Increased p53 staining in normal skin of posttransplant, immunocompromisedpatients and implications for carcinogenesis

The p53 tumor suppressor gene is a transcriptional activator involved in co ntrol of cell cycle. Nonmelanoma skin cancers and premalignant lesions in t ransplant patients have been associated with an increased rare of p53 mutat ion. It is possible that normal skin in transplant patients also has a more labile p53 tumor suppressor gene, predisposing them to the development of nonmelanocytic cutaneous malignancies. To test this hypothesis, we looked a t p53 expression in normal skin from posttransplant, immunocompromised pati ents and compared this to p53 expression in normal skin from immunocompeten t patients. Twenty-three skin biopsies of normal, non-sun-exposed skin from 23 immunosuppressed transplant patients and 6 skin biopsies of normal, non -sun-exposed skin from 3 immunocompetent patients were stained for p53 immu noreactivity. The skin biopsies from the immunocompromised patients showed increased staining for p53 when compared to the skin biopsies from the immu nocompetent patients (mean = 7.52/mm for the immunocompromised patients and mean = 1.05/mm for the normal control group). Background levels of p53 mut ation may be increased in normal skin of posttransplant immunocompromised p atients. This background increase in p53 expression could reflect mutation of the gene, which may play a role in the subsequent development of cutaneo us malignancies in this subgroup of patients.