Dietary fat intake and risk of skin cancer: a prospective study in Australian adults

Exposome and Skin. Part 2. The Influential Role of the Exposome, Beyond UVR, in Actinic Keratosis, Bowen's Disease and Squamous Cell Carcinoma: A Proposal

Actinic keratosis (AK) is the main risk factor for the development of cutaneous invasive squamous cell carcinoma (SCC). It represents the first sign of severe chronic ultraviolet radiation exposure, which has a clear significant effect. Nevertheless, the skin is exposed to many other exposome factors which should be thoroughly considered. Our aim was to assess the impact of exposome factors other than ultraviolet radiation (UVR) on the etiopathology of AK and Bowen's disease (BD) and progression of AK to SCC and to design tailored prevention strategies. We performed an exhaustive literature search in September 2021 through PubMed on the impact of exposome factors other than UVR on AK, BD and SCC. We conducted several parallel searches combining terms of the following topics: AK, BD, SCC and microbiome, hormones, nutrition, alcohol, tobacco, viral infections, chemical contaminants and air pollution. Notably, skin microbiome studies have shown how Staphylococcus aureus infections are associated with AK and AK-to-SCC progression by the production of chronic inflammation. Nutritional studies have demonstrated how a caloric restriction in fat intake, oral nicotinamide and moderate consumption of wine significantly reduce the number of premalignant keratoses and SCC. Regarding lifestyle factors, both alcohol and smoking are associated with the development of SCC in a dose-dependent manner. Relevant environmental factors are viral infections and chemical contaminants. Human papillomavirus infections induce deregulation of cellular proliferation and are associated with AK, BD and SCC. In addition to outdoor jobs, occupations such as industrial processing and farming also increase the risk of developing keratoses and SCC. The exposome of AK will undoubtedly help the understanding of its etiopathology and possible progression to SCC and will serve as a basis to design tailored prevention strategies.

Dietary components and the risk of non-melanoma skin cancer: A systematic review of epidemiological studies

Non-melanoma skin cancer (NMSC) is the most common cancer among white-skinned people. The main environmental risk factor for all types of skin cancer is ultraviolet (UV) exposure to the sun. However, significant modifiable risk factors, such as diet, have been studied about NMSC risk. Several original studies have been conducted on the link between various dietary components and the risk of NMSC in the past decade, but have not been systematically reviewed. This review focuses on the potential impact of dietary components in the prevention of NMSC and evaluates the findings of epidemiologic evidence for dietary factors. We conducted a systematic search of three databases, including Scopus, ISI Web of Science, and PubMed, to identify relevant epidemiological studies published between 2000 and July 6, 2021. Finally, forty-three articles were included. Because of the inherent limitations of epidemiological studies, no definitive conclusions can be drawn; however, the links between folate, citrus, caffeine, and alcohol with BCC are notable; thus, high dietary folate intake, as well as citrus and alcohol consumption, are associated with an increased risk of basal cell carcinoma (BCC), whereas caffeine is associated with a lower risk. More research is required to reach a definitive conclusion.

Nutrition and nonmelanoma skin cancers

Nonmelanoma skin cancer (NMSC), the most widely diagnosed cancer in the United States, is rising in incidence despite public health and educational campaigns that highlight the importance of sun avoidance. It is,therefore, important to establish other modifiable risk factors that may be contributing to this increase. There is a growing body of evidence in the literature suggesting certain nutrients may have protective or harmful effects on NMSC. We review the current literature on nutrition and its effect on NMSC with a focus on dietary fat, vitamin A, nicotinamide, folate, vitamin C, vitamin D, vitamin E, polyphenols, and selenium.

The role of drugs and selected dietary factors in cutaneous squamous cell carcinogenesis

Cutaneous squamous cell carcinoma represents the second most common non-melanoma skin cancer and its incidence increases worldwide. This review provides an overview of selected exogenous risk factors for cutaneous squamous cell carcinoma, which include drugs (azathioprine, calcineurin inhibitors, hydrochlorothiazide, angiotensin-converting-enzyme inhibitors) and few dietary factors (fat meet, whole milk products, arsenic) to better understand squamous skin cancer etiopathogenesis. Ingredients such as leafy vegetables, nuts, fish, caffeine, niacin are preventive factors for cutaneous squamous cell cancer. The heart transplant recipients have an increased risk of squamous cell carcinoma development than kidney or liver transplant ones and switching photosensitizing azathioprine to mycophenolate mofetil can reduce the incidence of cutaneous squamous cell carcinoma. The great attention should be paid to early change of cardiac photosensitizing antihypertensive drugs to non-photosensitizing ones among patients with a history of prior skin cancers and among organ transplant recipients. Based on current knowledge that ultra-violet radiation is the main risk factor for squamous cell carcinoma development, promotion of the skin self-examination, photoprotection, tanning bed avoidance and early skin cancer diagnosis is important for this tumour prevention.

Inflammatory Dietary Patterns and Risk of Keratinocyte Cancers in Kidney Transplant Recipients: Prospective Cohort Study

BACKGROUND

Kidney transplant recipients (KTRs) are at increased risk of cutaneous squamous (SCC) and basal cell carcinomas (BCC) due to immunosuppression and sun exposure. Skin carcinogenesis involves inflammation, and foods that promote inflammation may promote carcinogenesis.

METHODS

We prospectively examined the association between pro-inflammatory diets and SCC and BCC incidence in KTRs in Queensland, Australia. We recruited KTRs at high risk of skin cancer (aged ≥18 years and previously affected; or aged ≥40; or immunosuppressed ≥10 years) between 2012 and 2014 and followed up until June 2016. A baseline dietary questionnaire was used to calculate modified-Empirical Dietary Inflammatory Pattern (EDIP) scores to indicate dietary inflammatory capacity; higher scores indicated pro-inflammatory diets. EDIP scores were ranked into 3 groups. Outcomes were histologically confirmed SCC and BCC. Adjusted relative risks (RRadj) and 95% CIs were estimated using negative binomial regression.

RESULTS

Among 260 KTRs, 100 (38%) and 93 (36%) developed at least 1 new SCC and BCC, with 426 SCC and 343 BCC diagnosed in the follow-up period. The highest modified-EDIP score group (vs. lowest) were at increased risk of SCC (RRadj 1.79, 95% CI 1.01-3.16) but not BCC. Pro-inflammatory diets may increase SCC but not BCC risk among KTRs.

CONCLUSIONS

Inflammatory diets may increase the risk of SCC in KTRs.

Dietary Fat Intake and the Risk of Skin Cancer: A Systematic Review and Meta-Analysis of Observational Studies

We conducted a meta-analysis to evaluate the association between fat intake and the risk of three major types of skin cancer including basal cell carcinoma (BCC), squamous cell carcinoma (SCC) and cutaneous malignant melanoma (CMM). A comprehensive search of PubMed and EMBASE was performed to identify all relevant observational studies published up to December 1, 2018. Specific odds ratio (OR) or relative risk (RR) estimates for the highest versus the lowest intake of dietary fat and 95% confidence intervals (CI) from the included studies were pooled using random effect model. Three prospective cohort studies (175,675 participants and 30,915 BCC cases, 4,106 SCC cases and 1,638 CMM cases) and nine case-control studies (328 BCC cases, 493 SCC cases, 1,547 CMM cases and 2,660 controls) were identified. The pooled results indicated that dietary consumption of total fat and saturated fat were not associated with three major types of skin cancer. High consumption of monounsaturated fat was significantly associated with a decreased risk of BCC (RR: 0.90, 95% CI: 0.85-0.96) and high level of polyunsaturated fat intake was potentially positively associated with SCC (RR: 1.19, 95% CI: 1.06-1.33). Our findings should be confirmed by further evidence from well-designed and large-scale prospective cohort studies.

Fat Intake and Risk of Skin Cancer in U.S. Adults

Background: Fat intake has been associated with certain cancers, including colorectal, breast, and prostate cancers. However, literature on dietary fat and skin cancer has been limited.Methods: We examined the association between fat intake and risk of skin cancer including cutaneous malignant melanoma, squamous cell carcinoma (SCC), and basal cell carcinoma (BCC) within two prospective studies: the Nurses' Health Study (NHS) and the Health Professionals Follow-up Study (HPFS). Dietary information on total, saturated, monounsaturated, polyunsaturated, omega-6, and omega-3 fat and cholesterol was repeatedly assessed generally every 4 years. Incident cases were identified by self-report. Diagnosis on melanoma and SCC was confirmed by pathologic records.Results: A total of 794 melanoma, 2,223 SCC, and 17,556 BCC in the NHS (1984-2012) and 736 melanoma, 1,756 SCC, and 13,092 BCC in the HPFS (1986-2012) were documented. Higher polyunsaturated fat intake was associated with risk of SCC [pooled HR for highest vs. lowest quintiles, 1.16; 95% confidence interval (CI), 1.05-1.28; P_trend=0.001] and BCC (pooled HR, 1.06; 95% CI, 1.01-1.11; P_trend=0.01). Higher omega-6 fat intake was associated with risks of SCC, BCC, and melanoma. Omega-3 fat intake was associated with risk of BCC, but not with SCC or melanoma. No other fats were associated with melanoma risk. The associations were similar in women and men and by other skin cancer risk factors.Conclusions: Polyunsaturated fat intake was modestly associated with skin cancer risk.Impact: Further studies are needed to confirm our findings and to identify relevant biological mechanisms. Cancer Epidemiol Biomarkers Prev; 27(7); 776-82. ©2018 AACR.

A BET Bromodomain Inhibitor Suppresses Adiposity-Associated Malignant Transformation

Almost half a million of all new cancers have been attributed to obesity and epidemiologic evidence implicates visceral adipose tissue (VAT) and high-fat diets (HFD) in increasing cancer risk. We demonstrated that VAT-derived fibroblast growth factor 2 (FGF2) from mice fed an HFD or obese individuals stimulates the malignant transformation of epithelial cells. Mechanism-based strategies to prevent this VAT-enhanced tumorigenesis have not been explored. Clinical studies have indicated that bromodomain inhibitors have considerable potential as therapeutic agents for cancer by inhibiting the activity of several oncogenes, including c-Myc; however, their chemopreventive activity is unknown. We show herein that mice with visceral adiposity have elevated nuclear c-Myc expression in their epidermis. We hypothesized that the bromodomain inhibitor I-BET-762 (I-BET) would have efficacy in the prevention of malignant transformation by VAT and FGF2. We tested this hypothesis using our novel models of VAT-stimulated transformation in vitro and FGF2- stimulated tumor formation in vivo We found that I-BET significantly attenuates VAT and FGF2-stimulated transformation and inhibits VAT-induced c-Myc protein expression in several skin and breast epithelial cell lines. Moreover, I-BET attenuated tumor growth significantly in FGF2-treated nude mice. Work is ongoing to determine the role of visceral adiposity in c-Myc activity in several tissues and determine the inhibitory effect of I-BET on VAT-promoted tumors in vivoCancer Prev Res; 11(3); 129-42. ©2017 AACRSee related editorial by Berger and Scacheri, p. 125.

Fibroblast growth factor receptor is a mechanistic link between visceral adiposity and cancer

Epidemiological evidence implicates excess adipose tissue in increasing cancer risk. Despite a steeply rising global prevalence of obesity, how adiposity contributes to transformation (stage a non-tumorigenic cell undergoes to become malignant) is unknown. To determine the factors in adipose tissue that stimulate transformation, we used a novel ex vivo system of visceral adipose tissue (VAT)-condition medium-stimulated epithelial cell growth in soft agar. To extend this system in vivo, we used a murine lipectomy model of ultraviolet light B-induced, VAT-promoted skin tumor formation. We found that VAT from mice and obese human donors stimulated growth in soft agar of non-tumorigenic epithelial cells. The difference in VAT activity was associated with fibroblast growth factor-2 (FGF2) levels. Moreover, human and mouse VAT failed to stimulate growth in soft of agar in cells deficient in FGFR-1 (FGF2 receptor). We also demonstrated that circulating levels of FGF2 were associated with non-melanoma tumor formation in vivo. These data implicate FGF2 as a major factor VAT releases to transform epithelial cells-a novel, potential pathway of VAT-enhanced tumorigenesis. Strategies designed to deplete VAT stores of FGF2 or inhibit FGFR-1 in abdominally obese individuals may be important cancer prevention strategies as well as adjuvant therapies for improving outcomes.

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.

Parametrial fat tissue from high fat diet-treated SKH-1 mice stimulates transformation of mouse epidermal JB6 cells

Our previous studies indicated that decreasing visceral adipose tissue by surgical removal of the parametrial fat pads inhibited UVB-induced carcinogenesis in SKH-1 mice fed a high fat diet (HFD), but not a low fat diet (LFD) indicating that the parametrial fat tissue from mice fed a HFD played a role in skin carcinogenesis.

OBJECTIVE

In the present study, we sought to investigate how a HFD may influence the intrinsic properties of the parametrial fat tissue to influence UVB-induced skin tumor formation.

METHODS AND RESULTS

Immunohistochemical staining, adipokine array, and flow cytometry showed that parametrial fat tissue from mice fed a HFD had a higher density of macrophage-fused dead adipocytes (crown-like structures), more adipokines, and stimulated the production of more reactive oxygen species compared with parametrial fat tissue from mice fed a LFD. These differences between parametrial fat tissue from mice fed a HFD and LFD were associated with their effect on the in vitro transformation of mouse epidermal JB6 cells. Our results indicated that fat tissue filtrate (an aqueous filtrate made from the parametrial fat pad) from mice fed a HFD enhanced the conversion of JB6 cells from an epithelial-like morphology to cells with a fibroblast-like morphology to a greater extent than fat tissue filtrate from mice fed a LFD. Studies indicated that the fibroblast-like cells had decreased levels of E-cadherin, increased levels of Twist as assayed by western blot. Fat tissue filtrate made from the parametrial fat tissue of mice fed a HFD had 160% more transforming activity than that from mice fed a LFD and formed malignant mesenchymal tumors in vivo.

CONCLUSION

These studies provide the first in vitro demonstration of a parametrial fat tissue-induced transformation of an epidermal cell.

Low-fat diet and skin cancer risk: the women's health initiative randomized controlled dietary modification trial

BACKGROUND

Large cohort studies have reported no relationship between dietary fat and nonmelanoma skin cancer (NMSC), although a low-fat diet intervention reduced NMSC risk in a small clinical trial. In animal studies, skin tumor development has been reduced by low-fat diet. We evaluated the effect of a low-fat dietary pattern on NMSC and melanoma in the Women's Health Initiative Dietary Modification trial.

METHODS

Postmenopausal women aged 50 to 79 years (n = 48,835) were randomly assigned to the low-fat dietary pattern intervention (n = 19,541) or comparison group (n = 29,294). The intervention goals included decreasing fat intake to 20% or less of calories, increasing vegetable and fruit intake, and increasing grain intake. Self-reported incident NMSC (n = 4,907) and physician-adjudicated incident melanoma (n = 279) were ascertained every 6 months.

RESULTS

Over 8.1 years of follow-up, the low-fat diet intervention did not affect overall incidence of NMSC [HR 0.98; 95% confidence interval (CI), 0.92-1.04] or melanoma (HR, 1.04; 95% CI, 0.82-1.32). In subgroup analyses of melanoma risk, baseline fat intake interacted significantly with group assignment (Pinteraction = 0.006). Among women with higher baseline fat intake, the dietary intervention significantly increased risk (HR, 1.48; 95% CI, 1.06-2.07), whereas, among women with lower baseline fat intake, the intervention tended to reduce melanoma risk (HR, 0.72; 95% CI, 0.50-1.02).

CONCLUSIONS

In this large randomized trial, a low-fat dietary pattern did not affect overall incidence of NMSC or melanoma.

IMPACT

A low-fat diet does not reduce incidence of NMSC, but an interaction between baseline fat intake and dietary intervention on melanoma risk warrants further investigation.

Surgical removal of the parametrial fat pads stimulates apoptosis and inhibits UVB-induced carcinogenesis in mice fed a high-fat diet

Removal of the parametrial fat pads (partial lipectomy) from female SKH-1 mice fed a high-fat diet inhibited UVB-induced carcinogenesis, but this was not observed in mice fed a low-fat chow diet. Partial lipectomy in high-fat-fed mice decreased the number of keratoacanthomas and squamous cell carcinomas per mouse by 76 and 79%, respectively, compared with sham-operated control mice irradiated with UVB for 33 wk. Immunohistochemical analysis indicated that partial lipectomy increased caspase 3 (active form) positive cells by 48% in precancerous epidermis away from tumors, by 68% in keratoacanthomas, and by 224% in squamous cell carcinomas compared with sham-operated control mice. In addition, partial lipectomy decreased cell proliferation away from tumors and in tumors. RT-PCR analysis for adipokines revealed that mRNAs for TIMP1, MCP1, and SerpinE1 (proinflammatory/antiapoptotic cytokines) in the parametrial fat pads of sham-operated control mice were 54- to 83-fold higher than levels in compensatory fat that returned after surgery in partially lipectomized mice at the end of the tumor study. Feeding mice high-fat diets for 2 wk increased levels of TIMP1 and other adipokines in serum and epidermis, and these increases were inhibited by removal of the parametrial fat pads. Our results are a unique demonstration that surgical removal of a specific tissue fat results in inhibition of carcinogenesis in obese mice. This inhibition was associated with an increase in apoptosis and a decrease in proliferation in tumors and in precancerous areas away from tumors.

Metabolic risk factors and skin cancer in the Metabolic Syndrome and Cancer Project (Me-Can)

BACKGROUND

Little is known about the associations of metabolic aberrations with malignant melanoma (MM) and nonmelanoma skin cancer (NMSC).

OBJECTIVES

To assess the associations between metabolic factors (both individually and combined) and the risk of skin cancer in the large prospective Metabolic Syndrome and Cancer Project (Me-Can).

METHODS

During a mean follow-up of 12 years of the Me-Can cohort, 1728 (41% women) incident MM, 230 (23% women) fatal MM and 1145 (33% women) NMSC were identified. Most NMSC cases (76%) were squamous cell carcinoma (SCC) (873, 33% women). Hazard ratios (HRs) were estimated by Cox proportional hazards regression for quintiles and standardized z-scores (with a mean of 0 and SD of 1) of body mass index (BMI), blood pressure, glucose, cholesterol, triglycerides and for a combined metabolic syndrome score. Risk estimates were corrected for random error in the measurements.

RESULTS

Blood pressure per unit increase of z-score was associated with an increased risk of incident MM cases in men and women [HR 1·17, 95% confidence interval (CI) 1·04-1·31 and HR 1·18, 95% CI 1·03-1·36, respectively] and fatal MM cases among women (HR 2·39, 95% CI 1·58-3·64). In men, all quintiles for BMI above the reference were associated with a higher risk of incident MM. In women, SCC NMSC risk increased across quintiles for glucose levels (P-trend 0·02) and there was a trend with triglyceride concentration (P-trend 0·09).

CONCLUSION

These findings suggest that mechanisms linked to blood pressure may be involved in the pathogenesis of MM. SCC NMSC in women could be related to glucose and lipid metabolism.

New agents for prevention of ultraviolet-induced nonmelanoma skin cancer

With the incidence of nonmelanoma skin cancer on the rise, current prevention methods, such as the use of sunscreens, have yet to prove adequate to reverse this trend. There has been considerable interest in identifying compounds that will inhibit or reverse the biochemical changes required for skin cancers to develop, either by pharmacologic intervention or by dietary manipulation. By targeting different pathways identified as important in the pathogenesis of nonmelanoma skin cancers, a combination approach with multiple agents or the addition of chemopreventative agents to topical sunscreens may offer the potential for novel and synergistic therapies in treating nonmelanoma skin cancer.

Nutrition and nonmelanoma skin cancers

The incidence of nonmelanoma skin cancer is increasing every year. Basal cell carcinoma and squamous cell carcinoma are the two major types of nonmelanoma skin cancer. Among other factors, understanding the potential role of nutrients in the development, progression, and treatment of nonmelanoma skin cancer is critical. This contribution provides a review of the nutrients that have been more extensively investigated in the literature with regard to nonmelanoma skin cancer, including dietary fats, retinol, carotenoids, vitamin C, vitamin D, vitamin E, selenium, copper, iron, zinc, green tea, and black tea.

[What's new in oncodermatology?]

Several epidemiologic studies using the Surveillance, Epidemiology and End results program, have shown that the incidence of melanoma and of cutaneous lymphomas has clearly increased in the United States. Two independent groups have reported genome-wide association studies identifying variants associated to an increased risk of melanoma. Tumor stem cells were found to have an increased frequency when compared to previously reported studies, and also a greater plasticity. The Merkel cell polyoma virus seems rather ubiquitous, since it has been evidenced, without clonal integration, in several other types of cutaneous tumors, and even in healthy skin, with an increased frequency in photo-exposed skin and in immunodepressed patients. A recent study demonstrates for the first time a link between the exposure to pesticides and the occurrence of lymphomas. Another study has evidenced the association between topical treatments with steroids and the occurrence of lymphomas, especially cutaneous lymphomas. The risk is increased with the length of treatment and the potency of steroids. Adjuvant treatment of high-risk melanomas with alpha interferon does not achieve better results with the adjunction of a 4 weeks high-dose induction period, and development of autoantibodies is not significantly associated to an increased relapse free survival after correction of the time related biais. In contrast, the effect of interferon on relapse free survival, distant metastasis free survival and overall survival seems better in the subgroup of melanoma with primary ulceration. The development of new specific inhibitors of c-kit or BRAF is a great hope for the targeted treatment of peculiar groups of advanced melanomas. The main objectives of the new 2009-2013 Cancer Plan is to optimize the structuration of health organization in the field of oncology.