Vascular endothelial growth factor (VEGF), also known as vascular permeability factor, is strongly expressed by epidermal keratinocytes during wound healing, in psoriasis, and in bullous diseases such as erythema multiforme and bullous pemphigoid. All of these disorders are characterized by increased microvascular permeability and angiogenesis. Since the development of erythema as a result of hyperpermeable blood vessels is also a common feature after excess sun exposure, we speculated about an up-regulation of VEGF expression by ultraviolet (UV) light. To test this hypothesis, we analyzed the effect of UVB irradiation on VEGF expression in cultured keratinocytes. Thereby we found a large increase in VEGF mRNA and protein levels upon irradiation of quiescent keratinocytes with sublethal and physiologically relevant doses of UVB. Although H2O2 was also a potent inducer of VEGF expression, the effect of UVB irradiation is unlikely to be mediated by reactive oxygen species as determined by the use of antioxidants. Further experiments revealed that the UVB-induced overexpression of VEGF is dependent on de novo protein synthesis and might occur via release of soluble mediators, which subsequently turn on VEGF expression. In summary, our results suggest a novel role of VEGF in the induction of erythema after excess sun exposure.
A randomized, double-blind, multicentre study was performed to compare the efficacy of acitretin (50 mg/day) with hydroxychloroquine (400 mg/day) in 28 and 30 patients, respectively, suffering from cutaneous lupus erythematosus (LE). The study was carried out over an 8-week period. Improvement of facial LE lesions after treatment with acitretin and hydroxychloroquine was assessed using several clinical parameters. In the acitretin group there was marked improvement or clearing of erythema in 10/24 patients (42%), of infiltration in 15/24 (63%) and of scaling/hyperkeratosis in 12/20 (60%). In the hydroxychloroquine group there was complete clearing or marked improvement of erythema in 17/25 patients (68%), of infiltration in 17/25 (68%) and of scaling/hyperkeratosis in 15/23 (65%). Overall improvement occurred in 13/28 patients (46%) treated with acitretin and in 15/30 patients (50%) with hydroxychloroquine. The incidence of side-effects was higher in the acitretin group, and necessitated discontinuation of treatment in four patients. The present results demonstrate that both acitretin and hydroxychloroquine provide effective treatment in approximately 50% of cases of cutaneous LE.
The product of the p16/INK4a/CDKN2/MTS1 tumor-suppressor gene acts as a negative cell cycle regulator by inhibiting G1 cyclin-dependent kinases that phosphorylate the retinoblastoma protein. p16 is inactivated in a wide range of human malignancies, including familial melanoma. However, its expression and function in sporadic melanoma has not been extensively investigated. We studied p16 expression in 62 archival melanomas and 30 archival nevi and lentigines by immunohistochemistry. Eighteen of 26 (69%) superficial spreading melanomas, 17 of 28 (61%) nodular melanomas, all of three lentigo maligna melanomas, and all of five melanoma metastases were found to harbor less than 10% p16-positive tumor cells. In contrast, only six of 24 (25%) nevi had less than 10% positive cells. No correlation between tumor thickness and loss of p16 expression was found. Using DNA from micro-dissected tumor and matched normal tissues, five of seven (71%) p16-negative melanoma cases had 9p21 loss of heterozygosity (LOH), and one of these 9p21 LOH cases had promoter region hypermethylation of the remaining p16 allele. These data demonstrate that partial or complete loss of p16 expression is prevalent in sporadic melanoma and is frequently associated with 9p21 LOH.
We suggest the term mycosis fungoides-associated follicular mucinosis should be replaced by follicular mycosis fungoides in future lymphoma classification schemes.
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