Detection of epidermal P53 and Mdm2 in vitiligo patients

ABSTRACT

Vitiligo is a common depigmented skin disorder that is caused by selective destruction of melanocytes resulting in disfiguring milky white patches. Since melanin is a unique light- absorbing and ultra -violet filtering system it is generally accepted that its main function resides in the protection of these cells against the deleterious effect of U-V light. Association of vitiligo and skin cancer has been a subject of controversy, occurrence of skin cancer in long lasting vitiligio is rare and PUVA therapy associated squamous cell carcinomas are not reported. There are reports on increased functional wild type P53 expression in the patients with vitiligo and there may be direct association between this tumor suppressor gene and absence of photo damage and skin cancer. The major regulator of P53 is MDM2 protein which can trigger its degradation. Thus the aim of this work is to detect the degree of expression of P53 protein, MDM2 protein, in both depigmented as well as 'normal' pigmented skin of vitiligo patients and compare it to normal control. Thirty four patients with vitiligo and ten age and sex matched healthy volunteers as a control were selected. Skin biopsies were taken from each case and control subjects. Histopathological examination of hematoxylin-eosin-stained sections of lesions included analysis and scoring of histopathological parameters. Expression of P53 and Mdm2 proteins were examined immunohistochemically. The results showed that both P53 and Mdm2 were highly expressed in uninvolved as well as involved skin of vitiligo patients in comparison to the control. This expression involves the epidermis, skin adnexa and blood vessels. In conclusion the over expression of the functioning wild type of P53 protein in both pigmented and depigmented epidermis of patients with vitiligo, could contribute to the decreased occurrence of actinic damage and skin cancer