High p16 expression in glioblastoma is associated with senescence phenotype and better prognosis.

Glioblastoma, isocitrate dehydrogenase (IDH)-wildtype (GBM), is the most malignant brain tumor in adults, with limited therapeutic intervention. Previous studies have identified a few prognostic markers for GBM, including the methylation status of O-methylguanine-DNA methyltransferase (MGMT) promoter, TERT promoter mutation, EGFR amplification, and CDKN2A/2B deletion. However, the classification of GBM remains incomplete, necessitating a comprehensive analysis. In this study, we investigated the impact of p16 expression in GBM and found that p16-high GBM exhibits distinct characteristics compared to p16-low GBM. Specifically, tumor cells with p16-high expression display a senescent phenotype and are correlated with higher intra-tumoral immune cell infiltration. Furthermore, an association was observed between elevated p16 expression in GBM and extended overall survival of patients. Our in vivo and in vitro studies revealed that CCL13 is predominantly expressed by p16-high GBM cells. The released CCL13 enhances the infiltration of T cells within the tumor, potentially contributing to the improved prognosis observed in patients with high p16 expression. These findings suggest that tumor cells with a senescence phenotype in GBM, through the secretion of chemokines such as CCL13, may augment immune cell infiltration and potentially enhance patient outcomes by creating a more immunologically active tumor microenvironment.