Kaplan–Meier analysis showed that lower CHI3L1 serum concentration is related to longer astrocytoma patient overall survival (Log-rank test; χ2 = 5.417; df = 1; p = 0.0199) (Figure 2A), while higher AREG concentration is related to worse survival prognosis (Log-rank test; χ2 = 3.968; df = 1; p = 0.0464). Here, CHI3L1 is linked to astrocytoma (excluding glioblastoma).