Interleukin-6 overexpression as a marker of malignancy in human gliomas

Object. Glioblastomas multiforme (GBMs) grow rapidly and are highly resistant to treatment compared with other glioma types and grades. Consequently, it is of major interest to identify markers of aggressiveness in these tumors that could represent new therapeutic targets. Interleukin (IL)-6 is frequently produced in gliomas and, given its manifold properties, could be considered as a candidate marker. Expression of IL-6 may be involved in cell growth, resistance to chemotherapy and radiotherapy (via an antiapoptotic pathway), and angiogenesis. This study was conducted to test this hypotheses and to evaluate the suitability of IL-6 as a target in the treatment of GBMs. Methods. The authors studied the relationship between the level of IL-6 gene expression as assessed using semiquantitative reverse transcription-polymerase chain reaction and by determining various histological types and grades in a series of 59 gliomas. It was found that GBMs displayed a significantly higher level of IL-6 expression than other types of glioma (p < 0.001). Immunohistochemical analysis revealed that IL-6 was produced mainly by malignant cells and a few vascular endothelial cells. Conclusions. It can be inferred from these findings that IL-6 gene expression is related to glioma aggressiveness and that IL-6 may play a central role in GEM behavior. Interleukin-6, therefore, could be considered as a new potential target in the treatment of GBMs.