Expression of c‐sis and c‐fos genes in human meningiomas and neurinomas

Abstract

The HindIII c‐sis RFLP was analyzed in constitutional and tumor DNAs of 19 meningioma patients. Loss of a c‐sis allele (allele 1 in all cases) was observed in 6 out of 10 tumors from heterozygous patients. No alteration in the structure or dosage of the c‐sis gene was detected in any tumor sample. Northern analysis of c‐sis evidenced sis transcripts in 7 out of 8 meningiomas which were amenable to analysis. All tumors expressing c‐sis also expressed c‐fos, suggesting that the autocrine loop elicited by sisactivation may have c‐fos as its nuclear target. Co‐expression of c‐sis and c‐fos was also observed in 5 neuromas out of 7 analyzed. Very high levels of fos‐mRNA were observed in 2 neuromas, but were not found to be caused by apparent alteration or amplification of the c‐fos gene.