Quantitative analysis of NF1 and OMGP gene transcripts in sporadic gliomas, sporadic meningiomas and neurofibromatosis type 1-associated plexiform neurofibromas
N. Peters et al., Quantitative analysis of NF1 and OMGP gene transcripts in sporadic gliomas, sporadic meningiomas and neurofibromatosis type 1-associated plexiform neurofibromas, ACT NEUROP, 97(6), 1999, pp. 547-551
The close association of neurofibromatosis type 1 (NF1) with gliomas raises
the question of whether the NF1 gene may be involved in the pathogenesis o
f sporadic astrocytic brain tumors. However, no frequent mutations within N
F1 have been described in these tumors. Recent data on a limited series of
gliomas indicate that NF1 expression may even be increased, thereby questio
ning the role of NF1 as a tumor suppressor in astrocytomas. In the present
study, we examined the expression of NF1 in a series of 96 tumors including
astrocytomas, meningiomas and plexiform neurofibromas. NF1 RNA transcripti
on levels were compared to those of the reference genes B2M, ACTB and GAPD.
The expression of OMGP, which is interposed in the NF1 gene, served as an
additional control. NF1 expression did not significantly diverge among diff
erent malignancy stages of astrocytomas. As expected, the plexiform neurofi
bromas showed only very low NF1 expression. A striking finding was the high
ly variable expression of those genes selected to serve as references. Whil
e B2M and ACTB exhibited comparable levels of expression within different g
rades of astrocytomas and meningiomas, GAPD showed an inverse pattern in th
ese tumors. In conclusion, NF1 expression is strongly reduced in NF1-associ
ated plexiform neurofibromas but not in astrocytic tumors. The significant
differences between B2M, ACTB and GAPD transcript levels brings into questi
on the common practice of defining gene expression as a ratio between the t
ranscripts of interest and those of these reference genes.