CHI3L1 and glioblastoma: In glioma tissues of GBM, mesenchymal subtype cells have the high expression of mesenchymal subtype signature genes, including chitinase 3 like 1 (CHI3L1), collagen type V alpha 1 chain (COL5A1), fibronectin 1 (FN1), cyclin B1 (CCNB1), and maternal embryonic leucine zipper kinase (MELK) [6,7].