Expression of selected growth factors and oncogenes in neurofibrosarcomas complicating von Recklinghausen disease

One neurofibrosarcoma from each of three patients with von Recklinghausen neurofibromatosis (VRNF) was studied for the expression of selected growth factor genes and oncogenes. Comparative analyses were also performed on four neurofibromas and skin, nerve and muscle specimens from one of the patients with neurofibrosarcoma, an autopsy kidney specimen from a fifth VRNF patient, and normal liver and term placenta specimens from healthy control subjects. Northern blot hybridization techniques were used to analyze the amounts and sizes of mRNA resulting from the expression of eight genes. Insulin-like growth factor I showed a moderate level of expression in normal nerve and lower expression in two neurofibrosarcomas. Insulin-like growth factor II was moderately to heavily expressed in all specimens, and differential splicing patterns were seen. Platelet-derived growth factor showed low levels of expression in all three neurofibrosarcomas, skin, nerve, muscle and normal liver, low to moderate levels of expression in the neurofibromas, and high expression in normal control placenta. Beta-nerve growth factor was expressed at low levels in two neurofibrosarcomas and skin, but was not seen in other specimens. N-myc showed a low level of expression in one neurofibrosarcoma and a neurofibroma, and a higher level of expression in a second neurofibrosarcoma (and in this same subject's skin and nerve). Tissue-type plasminogen activator showed moderate levels of expression in two neurofibrosarcomas and one neurofibroma, but it was not seen in skin, nerve, kidney and normal term placenta specimens.