Selective expression of interleukin-10 gene within glioblastoma multiforme

Little information exists regarding which glioma cells are able to escape immune system detection and progress within the host. In order to elucidate some of the mediators which facilitate the growth and spread of glioma cells, the expression of cytokines, TNF-alpha, IL-6, gamma-IFN, IL-10, and GM-CSF, within 12 human glioma specimens was investigated by the polymerase chain reaction. The twelve patients with malignant glioma were categorized into a localized (n = 4) and an invasive glioma (n = 8) groups, mostly glioblastoma multiforme, based upon the CT and MRI scans. We examined the correlation between specific cytokine gene expression and the clinical category of each patient. The results showed that while IL-10 mRNA transcripts were expressed in most of the tumors from the invasive glioma group (7/8), they were not expressed in tumors from the localized group. On the other hand, gamma-IFN gene expression was more frequent in tumors from the localized group (3/4 vs 1/8 from the invasive group). The mRNA transcripts of IL-6 and GM-CSF were more frequently expressed in tumors from the localized group. No consistent pattern was seen in TNF-alpha gene expression between the two groups. Among the five cytokines studied, IL-10 mRNA was selectively expressed within invasive gliomas compared to less malignant, localized glioma group. Our results demonstrate specific cytokine mRNA profiles in glioma patients, which might have prognostic significance for immunotherapy.