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Notes: The aim of this study was to investigate whether increased oxidative stress occurs in erosive lichen planus of the vulva. Skin biopsies from six patients with untreated, histologically confirmed erosive lichen planus of the vulva were examined immunohistochemically using antibodies against antioxidant enzymes. The protein-bound lipid peroxidation products malondialdehyde (MDA) and 4-hydroxynonenale (4-HNE) and the oxidative DNA damage marker 8-hydroxy-2′-deoxyguanosine (8-OHdG) were investigated. Protein carbonyls as markers of protein oxidation were visualised using the dinitrophenylhydrazone (DNPH) method. Normal vulval tissues from 12 subjects served as controls. In vulval lichen planus tissue the enzymatic antioxidant defence was found to be significantly decreased in the epidermal layers. Furthermore, a significant increase of lipid peroxidation products and oxidative DNA damage was found within the epidermis. Protein oxidation occurred predominantly in the papillary dermis. This is the first study to demonstrate a decreased antioxidant defence and increased oxidative damage to lipids, DNA and proteins in lichen planus. These oxidative modifications point to pathophysiological alterations mainly within the basal cell layers of the epidermis and at the dermoepidermal junction. Further studies are warranted to investigate the potential role of oxidative stress in the development of autoimmunity in this disease.

Notes: Summary Background Solar ultraviolet (UV) radiation is considered to be a major aetiological factor in melanoma and non-melanoma skin cancer. A growing body of evidence indicates that oxidative stress is involved in photocarcinogenesis. However, in vivo data for human skin are still lacking. Reactive oxygen species participate in a number of pathophysiological processes including DNA damage and lipid peroxidation (LPO) and are considered to be a key factor in tumour progression. Objectives We hypothesized that in human skin cancer the natural redox balance is disturbed and that this imbalance may result in an accumulation of LPO products. Methods To test this, skin biopsies of superficial spreading melanoma were compared with age-matched benign melanocytic naevi and young healthy controls. Additionally, non-melanoma skin cancers (basal cell carcinoma, squamous cell carcinoma) and actinic keratosis were investigated (n = 18 each). Expression of the antioxidant enzymes, copper–zinc superoxide dismutase, manganese superoxide dismutase and catalase was analysed by immunohistochemical techniques. To detect LPO products, protein-bound malondialdehyde (MDA) was visualized. Results In human melanoma biopsies, a significant overexpression of the antioxidant enzymes was found when compared with surrounding non-tumour tissue, benign melanocytic naevi, and young controls. Intriguingly, the LPO marker MDA was significantly increased in melanoma tissue. MDA was located not only in typical melanoma cells, but also occurred in surrounding keratinocytes. In contrast, a severely disturbed antioxidant balance with diminished antioxidant enzymes was found in non-melanoma tumours, whereas MDA was elevated only in squamous cell carcinomas. Conclusions These findings indicate that oxidative stress may play different roles in the pathogenesis of human skin cancers. In non-melanoma skin cancer, a diminished antioxidant defence caused by chronic UV exposure might contribute to multistep carcinogenesis, whereas melanoma cells exhibit increased oxidative stress which could damage surrounding tissue and thus support the progression of metastasis.

Notes: Background  Lichen sclerosus (LS) is a chronic inflammatory skin disease of unknown aetiology which can be associated with secondary malignancies. Recent evidence supports an autoimmune basis for this disorder, as demonstrated by autoantibodies to extracellular matrix protein 1 (ECM-1). The pathophysiological mechanisms leading to autoimmunity and carcinogenesis are poorly understood.Objectives  We hypothesized that oxidative stress, which has been demonstrated to be involved in the pathogenesis of several autoimmune and malignant disorders, contributes to these processes in LS.Methods  Skin biopsies from 16 patients with untreated, histologically confirmed vulval LS were examined immunohistochemically using antibodies against the lipid peroxidation products malondialdehyde and 4-hydroxynonenale and against the oxidative DNA damage marker 8-hydroxy-2′-deoxyguanosine. Protein carbonyls as markers of protein oxidation were visualized using the dinitrophenylhydrazone method. Expression of antioxidant enzymes was investigated. Normal vulval tissue from 16 subjects served as control.Results  In vulval LS tissue a significant increase of lipid peroxidation products was found particularly within the basal cell layers of the epidermis, thus colocalizing with ECM-1. Oxidative DNA damage was detected throughout LS biopsies. Intriguingly, protein oxidation was significantly increased within the dermis of LS lesions, indicating oxidative protein damage in the areas of sclerosis and inflammation. The enzymatic antioxidant defence in LS was found to be significantly disturbed.Conclusions  This is the first study to demonstrate oxidative damage to lipids, DNA and proteins in LS, revealing a novel pathophysiological mechanism which may contribute to sclerosis, autoimmunity and carcinogenesis. Therapeutic strategies using antioxidants might be a useful new approach in the treatment of LS and could also help to prevent secondary malignancies.