Vitamin D in cutaneous carcinogenesis: part II

Epidemiology and Risk Factors of Actinic Keratosis. What is New for The Management for Sun-Damaged Skin

Actinic keratosis (AK) is considered a chronic skin disease mostly caused by long-term exposure to UV radiation and other risk factors such as immunosuppression, leading to an individual susceptibility for skin cancer manifestation. The treatment of AK is laborious and costly, and the incidence of skin cancer is forecasted to double until the year 2030 in an aging society.Risk factors in AK for malignant transformation in cutaneous squamous cell carcinoma (cSCC) are not fully understood, but studies suggest that histological features, such as atypia in the basal epidermal third and basal proliferation (PRO score) in AK play a pivotal role for development of malignancy. As the clinical appearance of AK does not correlate with the risk for malignancy, guidelines suggest treating every single AK lesion upon diagnosis. Skin imaging techniques, such as line-field confocal optical coherence tomography (LC-OCT) can help to provide an individual holistic follow-up for AK lesions by non-invasive visualization of atypia and basal proliferation. A follow-up for patients with AK may be critical for treatment success in terms of strengthening therapy adherence. When AK presents therapy refractory, cSCC manifests in nearly 30% of the cases after several years. Patients with AK suffering from field cancerization and immunosuppression are susceptible for a severe course of disease including metastasis and high mortality rates. Those vulnerable subgroups benefit from close skin cancer screening, early adequate treatment and chemoprevention, such as niacinamide or acitretin. Skin cancer prevention is substantial. Primary prevention should include chemical and physical UV-light protection and avoidance of indoor tanning. Secondary prevention is essential in high-risk populations, such as fair skin type elderly men and STORs. Tertiary prevention should comprise adequate treatment strategies to prevent therapy resistance, reoccurrence and cSCC, especially when field cancerization and immunosuppression are present.

Significant Association of Poly-A and Fok1 Polymorphic Alleles of the Vitamin D Receptor with Vitamin D Serum Levels and Incidence of Squamous Cutaneous Neoplasia

Vitamin D3, a prohormone, is converted to circulating calcidiol and then to calcitriol, the hormone that binds to the vitamin D receptor (VDR) (a nuclear transcription factor). Polymorphic genetic sequence variants of the VDR are associated with an increased risk of breast cancer and melanoma. However, the relationship between VDR allelic variants and the risk of squamous cell carcinoma and actinic keratosis remains unclear. We examined the associations between two VDR polymorphic sites, Fok1 and Poly-A, and serum calcidiol levels, actinic keratosis lesion incidence, and the history of cutaneous squamous cell carcinoma in 137 serially enrolled patients. By evaluating the Fok1 (F) and (f) alleles and the Poly-A long (L) and short (S) alleles together, a strong association between genotypes FFSS or FfSS and high calcidiol serum levels (50.0 ng/ml) was found; conversely, ffLL patients showed very low calcidiol levels (29.1 ng/ml). Interestingly, the FFSS and FfSS genotypes were also associated with reduced actinic keratosis incidence. For Poly-A, additive modeling showed that Poly-A (L) is a risk allele for squamous cell carcinoma, with an OR of 1.55 per copy of the L allele. We conclude that actinic keratosis and squamous cell carcinoma should be added to the list of squamous neoplasias that are differentially regulated by the VDR Poly-A allele.

Serum Vitamin D Levels Explored in the Latvian Cohort of Patients with Basal Cell Carcinoma Linked to the Sonic Hedgehog and Vitamin D Binding Protein Cutaneous Tissue Indices

Ultraviolet radiation is known as one of the major contributors to skin malignancies, including basal cell carcinoma (BCC), which is the most common type of skin cancer. It is a heterogeneous tumor, which presents with various types that are stratified into low- and high-risk tumors. Sunlight is important for overall health and vitamin D synthesis in the skin, whereas deviations from the optimal level of vitamin D are shown to be associated with the risk of the development of BCC. The accumulating evidence suggests the ability of vitamin D to antagonize the Sonic Hedgehog (SHH) signaling, the key tumor pathway, and play a protective role in the development of BCC. Additionally, a vitamin D binding protein (DBP) is shown to be implicated in the complex regulation of vitamin D. Here, we aimed to explore serum vitamin D in patients with different primary and recurrent BCC of the head and neck and investigate cutaneous DBP and SHH indices, confirmed immunohistochemically in these subjects. According to the results, 94.9% of the Latvian cohort of BCC patients were found to be deficient in vitamin D. No significant differences in serum vitamin D levels were found between genders, primary and recurrent tumors, and different types of BCC. Serum vitamin D was inversely associated with tumor size. Susceptible male individuals with low blood vitamin D levels were recognized at risk of developing aggressive and recurrent BCC confirmed by the use of hierarchical clustering analysis. In smaller tumors with a favorable course, such as superficial and nodular BCC, the association between high DBP and low SHH tissue expression was found, providing supportive evidence of the existence of a link between vitamin D, proteins involved in its metabolism, as exemplified by the DBP and SHH signaling pathway. The assumption of a deficiency in the protective effect of vitamin D in patients with high-risk BCCs was proposed in low DBP and high SHH tissue indices. New extensions to existing knowledge and characterization of the BCC signaling pathways and their cross-talk with vitamin D are warranted when searching for a preferential effect of vitamin D on skin cancer.

Vitamin D Signaling in Psoriasis: Pathogenesis and Therapy

Psoriasis is a systemic, chronic, immune-mediated disease that affects approximately 2-3% of the world's population. The etiology and pathophysiology of psoriasis are still unknown, but the activation of the adaptive immune system with the main role of T-cells is key in psoriasis pathogenesis. The modulation of the local neuroendocrine system with the downregulation of pro-inflammatory and the upregulation of anti-inflammatory messengers represent a promising adjuvant treatment in psoriasis therapies. Vitamin D receptors and vitamin D-mediated signaling pathways function in the skin and are essential in maintaining the skin homeostasis. The active forms of vitamin D act as powerful immunomodulators of clinical response in psoriatic patients and represent the effective and safe adjuvant treatments for psoriasis, even when high doses of vitamin D are administered. The phototherapy of psoriasis, especially UVB-based, changes the serum level of 25(OH)D, but the correlation of 25(OH)D changes and psoriasis improvement need more clinical trials, since contradictory data have been published. Vitamin D derivatives can improve the efficacy of psoriasis phototherapy without inducing adverse side effects. The anti-psoriatic treatment could include non-calcemic CYP11A1-derived vitamin D hydroxyderivatives that would act on the VDR or as inverse agonists on RORs or activate alternative nuclear receptors including AhR and LXRs. In conclusion, vitamin D signaling can play an important role in the natural history of psoriasis. Selective targeting of proper nuclear receptors could represent potential treatment options in psoriasis.

Disturbed expression of vitamin D and retinoic acid-related orphan receptors α and γ and of megalin in inflammatory skin diseases

The pathogenesis of inflammatory skin diseases is associated with the abnormal activity of keratinocytes and immune cells infiltrate. Vitamin D₃ deficiency can correlate with the increased incidence, severity and duration of inflammatory skin disorders. The exact mechanism on how vitamin D₃ influences inflammatory skin diseases still requires clarification. However, it can be associated with the disturbances in transmembrane glycoprotein-LRP2/megalin, which is implicated in vitamin D₃ transport to the cell, and defects in vitamin D-signalling through the nuclear receptors. Therefore, by using immunohistochemistry, we analysed the expression of LRP2/megalin, VDR, RORα and RORγ in allergic contact dermatitis, lichen simplex chronicus, sarcoidosis and psoriasis in comparison with the normal skin. We observed decreased expression of LRP2/megalin in all inflammatory lesions in comparison with the normal skin. Significant differences were also noticed in VDR, RORα and RORγ levels between inflammatory lesions and normal skin. Our research indicates disturbed expression of LRP2/megalin, VDR, RORα and RORγ in inflammatory skin lesions in comparison with normal skin. Therefore, we suggest that changes in the activity of these proteins may play role in pathogenesis of inflammatory skin disorders. Furthermore, we suggest that LRP2/megalin, VDR, RORα and RORy may serve as targets in therapy of these diseases.

Vitamin D and Skin Cancer: An Epidemiological, Patient-Centered Update and Review

BACKGROUND

The current vitamin D deficiency epidemic is accompanied by an increase in endemic skin cancer. There are still multiple controversies. This review aims to give practical recommendations regarding vitamin D among people at risk or with a personal history of skin cancer.

METHODS

Narrative review including human research articles published between 2011 and 2021, elaborated bearing in mind an epidemiological, patient-centered approach.

RESULTS

Ultraviolet (UV) exposure (neither artificial nor natural) is not the ideal source to synthesize vitamin D. There is conflicting epidemiological evidence regarding vitamin D, non-melanoma skin cancer (NMSC), and cutaneous melanoma (CMM), confounded by the effect of sun exposure and other factors.

CONCLUSIONS

Current evidence is controversial, and there are no widely applicable strategies. We propose three practical recommendations. Firstly, sun protection recommendations should be kept among people at risk or with a personal history of skin cancer. Secondly, vitamin D should preferably be sourced through diet. In patients with melanoma or at risk of cutaneous cancer, serum vitamin D checks are warranted to detect and avoid its insufficiency.

Nutritional Interventions for Patients with Melanoma: From Prevention to Therapy-An Update

Melanoma is an aggressive skin cancer, whose incidence rates have increased over the past few decades. Risk factors for melanoma are both intrinsic (genetic and familiar predisposition) and extrinsic (environment, including sun exposure, and lifestyle). The recent advent of targeted and immune-based therapies has revolutionized the treatment of melanoma, and research is focusing on strategies to optimize them. Obesity is an established risk factor for several cancer types, but its possible role in the etiology of melanoma is controversial. Body mass index, body surface area, and height have been related to the risk for cutaneous melanoma, although an 'obesity paradox' has been described too. Increasing evidence suggests the role of nutritional factors in the prevention and management of melanoma. Several studies have demonstrated the impact of dietary attitudes, specific foods, and nutrients both on the risk for melanoma and on the progression of the disease, via the effects on the oncological treatments. The aim of this narrative review was to summarize the main literature results regarding the preventive and therapeutic role of nutritional schemes, specific foods, and nutrients on melanoma incidence and progression.

Vitamin D and Vitamin D Analogs as Adjuncts to Field Therapy Treatments for Actinic Keratoses: Current Research and Future Approaches

Actinic keratoses (AK), also known as solar keratoses, are precancerous hyperkeratotic papules caused by long-term exposure to ultraviolet radiation. Management of AK prior to progression to cutaneous malignancy represents an important window of intervention. This is important on a population level, given the high incidence, morbidity, financial costs, and the low but measurable risk of mortality from cutaneous neoplasia. Treatments for AK have been refined for many years with significant progress over the past decade. Those recent advancements lead to questions about current treatment paradigms and the role of harnessing the immune system in field therapies. Recent studies suggest a key interplay between vitamin D and cancer immunity; in particular, the systemic and/or topical vitamin D analogs can augment field therapies used for severe actinic damage. In this review, we will examine the literature supporting the use of vitamin D-directed therapies to improve field therapy approaches. An enhanced understanding of these recent concepts with a focus on mechanisms is important in the optimized management of AK. These mechanisms will be critical in guiding whether selected populations, including those with immunosuppression, heritable cancer syndromes, and other risk factors for skin cancer, can benefit from these new concepts with vitamin D analogs and whether the approaches will be as effective in these populations as in immunocompetent patients.

Risk of keratinocyte carcinomas with vitamin D and calcium supplementation: a secondary analysis of a randomized clinical trial

BACKGROUND

It is unknown whether dietary supplementation with vitamin D or calcium prevents keratinocyte carcinomas, also known as nonmelanoma skin cancers.

OBJECTIVES

This study aimed to determine whether daily vitamin D or calcium supplementation alters the risk of basal cell carcinoma (BCC) or invasive cutaneous squamous cell carcinoma (SCC).

METHODS

The Vitamin D/Calcium Polyp Prevention Study is a completed multicenter, double-blind, placebo-controlled, partial 2 × 2 factorial, randomized clinical trial of vitamin D, calcium, or both for the prevention of colorectal adenomas. During 2004-2008, a total of 2259 men and women, 45-75 y of age, recently diagnosed with a colorectal adenoma, were randomly assigned to 1000 IU/d of vitamin D3 or placebo and 1200 mg/d of calcium carbonate or placebo for 3 or 5 y, and followed after treatment ended. Reports of incident BCC or SCC were confirmed from pathology records.

RESULTS

During a median follow-up of 8 y, 200 (9%) participants were diagnosed with BCC and 68 (3%) participants were diagnosed with SCC. BCC incidence was unrelated to treatment with vitamin D compared with no vitamin D (HR: 0.96; 95% CI: 0.73, 1.26), calcium compared with no calcium (HR: 1.01; 95% CI: 0.74, 1.39), and both agents compared with neither (HR: 0.99; 95% CI: 0.65, 1.51). SCC incidence was unrelated to treatment with vitamin D compared with no vitamin D (HR: 0.79; 95% CI: 0.49, 1.27), but there was suggestive evidence of beneficial treatment effects for calcium compared with no calcium (HR: 0.60; 95% CI: 0.36, 1.01) and both agents compared with neither (HR: 0.42; 95% CI: 0.19, 0.91).

CONCLUSIONS

Calcium alone or in combination with vitamin D may reduce the risk of SCC, but not BCC. This trial was registered at clinicaltrials.gov as NCT00153816.

Genetic and environmental factors underlying keratinocyte carcinoma risk

Recent large-scale GWAS and large epidemiologic studies have accelerated the discovery of genes and environmental factors that contribute to the risk of keratinocyte carcinoma (KC), which includes basal cell carcinoma (BCC) and squamous cell carcinoma (SCC). This Review summarizes the genomic regions associated with SCC and BCC risk, examines the genetic overlap between SCC and BCC, and discusses biological pathways involved in SCC and BCC development. Next, we review environmental factors that are associated with KC risk, including those that are shared between SCC and BCC as well as others that associated with only one type of KC. We conclude with a critical appraisal of current research and potential directions for future research.

Vitamin D and Other Differentiation-promoting Agents as Neoadjuvants for Photodynamic Therapy of Cancer

The efficacy of photodynamic therapy (PDT) using aminolevulinic acid (ALA), which is preferentially taken up by cancerous cells and converted to protoporphyrin IX (PpIX), can be substantially improved by pretreating the tumor cells with vitamin D (Vit D). Vit D is one of several "differentiation-promoting agents" that can promote the preferential accumulation of PpIX within the mitochondria of neoplastic cells, making them better targets for PDT. This article provides a historical overview of how the concept of using combination agents ("neoadjuvants") for PDT evolved, from initial discoveries about neoadjuvant effects of methotrexate and fluorouracil to later studies to determine how vitamin D and other agents actually work to augment PDT efficacy. While this review focuses mainly on skin cancer, it includes a discussion about how these concepts may be applied more broadly toward improving PDT outcomes in other types of cancer.

Crosstalk Between Vitamin D and p53 Signaling in Cancer: An Update

It has now been convincingly shown that vitamin D and p53 signaling protect against spontaneous or carcinogen-induced malignant transformation of cells. The vitamin D receptor (VDR) and the p53/p63/p73 proteins (the p53 family hereafter) exert their effects as receptors/sensors that turn into transcriptional regulators upon stimulus. While the p53 clan, mostly in the nucleoplasm, responds to a large and still growing number of alterations in cellular homeostasis commonly referred to as stress, the nuclear VDR is transcriptionally activated after binding its naturally occurring biologically active ligand 1,25-dihydroxyvitamin D with high affinity. Interestingly, a crosstalk between vitamin D and p53 signaling has been demonstrated that occurs at different levels, has genome-wide implications, and is of high importance for many malignancies, including non-melanoma skin cancer. These interactions include the ability of p53 to upregulate skin pigmentation via POMC derivatives including alpha-MSH and ACTH. Increased pigmentation protects the skin against UV-induced DNA damage and skin photocarcinogenesis, but also inhibits cutaneous synthesis of vitamin D. A second level of interaction is characterized by binding of VDR and p53 protein, an observation that may be of relevance for the ability of 1,25-dihydroxyvitamin D to increase the survival of skin cells after UV irradiation. UV irradiation-surviving cells show significant reductions in thymine dimers in the presence of 1,25-dihydroxyvitamin D that are associated with increased nuclear p53 protein expression and significantly reduced NO products. A third level of interaction is documented by the ability of vitamin D compounds to regulate the expression of the murine double minute (MDM2) gene in dependence of the presence of wild-type p53. MDM2 has a well-established role as a key negative regulator of p53 activity. Finally, p53 and its family members have been implicated in the direct regulation of the VDR. This review gives an update on some of the implications of the crosstalk between vitamin D and p53 signaling for carcinogenesis in the skin and other tissues, focusing on a genome-wide perspective.

Overview on vitamin D and sunbed use

Vitamin D seems to be associated with a protective effect in a vast range of diseases, including cardiovascular, autoimmune and oncologic conditions. Since ultraviolet (UV) B light is the most important prerequisite for the cutaneous synthesis of vitamin D, sunbeds are able to increase serum vitamin D levels, although only transiently in most cases. In this scenario, the artificial tanning industry relentlessly tries to promote the use of sunbeds as a 'safe' therapeutic measure to achieve an adequate serum vitamin D status. The World Health Organization classified UV-emitting tanning devices, as well as the whole UV spectrum, as group-1 carcinogens, as they significantly increase the risk of melanoma and non-melanoma skin cancer. In case of vitamin D deficiency or insufficiency, the current risk-benefit ratio is therefore in favour of vitamin D supplementation instead of sunbed use. Artificial tanning devices should never be considered as an option to achieve an appropriate vitamin D status. Their supposedly beneficial effects, vastly publicised by the artificial tanning industry, are not worth the carcinogenic risk associated with sunbed use.

Vitamin D and the Skin: A Review for Dermatologists

In recent years, the growing interest in the role played by vitamin D in skin disease has given rise to the publication of many studies of the relationship between this vitamin and certain skin conditions. As dermatologists, we need to understand, among other aspects, how vitamin D is synthesized and the main sources in humans, as well as plasma levels and the factors that can modify them. Of particular interest are the latest discoveries about the role of vitamin D in skin diseases such as lupus erythematosus, ichthyosis, atopic dermatitis, hidradenitis suppurativa, acne, alopecia areata, androgenetic alopecia, melanoma, and nonmelanoma skin cancer. Also of interest is the importance of vitamin D as adjuvant therapy in patients on long-term treatment with corticosteroids. In this review, we provide an overview of the most important and most recent information regarding the relationship between vitamin D and skin disease and discuss the importance of assessing individual vitamin D status and correcting deficiencies.

Vitamin D levels in actinic keratosis: a preliminary study

BACKGROUND

Recent studies that investigated the effect of vitamin D on skin cancer risk have exhibited inconsistent results.

OBJECTIVE

The aim of the study was to evaluate vitamin D status in patients with actinic keratosis.

METHODS

A cross-sectional study was conducted on 31 patients with actinic keratosis and 29 healthy controls. Serum vitamin D levels in the study group were determined by liquid chromatography/tandem mass spectrometry.

RESULTS

Serum 25(OH)D levels in patients with actinic keratosis were significantly higher than those of the healthy controls (P=0.04). Prevalence of 25(OH)D deficiency was significantly higher in the healthy controls (75.9%) compared to the patients with actinic keratosis (54.8%), but the difference was not statistically significant (P= 0.09).

STUDY LIMITATIONS

The cross-sectional design of the study, data on smoking based on patient self-report, and subjects' different dietary habits, which can influence 25(OH)D levels, are the study's limitations.

CONCLUSION

Serum vitamin D level can be used as a marker for ultraviolet B radiation from sun exposure; therefore, it can be used in individuals at risk of actinic keratosis. Oral intake of vitamin D through diet or supplements is proposed instead of prolonged ultraviolet exposure to maintain adequate vitamin D serum levels. Further research is needed to elucidate the role of vitamin D in skin carcinogenesis.

The Biological Activities of Vitamin D and Its Receptor in Relation to Calcium and Bone Homeostasis, Cancer, Immune and Cardiovascular Systems, Skin Biology, and Oral Health

Vitamin D plays an important role in calcium homeostasis and bone metabolism, with the capacity to modulate innate and adaptive immune function, cardiovascular function, and proliferation and differentiation of both normal and malignant keratinocytes. 1,25(OH)2D, the biologically active form of vitamin D, exerts most of its functions through the almost universally distributed nuclear vitamin D receptor (VDR). Upon stimulation by 1,25(OH)2D, VDR forms a heterodimer with the retinoid X receptor (RXR). In turn, VDR/RXR binds to DNA sequences termed vitamin D response elements in target genes, regulating gene transcription. In order to exert its biological effects, VDR signalling interacts with other intracellular signalling pathways. In some cases 1,25(OH)2D exerts its biological effects without regulating either gene expression or protein synthesis. Although the regulatory role of vitamin D in many biological processes is well documented, there is not enough evidence to support the therapeutic use of vitamin D supplementation in the prevention or treatment of infectious, immunoinflammatory, or hyperproliferative disorders. In this review we highlight the effects of 1,25(OH)2D on bone and calcium homeostasis, on cancer, and refer to its effects on the cardiovascular and immune systems.

A protocol for prospective studies of 25-hydroxyvitamin D, leptin and body mass index in relation to cutaneous melanoma incidence and survival

INTRODUCTION

The incidence and mortality rates of cutaneous melanoma (CM) are increasing among fair-skinned populations worldwide. Ultraviolet radiation (UVR) is the principal risk factor for CM, but is also the main source of 25-hydroxyvitamin D (25(OH)D), which has been associated with reduced risk and better prognosis of some cancer types. However, both low and high 25(OH)D levels have been associated with increased risk of CM. Obesity as measured by body mass index (BMI) is associated with risk of several cancers and has also been suggested as a risk factor for CM, and may also be related to insufficient 25(OH)D and/or high leptin levels. Moreover, contracting a CM diagnosis has been associated with increased risk of developing second cancer. We aim to study whether low prediagnostic serum levels of 25(OH)D, high prediagnostic levels of BMI and high serum leptin levels influence CM incidence, Breslow thickness and CM mortality, and risk of second cancer and survival after a CM diagnosis.

METHODS AND ANALYSIS

Cohort and nested case-control studies will be carried out using the population-based Janus Serum Bank Cohort (archival prediagnostic sera, BMI, smoking and physical activity), with follow-up from 1972 to 2014. Additional data will be received from the Cancer Registry of Norway, the national Cause of Death Registry, Statistics Norway (education and occupation) and exposure matrices of UVR. Time-to-event regression models will be used to analyse the cohort data, while the nested case-control studies will be analysed by conditional logistic regression. A multilevel approach will be applied when incorporating group-level data.

ETHICS AND DISSEMINATION

The project is approved by the Regional Committee for Medical Research Ethics and is funded by the Norwegian Cancer Society. Results will be published in peer-reviewed journals, at scientific conferences and in the news media.

Serum Vitamin D and Vitamin D Receptor Gene Polymorphism in Mycosis Fungoides Patients: A Case Control Study

BACKGROUND

Vitamin D has been considered a key player in various malignancies including cutaneous cancers. To date, mycosis fungoides (MF) has been the least studied in relation to vitamin D. Furthermore, the vitamin D receptor (VDR) single nucleotide polymorphisms (SNPs) have not been tackled before in the context of MF, despite their incrimination in numerous diseases.

AIM OF STUDY

To assess the role of vitamin D in MF by measuring its serum level, and studying VDR SNPs (TaqI, BsmI, FokI) in different stages of MF.

PATIENTS AND METHODS

48 patients with various stages of MF, and 45 healthy controls were included. Complete history, full clinical examination and a five mm punch skin biopsy were performed to all recruited patients. Venous blood samples were withdrawn from both patients and controls to determine the serum vitamin D level and VDR gene polymorphisms.

RESULTS

Serum vitamin D level was significantly lower in patients (5.3-33.7 nmol/L)] compared to controls (8.3-90.1 nmol/L)] (P<0.001). A significant difference was observed between patients and controls regarding the FokI polymorphism only, being higher in patients (P = 0.039). Also Vitamin D serum levels differed significantly in patients with FokI genotypes (P = 0.014). No significant correlations were detected between any of the studied parameters and the demographic and clinical data of the included subjects.

CONCLUSION

Depressed vitamin D and FokI polymorphism are potentially involved in the context of MF. VDR gene polymorphisms warrant further larger scale investigations to detect the exact genes involved in the pathogenesis of such an enigmatic disease.

Vitamin D and the skin: Focus on a complex relationship: A review

The "sunshine" vitamin is a hot topic that attracted ample attention over the past decades, specially that a considerable proportion of the worldwide population are deficient in this essential nutrient. Vitamin D was primarily acknowledged for its importance in bone formation, however; increasing evidence point to its interference with the proper function of nearly every tissue in our bodies including brain, heart, muscles, immune system and skin. Thereby its deficiency has been incriminated in a long panel of diseases including cancers, autoimmune diseases, cardiovascular and neurological disorders. Its involvement in the pathogenesis of different dermatological diseases is no exception and has been the subject of much research over the recent years. In the current review, we will throw light on this highly disputed vitamin that is creating a significant concern from a dermatological perspective. Furthermore, the consequences of its deficiency on the skin will be in focus.

Melanoma risk perception and prevention behavior among African-Americans: the minority melanoma paradox

Introduction

Melanoma is the most deadly type of skin cancer with 75% of all skin cancer deaths within the US attributed to it. Risk factors for melanoma include ultraviolet exposure, genetic predisposition, and phenotypic characteristics (eg, fair skin and blond hair). Whites have a 27-fold higher incidence of melanoma than African-Americans (AA), but the 5-year survival is 17.8% lower for AA than Whites. It is reported continuously that AA have more advanced melanomas at diagnosis, and overall lower survival rates. This minority melanoma paradox is not well understood or studied.

Objective

To explore further, the possible explanations for the difference in melanoma severity and survival in AA within the US.

Methods

Qualitative review of the literature.

Results

Lack of minority-targeted public education campaigns, low self-risk perception, low self-skin examinations, intrinsic virulence, vitamin D differences, and physician mistrust may play a role in the melanoma survival disparity among AA.

Conclusion

Increases in public awareness of melanoma risk among AA through physician and media-guided education, higher index of suspicion among individuals and physicians, and policy changes can help to improve early detection and close the melanoma disparity gap in the future.

Vitamin D, Cancer Risk, and Mortality

Antiproliferative effects of 1,25-dihydroxyvitamin D, the biologically active form of vitamin D, are well established in various cell types by influencing cell differentiation and decreasing cell proliferation, growth, invasion, angiogenesis, and metastasis. Several meta-analyses showed that low serum levels of 25(OH)D was associated with colorectal cancer and overall mortality, while the association with cancer mortality was less consistent. VDR is a crucial mediator for the cellular effects of vitamin D and conflicting data have been reported for most malignancies. Beyond VDR, the biological effects of vitamin D are mediated by the vitamin D-binding protein. The GC (group-specific component) gene, encoding DBP, is highly polymorphic and several polymorphisms were investigated in association with cancer development with controversial results. Vitamin D supplementation was found to be associated with a reduced risk of overall mortality, reviewing all published trials on healthy subjects, whereas the evidence of an effect on cancer risk and mortality is less clear. Furthermore, long-term health effects of high doses of vitamin D, extended duration of supplementation, and the association with different baseline vitamin D levels remain to be investigated. In summary, epidemiological and preclinical studies support the development of vitamin D as preventative and therapeutic anticancer agents, with significant associations especially found for low vitamin D status with overall mortality and cancer outcome, more than cancer incidence. However, a definitive conclusion cannot be drawn and only large randomized clinical trials, both in healthy subjects and in cancer patients, will allow to draw definitive conclusions on the effect of vitamin D supplementation on cancer risk, prognosis, and mortality.

Immune Modulation by Vitamin D and Its Relevance to Food Allergy

Apart from its classical function in bone and calcium metabolism, vitamin D is also involved in immune regulation and has been linked to various cancers, immune disorders and allergic diseases. Within the innate and adaptive immune systems, the vitamin D receptor and enzymes in monocytes, dendritic cells, epithelial cells, T lymphocytes and B lymphocytes mediate the immune modulatory actions of vitamin D. Vitamin D insufficiency/deficiency early in life has been identified as one of the risk factors for food allergy. Several studies have observed an association between increasing latitude and food allergy prevalence, plausibly linked to lower ultraviolet radiation (UVR) exposure and vitamin D synthesis in the skin. Along with mounting epidemiological evidence of a link between vitamin D status and food allergy, mice and human studies have shed light on the modulatory properties of vitamin D on the innate and adaptive immune systems. This review will summarize the literature on the metabolism and immune modulatory properties of vitamin D, with particular reference to food allergy.

Vitamin D Supplementation Does Not Improve the Severity or the Resolution of Ultraviolet B-Induced Acute Erythema

BACKGROUND

Whether vitamin D supplementation alleviates the severity of ultraviolet B (UVB)-induced erythema and/or facilitates its resolution remains undetermined.

OBJECTIVE

To study the effect of oral vitamin D on UVB-induced erythema and its resolution in fair-skinned subjects.

METHODS

UVB-induced erythema was quantified using a Chroma Meter® in 50 volunteers 48 h before and 10 days after the random administration of 200,000 IU vitamin D (n = 40) or placebo (n = 10). Resolution of erythema in both groups was assessed by chromametry 24, 48, and 72 h after vitamin D administration.

RESULTS

No statistical difference between erythema values before and after administration in the vitamin D-supplemented group (p = 0.44) or the placebo group (p = 0.34) was noted. No statistical difference was evident between both groups with respect to resolution of erythema (p = 0.30).

CONCLUSION

Oral vitamin D supplementation neither improves protection against UVB-induced erythema nor facilitates its resolution.

Serum level of vitamin D3 in cutaneous melanoma

OBJECTIVE

To compare the level of vitamin D3 in cutaneous melanoma patients, with or without disease activity, with reference values and with patients from a general hospital.

METHODS

The serum levels of vitamin D3 were measured in cutaneous melanoma patients, aged 20 to 88 years, both genders, from January 2010 to December 2013. The samples from the general group were processed at Hospital Israelita Albert Einstein (control group). Data analysis was performed using the Statistics software.

RESULTS

A total of 100 patients were studied, 54 of them men, with mean age of 54.67 years, and 95 Caucasian. Out of these 100 patients, 17 had active disease. The average levels of vitamin D3 in the melanoma patients were lower than the level considered sufficient, but above the average of the control group. Both groups (with or without active disease) of patients showed a similar distribution of vitamin D3 deficiency.

CONCLUSION

Vitamin D3 levels in melanoma patients were higher than those of general patients and lower than the reference level. If the reference values are appropriate, a large part of the population had insufficient levels of vitamin D, including those with melanoma, or else, this standard needs to be reevaluated. No difference in vitamin D3 levels was found among melanoma patients with or without active disease. More comprehensive research is needed to assess the relation between vitamin D and melanoma.

Vitamin D in cancer chemoprevention

CONTEXT

There is increasing evidence that Vitamin D (Vit D) and its metabolites, besides their well-known calcium-related functions, may also exert antiproliferative, pro-differentiating, and immune modulatory effects on tumor cells in vitro and may also delay tumor growth in vivo.

OBJECTIVE

The aim of this review is to provide fresh insight into the most recent advances on the role of Vit D and its analogues as chemopreventive drugs in cancer therapy.

METHODS

A systematic review of experimental and clinical studies on Vit D and cancer was undertaken by using the major electronic health database including ISI Web of Science, Medline, PubMed, Scopus and Google Scholar.

RESULTS AND CONCLUSION

Experimental and clinical observations suggest that Vit D and its analogues may be effective in preventing the malignant transformation and/or the progression of various types of human tumors including breast cancer, prostate cancer, colorectal cancer, and some hematological malignances. These findings suggest the possibility of the clinical use of these molecules as novel potential chemopreventive and anticancer agents.

High prevalence of vitamin D deficiency in patients with xeroderma pigmetosum-A under strict sun protection

BACKGROUND/OBJECTIVES

Xeroderma pigmentosum (XP) is a rare autosomal recessive disease characterized by defective repair of ultraviolet (UV) irradiation-induced DNA damage and high risk of skin cancer. Thus, these patients require strict photoprotection. Considering the importance of UV-mediated cutaneous vitamin D production, such rigorous photoprotection would cause vitamin D deficiency. Then, we have studied the vitamin D status in patients with XP-A, a group requiring the most strict photoprotection.

SUBJECTS/METHODS

Twenty-one patients with XP-A (aged 6-25) were evaluated for their vitamin D intake, serum levels of 25-hydroxy-vitamin D (25OHD) and parathyroid hormone (PTH). Vitamin D intake was assessed by a 2-day food weighing method.

RESULTS

Median dietary intake of vitamin D was 4.1 μg/day, and the median concentrations of serum 25OHD and PTH were 7.7 and 49.9 pg/ml, respectively. In 76% of the patients, serum 25OHD level was lower than 10 ng/ml, indicating vitamin D deficiency. Vitamin D intake and serum 25OHD level were significantly lower in patients under enteral nutrition (EN) than those with oral intake (OI). Multivariate analyses revealed that EN was a significant predictor of decreased serum 25OHD level (β coefficient=-0.59, P=0.03).

CONCLUSIONS

Vitamin D deficiency is highly prevalent in XP-A patients, and supplementation should be considered to avoid unfavorable skeletal consequences in these patients. In addition, determination of dietary vitamin D requirement has been a difficult work issue in the decision of dietary reference intakes (DRIs) because of its cutaneous production. Data from XP patients would yield useful information for the determination of DRIs for vitamin D.

Diet in dermatology: Part I. Atopic dermatitis, acne, and nonmelanoma skin cancer

Patients commonly inquire about dietary modifications as a means to prevent or manage skin disease. Answering these questions is often challenging, given the vast and conflicting evidence that exists on this topic. This 2-part continuing medical education article summarizes the evidence to date to enable physicians to answer patients' questions in an evidence-based manner. Part I includes atopic dermatitis, acne, and nonmelanoma skin cancer. The role of dietary supplementation, dietary exclusion, food allergy, maternal diet, and breastfeeding in the development and/or prevention of atopic dermatitis is summarized. The dermatoendocrinologic mechanism for the effects of glycemic index/glycemic load and milk on acne is described, as well as related clinical evidence for dietary modifications. Finally, evidence and recommendations for restriction or supplementation of dietary factors in the prevention of nonmelanoma skin cancer, including fat, vitamins A, C, D, and E, and selenium, are reported.

Vitamin D and melanoma and non-melanoma skin cancer risk and prognosis: a comprehensive review and meta-analysis

Vitamin D is formed mainly in the skin upon exposure to sunlight and can as well be taken orally with food or through supplements. While sun exposure is a known risk factor for skin cancer development, vitamin D exerts anti-proliferative and pro-apoptotic effects on melanocytes and keratinocytes in vitro. To clarify the role of vitamin D in skin carcinogenesis, we performed a review of the literature and meta-analysis to evaluate the association of vitamin D serum levels and dietary intake with cutaneous melanoma (CM) and non-melanoma skin cancer (NMSC) risk and melanoma prognostic factors. Twenty papers were included for an overall 1420 CM and 2317 NMSC. The summary relative risks (SRRs) from random effects models for the association of highest versus lowest vitamin D serum levels was 1.46 (95% confidence interval (CI) 0.60-3.53) and 1.64 (95% CI 1.02-2.65) for CM and NMSC, respectively. The SRR for the highest versus lowest quintile of vitamin D intake was 0.86 (95% CI 0.63-1.13) for CM and 1.03 (95% CI 0.95-1.13) for NMSC. Data were suggestive of an inverse association between vitamin D blood levels and CM thickness at diagnosis. Further research is needed to investigate the effect of vitamin D on skin cancer risk in populations with different exposure to sunlight and dietary habits, and to evaluate whether vitamin D supplementation is effective in improving CM survival.

Tumor suppression in skin and other tissues via cross-talk between vitamin D- and p53-signaling

P53 and its family members have been implicated in the direct regulation of the vitamin D receptor (VDR). Vitamin D- and p53-signaling pathways have a significant impact on spontaneous or carcinogen-induced malignant transformation of cells, with VDR and p53 representing important tumor suppressors. VDR and the p53/p63/p73 proteins all function typically as receptors or sensors that turn into transcriptional regulators upon stimulus, with the main difference being that the nuclear VDR is activated as a transcription factor after binding its naturally occurring ligand 1,25-dihydroxyvitamin D with high affinity while the p53 family of transcription factors, mostly in the nucleoplasm, responds to a large number of alterations in cell homeostasis commonly referred to as stress. An increasing body of evidence now convincingly demonstrates a cross-talk between vitamin D- and p53-signaling that occurs at different levels, has genome-wide implications and that should be of high importance for many malignancies, including non-melanoma skin cancer. One interaction involves the ability of p53 to increase skin pigmentation via POMC derivatives including alpha-MSH and ACTH. Pigmentation protects the skin against UV-induced DNA damage and skin carcinogenesis, yet on the other hand reduces cutaneous synthesis of vitamin D. A second level of interaction may be through the ability of 1,25-dihydroxyvitamin D to increase the survival of skin cells after UV irradiation. UV irradiation-surviving cells show significant reductions in thymine dimers in the presence of 1,25-dihydroxyvitamin D that are associated with increased nuclear p53 protein expression, and significantly reduced NO products. A third level of interaction is documented by the ability of vitamin D compounds to regulate the expression of the murine double minute 2 (MDM2) gene in dependence of the presence of wild-type p53. MDM2 has a well-established role as a key negative regulator of p53 activity. Finally, p53 and family members have been implicated in the direct regulation of VDR. This overview summarizes some of the implications of the cross-talk between vitamin D- and p53-signaling for carcinogenesis in the skin and other tissues.

The role of vitamin D in reducing cancer risk and progression

Vitamin D is not really a vitamin but the precursor to the potent steroid hormone calcitriol, which has widespread actions throughout the body. Calcitriol regulates numerous cellular pathways that could have a role in determining cancer risk and prognosis. Although epidemiological and early clinical trials are inconsistent, and randomized control trials in humans do not yet exist to conclusively support a beneficial role for vitamin D, accumulating results from preclinical and some clinical studies strongly suggest that vitamin D deficiency increases the risk of developing cancer and that avoiding deficiency and adding vitamin D supplements might be an economical and safe way to reduce cancer incidence and improve cancer prognosis and outcome.

The relevance of the vitamin D endocrine system (VDES) for tumorigenesis, prevention, and treatment of non-melanoma skin cancer (NMSC): Present concepts and future perspectives

Solar UV (UV)-B-radiation exerts both beneficial and adverse effects on human health. On the one hand, it is the most important environmental risk factor for the development of non-melanoma skin cancer [NMSC; most importantly basal (BCC) and squamous (SCC) cell carcinomas], that represent the most common malignancies in Caucasian populations. On the other hand, the human body's requirements of vitamin D are mainly achieved by UV-B-induced cutaneous photosynthesis. This dilemma represents a serious problem in many populations, for an association of vitamin D-deficiency and multiple independent diseases including various types of cancer has been convincingly demonstrated. In line with these findings, epidemiologic and laboratory investigations now indicate that vitamin D and its metabolites have a risk reducing effect for NMSC. Potential mechanisms of action include inhibition of the hedgehog signaling pathway (BCC) and modulation of p53-mediated DNA damage response (SCC). As a consequence of these new findings it can be concluded that UV-B-radiation exerts both beneficial and adverse effects on risk and prognosis of NMSC. It can be assumed that many independent factors, including frequency and dose of UV-B exposure, skin area exposed, and individual factors (such as skin type and genetic determinants of the skin`s vitamin D status and of signaling pathways that are involved in the tumorigenesis of NMSC) determine whether UV-B exposure promotes or inhibits tumorigenesis of NMSC. Moreover, these findings may help to explain many of the differential effects of UV-B radiation on risk of NMSC, including variation in the dose-dependent risk for development of SCC in situ (actinic keratosis, AK), invasive SCC, and BCC. In this review, we analyze the relevance of the vitamin D endocrine system (VDES) for tumorigenesis, prevention, and treatment of NMSC and give an overview of present concepts and future perspectives.