Skin cancer Sunburns do double harm

Study: Sunburns damage the skin twice

03/01/2014

Black skin cancer is considered particularly dangerous because it can form colonies in vital organs. The most important triggering factor is UV radiation. Bonn scientists have only found that sunburns contribute to disease development through inflammatory processes in the surrounding tissue.

Black skin cancer particularly dangerous because of settlements
Because black skin cancer can form colonies in vital organs such as the lungs, liver or brain, it is particularly dangerous. The most important triggering factor is UV radiation. Now, an interdisciplinary team of researchers from the University Hospital and the LIMES Institute of the University of Bonn has found that sunburns contribute to the development of this malignant disease not only directly through genetic changes in pigment cells, but also indirectly through inflammatory processes in the surrounding tissue. A few days ago, the results were in the journal „Nature“ released.

In 2014, 20,000 people will develop black skin cancer
In 2014, according to forecasts by the Robert Koch Institute, about 20,000 people in Germany will contract a black skin cancer, also known as malignant melanoma. Over 2,500 sufferers will die of secondary tumors in internal organs called metastases. „The inflammatory reaction of the skin after exposure to strong sun promotes the early emigration of degenerated pigment cells along vessels into the body“, Prof. Dr. Thomas Tüting, Professor of Experimental Dermatology at the University Hospital Bonn and head of the study.

Increasingly, melanoma metastases in the lungs of mice are observed
The researchers have developed experimental models in the mouse that can be used to study the effect of UV rays to understand the origin and early removal of degenerate pigment cells. „Time and again, we have seen more and more melanoma metastases in the lungs of UV-irradiated mice“, explained the dermatologist Dr. Evelyn Gaffal. It was noted in tissue sections that melanoma cells in inflamed skin frequently spread on the surface of blood vessels. Using the latest methods of fluorescence and electron microscopy, the scientists found a close relationship between melanoma cells, cells of the inner blood vessel walls and immune cells, especially the neutrophil granulocytes. Further experiments showed that neutrophil granulocytes play an important role in metastasis. These are attracted by alarm signals that emit UV-damaged cells in the epidermis. The signaling pathways involved were elucidated with the help of special mouse strains that lack important molecules for innate immune activation.

Melanoma cell motility increases in inflammatory environment
The researchers at the LIMES Institute of the University of Bonn observed the interaction between melanoma cells and the cells of the inner blood vessel walls with new experimental methods and found that melanoma cells on blood vessel surfaces can move particularly effectively. „The mobility of melanoma cells increases in an inflammatory environment“, so Prof. dr. Waldemar Kolanus. In addition, it could be clarified how inflammatory messengers stimulate the melanoma cells to migrate. Prof. Dr. Michael Hölzel from the Institute of Clinical Chemistry and Clinical Pharmacology of the University Hospital Bonn, said: „The precursors of pigment cells, during embryonic development, travel long distances along blood vessels in the body to get into their proper place in the skin. It is precisely these shut-down programs that are erroneously reactivated by inflammation.“

Researchers hope for new therapies
„Now we may also know why patients with superficially ulcerated melanoma interspersed with neutrophilic granulocytes are particularly likely to develop organ metastases“, says Prof. Tüting. The researchers hope to develop new therapies in the future, which can specifically intervene in signaling cascades of inflammation and inhibit the migration of melanoma cells on blood vessel surfaces.

Beware of intensive sunbathing
Black skin cancer is by far the most dangerous skin cancer variant and the most frequently fatal skin disease worldwide. When the metastases begin to spread, around 90 percent of patients die within five years. Excessive solar radiation is one of the major risk factors for black skin cancer. Intense sunbathing in the open air, but above all the use of sunbeds, should therefore be treated with caution, according to the World Health Organization (WHO). Thus, the WHO as well as the German Commission on Radiation Protection rejects the cosmetic tanning and advises against general abandonment. (Ad)

Image: William Veder