Vitiligo: is it grace or curse?

Vitiligo is a common skin disease, affecting approximately 0.5% of the general population. It is characterized by milky white macules and patches, which are a psychological burden to many patients. Although this disease has been known for a long time, the etiology is still under debate. Since melanin is a unique light absorbing and ultraviolet filtering pigment, it is generally accepted that its main function resides in the protection of skin cells against the deleterious effect of ultraviolet rays (UVRs). The occurrence of skin cancer in long lasting vitiligo is rare despite multiple evidence of DNA damage. The aim of this study was the immunohistochemical detection of p53 and Mdm2 in depigmented and "normal" pigmented skin of vitiligo patients to demonstrate the possible role of these proteins in the protection of vitiligo patients against actinic damage and non-melanoma skin cancer. Using standard immunohistochemical techniques, we examined 34 patients with vitiligo and 30 age- and sex-matched patients with noduloulcerative basal cell carcinoma as a control group. Both patients and control subjects had outdoor occupations. Skin biopsies were obtained from each case (from depigmented and "normal" pigmented UVR-exposed skin) and control subjects (from perilesional healthy skin). Both p53 and Mdm2 were strongly expressed in depigmented as well as "normal" pigmented skin of vitiligo patients. This expression involved the epidermis, skin adnexa and blood vessels, with significant differences between cases and controls. Both proteins showed nuclear and nucleo-cytoplasmic pattern of expression. Intense p53 and Mdm2 expression was in favor of generalized vitiligo. These results suggested that the over-expression of p53 and Mdm2 proteins in both depigmented and "normal" pigmented skin of patients with vitiligo could contribute to the decreased occurrence of actinic damage and non-melanoma skin cancer in these patients.

Expression of matrix metalloproteinase-2 in renal cell carcinoma.

BACKGROUND: Renal cell carcinoma (RCC) is a family of carcinomas arising from the renal tubular epithelium through different genetic lesions. The most common characterstics of RCC are hypervascularity, tendency to metastasize widely before giving rise to any symptoms or signs, and poor prognosis. It has been reported that matrix metallopropteinases (MMPs) are a family of endopeptidases implicated in tissue remodeling and cancer invasion. Therefore, the aim of the present study was to investigate the expression of MMP-2 in RCC and correlate its expression with the clinicopathologic prognostic parameters. MATERIAL AND METHODS: Fifty cases of primary RCC comprised the material of this study. Formalin-fixed paraffin-embedded tissues were stained with MMP-2 immunostaining, using improved streptavidin-biotin amplified system. The intensity of staining and percentage of positive cells were assessed. RESULTS: MMP-2 was expressed as diffuse brown cytoplasmic staining in positive cells. The non-tumorous renal tissue showed negative staining whereas the tumor cells, fibroblasts and vascular endothelial cells showed immunoreactivity in positive cases. 43/50 RCC cases studied were positive for MMP-2. A positive correlation was observed between MMP-2 expression and tumor size, histologic type, capsular & vascular invasion and high levels of cellular proliferation. CONCLUSION: It seems that MMP-2 is involved in tumor expansion phenomena associated with tumor progression, invasion of the microvasculature and distant metastasis of RCC.