ras Gene Mutations in Malignant Fibrous Histiocytoma

ABSTRACT

BACKGROUND: ras gene mutations have been described in various human malignancies, suggesting that their activation may play a role in oncogenesis. However, there are few reports concerning ras gene alterations in malignant fibrous histiocytomas. We therefore designed a study to determine the prevalence and type of mutations in the first exons of H-ras and K-ras genes in these tumors. METHODS: Twenty-seven malignant fibrous histiocytomas were investigated by direct sequencing analysis with the automated DNA sequencing of polymerase chain reaction-amplified ras sequences. RESULTS: Twenty-four mutations were found in 18 (67%) of the tumors GGC to GAC transition mutations at codon 13 of K-ras (coding for aspartic acid instead of glycine) in 18 of the samples and GGC to GTC transversions at codon 12 of H-ras (coding for valine instead of glycine) in six of the lesions. CONCLUSIONS: Our data suggest an involvement of the ras gene mutation in conjunction with other yet unknown events in the tumorigenesis and/or progression of malignant fibrous histiocytomas. The K-ras gene activation predominated in these tumors by a mutation at codon 13. It is noteworthy that H-ras mutations were detected only in association with the lesions containing K-ras mutated genes, the significance of which remains to be determined.