Climate change and skin cancer

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.

Weather-Related Human Outdoor Behavior with Respect to Solar Ultraviolet Radiation Exposure in a Changing Climate

Climate-related changes in human sun exposure behavior can be an important influence on future ultraviolet radiation (UVR) related disease risks. In particular, active leisure mobility and leisure activities are more dependent on weather conditions than routine activities. However, the direction and extent of the effects vary. For temperate and cold climates, the available studies provide indications that a possible increase in UVR exposure would primarily result from a reduction in clothing and only secondarily from changes in the time spent outdoors. Existing studies suggest a nonlinear, bell-shaped relationship with threshold value effects for the relationship between outdoor time and thermal conditions. If the local climate is already very warm and there are only minor seasonal differences, there is no statistically significant evidence of changes in behavior. If there is significant warm discomfort, there is a tendency to avoid being outdoors or in the sun. It is not justified to simply transfer and generalize results and conclusions to different climates and seasons and between different leisure activities and forms of active mobility. The geographical context must be considered also in terms of cultures and habits, adaptations, traffic and land use (urban, rural). In addition, changes in behavior can develop differently depending on individual characteristics of people such as heat affinity, leisure type, age and gender. Differentiated analyses are required that take into account and balance opposing effects.

The Aryl Hydrocarbon Receptor in the Pathogenesis of Environmentally-Induced Squamous Cell Carcinomas of the Skin

Cutaneous squamous cell carcinoma (SCC) is one of the most frequent malignancies in humans and academia as well as public authorities expect a further increase of its incidence in the next years. The major risk factor for the development of SCC of the general population is the repeated and unprotected exposure to ultraviolet (UV) radiation. Another important risk factor, in particular with regards to occupational settings, is the chronic exposure to polycyclic aromatic hydrocarbons (PAH) which are formed during incomplete combustion of organic material and thus can be found in coal tar, creosote, bitumen and related working materials. Importantly, both exposomal factors unleash their carcinogenic potential, at least to some extent, by activating the aryl hydrocarbon receptor (AHR). The AHR is a ligand-dependent transcription factor and key regulator in xenobiotic metabolism and immunity. The AHR is expressed in all cutaneous cell-types investigated so far and maintains skin integrity. We and others have reported that in response to a chronic exposure to environmental stressors, in particular UV radiation and PAHs, an activation of AHR and downstream signaling pathways critically contributes to the development of SCC. Here, we summarize the current knowledge about AHR's role in skin carcinogenesis and focus on its impact on defense mechanisms, such as DNA repair, apoptosis and anti-tumor immune responses. In addition, we discuss the possible consequences of a simultaneous exposure to different AHR-stimulating environmental factors for the development of cutaneous SCC.

Cancer and climate change

The acute impact of climate change on human health is receiving increased attention, but little is known or appreciated about the effect of climate change on chronic diseases, particularly cancer. This Review provides a synopsis of what is known about climate change and the exposures it generates relevant to cancer. In the context of the world's cancer burden and the probable direction we could expect to follow in the absence of climate change, this scoping review of the literature summarises the effects that climate change is having on major cancers, from environmental exposures to ultraviolet radiation, air pollution, disruptions in the food and water supply, environmental toxicants, and infectious agents. Finally, we explore the effect of climate change on the possible disruption of health systems that have been essential to cancer control practice. We conclude with potential responses and opportunities for intervention.

Environmental changes and their impact on human behaviour - Case study of the incidence of skin cancer

Climatological research over the past two decades makes it clear that the Earth's climate will change. Climate change has many, mostly adverse, effects on the human health. Environmental anthropogenic changes represent significant health risks including factors that may increase probability and seriousness of skin cancer diseases. There are many scientific studies on skin cancer but only a few of them are focused on environment changes and their influence on the behaviour of humans, which may lead to skin cancer. The goal of the research was to analyse environment changes in the city of Brno (Czech Republic) and their influence on the behaviour of people and some skin diseases. A research hypothesis was set up that total increase in the incidence of skin diseases would be monitored. 1757 patients aged 25-65 years participated in the research. The analysis was performed based on measured (mean annual temperatures, average monthly temperatures, ultraviolet index values, and numbers of sunny days and sunny hours) data in 2011-2019. In order to monitor the trend, temperature data from 1961 to 2019 were evaluated too. The analysed data indicate that the trend of average monthly and annual temperatures observed was increasing in recent years. Moreover, based on data obtained from the analysed doctor's office it was found out that the incidence of skin diseases increased in the studied period. The main reasons to increase include excessive exposure to sun, extended average age of the population, ozone layer depletion, climatic and weather changes, increased migration and behaviour of people.