PFS) and overall survival (OS) were analyzed by means of multivariable stratified Cox regression models; disease control rate (DCR) was analyzed by multivariable stratified logistic regression models. Subgroup analyzes according to the type of treatments received, and in BRAF-mutated patients were pre-planned. All multivariable models included BMI, age, gender, American Joint Committee on Cancer stage, performance status, lactate dehydrogenase and treatment sequencing strategy as covariates.

RESULTS

Between November 2010 and November 2018, 688 patients from three Italian and two Polish centers were enrolled. 379 (57%) patients had M1c/d disease, 273 (41%) were female and the mean BMI was 27.1 (SD=4.9). Considering first-line treatment, 446 patients (66.8%) received ICIs and 222 MAPKi. No impact of BMI on OS was detected either considering the first line of ICIs, or ICIs sequencing (HR=1.02, 95% CI: 0.99 to 1.05, p=0.202, and HR=1.02, 95% CI: 0.99 to 1.04, p=0.237, respectively). A late effect of BMI on OS was found in patients treated with MAPKi: for five units increment, a 51% of risk reduction at 18 months and a 76% of risk reduction at 30 months were observed. No significant effect of BMI on PFS and DCR was found in any of the subgroup analyzes.

CONCLUSION

In patients with metastatic melanoma receiving ICIs, there is no impact of BMI on DCR, PFS and OS. The late prognostic effect of BMI in patients treated with MAPKi should be considered hypothesis generating and needs to be further investigated.

Daily Lifestyle and Cutaneous Malignancies

Daily lifestyle is a fundamental part of human life and its influence accumulates daily in the human body. We observe that a good daily lifestyle has a beneficial impact on our health; however, the actual effects of individual daily lifestyle factors on human skin diseases, especially skin cancers, have not been summarized. In this review, we focused on the influence of daily lifestyle on the development of skin cancer and described the detailed molecular mechanisms of the development or regulation of cutaneous malignancies. Several daily lifestyle factors, such as circadian rhythm disruption, smoking, alcohol, fatty acids, dietary fiber, obesity, and ultraviolet light, are known to be associated with the risk of cutaneous malignancies, malignant melanoma, squamous cell carcinoma, basal cell carcinoma, and Merkel cell carcinoma. Although the influence of some daily lifestyles on the risk of skin cancers is controversial, this review provides us a better understanding of the relationship between daily lifestyle factors and skin cancers.

Melanoma Progression under Obesity: Focus on Adipokines

Simple Summary

Obesity is a rapidly growing public health problem and the reason for numerous diseases in the human body, including cancer. This article reviews the current knowledge of the effect of molecules secreted by adipose tissue-adipokines on melanoma progression. We also discuss the role of these factors as markers of incidence, metastasis, and melanoma patient survival. Understanding the functions of adipokines will lead to knowledge of whether and how obesity promotes melanoma growth.

Abstract

Obesity is a growing problem in the world and is one of the risk factors of various cancers. Among these cancers is melanoma, which accounts for the majority of skin tumor deaths. Current studies are looking for a correlation between obesity and melanoma. They suspect that a potential cause of its development is connected to the biology of adipokines, active molecules secreted by adipose tissue. Under physiological conditions, adipokines control many processes, including lipid and glucose homeostasis, insulin sensitivity, angiogenesis, and inflammations. However, when there is an increased amount of fat in the body, their secretion is dysregulated. This article reviews the current knowledge of the effect of adipokines on melanoma growth. This work focuses on the molecular pathways by which adipose tissue secreted molecules modify the angiogenesis, migration, invasion, proliferation, and death of melanoma cells. We also discuss the role of these factors as markers of incidence, metastasis, and melanoma patient survival. Understanding the functions of adipokines will lead to knowledge of whether and how obesity promotes melanoma growth. Further studies may contribute to the innovations of therapies and the use of adipokines as predictive and/or prognostic biomarkers.

The Impact of Obesity on Surgically Treated Locoregional Melanoma

BACKGROUND

The impact of obesity on early-stage melanoma is poorly understood. We examined the impact of overweight and obesity on clinical outcomes in locoregional melanoma.

METHODS

Adults who underwent surgery at Emory University Healthcare between 2010 and 2017 for clinically stage I-II cutaneous melanoma, with known stage, height, and weight at the time of presentation, were identified. The relationship between body mass index (BMI) and clinicopathologic characteristics was assessed.

RESULTS

Of 1756 patients, 584 were obese (33.2%; BMI ≥ 30), 658 were overweight (37.5%; BMI ≥ 25 and < 30), and 514 were normal weight (29.3%; BMI < 25). Demographics associated with obesity included male sex (odds ratio [OR] 2.6, 95% confidence interval [CI] 2.1-3.3; p < 0.001) and lower income (OR 1.5, 95% CI 1.2-1.9; p = 0.003). Melanomas in obese patients were thicker (2.0 ± 0.2 mm) than in overweight (1.7 ± 0.1 mm) or normal-weight patients (1.4 ± 0.1 mm; p = 0.002). Ulceration, mitoses, BRAF status, and sentinel lymph node (SLN) status were not affected by obesity. In multivariable analysis, obesity independently predicted increased odds of pathologic stage II melanoma (vs. stage 0 or I; OR 1.9, 95% CI 1.4-2.7, p = 0.001), but not pathologic stage III melanoma (p > 0.05). At 33 months' median follow-up, obesity was not an independent predictor of stage-specific overall survival (p > 0.05).

CONCLUSION

Obese patients are nearly twice as likely as their normal-weight peers to present with thicker melanomas, but they have similar stage-specific overall survival and SLN positivity. Obesity may promote more aggressive growth of the primary tumor, and barriers to preventive care in obese patients may exacerbate later-stage presentation.

Relevance of body mass index as a predictor of systemic therapy outcomes in metastatic melanoma: analysis of the MelBase French cohort data☆

BACKGROUND

The 'obesity paradox' suggests that higher body mass index (BMI) is associated with better survival values in metastatic melanoma patients, especially those receiving targeted and immune checkpoint inhibitor therapy. Higher BMI is also associated with higher incidences of treatment-related adverse events (TRAEs). This study assesses whether BMI is associated with survival outcomes and adverse events in metastatic melanoma patients with systemic therapy.

PATIENTS AND METHODS

This multicentric retrospective study, conducted from 1 March 2013 to 29 April 2019, enrolled adults with unresectable stage III or IV melanoma from the French multicentric prospective cohort-MelBase (NCT02828202). Patients with first-line chemotherapy and targeted and immune therapy were included. Underweight people and those with metastatic mucosal or ocular melanoma were excluded. BMI was categorized using the World Health Organization criteria. Co-primary outcomes included the association between BMI and progression-free survival and overall survival, stratified by treatment type, sex, and age. Secondary endpoints were the association of BMI with overall response and TRAEs. Multivariate analyses were carried out.

RESULTS

A total of 1214 patients were analyzed. Their median age was 66.0 years (range, 53-75). Male predominance was observed [n = 738 (61%)]. Most patients received immune checkpoint inhibitor therapy (63%), followed by targeted therapy (32%), and had stage M1c disease (60.5%). Obese patients represented 22% of the cohort. The median follow-up duration was 13.5 months (range, 6.0-27.5). In the pooled analysis, no positive or negative association between BMI and progression-free survival (P = 0.88)/overall survival (P = 0.25) was observed, regardless of treatment type, sex, and age. These results were nonsignificant in the univariate and multivariate analyses. The objective response rate, according to BMI category, did not differ significantly regardless of age. TRAEs were not associated with BMI.

CONCLUSION

The observed lack of an association between BMI and survival demonstrates that BMI is not a valuable marker of systemic treatment-related outcomes in metastatic melanoma. Future approaches might focus on the whole-body distribution.

Obesity and Cancer Metastasis: Molecular and Translational Perspectives

Obesity is a modern health problem that has reached pandemic proportions. It is an established risk factor for carcinogenesis, however, evidence for the contribution of adipose tissue to the metastatic behavior of tumors is also mounting. Over 90% of cancer mortality is attributed to metastasis and metastatic tumor cells must communicate with their microenvironment for survival. Many of the characteristics observed in obese adipose tissue strongly mirror the tumor microenvironment. Thus in the case of prostate, pancreatic and breast cancer and esophageal adenocarcinoma, which are all located in close anatomical proximity to an adipose tissue depot, the adjacent fat provides an ideal microenvironment to enhance tumor growth, progression and metastasis. Adipocytes provide adipokines, fatty acids and other soluble factors to tumor cells whilst immune cells infiltrate the tumor microenvironment. In addition, there are emerging studies on the role of the extracellular vesicles secreted from adipose tissue, and the extracellular matrix itself, as drivers of obesity-induced metastasis. In the present review, we discuss the major mechanisms responsible for the obesity-metastatic link. Furthermore, understanding these complex mechanisms will provide novel therapies to halt the tumor-adipose tissue crosstalk with the ultimate aim of inhibiting tumor progression and metastatic growth.

Lipid metabolic Reprogramming: Role in Melanoma Progression and Therapeutic Perspectives

Simple Summary

Melanoma is a devastating skin cancer characterized by an impressive metabolic plasticity. Melanoma cells are able to adapt to the tumor microenvironment by using a variety of fuels that contribute to tumor growth and progression. In this review, the authors summarize the contribution of the lipid metabolic network in melanoma plasticity and aggressiveness, with a particular attention to specific lipid classes such as glycerophospholipids, sphingolipids, sterols and eicosanoids. They also highlight the role of adipose tissue in tumor progression as well as the potential antitumor role of drugs targeting critical steps of lipid metabolic pathways in the context of melanoma.

Abstract

Metabolic reprogramming contributes to the pathogenesis and heterogeneity of melanoma. It is driven both by oncogenic events and the constraints imposed by a nutrient- and oxygen-scarce microenvironment. Among the most prominent metabolic reprogramming features is an increased rate of lipid synthesis. Lipids serve as a source of energy and form the structural foundation of all membranes, but have also emerged as mediators that not only impact classical oncogenic signaling pathways, but also contribute to melanoma progression. Various alterations in fatty acid metabolism have been reported and can contribute to melanoma cell aggressiveness. Elevated expression of the key lipogenic fatty acid synthase is associated with tumor cell invasion and poor prognosis. Fatty acid uptake from the surrounding microenvironment, fatty acid β-oxidation and storage also appear to play an essential role in tumor cell migration. The aim of this review is (i) to focus on the major alterations affecting lipid storage organelles and lipid metabolism. A particular attention has been paid to glycerophospholipids, sphingolipids, sterols and eicosanoids, (ii) to discuss how these metabolic dysregulations contribute to the phenotype plasticity of melanoma cells and/or melanoma aggressiveness, and (iii) to highlight therapeutic approaches targeting lipid metabolism that could be applicable for melanoma treatment.

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.

Obesity and the Impact on Cutaneous Melanoma: Friend or Foe?

Excess body weight has been identified as a risk factor for many types of cancers, and for the majority of cancers, it is associated with poor outcomes. In contrast, there are cancers in which obesity is associated with favorable outcomes and this has been termed the “obesity paradox”. In melanoma, the connection between obesity and the increased incidence is not as strong as for other cancer types with some but not all studies showing an association. However, several recent studies have indicated that increased body mass index (BMI) improves survival outcomes in targeted and immune therapy treated melanoma patients. The mechanisms underlying how obesity leads to changes in therapeutic outcomes are not completely understood. This review discusses the current evidence implicating obesity in melanoma progression and patient response to targeted and immunotherapy, and discusses potential mechanisms underpinning these associations.

PPARγ inhibition boosts efficacy of PD-L1 Checkpoint Blockade Immunotherapy against Murine Melanoma in a sexually dimorphic manner

Immune checkpoint blockade-based immunotherapy has become standard of care for multiple cancer types. However, the overall response rates among various cancer types still remain unsatisfactory. There is a pressing clinical need to identify combination therapies to improve efficacy of anticancer immunotherapy. We previously showed that pharmacologic inhibition of PPARγ by GW9662 boosts αPD-L1 and αPD-1 antibody efficacy in treating murine mammary tumors. In addition, we defined sexually dimorphic αPD-L1 efficacy in B16 melanoma. Here, we show a sexually dimorphic response to the combination of GW9662 and αPD-L1 immunotherapy in B16 melanoma. Combination effects were observed in female, but not male hosts. Neither female oöphorectomy impairs, nor does male castration rescue the combination effects, suggesting a sex hormone-independent response to this combination therapy. In diet-induced obese females, melanoma growth remained responsive to the combination treatment, albeit less robustly than lean females. These findings are informative for future design and application of immunotherapy-related combination therapy for treating human melanoma patients by taking gender and obesity status into consideration.

Adipocyte extracellular vesicles carry enzymes and fatty acids that stimulate mitochondrial metabolism and remodeling in tumor cells

Extracellular vesicles are emerging key actors in adipocyte communication. Notably, small extracellular vesicles shed by adipocytes stimulate fatty acid oxidation and migration in melanoma cells and these effects are enhanced in obesity. However, the vesicular actors and cellular processes involved remain largely unknown. Here, we elucidate the mechanisms linking adipocyte extracellular vesicles to metabolic remodeling and cell migration. We show that adipocyte vesicles stimulate melanoma fatty acid oxidation by providing both enzymes and substrates. In obesity, the heightened effect of extracellular vesicles depends on increased transport of fatty acids, not fatty acid oxidation-related enzymes. These fatty acids, stored within lipid droplets in cancer cells, drive fatty acid oxidation upon being released by lipophagy. This increase in mitochondrial activity redistributes mitochondria to membrane protrusions of migrating cells, which is necessary to increase cell migration in the presence of adipocyte vesicles. Our results provide key insights into the role of extracellular vesicles in the metabolic cooperation that takes place between adipocytes and tumors with particular relevance to obesity.

The complex relationship between body mass index and response to immune checkpoint inhibition in metastatic melanoma patients

Despite major improvements in combatting metastatic melanoma since the advent of immunotherapy, the overall survival for patients with advanced disease remains low. Recently, there is a growing number of reports supporting an “obesity paradox,” in which patients who are overweight or mildly obese may exhibit a survival benefit in patients who received immune checkpoint inhibitors. We studied the relationship between body mass index and progression-free survival and overall survival in a cohort of 423 metastatic melanoma patients receiving immunotherapy, enrolled and prospectively followed up in the NYU Interdisciplinary Melanoma Cooperative Group database. We analyzed this association stratified by first vs. second or greater-line of treatment and treatment type adjusting for age, gender, stage, lactate dehydrogenase, Eastern Cooperative Oncology Group performance status, number of metastatic sites, and body mass index classification changes. In our cohort, the patients who were overweight or obese did not have different progression-free survival than patients with normal body mass index. Stratifying this cohort by first vs. non-first line immunotherapy revealed a moderate but insignificant association between being overweight or obese and better progression-free survival in patients who received first line. Conversely, an association with worse progression-free survival was observed in patients who received non-first line immune checkpoint inhibitors. Specifically, overweight and obese patients receiving combination immunotherapy had a statistically significant survival benefit, whereas patients receiving the other treatment types showed heterogeneous trends. We caution the scientific community to consider several important points prior to drawing conclusions that could potentially influence patient care, including preclinical data associating obesity with aggressive tumor biology, the lack of congruence amongst several investigations, and the limited reproduced comprehensiveness of these studies.

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.

Clinicopathologic Features and Prognostic Factors of Primary Cutaneous Melanoma: a Multicenter Study in Korea

BACKGROUND

Malignant melanoma is a cutaneous malignancy with a high mortality rate and high potential for metastases. Detailed information on the clinicopathologic characteristics and prognostic factors of cutaneous melanoma is currently limited in Korea. This study aimed to identify the epidemiological and clinicopathologic characteristics of primary cutaneous melanoma in Korean patients, and to assess which prognostic variables could influence both the development of metastases in primary cutaneous melanoma and overall survival (OS).

METHODS

A total of 261 patients diagnosed with primary cutaneous melanoma in seven medical centers between 1997 and 2017 were retrospectively investigated with regard to clinical presentation, localization of the tumor, histopathologic subtype, and survival time.

RESULTS

The nodular histologic subtype, ulceration, and Breslow thickness were significantly associated with the development of metastasis; and overweight and obesity (body mass index > 23) were significantly associated with increased Breslow thickness. The location of the metastases appeared to influence OS: brain metastases were associated with the highest risk of death, followed by gastrointestinal, lung, and extra-regional lymph node metastases.

CONCLUSION

In this study, tumor thickness, nodular histologic subtype, and ulceration predicted metastatic spread of primary cutaneous melanoma. In addition, OS was associated with the location of metastases. Obesity was related to the prognosis of primary cutaneous melanoma. Clinicians should bear these findings in mind when forming a diagnosis because of the risk of a poor prognosis.

Body mass index may predict the response to ipilimumab in metastatic melanoma: An observational multi-centre study

Introduction

Immunotherapy is a well-established treatment option in patients with metastatic melanoma. However, biomarkers that can be used to predict a response in these patients have not yet been found, putting patients at risk of severe side effects.

Methods

In this retrospective analysis, we investigated the association between the body mass index and ipilimumab treatment response in patients with metastatic melanoma. Patients with metastatic melanoma who received a monotherapy of up to 4 doses of ipilimumab (3 mg/kg) every 3 weeks from 2011 to 2014 in three major hospitals in Austria were included. Patients were classified into two groups: normal group (BMI<25) and overweight group (BMI≥25).

Results

40 patients had a normal BMI, and 36 had a BMI above normal. Patients with a BMI that was above normal showed significantly higher response rates (p = 0.024, χ²), and lower likelihood of brain metastases (p = 0.012, χ²). No differences were found between both groups with respect to gender (p = 0.324, χ²), T-stage (p = 0.197, χ²), or the occurrence of side effects (p = 0.646, χ²). Patients with a BMI above normal showed a trend towards longer overall survival (p = 0.056, Log-Rank), but no difference was found regarding progression-free survival (p = 0.924, Log-Rank).

Conclusions

The BMI correlated with the response to ipilimumab treatment in a cohort of metastatic melanoma patients.

Association of body-mass index and outcomes in patients with metastatic melanoma treated with targeted therapy, immunotherapy, or chemotherapy: a retrospective, multicohort analysis

BACKGROUND

Obesity has been linked to increased mortality in several cancer types; however, the relation between obesity and survival outcomes in metastatic melanoma is unknown. The aim of this study was to examine the association between body-mass index (BMI) and progression-free survival or overall survival in patients with metastatic melanoma who received targeted therapy, immunotherapy, or chemotherapy.

METHODS

This retrospective study analysed independent cohorts of patients with metastatic melanoma assigned to treatment with targeted therapy, immunotherapy, or chemotherapy in randomised clinical trials and one retrospective study of patients treated with immunotherapy. Patients were classified according to BMI, following the WHO definitions, as underweight, normal, overweight, or obese. Patients without BMI and underweight patients were excluded. The primary outcomes were the associations between BMI and progression-free survival or overall survival, stratified by treatment type and sex. We did multivariable analyses in the independent cohorts, and combined adjusted hazard ratios in a mixed-effects meta-analysis to provide a precise estimate of the association between BMI and survival outcomes; heterogeneity was assessed with meta-regression analyses. Analyses were done on the predefined intention-to-treat population in the randomised controlled trials and on all patients included in the retrospective study.

FINDINGS

The six cohorts consisted of a total of 2046 patients with metastatic melanoma treated with targeted therapy, immunotherapy, or chemotherapy between Aug 8, 2006, and Jan 15, 2016. 1918 patients were included in the analysis. Two cohorts containing patients from randomised controlled trials treated with targeted therapy (dabrafenib plus trametinib [n=599] and vemurafenib plus cobimetinib [n=240]), two cohorts containing patients treated with immunotherapy (one randomised controlled trial of ipilimumab plus dacarbazine [n=207] and a retrospective cohort treated with pembrolizumab, nivolumab, or atezolizumab [n=331]), and two cohorts containing patients treated with chemotherapy (two randomised controlled trials of dacarbazine [n=320 and n=221]) were classified according to BMI as normal (694 [36%] patients), overweight (711 [37%]), or obese (513 [27%]). In the pooled analysis, obesity, compared with normal BMI, was associated with improved survival in patients with metastatic melanoma (average adjusted hazard ratio [HR] 0·77 [95% CI 0·66-0·90] for progression-free survival and 0·74 [0·58-0·95] for overall survival). The survival benefit associated with obesity was restricted to patients treated with targeted therapy (HR 0·72 [0·57-0·91] for progression-free survival and 0·60 [0·45-0·79] for overall survival) and immunotherapy (HR 0·75 [0·56-1·00] and 0·64 [0·47-0·86]). No associations were observed with chemotherapy (HR 0·87 [0·65-1·17, pinteraction=0·61] for progression-free survival and 1·03 [0·80-1·34, pinteraction=0·01] for overall survival). The association of BMI with overall survival for patients treated with targeted and immune therapies differed by sex, with inverse associations in men (HR 0·53 [0·40-0·70]), but no associations observed in women (HR 0·85 [0·61-1·18, pinteraction=0·03]).

INTERPRETATION

Our results suggest that in patients with metastatic melanoma, obesity is associated with improved progression-free survival and overall survival compared with those outcomes in patients with normal BMI, and that this association is mainly seen in male patients treated with targeted or immune therapy. These results have implications for the design of future clinical trials for patients with metastatic melanoma and the magnitude of the benefit found supports further investigation of the underlying mechanism of these associations.

FUNDING

ASCO/CCF Young Investigator Award, ASCO/CCF Career Development Award, MD Anderson Cancer Center (MDACC) Melanoma Moonshot Program, MDACC Melanoma SPORE, and the Dr Miriam and Sheldon G Adelson Medical Research Foundation.

Exosomes as a novel pathway for regulating development and diseases of the skin

Exosomes are one of the most potent intercellular communicators, which are able to communicate with adjacent or distant cells. Exosomes deliver various bioactive molecules, including membrane receptors, proteins, mRNA and microRNA, to target cells and serve roles. Recent studies have demonstrated that exosomes may regulate the functions and diseases of the skin, which is the largest organ of the human body. The abnormal functions of the skin lead to the progression of scleroderma, melanoma, baldness and other diseases. A previous study has demonstrated that epithelial progenitor cells are rich in several subunits of exosomes that may maintain the proliferative capacity of these epithelial progenitor cells, which is essential for the development of the epidermis. Exosomes derived from human adipose mesenchymal stem cells accelerate skin wound healing by optimizing fibroblast properties; this is beneficial for the recovery of postoperative and other wounds. Exosomes derived from adipocytes promote melanoma migration and invasion through fatty acid oxidation; therefore, in the clinic, it may be possible to improve the prognosis of patients with melanoma by reducing their body fat content. Exosomes derived from keratinocytes modulate melanocyte pigmentation, which has been utilized as a novel mechanism for the regulation of pigmentation in conditions including Moynahan syndrome and albinism. Meanwhile, scleroderma patients with vascular abnormalities may experience decreased serum exosome levels; it may therefore be possible to detect the exosome content in sera in order to diagnose and treat scleroderma. In addition, the use of exosomes has been suggested to promote or enhance hair growth, which has been demonstrated to be highly effective. These studies have provided new opportunities and therapeutic strategies for understanding how exosomes regulate intercellular communication in pathological processes of the skin.

Epidemiological and histopathological aspects of primary cutaneous melanoma in residents of Joinville, 2003-2014

BACKGROUND

The worldwide incidence of cutaneous melanoma (CM) has been continuously increasing over the last decades. Primary and secondary prevention, with attention to risk factors and early diagnosis, remain the cornerstone for reducing the burden of cutaneous melanoma. Detailed information with respect to clinical and pathological data on cutaneous melanoma is scarce in Brazil.

OBJECTIVE

The purpose of our study was to analyze epidemiological and pathological characteristics of primary cutaneous melanoma in Joinville, southern Brazil.

METHODS

Observational, cross-sectional, retrospective study in which 893 reports of primary cutaneous melanoma from the local population were analyzed in the period 2003-2014. The study was approved by the local Ethics and Research Committee.

RESULTS

We observed a female predominance of cutaneous melanoma (56.3%). The age standardized incidence rate of primary cutaneous melanoma for the world population in the period 2003-06 was 11.8 per 100,000 population (CI 95%, 10.3-13.4), and 17.5 (CI 95%, 15.7-19.3) in 2011-14, revealing a significant increase of 48.3% (p < 0,05). Six and a half percent of patients had multiple cutaneous melanomas (mean 2.2 years and a maximum of 10.0 years between diagnoses). We observed significant differences between the location head/neck and cutaneous melanoma in situ, lower limb with Breslow depth S III and upper limb with Breslow depth S I. The comparison of the characteristics of cutaneous melanoma in the elderly and non-elderly (< 60 years old) showed significant differences with respect to all the variables studied.

STUDY LIMITATIONS

Using secondary data source.

CONCLUSION

Joinville has high incidence coefficients for Brazilian standards, showing an increase in the incidence of cutaneous melanoma.

Obesity and melanoma: could fat be fueling malignancy?

Over the last decade, it has become increasingly clear that adipose tissue, and particularly adipocytes, contributes to tumor progression. Obesity, an ever-increasing worldwide phenomenon, exacerbates this effect. The influence of obesity on melanoma remains poorly studied, although recent data do underline an association between the two diseases in both humans and murine models. Herein, we review the impact of obesity on melanoma incidence and progression and discuss the underlying mechanisms known to be involved. Adipose tissue favors the proliferation and aggressiveness of melanoma cells through a direct dialog, mediated by soluble factors and by exosomes, and through remodeling of the tumor microenvironment. This knowledge could, in the future, help to design new personalized therapeutic options for obese melanoma patients.

Adipocyte Exosomes Promote Melanoma Aggressiveness through Fatty Acid Oxidation: A Novel Mechanism Linking Obesity and Cancer

Malignant progression results from a dynamic cross-talk between stromal and cancer cells. Recent evidence suggests that this cross-talk is mediated to a significant extent by exosomes, nanovesicles secreted by most cell types and which allow the transfer of proteins, lipids, and nucleic acids between cells. Adipocytes are a major component of several tumor microenvironments, including that of invasive melanoma, where cells have migrated to the adipocyte-rich hypodermic layer of the skin. We show that adipocytes secrete exosomes in abundance, which are then taken up by tumor cells, leading to increased migration and invasion. Using mass spectrometry, we analyzed the proteome of adipocyte exosomes. Interestingly, these vesicles carry proteins implicated in fatty acid oxidation (FAO), a feature highly specific to adipocyte exosomes. We further show that, in the presence of adipocyte exosomes, FAO is increased in melanoma cells. Inhibition of this metabolic pathway completely abrogates the exosome-mediated increase in migration. Moreover, in obese mice and humans, both the number of exosomes secreted by adipocytes as well as their effect on FAO-dependent cell migration are amplified. These observations might in part explain why obese melanoma patients have a poorer prognosis than their nonobese counterparts. Cancer Res; 76(14); 4051-7. ©2016 AACR.