Combined erbB gene overexpression and decreased H-ras gene expression in human gliomas

The expression of 15 oncogenes including erbB and H-ras in 18 human glial tumors -10 glioblastomas, 1 astrocytoma grade III-IV, 2 oligodendrogliomas grade III, 2 astrocytomas grade II-III, 1 astrocytoma grade II, 1 oligodendroglioma grade II and 1 oligoastrocytoma grade II--was determined by hybridizing RNA against oncogene probes using the Dot Blot technique. Compared with bovine cerebrum (control), the oncogenes abl, erbA, fms, fos, K-ras, mil, mos, myb, rel, sis, src and yes were expressed equally in both bovine cerebrum and the gliomas. However, the expression of erbB was increased 2-9-fold in all except one glioma, and the expression of H-ras was decreased by the factor 0.3-0.7 in 15 tumors. No obvious correlation was found between tumor histology and changed expression of erbB and/or H-ras or between the grade of malignancy and the expression of any oncogene tested. A connection between erbB and H-ras has been shown by several studies. Our results confirm the relationship between H-ras and erbB. However, the meaning of the H-ras decrease in combination with the erbB elevation has to be clarified.