Role of the circulatory interleukin-6 in the pathogenesis of gliomas: A systematic review

Table 1 Characteristics of the selected studies included in this review literature

No.	Author name	Year	Region	Sample	Case (glioma)	Control	IL-6 level (pg/mL)
1	Doroudchi et al[42]	2013	Iran	serum	38	26	Decreased as compared to controls
2	Shan et al[43]	2015	China	Serum	86	18	IL-6 level increased with the elevation of grade
3	Albulescu et al[8]	2013	Romania	Serum	55	20	3-fold upregulated than control
4	Schwartzbaum et al[44]	2017	Norway	Serum	487	487	insignificant association with the disease
5	Zhenjiang et al[45]	2018	Sweden	Serum	GBM = 145	Non-GBM = 60	45%–50% cases of GBM observed with detectable level of IL-6 & 55%–60% cases of Non-GBM malignant glioma observed with detected level of IL-6

IL-6: Interleukin-6; GBM: Glioblastoma.