Unraveling the peripheral and local role of inflammatory cytokines in glioblastoma survival

Abstract

Glioblastoma (GBM) is a life-threatening disease that presents high morbidity and mortality. The standardized treatment protocol results in a global survival of less than three years in the majority of cases. Immunotherapies have gained wide recognition in cancer treatment; however, GBM has an immunosuppressive microenvironment diminishing the possible effectiveness of this therapy. In this sense, investigating the inflammatory settings and the tumoral nature of GBM patients are an important goal to create an individual plan of treatment to improve overall survival rate and quality of life of these patients. Thirty-two patients who underwent surgical resection of GBM were included in this study. Tumor samples and 10 mL of peripheral blood were collected and immediately frozen. TNF-a, IL-1a and IL-4 were evaluated in the tumor and TNF-a, IL-1a and TGF-b in the plasma by Luminex assay. Immunohistochemistry analysis to determine immune celular profile was done, including immunohisto-chemistry for CD20, CD68 and CD3. Three cases were excluded. Tumor topography, tumor nature, and tumor volume reconstructions were accurately analyzed by T1-weighted, T2-weighted, and FLAIR magnetic resonance imaging. We found that GBM patients with below median peripheral levels of TNF-a and IL-1a had a decreased survival rate when compared to above median patients. On the other hand, patients with below median pe-ripheral levels of TGF-b increased overall survival rate. Intratumoral IL-1a above median was associated with higher number of macrophages and fewer with B cells. Furthermore, plasmatic TNF-a levels were correlated with intratumoral TNF-a levels, suggesting that peripheral cytokines are related to the tumoral microenvironment. Even though tumor size has no difference regarding survival rate, we found a negative correlation between intratumoral IL-4 and tumor size, where larger tumors have less IL-4 expression. Nevertheless, the tumoral nature had a significant effect in overall survival rate, considering that infiltrative tumors showed decreased survival rate and intratumoral TNF-a. Moreover, expansive tumors revealed fewer macrophages and higher T cells. In multiple variation analyzes, we demonstrated that infiltrative tumors and below median peripheral IL-1a expression represent 3 times and 5 times hazard ratio, respectively, demonstrating a poor prognosis. Here we found that peripheral cytokines had a critical role as prognostic tools in a small cohort of GBM patients.