Frequent p53 gene mutations in soft tissue sarcomas arising in burn scar.

Squamous cell carcinoma (SCC) is the commonest malignancy that arises in burn scars, which frequently contain p53 mutations. Soft tissue sarcoma (STS) also develops, though less frequently, in burn scars. p53 gene mutations were analyzed in paraffin-embedded specimens from 5 patients with STS (4 males and 1 female) that had arisen in a burn scar, by means of polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) followed by direct sequencing. Age at burn injury ranged from 2 to 10 (median 3) years, and STS developed with a latent period ranging from 29 to 79 (median 60) years. Histologically, all were malignant fibrous histiocytoma. The PCR-SSCP revealed aberrant bands in 4 (80%) of 5 cases. Direct sequencing revealed a total of 11 mutations in these 4 cases: 1 case had a single mutation, 1 had 2 mutations, and 2 had 4 mutations. Every tumor had at least 1 mutation that changed an amino acid, which may have provided the selection pressure for expansion. Thus, there is a high frequency of p53 gene mutations in STS appearing in burn scars. p53 mutations were also frequent in pyothorax-associated lymphoma (PAL), a lymphoma that develops in patients with long-standing pyothorax, so p53 mutations might be frequent in malignancies that develop in chronic inflammatory sites.