CHI3L1 and glioblastoma: Once compared to GBM, AA showed overexpression of two gene probes (CNTN3 and ETNPPL genes) and underexpression of another 11 gene probes corresponding to 7 genes: CHI3L1, COL1A1, COL3A1, POSTN, NNMT, PTX3, COL1A2 (Fig. 1; Table 1).