Ozone Layer Depletion and Emerging Public Health Concerns - An Update on Epidemiological Perspective of the Ambivalent Effects of Ultraviolet Radiation Exposure

Longitudinal analysis of hospital morbidity and mortality due to skin cancer from 2012 to 2022: comparison with demographic and geographic factors in Brazilian states

BACKGROUND

Skin cancer is the most common neoplasm among Brazilians, accounting for 31.3% of all cancer cases in the country.

OBJECTIVES

To analyze the longitudinal morbimortality of skin cancer and compare it with the latitude and the prevalence of white skin color in each federative unit of the country.

METHODS

An ecological observational study was carried out using data from the Hospital Information System (SIH) and the Mortality Information System (SIM).

RESULTS

In Brazil, morbidity rates (per 100,000 inhabitants) increased from 14.88 to 27.69 (p < 0.05) when comparing the years 2012 and 2022, whereas the mortality rates (per 100,000 inhabitants) increased from 0.35 to 0.54 (p < 0.05) during the same period. Furthermore, most states showed an increase in morbimortality rates. Concerning race/ethnicity, individuals with white skin had the highest morbimortality rates. Regarding the age groups, individuals over 50 years old had the highest morbidity rates, while patients over 80 years old had the highest mortality rates, at 23.29%. Finally, the latitude showed a negative correlation, meaning that lower latitudes presented higher rates of morbidity and mortality from skin cancer.

STUDY LIMITATIONS

Self-reporting of skin color by participants, which may not fully correspond to phototypes. Data was analyzed exclusively from hospitalizations through the Unified Health System (SUS) and severe cases of the disease, as this study focused on hospitalizations and mortality, considering that the main treatment for skin cancer is carried out on an outpatient basis.

CONCLUSIONS

The majority of Brazilian states showed rising morbimortality rates during the period, with the white-skinned population being the most affected. Additionally, a negative correlation with latitude was observed.

Atractylodin mitigates UVB radiation-induced oxidative stress and photoaging responses by enhancing NrF2 signaling in human epidermal keratinocytes

This study explores the protective role of Atractylodin (ATN) on ultraviolet-B (UVB) radiation-exposed oxidative damage and photoaging responses in human epidermal keratinocytes (HaCaT). In vitro, experiments involved subjecting HaCaT cells to UVB radiation (50 mJ/cm2) for a 24 h incubation period, leading to cell death, increased reactive oxygen species (ROS), and DNA damaged lesion (8-Oxo Gunosine). ATN treatment effectively mitigated cell toxicity, ROS generation, and 8-Oxo Gunosine in UVB-exposed HaCaT cells. Furthermore, ATN demonstrated its ability to counteract UVB radiation-exposed oxidative stress by inhibiting the activation of phosphorylated-extracellular signal-regulated kinase-1 (Erk-1), phosphorylated-c-Jun N-terminal kinase (p-Jnk), and phosphorylated p38 Mitogen-Activated Protein Kinase (p-p38) in HaCaT cells. Nuclear factor erythroid 2-related factor 2 (NrF2), recognized for its antioxidant properties, emerged as a key player in protecting against oxidative damage. ATN was observed to inhibit the depletion of NrF2 expression, thereby preventing the depletion of superoxide dismutase (SOD), and glutathione (GSH) in UVB-exposed HaCaT cells. Additionally, ATN inhibited activator protein-1 (AP-1) and matrix metalloproteinases such as MMP-1 and MMP-9 in UVB-exposed HaCaT cells. In conclusion, our findings highlight that ATN effectively prevents UVB-exposed skin oxidative damage and photoaging by modulating NrF2 expression.

Oxidative State in Cutaneous Melanoma Progression: A Question of Balance

Reactive oxygen species (ROS) are highly bioactive molecules involved not only in tissue physiology but also in the development of different human conditions, including premature aging, cardiovascular pathologies, neurological and neurodegenerative disorders, inflammatory diseases, and cancer. Among the different human tumors, cutaneous melanoma, the most aggressive and lethal form of skin cancer, is undoubtedly one of the most well-known "ROS-driven tumor", of which one of the main causes is represented by ultraviolet (UV) rays' exposure. Although the role of excessive ROS production in melanoma development in pro-tumorigenic cell fate is now well established, little is known about its contribution to the progression of the melanoma metastatic process. Increasing evidence suggests a dual role of ROS in melanoma progression: excessive ROS production may enhance cellular growth and promote therapeutic resistance, but at the same time, it can also have cytotoxic effects on cancer cells, inducing their apoptosis. In this context, the aim of the present work was to focus on the relationship between cell redox state and the signaling pathways directly involved in the metastatic processes. In addition, oxidative or antioxidant therapeutic strategies for metastatic melanoma were also reviewed and discussed.

Patients poorly recognize lesions of concern that are malignant melanomas: is self-screening the correct advice?

Background

Australia is known for its outdoor culture, with a large percentage of its population engaging in outdoor recreational activities, aquatic, non-aquatic and outdoor occupational activities. However, these outdoor enthusiasts face increased exposure to ultraviolet radiation (UVR), leading to a higher risk of skin cancer, including malignant melanoma (MM). Over the past 40 years, there has been a significant rise in skin cancer rates in Australia, with two out of three Australians expected to develop some form of skin cancer by age 70. Currently, skin cancer examinations are not endorsed in asymptomatic or low-risk individuals in Australia, with only high-risk individuals recommended to undergo regular skin examinations. Notably, the Melanoma Institute Australia suggests that one-half of patients identify MMs themselves, although this claim appears to be based on limited Australian data which may not reflect contemporary practice. Therefore this study sought to determine the percentage of patients who were able to self-identify MMs as lesions of concern when presenting for a skin cancer examination.

Methods

Multi-site, cross-sectional study design incorporating a descriptive survey and total body skin cancer screening, including artificial intelligence by a skin cancer doctor.

Results

A total of 260 participants with suspect MM lesions were biopsied, with 83 (31.9%) found to be melanomas. Of the true positive MMs only a small percentage of participants (21.7% specificity) correctly had concerns about the suspect lesion being a MM. These MMs were located primarily on the back (44.4%), shoulder (11.1%) and upper leg (11.1%). There was no significant difference in the size between those participants aware of a MM versus those who were not (P = 0.824, 24.6 vs 23.4 mm2). Significantly more males identified lesions of concern that were MMs as compared to females (P = 0.008, 61.1% vs 38.9%, respectively). With regard to true negatives males and females were similar (52.1% vs 47.9%, respectively). With regard to false negatives (n = 65), a greater percentage of males than females did not recognize the MM as a lesion of concern (66.2% vs 33.8%, respectively). Participants were more likely to correctly identify an invasive MM as opposed to an in situ MM (27.3% versus 21.3%).

Conclusions

Only a small percentage of participants in this study were able to self-identify either in situ or invasive MM as a lesion of concern with a tendency to identify the more advanced, thicker MMs. Given that MM is associated with a high mortality and cost of treatment, particularly when invasive, the inability of lay persons to identify these cancerous lesions will likely lead to delayed treatment and a possible adverse outcome. We believe the current melanoma screening practices in Australian general practice should be revisited to improve patient outcomes with regard to MM. Additionally, prevention campaigns should include images and primary risk factors for MM.

Grouping strategies for assessing and managing persistent and mobile substances

Background

Persistent, mobile and toxic (PMT), or very persistent and very mobile (vPvM) substances are a wide class of chemicals that are recalcitrant to degradation, easily transported, and potentially harmful to humans and the environment. Due to their persistence and mobility, these substances are often widespread in the environment once emitted, particularly in water resources, causing increased challenges during water treatment processes. Some PMT/vPvM substances such as GenX and perfluorobutane sulfonic acid have been identified as substances of very high concern (SVHCs) under the European Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH) regulation. With hundreds to thousands of potential PMT/vPvM substances yet to be assessed and managed, effective and efficient approaches that avoid a case-by-case assessment and prevent regrettable substitution are necessary to achieve the European Union's zero-pollution goal for a non-toxic environment by 2050.

Main

Substance grouping has helped global regulation of some highly hazardous chemicals, e.g., through the Montreal Protocol and the Stockholm Convention. This article explores the potential of grouping strategies for identifying, assessing and managing PMT/vPvM substances. The aim is to facilitate early identification of lesser-known or new substances that potentially meet PMT/vPvM criteria, prompt additional testing, avoid regrettable use or substitution, and integrate into existing risk management strategies. Thus, this article provides an overview of PMT/vPvM substances and reviews the definition of PMT/vPvM criteria and various lists of PMT/vPvM substances available. It covers the current definition of groups, compares the use of substance grouping for hazard assessment and regulation, and discusses the advantages and disadvantages of grouping substances for regulation. The article then explores strategies for grouping PMT/vPvM substances, including read-across, structural similarity and commonly retained moieties, as well as the potential application of these strategies using cheminformatics to predict P, M and T properties for selected examples.

Conclusions

Effective substance grouping can accelerate the assessment and management of PMT/vPvM substances, especially for substances that lack information. Advances to read-across methods and cheminformatics tools are needed to support efficient and effective chemical management, preventing broad entry of hazardous chemicals into the global market and favouring safer and more sustainable alternatives.

The impact of sunlight exposure on brain structural markers in the UK Biobank

Sunlight is closely intertwined with daily life. It remains unclear whether there are associations between sunlight exposure and brain structural markers. General linear regression analysis was used to compare the differences in brain structural markers among different sunlight exposure time groups. Stratification analyses were performed based on sex, age, and diseases (hypertension, stroke, diabetes). Restricted cubic spline was performed to examine the dose-response relationship between natural sunlight exposure and brain structural markers, with further stratification by season. A negative association of sunlight exposure time with brain structural markers was found in the upper tertile compared to the lower tertile. Prolonged natural sunlight exposure was associated with the volumes of total brain (β: - 0.051, P < 0.001), white matter (β: - 0.031, P = 0.023), gray matter (β: - 0.067, P < 0.001), and white matter hyperintensities (β: 0.059, P < 0.001). These associations were more pronounced in males and individuals under the age of 60. The results of the restricted cubic spline analysis showed a nonlinear relationship between sunlight exposure and brain structural markers, with the direction changing around 2 h of sunlight exposure. This study demonstrates that prolonged exposure to natural sunlight is associated with brain structural markers change.

Epidemiological and clinical analysis of exposure-related factors in non-melanoma skin cancer: A retrospective cohort study

BACKGROUND

The incidence of non-melanoma skin cancers (NMSCs) increased over last decades, probably due to environmental concerns or to the increase of frail patients with age related comorbidities. Currently, the relationship of increasing global skin cancer rates with increased ultraviolet radiations (UVRs) resulting from stratospheric ozone depletion, global warming, and air pollution from fossil-fuel combustion.

AIMS

We conducted a retrospective epidemiological study including 546 NMSC patients managed at the Dermatology Unit of the Tor Vergata Hospital to highlight different trends of sun exposure or different comorbidities.

METHODS

Descriptive and inferential statistical analyses were performed to evidence differences between continous variable and Spearman rank test for dicotomical variables. Charlson Comorbidity Index was calculated to obtain the 10-years survival rate in order to identify the mean comorbidity burden of our patients.

RESULTS

Considering patients with comorbidities (73.81%), actinic keratoses (AKs) was the most frequent lesion. In patients with a history of previous melanoma, basal cell carcinoma (BCC) was predominant (ANOVA test, p < 0.05) with a statistically significant correlation (rho = 0.453; p < 0.01). Squamous cell carcinoma (SCC) showed a higher rate in arterial hypertension patients, followed by the chronic heart failure and hematologic neoplasms (60%, 29.7% and 32.1%, respectively) groups. Men were more affected than women, representing 61.54% of patients. Chronic sun exposure is directly correlated with SCC rho = 0.561; p < 0.01), whereas BCC correlated with a history of sunburns (rho = 0.312; p < 0.05).

CONCLUSIONS

History of photo-exposition had an important role on NMSC development especially for work or recreational reasons. Sex, age, and presence of comorbidities influenced different NMSC types. BCC was more frequent in younger patients, associated with melanoma and sunburns. The presence of SCC is associated with older patients and the hypertension group. AKs were diagnosed predominantly in oldest men, with a chronic sun-exposure history, and hematologic neoplasms group.

Natural resistance to cancer: A window of hope

As healthcare systems are improving and thereby the life expectancy of human populations is increasing, cancer is representing itself as the second leading cause of death. Although cancer biologists have put enormous effort on cancer research so far, we still have a long way to go before being able to treat cancers efficiently. One interesting approach in cancer biology is to learn from natural resistance and/or predisposition to cancer. Cancer-resistant species and tissues are thought-provoking models whose study shed light on the inherent cancer resistance mechanisms that arose during the course of evolution. On the other hand, there are some syndromes and factors that increase the risk of cancer development, and revealing their underlying mechanisms will increase our knowledge about the process of cancer formation. Here, we review natural resistance and predisposition to cancer and the known mechanisms at play. Further insights from these natural phenomena will help design future cancer research and could ultimately lead to the development of novel cancer therapeutic strategies.

Incidence and survival rates of primary cutaneous malignancies in Korea, 1999-2019: A nationwide population-based study

Primary cutaneous malignancies are among the most commonly diagnosed types of cancer worldwide. We aimed to examine the incidence and 5-year survival rates of all types of primary cutaneous malignancies in the Korean population. Data from the Korean Nationwide Cancer Registry from 1999 to 2019 were analyzed. The crude incidence rates, age-standardized incidence rates, and 5-year relative survival rates of each type of skin cancer were calculated. A total of 89 965 patients were diagnosed with primary cutaneous malignancies, which was a 7-fold increase from 1999 to 2019. The age-standardized incidence rates increased 3.4-fold in basal cell carcinoma (3.7/100 000 person-years), 2.0-fold in squamous cell carcinoma (1.6/100 000 person-years), 12.0-fold in Bowen disease (1.2/100 000 person-years), and 1.8-fold in malignant melanoma (0.7/10 000 person-years) in 2019. Average annual percentage changes in age-standardized incidence rates were statistically significant in basal cell carcinoma (15.8%), Bowen disease (5.8%), squamous cell carcinoma (5.1%), malignant melanoma (1.2%), melanoma in situ (1.1%), dermatofibrosarcoma protuberans (1.2%), mycosis fungoides (0.5%), primary cutaneous CD30+ T-cell proliferations (0.5%), adnexal and skin appendage carcinoma (0.4%), extramammary Paget's disease (0.2%), and Merkel cell carcinoma (0.2%). The 5-year relative survival rates were the highest in basal cell carcinoma (103.3%), followed by dermatofibrosarcoma protuberans (99.7%) and mycosis fungoides (96.6%), and lowest in angiosarcoma (24.7%). The 5-year relative survival rates steadily increased in extramammary Paget's disease (23.6%), cutaneous B-cell lymphoma (21.3%), mycosis fungoides (20.2%), extranodal NK/T-cell lymphoma, nasal type (18.1%), and malignant melanoma (16.1%) from 1996-2000 to 2015-2019. Most primary cutaneous malignancies have increased in incidence and survival rates in the Korean population, but to varying extents depending on the type of skin cancer.

Relationship between climate change and skin cancer and implications for prevention and management: a scoping review

OBJECTIVES

This study aimed to explore the published research on the relationship between climate change and skin cancer and the implications for prevention, management and further research.

STUDY DESIGN

Scoping review.

METHODS

This scoping review following JBI methodology reviewed English articles identified in searches of MEDLINE, Embase, CINAHL, Web of Science and Scopus on 14 April 2023. The screening of articles was completed by two independent reviewers. Data were extracted by a single reviewer and checked by another. A causal pathway diagram was iteratively developed throughout the review and was used to categorise the findings.

RESULTS

The search identified 1376 papers, of which 45 were included in the final review. Nine papers reported primary research, and 36 papers were reviews, perspectives, commentaries, editorials, or essays. The papers examined climate change influencing behaviours related to ultraviolet exposure (30 papers), ambient temperature (21 papers) and air pollution (five papers) as possible risk factors; occupational, rural, and contextual factors affecting skin cancer (11 papers); and prevention and access to health care in the context of climate change (seven papers). Most papers were published in journals in subject areas other than health.

CONCLUSIONS

This review identified ultraviolet radiation, occupation, rising temperature, individual behaviour and air pollution as possible influences on skin cancer rates. Furthermore, it highlights the complexity and uncertainties in the relationship between climate change and skin cancer and the need for further research on this relationship, including primary epidemiological research and reviews that follow recognised review guidelines and include assessment of health services and social determinants in the causal pathways of this relationship.

A Review of Recent Advances in Computer-Aided Detection Methods Using Hyperspectral Imaging Engineering to Detect Skin Cancer

Skin cancer, a malignant neoplasm originating from skin cell types including keratinocytes, melanocytes, and sweat glands, comprises three primary forms: basal cell carcinoma (BCC), squamous cell carcinoma (SCC), and malignant melanoma (MM). BCC and SCC, while constituting the most prevalent categories of skin cancer, are generally considered less aggressive compared to MM. Notably, MM possesses a greater capacity for invasiveness, enabling infiltration into adjacent tissues and dissemination via both the circulatory and lymphatic systems. Risk factors associated with skin cancer encompass ultraviolet (UV) radiation exposure, fair skin complexion, a history of sunburn incidents, genetic predisposition, immunosuppressive conditions, and exposure to environmental carcinogens. Early detection of skin cancer is of paramount importance to optimize treatment outcomes and preclude the progression of disease, either locally or to distant sites. In pursuit of this objective, numerous computer-aided diagnosis (CAD) systems have been developed. Hyperspectral imaging (HSI), distinguished by its capacity to capture information spanning the electromagnetic spectrum, surpasses conventional RGB imaging, which relies solely on three color channels. Consequently, this study offers a comprehensive exploration of recent CAD investigations pertaining to skin cancer detection and diagnosis utilizing HSI, emphasizing diagnostic performance parameters such as sensitivity and specificity.

Isolation and Structure Elucidation of Novel Mycosporine-like Amino Acids from the Two Intertidal Red Macroalgae Bostrychia scorpioides and Catenella caespitosa

This study presents a phytochemical survey of two common intertidal red algal species, Bostrychia scorpioides and Catenella caespitosa, regarding their MAA (mycosporine-like amino acid) composition, which are known as biogenic sunscreen compounds. Six novel MAAs from Bostrychia scorpioides named bostrychines and two novel MAAs from Catenella caespitosa named catenellines were isolated using a protocol which included silica gel column chromatography, flash chromatography on reversed phase material and semipreparative HPLC (High-Performance Liquid Chromatography). The structure of the novel MAAs was elucidated using NMR (Nuclear Magnetic Resonance) and HR-MS (High-Resolution Mass Spectrometry), and their absolute configuration was confirmed by ECD (Electronic Circular Dichroism). All isolated MAAs possess a cyclohexenimine scaffold, and the metabolites from B. scorpioides are related to the known MAAs bostrychines A-F, which contain glutamine, glutamic acid and/or threonine in their side chains. The new MAAs from C. caespitosa contain taurine, an amino sulfonic acid that is also present in another MAA isolated from this species, namely, catenelline. Previous and new data confirm that intertidal red algae are chemically rich in MAAs, which explains their high tolerance against biologically harmful ultraviolet radiation.

Protective effect of Salvia plebeia R. Br ethanol extract on UVB-induced skin photoaging in vitro and in vivo

BACKGROUND

UV exposure is one of the primary factors responsible for photoaging, causing the increase in matrix metalloproteinases (MMPs) and the reduction in collagen. Salvia plebeia R. Br (SP), as an herbaceous plant, contains abundant flavonoids and possesses excellent anti-inflammatory and antioxidant activities. This study aimed to investigate the photoprotective effects of SP on UVB-induced photodamage in immortalized human keratinocytes (HaCaTs) and Kunming mice, as well as its main active components such as homoplantaginin (HP).

METHODS

CCK-8 was applied to detect the cell viability in UVB-irradiated or non-irradiated HaCaTs. Commercial kits were used to evaluate the levels of ROS, MDA, SA-β-Gal, MMP-1, and IL-6. The expression of MAPK and TGF-β/Smad pathways was detected by western blot. HE and Masson's trichrome staining were performed to examine the epidermis thickness and collagen degradation of Kunming mice.

RESULTS

Our results found that SP and HP notably decreased UVB-induced ROS, MDA, and SA-β-Gal production, and inhibited MMP-1 and IL-6 secretion by inhibiting the MAPK signaling pathway. In addition, SP and HP significantly promoted type I procollagen synthesis by activation of TGF-β/Smad pathway. Consistently, the in vivo experiments also indicated that SP and HP had a photoprotective effect, which significantly reversed UVB-induced epidermis thickness and collagen degradation.

CONCLUSION

This study demonstrated that SP effectively could protect skin from UVB-induced photoaging, while HP acted as the active substance in SP. All these findings provided a new strategy for skin photoaging treatment.

Implementation of artificial intelligence for the detection of cutaneous melanoma within a primary care setting: prevalence and types of skin cancer in outdoor enthusiasts

Background

There is enthusiasm for implementing artificial intelligence (AI) to assist clinicians detect skin cancer. Performance metrics of AI from dermoscopic images have been promising, with studies documenting sensitivity and specificity values equal to or superior to specialists for the detection of malignant melanomas (MM). Early detection rates would particularly benefit Australia, which has the worlds highest incidence of MM per capita. The detection of skin cancer may be delayed due to late screening or the inherent difficulty in diagnosing early skin cancers which often have a paucity of clinical features and may blend into sun damaged skin. Individuals who participate in outdoor sports and recreation experience high levels of intermittent ultraviolet radiation (UVR), which is associated with the development of skin cancer, including MM. This research aimed to assess the prevalence of skin cancer in individuals who regularly participate in activities outdoors and to report the performance parameters of a commercially available AI-powered software to assess the predictive risk of MM development.

Methods

Cross-sectional study design incorporating a survey, total body skin cancer screening and AI-embedded software capable of predictive scoring of queried MM.

Results

A total of 423 participants consisting of surfers (n = 108), swimmers (n = 60) and walkers/runners (n = 255) participated. Point prevalence for MM was highest for surfers (6.48%), followed by walkers/runners (4.3%) and swimmers (3.33%) respectively. When compared to the general Australian population, surfers had the highest odds ratio (OR) for MM (OR 119.8), followed by walkers/runners (OR 79.74), and swimmers (OR 61.61) rounded out the populations. Surfers and swimmers reported comparatively lower lifetime hours of sun exposure (5,594 and 5,686, respectively) but more significant amounts of activity within peak ultraviolet index compared with walkers/runners (9,554 h). A total of 48 suspicious pigmented lesions made up of histopathology-confirmed MM (n = 15) and benign lesions (n = 33) were identified. The performance of the AI from this clinical population was found to have a sensitivity of 53.33%, specificity of 54.44% and accuracy of 54.17%.

Conclusions

Rates of both keratinocyte carcinomas and MM were notably higher in aquatic and land-based enthusiasts compared to the general Australian population. These findings further highlight the clinical importance of sun-safe protection measures and regular skin screening in individuals who spend significant time outdoors. The use of AI in the early identification of MM is promising. However, the lower-than-expected performance metrics of the AI software used in this study indicated reservations should be held before recommending this particular version of this AI software as a reliable adjunct for clinicians in skin imaging diagnostics in patients with potentially sun damaged skin.

Environmental Air Pollutants Affecting Skin Functions with Systemic Implications

The increase in air pollution worldwide represents an environmental risk factor that has global implications for the health of humans worldwide. The skin of billions of people is exposed to a mixture of harmful air pollutants, which can affect its physiology and are responsible for cutaneous damage. Some polycyclic aromatic hydrocarbons are photoreactive and could be activated by ultraviolet radiation (UVR). Therefore, such UVR exposure would enhance their deleterious effects on the skin. Air pollution also affects vitamin D synthesis by reducing UVB radiation, which is essential for the production of vitamin D3, tachysterol, and lumisterol derivatives. Ambient air pollutants, photopollution, blue-light pollution, and cigarette smoke compromise cutaneous structural integrity, can interact with human skin microbiota, and trigger or exacerbate a range of skin diseases through various mechanisms. Generally, air pollution elicits an oxidative stress response on the skin that can activate the inflammatory responses. The aryl hydrocarbon receptor (AhR) can act as a sensor for small molecules such as air pollutants and plays a crucial role in responses to (photo)pollution. On the other hand, targeting AhR/Nrf2 is emerging as a novel treatment option for air pollutants that induce or exacerbate inflammatory skin diseases. Therefore, AhR with downstream regulatory pathways would represent a crucial signaling system regulating the skin phenotype in a Yin and Yang fashion defined by the chemical nature of the activating factor and the cellular and tissue context.

Immunotherapy for the Treatment of Squamous Cell Carcinoma: Potential Benefits and Challenges

Melanoma and nonmelanoma skin cancers (NMSCs) are recognized as among the most common neoplasms, mostly in white people, with an increasing incidence rate. Among the NMSCs, squamous cell carcinoma (SCC) is the most prevalent malignancy known to affect people with a fair complexion who are exposed to extreme ultraviolet radiation (UVR), have a hereditary predisposition, or are immunosuppressed. There are several extrinsic and intrinsic determinants that contribute to the pathophysiology of the SCC. The therapeutic modalities depend on the SCC stages, from actinic keratosis to late-stage multiple metastases. Standard treatments include surgical excision, radiotherapy, and chemotherapy. As SCC represents a favorable tumor microenvironment with high tumor mutational burden, infiltration of immune cells, and expression of immune checkpoints, the SCC tumors are highly responsive to immunotherapies. Until now, there are three checkpoint inhibitors, cemiplimab, pembrolizumab, and nivolumab, that are approved for the treatment of advanced, recurrent, or metastatic SCC patients in the United States. Immunotherapy possesses significant therapeutic benefits for patients with metastatic or locally advanced tumors not eligible for surgery or radiotherapy to avoid the potential toxicity caused by the chemotherapies. Despite the high tolerability and efficiency, the existence of some challenges has been revealed such as, resistance to immunotherapy, less availability of the biomarkers, and difficulty in appropriate patient selection. This review aims to accumulate evidence regarding the genetic alterations related to SCC, the factors that contribute to the potential benefits of immunotherapy, and the challenges to follow this treatment regime.

Oxidative-Stress-Sensitive microRNAs in UV-Promoted Development of Melanoma

Melanoma is the most aggressive and life-threatening form of skin cancer. Key molecular events underlying the melanocytic transformation into malignant melanoma mainly involve gene mutations in which exposure to ultraviolet (UV) radiation plays a prominent role. However, several aspects of UV-induced melanomagenesis remain to be explored. Interestingly, redox-mediated signaling and perturbed microRNA (miRNA) profiles appear to be interconnected contributing factors able to act synergistically in melanoma initiation and progression. Since UV radiation can promote both redox imbalance and miRNA dysregulation, a harmful crosstalk between these two key cellular networks, with UV as central hub among them, is likely to occur in skin tissue. Therefore, decoding the complex circuits that orchestrate the interaction of UV exposure, oxidative stress, and dysregulated miRNA profiling can provide a deep understanding of the molecular basis of the melanomagenesis process. Furthermore, these mechanistic insights into the reciprocal regulation between these systems could have relevant implications for future therapeutic approaches aimed at counteracting UV-induced redox and miRNome imbalances for the prevention and treatment of malignant melanoma. In this review, we illustrate current information on the intricate connection between UV-induced dysregulation of redox-sensitive miRNAs and well-known signaling pathways involved in the malignant transformation of normal melanocytes to malignant melanoma.