COMPARISON OF P53 EXPRESSION IN DERMATOFIBROSARCOMA PROTUBERANS AND DERMATOFIBROMA - LACK OF CORRELATION WITH PROLIFERATION RATE

p53 protein plays an important role in control of cell proliferation b y suppressing proliferation of cells with DNA damage. Mutations of the p53 gene increase the stability of the encoded nonfunctional protein which accumulates in the nuclei, allowing it to be detectable by immun ohistochemistry. Mutant p53 protein has been observed in preneoplastic and neoplastic conditions supporting its role in the development of s ome human cancers. In this immunohistochemical study, we examined p53 expression in 12 Dermatofibrosarcoma Protuberans (DFSP) and 10 Dermato fibromas (DF). Results were compared with the cellular proliferation r ate by using the monoclonal antibody Mib-1 which detects Ki-67 antigen expression. Nuclear accumulation of the p53 protein was observed in 1 1 DFSP. All DF were negative for p53. No statistical correlation could be established between p53 and Mib-1 staining in our cases. We conclu de that mutations of the p53 gene may be in involved in the molecular pathogenesis of DFSP but not of DF. Mib-1 index can not be successfull y used to distinguish DFSP from DF.