ESTRO meets Asia 2024 - Abstract Book

S47

Interdisciplinary – Biomarkers

ESTRO meets Asia 2024

Survival analysis could confirm the significance of these "Key genes" in terms of their clinical impact. The expression levels of IL8 had a significant relationship with PFS in Gr. 4 patients (P=0.028) and had no impact in Gr. 3 glioma patients (P=0.522) (Figure 1B). Furthermore, the receiver operating characteristic (ROC) curve revealed the critical role of IL8 with an accuracy value of 0.899 for discriminating Gr. 4 from Gr. 3 in TCGA and 0.644 in CGGA(Figure 1C). CXCL8 expression was associated with immune infiltration. The main immune cells affected by CXCL8 expression were the levels of macrophages (r = 0.660, P < 0.001) and neutrophils (r = 0.637, P < 0.001) were highly correlated with CXCL8 expression and levels of immune cell infiltration (Figure 2A). Furthermore, we evaluated the relationship between the expression of CXCL8 and immune cell markers, including markers of M2 macrophages (CD163, VSIG4, MS4A4A), using the TIMER database. After adjusting for tumor purity, CXCL8 expression was significantly associated with macrophage markers in GBM, predominantly M2 markers (Figure 2B). Although we found that CXCL8 expression significantly affects the primary Gr. 3 and Gr. 4 gliomas (Figure 2C), it was specific to only decreasing significance for recurrent Gr. 3 glioma of all M2 markers(R value primaryàrecurrence of CD163:0.622à0.475; VSIG4: 0.433à0.285, MS4A4A:0.434à0.177). In contrast, all M2 macrophage markers had increasing correlative efficiency from primary GBM to the recurrence group (R value primaryàrecurrence of CD163:0.617à0.677; VSIG4: 0.437à0.496, MS4A4A:0.458à0.522). These immune analyses provide meaningful information that CXCL8 might be more involved in M2 macrophage infiltration, with a significantly higher correlation coefficient in recurrent GBM than in recurrent Gr. 3 glioma.

Conclusion:

IL8 has a significant impact on disease prognosis and tumor immunity in GBM. The infiltration of M2 macrophages associated with IL8 could serve as a prognostic biomarker for classifying GBM and Gr. 3 gliomas. In the future, immunohistochemical staining of high-grade glioma and survival analysis based on IL8 expression in clinical patients might prove that IL8 is a unique factor and therapeutic target of GBM.