title: Plasminogen activator inhibitor-1 in brain tumors: relation to malignancy and necrosis.
abstract: Tumor necrosis is a common feature of malignant neoplasms. The pathogenesis of tumor necrosis remains poorly documented. Recent evidence has shown a correlation between the presence of tumor necrosis and low content of tissue plasminogen activator in brain tumors and significantly higher levels of plasminogen activator inhibitor-1 (PAI-1) in human glioblastomas. We subjected fresh brain tumor tissue samples (n = 197) to an enzyme-linked immunosorbent assay to determine PAI-1 content. The results were correlated with the presence of edma and necrosis on imaging studies. The samples studied were from normal brain (n = 10), low-grade gliomas (n = 26), meningiomas (n = 47), acoustic neuromas (n = 18), glioblastomas (n = 45), metastases (n = 45), and areas of tumor necrosis (n = 6). The benign tumor samples (n = 96) had 3.5 times less PAI-1 than did the malignant tumors (n = 101). Tumor necrosis samples contained 3.8 times more PAI-1 than did the nonnecrotic malignant tumor samples (P < 0.000001). The benign meningioma samples showed a similar ratio compared with their malignant counterparts (0.35 versus 1.59 ng/mg, respectively, P = 0.0004). Regression analysis results showed a strong correlation between PAI-1 and necrosis (r = 0.47, P < 0.0000028) and, to a lesser extent, brain edema (r = 0.26, P = 0.001). A negative correlation between PAI-1 and tissue plasminogen activator levels almost reached statistical significance (P = 0.07). There was no correlation between PAI-1 content and the tumor size, duration of symptoms, or the sex or age of the patients. The results of this study indicate that malignant transformation is associated with a significant increase in PAlI1 and that PAI-1 may play an integral role in the pathogenesis of tissue necrosis, perhaps via the inhibition of tissue plasminogen activator and the promotion of microthrombosis.
authors.affiliation: Department of Neurosurgery, University of Texas M.D. Anderson Cancer Center, Houston, USA.
authors.forename: R
authors.initials: R
authors.lastname: Sawaya
authors.forename: M
authors.initials: M
authors.lastname: Yamamoto
authors.forename: O J
authors.initials: OJ
authors.lastname: Rämö
authors.forename: M L
authors.initials: ML
authors.lastname: Shi
authors.forename: A
authors.initials: A
authors.lastname: Rayford
authors.forename: J S
authors.initials: JS
authors.lastname: Rao
mesh_terms: D001483:Base Sequence; D001921:Brain / Q000378:metabolism; D001932:Brain Neoplasms / Q000378:metabolism* / Q000473:pathology*; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D017403:In Situ Hybridization; D008969:Molecular Sequence Data; D009336:Necrosis; D015345:Oligonucleotide Probes / Q000235:genetics; D017395:Plasminogen Activator Inhibitor 1 / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D012016:Reference Values; D014018:Tissue Distribution
chemical_list: D015345:Oligonucleotide Probes; D017395:Plasminogen Activator Inhibitor 1; D012333:RNA, Messenger