DIFFERENTIAL EXPRESSION OF INDUCIBLE NITRIC-OXIDE SYNTHASE MESSENGER-RNA IN HUMAN BRAIN-TUMORS

MESSENGER RNA encoding the inducible form of human nitric oxide syntha se (iNOS) was quantified by reverse transcription and polymerase chain reaction (RT-PCR) in tissue samples from glioblastomas and meningioma s. iNOS mRNA expression was considerably higher in the glioblastoma th an in the meningioma specimens (mean +/- s.e.m., 41.18 +/- 11.5, n = 2 5, vs 5.31 +/- 0.98, n = 21; p < 0.0001). Moreover, iNOS expression ap peared as a polymorphic character among glioblastomas, as individual t umours expressed either high (n = 6), intermediate (n = 10) or low (n = 9) levels of iNOS mRNA.