P53 STATUS IN RADIATION-INDUCED SOFT-TISSUE SARCOMAS

Background: Following therapeutic irradiation after a latency period o f many years radiation-induced tumors, often sarcomas, can arise. Resu lts of radiation-induced DNA damage can be 1. p53 over-expression, ind ucing growth arrest or apoptosis, and 2. occurrence of mutations, freq uently including the p53 gene, as one molecular promotor for carcinoge nesis. We were interested whether radiation-induced sarcomas are assoc iated with alterations of the p53 status. Material and Methods: Sample s from 11 radiation-induced soft-tissue sarcomas (STS) were studied by a non-radioactive PCR-SSCP sequencing analysis and by immunohistochem istry with five antibodies for their p53 status. Results: A tumor of o ne patient possessed a G-->A transition in codon 280 (exon 8). Of 11 t umors, 9 showed nuclear p53 positivity, detected by monoclonal antibod y DO-1. Of these 9 patients, 7 died during the observation period, whe reas the 2 patients with DO-1 negative tumor samples are still alive. Conclusions: p53 over-expression and p53 mutation occur in radiation-i nduced STS. p53 status is expected to have prognostic impact for radia tion-induced STS.