CYTOKINE GENE-EXPRESSION IN PRIMARY BRAIN-TUMORS, METASTASES AND MENINGIOMAS SUGGESTS SPECIFIC TRANSCRIPTION PATTERNS

To obtain an insight into the network of cytokine gene transcription i n the brain tumour microenvironment, we investigated the expression of genes encoding for interleukin (IL)-1alpha, IL-1beta, IL-2, IL-4, IL- 5, IL-6, IL-10, interferon (IFN)-gamma, granulocyte-macrophage colony- stimulating factor, tumour necrosis factor (TNF)-alpha and transformin g growth factor (TGF)-beta1, -beta2 and -beta3 in freshly excised brai n tumour. samples and autologous peripheral blood mononuclear cells. T issue specimens from 15 primary brain tumours, three brain metastases, five meningiomas, autologous peripheral blood mononuclear cells (PBMC ) and three brain tumour cell lines were tested by reverse polymerase chain reaction. Despite the presence of T-lymphocytes, cytokine gene t ranscripts typically detectable upon T cell receptor triggering could not be observed in central nervous system tumours of diverse histology . In primary brain neoplasms, transcription of genes encoding for the inhibitory cytokines TGF-beta and IL-10 was detectable in more than 50 % of samples. IL-6 transcripts could only be detected in malignant gli omas. In brain metastases, virtually no cytokine gene transcripts coul d be observed. Surprisingly, TGF-beta transcripts were also detected i n all meningiomas. Thus, transcription of genes encoding for inhibitor y factors appears to prevail in primary brain neoplasms.