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.

• Keywords: Malignant fibrous histiocytoma;H-ras;K-ras;