Background We determined the frequency of cancer, neurologic degeneration and mortality in xeroderma pigmentosum (XP) patients with defective DNA repair in a four decade natural history study. Methods All 106 XP patients admitted to the NIH from 1971 to 2009 were evaluated from clinical records and follow-up. Results In the 65 percent (n=69) of patients with skin cancer, non-melanoma skin cancer (NMSC) was increased 10,000–fold and melanoma was increased 2,000-fold in patients under age 20. The 9 year median age at diagnosis of first non-melanoma skin cancer (NMSC) (n=64) was significantly younger than the 22 year median age at diagnosis of first melanoma (n= 38), a relative age reversal from the general population suggesting different mechanisms of carcinogenesis between NMSC and melanoma. XP patients with marked burning on minimal sun exposure (n=65) were less likely to develop skin cancer than those who did not. This may be related to the extreme sun protection they receive from an earlier age, decreasing their total UV exposure. Progressive neurologic degeneration was present in 24% (n=25) with 16/25 in complementation group XP-D. The most common causes of death were skin cancer (34%, n=10), neurologic degeneration (31%, n=9), and internal cancer (17%, n=5). The median age at death (29 years) in XP patients with neurodegeneration was significantly younger than those XP patients without neurodegeneration (37 years) (p=0.02). Conclusion This 39 year follow-up study of XP patients indicates a major role of DNA repair genes in the etiology of skin cancer and neurologic degeneration.

While investigating the novel anticancer drug ecteinascidin 743 (Et743), a natural marine product isolated from the Caribbean sea squirt, we discovered a new cell-killing mechanism mediated by DNA nucleotide excision repair (NER). A cancer cell line selected for resistance to Et743 had chromosome alterations in a region that included the gene implicated in the hereditary disease xeroderma pigmentosum (XPG, also known as Ercc5). Complementation with wild-type XPG restored the drug sensitivity. Xeroderma pigmentosum cells deficient in the NER genes XPG, XPA, XPD or XPF were resistant to Et743, and sensitivity was restored by complementation with wild-type genes. Moreover, studies of cells deficient in XPC or in the genes implicated in Cockayne syndrome (CSA and CSB) indicated that the drug sensitivity is specifically dependent on the transcription-coupled pathway of NER. We found that Et743 interacts with the transcription-coupled NER machinery to induce lethal DNA strand breaks.

The ability to produce cold plasma at atmospheric pressure conditions was the basis for the rapid growth of plasma-related application areas in biomedicine. Plasma comprises a multitude of active components such as charged particles, electric current, UV radiation, and reactive gas species which can act synergistically. Anti-itch, antimicrobial, anti-inflammatory, tissue-stimulating, blood flow-enhancing, and proapoptotic effects were demonstrated in in vivo and in vitro experiments, and until now, no resistance of pathogens against plasma treatment was observed. The combination of the different active agents and their broad range of positive effects on various diseases, especially easily accessible skin diseases, renders plasma quite attractive for applications in medicine. For medical applications, two different types of cold plasma appear suitable: indirect (plasma jet) and direct (dielectric barrier discharge—DBD) plasma sources. The DBD device PlasmaDerm® VU-2010 (CINOGY Technologies GmbH), the atmospheric pressure plasma jet (APPJ) kINPen® MED (INP Greifswald/neoplas tools GmbH), and the SteriPlas (Adtec Ltd., London, United Kingdom) are CE-certified as a medical product to treat chronic wounds in humans and showed efficacy and a good tolerability. Recently, the use of plasma in cancer research and oncology is of particular interest. Plasma has been shown to induce proapoptotic effects more efficiently in tumor cells compared with the benign counterparts, leads to cellular senescence, and—as shown in vivo—reduces skin tumors. To this end, a world-wide first Leibniz professorship for plasmabiotechnology in dermatology has been introduced to establish a scientific network for the investigation of the efficacy and safety of cold atmospheric plasma in dermatooncology. Hence, plasma medicine especially in dermatology holds great promise.

Cold atmospheric plasma displays favourable antibacterial effects. We demonstrated that plasma treatment with the PlasmaDerm® VU-2010 device is safe and effective in patients with chronic venous leg ulcers. Thus, larger controlled trials and the development of devices with larger application surfaces are warranted.