Chromosome aberrations and expression of ras and myc oncogenes in leiomyomas and a leiomyosarcoma of the uterus.

Twenty eight leiomyomas and one leiomyosarcoma were cytogenetically analysed and also examined for ras and myc oncoprotein expression. Chromosome alterations were found in seven leiomyoma cases. In four of them 12q14-15 was involved. P21 product of H-ras and P62 product of c-myc genes were detected in paraffin embedded parallel tissue sections. A high expression of H-ras was apparent in most tumors. C-myc expression was weak or negative in most leiomyomas with normal karyotype while on the contrary in three out of seven cases with abnormal cytogenetic findings the gene product stained moderately positive. Considerable chromosome abnormalities and oncogene overexpression were also identified in the leiomyosarcoma.